FOREIGN LANGUAGES PUBLISHING HOUSE

M o s c o w I 9 5 8

GEOCHEMISTRY EVERYONE

R A N S L A T t D K R O M T H E R U S S I A N B Y

D A V I D A . M Y S H N E

D E S I G N E D B Y G . D A U M A N N

This Book Brought To You By gnv64

C O N T E N T S

Foreword 5 Introduct ion - I I

1'iirl One

The Atom

W h a t is Geochemis t ry? IV Wor ld of the Invisible. T h e A t o m and the Chemical E l emen t 24 The Atoms Around Us 31 Birth and Behaviour of the A tom in the Universe 39 H o w Mendeleyev Discovered His I .aw 47 Mendeleyev ' s Periodic Svstem of E lements in Our Days 54 Mendeleycv ' s Periodic System of E lements in Geochemist ry 63 T h e Atom Disintegrates . Uranium and Rad ium 69 The Atom and T ime

i'n r I 7'icu

Chemical E lements in N a t u r e

Si l icon-Basis of the Ea r th ' s Crust C a r b o n - B a s i s of All Life 104 P h o s p h o r u s - E l e m e n t of Life and Though t I I S Sulphur-BaMs of the Chemical Industry 125 Ca lc ium-Symbol of Durabi l i ty 133 Potass ium-Bas i s of Plant Life 144 Iron and the Iron Age 156 S t ron t ium- Metal of Red Lights 164 T i n - M e t a l of the Food-Can 174 I o d i n e - t h e Omnipresen t 183 F l u o r i n e - t h c Omnivorous 190 A l u m i n i u m - M e t a l of the 20th Century 202 Bery l l ium-Meta l of the Future 212

V a n a d i u m - B a s i s of the Automobi le 218 G o l d - K i n g of Meta ls 226 Rare Dispersed Elements 236

Part Three

History of the A t o m in N a t u r e

M e t e o r i t e s - H e r a l d s of the Universe 247 Atoms in the Ear th ' s Interior 267 History of the Atoms in the History of the Ea r th 279 Atoms in the Air 293 Atoms in Wate r 300 Atoms Oil the Surface of the Ear th . From the Arctic to the Subtropics . . 308 Atoms in the Living Cell 318 Atoms in the History of Mankind 324

Part boar

Past and Future of Geochemist ry

From the History of Geochcmical Ideas 343 How the Chemical E lements and Minerals W e r e N a m e d 363 Chcmistrv and Geochemist ry in O u r T ime 369 Fantastic Tr ip Through Mendeleyev ' s Periodic T a b l e 378 Future Conquests 386 End of Book 392

Siiiiplement

The Geochemist in the Field 403 Brief Informat ion About Chemical E lements 418 Glossary 435

F O R E W O R D

I n t h e b o o k Giochemistry for Everyone A c a d e m i c i a n A. F e r s m a n of fe rs a n e n t e r t a i n i n g a c c o u n t of t h e m a n y y e a r s of w o r k h e d e v o t e d to d e v e l o p i n g g e o c h e m i s t r y , t h e n e w b r a n c h of geo log i ca l sc ience , a n d s t r ives to s h o w t h e c h e m i c a l life of o u r p l a n e t as it a p p e a r e d t o his i m a g i n a t i o n e n r i c h e d b y ex-t ens ive sc ien t i f i c e x p e r i e n c e .

T h i s n e w b r a n c h of sc i ence a b o u t t h e e a r t h c a m e i n t o b e i n g in t h e b e g i n n i n g of o u r c e n t u r y a n d is set f o r t h in t h e w o r k s of t h e o u t s t a n d i n g Sovie t sc i en t i s t s— A c a d e m i c i a n s V . V e r n a d s k y a n d A . F e r s m a n .

I t took a lot of w o r k a n d t i m e b e f o r e g e n e r a l i d e a s of t h e c h e m i c a l c o m p o s i t i o n of t h e e a r t h ' s c r u s t c o u l d e m e r g e f r o m t h e s e p a r a t e a n d i so la ted o b s e r v a t i o n s . T h e p r o g r e s s m a d e b y n u c l e a r phys i c s a n d c h e m i s t r y , t h e sc iences a b o u t t h e s t r u c t u r e of m a t t e r , h e l p e d t h e geologis t a n d m i n e r a l o g i s t t o ge t a c l ea r i n s igh t i n t o t h e d i s t r i b u t i o n a n d cyc le of m a t t e r in t h e e a r t h ' s c r u s t . M a n w a s a b l e t o g r a s p t h e u n i t y of p rocesses w h i c h t a k e p l a c e in t h e m i n u t e s t p a r t i c l e s of m a t t e r , i .e. , a t o m s a n d m o l e c u l e s , a n d in its t r e m e n d o u s u n i v e r s a l c o n d e n -sa t ions , i .e . , t h e suns a n d t h e r e m o t e s t s tars .

T h e sc ience of g e o c h e m i s t r y w a s c o m i n g i n t o b e i n g , a sc i ence w h i c h l eads us i n t o t h e field of a c c o m p l i s h m e n t s m a d e b y c h e m i c a l phys ics , c o s m i c c h e m i s t r y a n d a s t r o p h y s i c s a n d w h i c h , a t t h e s a m e t i m e , s u b j o i n s t h e a c h i e v e m e n t s of t he se sc iences t o t h e p r o b l e m s of s t u d y i n g m i n e r a l s .

A l e x a n d e r F e r s m a n w a s a n e n t h u s i a s t of g e o c h e m i s t r y , o n e w h o h a d a p r o -f o u n d u n d e r s t a n d i n g of its s i g n i f i c a n c e t o t h e e c o n o m i c a n d c u l t u r a l life of t h e c o u n t r y .

H e w o n w i d e p o p u l a r i t y w i t h t h e Sov ie t y o u t h b y his a r d e n t love of sc ience a n d life w h i c h i n s p i r e d h i m in w r i t i n g t h e r e m a r k a b l e p o p u l a r - s c i e n c e books for t h e y o u n g p e o p l e ; t h e bes t of these b o o k s i n c l u d e his Mineralogy for Everyone a n d Geochemistry for Everyone.

I t is a m a t t e r of r e g r e t t h a t t h e a u t h o r w a s u n a b l e t o f inish his Geochemistry for Everyone a n d s o m e c h a p t e r s h a d t o b e c o m p l e t e d b y his f r i e n d s a n d p u p i l s .

T h u s , t h e c h a p t e r s " W o r l d of t h e I n v i s i b l e " a n d t h e " A t o m D i s i n t e g r a t e s " w e r e w r i t t e n b y A c a d e m i c i a n V . K h l o p i n , t h e c h a p t e r s " C a r b o n " a n d " A t o m s in W a t e r " w e r e c o n t r i b u t e d by A c a d e m i c i a n A. V i n o g r a d o v , w h i l e t h e c h a p t e r

5

" R a r e D i s p e r s e d E l e m e n t s " b e l o n g s t o t h e p e n of Professor V . S h c h e r b i n a . M a t e r i a l s c o m p i l e d b y A. F e r s m a n w e r e u sed in t h e c h a p t e r " F r o m the. H i s t o r y of G e o c h e m i c a l I d e a s , " w r i t t e n b y A c a d e m i c i a n D . S h c h e r b a k o v , a n d " A t o m s in t h e H i s t o r y of M a n k i n d , " p r e s e n t e d b y P ro fes so r N . R a z u m o v s k y .

The b o o k w a s first p u b l i s h e d in 1948 u n d e r t h e g e n e r a l sc ien t i f i c e d i t o r s h i p of Professor N . R a z u m o v s k y w i t h A c a d e m i c i a n V . K h l o p i n a c t i n g as c o n s u l t a n t . T h e y d id all t h e y c o u l d to b r i n g t h e b o o k as close t o A. F e r s m a n ' s o w n i d e a as poss ib le .

A. F e r s m a n is w i d e l y k n o w n as a n o u t s t a n d i n g m i n e r a l o g i s t , g e o c h e m i s t a n d g e o g r a p h e r , as a pe r s i s t en t e x p l o r e r of t h e m i n e r a l r e s o u r c e s of t h e U . S . S . R . , as a t ireless t r a v e l l e r a n d a b r i l l i a n t p o p u l a r i z e r of geo log i ca l k n o w l e d g e .

H e w a s b o r n in .St. P e t e r s b u r g in 1883. T h e f u t u r e sc ient i s t s p e n t his c h i l d h o o d in t h e C r i m e a w h e r e h e l e a r n e d to love the sc ience a b o u t s tones . " T h e C r i m e a was m y first u n i v e r s i t y , " t h e A c a d e m i c i a n u s e d to say.

T h e y o u t h , w h o w a s a t first a t t r a c t e d by t h e e x t e r n a l b e a u t y of s tones , g r a d -ua l ly b e c a m e i n t e r e s t e d in q u e s t i o n s of t h e i r c o m p o s i t i o n a n d o r ig in .

A f t e r g r a d u a t i o n f r o m s e c o n d a r y schoo l A. F e r s m a n s t u d i e d a t M o s c o w U n i v e r s i t y w h e r e h e a t t e n d e d lec t u r e s on m i n e r a l o g y a n d w o r k e d u n d e r t h e supe rv i s ion of A c a d e m i c i a n V l a d i m i r Y e r n a d s k y .

Before V e r n a d s k y m i n e r a l o g y w a s t a u g h t a t t h e u n i v e r s i t y as a d r y a n d I od ious s u b j e c t . The m i n e r a l o g i s t s of t h e e n d of t h e 19th c e n t u r y m a i n l y d e s c r i b e d t h e m i n e r a l s , s t u d i e d t h e i r c r y s t a l l o g r a p h i c f o r m s a n d s y s t e m a t i z e d t h e m .

Y e r n a d s k y b r o u g h t a b r e a t h of f resh a i r i n t o th i s d e s c r i p t i v e m i n e r a l o g y . H e b e g a n t o r e g a r d m i n e r a l s as p r o d u c t s of n a t u r a l ( t e r r e s t r i a l ) c h e m i c a l r e a c t i o n s a n d took a n in te res t in t h e c o n d i t i o n s u n d e r w h i c h t h e y h a d f o r m e d , i.e., t he i r b i r t h , t h e i r life a n d t h e i r t r a n s f o r m a t i o n i n t o o t h e r m i n e r a l s .

T h i s was n o l o n g e r t h e o ld m i n e r a l o g y w h i c h i n d i f f e r e n t l y d e s c r i b e d t h e w o n d e r s of t h e e a r t h ' s en t ra i l s . T h e y o u n g r e s e a r c h e r s h a d n e w pass ions a n d n e w ideas . T h e y w e r e no t m e r e l y m i n e r a l o g i s t s , b u t c h e m i c o - m i n e r a l o g i s t s . " T h a t w a s h o w o u r t e a c h e r t a u g h t u s , " A . F e r s m a n l a t e r r eca l l ed . " H e c o m -b i n e d c h e m i s t r y w i t h n a t u r e a n d c h e m i c a l t h i n k i n g w i t h t h e m e t h o d s of a n a t u r a l i s t . I t w a s a schoo l of n e w n a t u r a l sc i ence b a s e d on t h e e x a c t d a t a f u r -n i shed by t h e sc ience a b o u t t h e c h e m i c a l life of t h e e a r t h . " T h e sc ien t i f ic w o r k was d o n e m o r e in t h e field t h a n in t h e sec lus ion of u n i v e r s i t y s tud i e s a n d l a b o r a t o r i e s . E x c u r s i o n s a n d e x p e d i t i o n s , w h i c h w e r e l a t e r r e c a l l e d b y A . F e r s m a n t i m e a n d a g a i n , f o r m e d p a r t a n d p a r c e l of l e a r n i n g .

l i m e w o r e on . K n o w l e d g e w a s a c q u i r e d t h r o u g h h a r d w o r k . T h e y o u n g scient is ts s t u d i e d d a y a n d n i g h t s o m e t i m e s s t a y i n g in t h e u n i v e r s i t y b u i l d i n g for d a y s o n e n d .

A. F e r s m a n was g r a d u a t e d f r o m M o s c o w U n i v e r s i t y in 1907, b u t e v e n as a n u n d e r g r a d u a t e h e h a d w r i t t e n five sc ien t i f ic p a p e r s on p r o b l e m s of c rys t a l lo -g r a p h y , c h e m i s t r y a n d m i n e r a l o g y u n d e r V . V e r n a d s k y ' s s u p e r v i s i o n . F o r these p a p e r s h e w a s a w a r d e d t h e A n t i p o v G o l d M e d a l , g r a n t e d t o y o u n g scient is ts by t h e M i n e r a l o g i c a l Soc ie ty .

At t h e a g e of 27 A l e x a n d e r F e r s m a n w a s e l e c t e d p ro fe s so r of m i n e r a l o g y a n d in 1912 h e b e g a n t o t e a c h a n e w s u b j e c t — g e o c h e m i s t r y — f o r t h e first t i m e ir 1 t h e h i s to ry of sc ience .

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I n his l c c t u r e s A. F e r s m a n espec ia l ly e m p h a s i z e d t h a t " . . . W e m u s t be c h e m i s t s of t h e e a r t h ' s c r u s t . W e m u s t s t u d y n o t o n l y t h e d i s t r i b u t i o n a n d f o r m a t i o n of m i n e r a l s , t h e s e t e m p o r a r i l y s t a b l e c o m b i n a t i o n s of e l e m e n t s , b u t a l so t h e v e r y e l e m e n t s , t h e i r d i s t r i b u t i o n , t h e i r t r a n s i t i o n s a n d t h e i r l i f e . "

T h e s a m e y e a r m a r k e d t h e b e g i n n i n g of A . F e r s m a n ' s u n i n t e r r u p t e d , l i f e long ac t iv i t i e s in t h e R u s s i a n A c a d e m y of Sc iences , f i rs t in P e t e r s b u r g a n d t h e n in M o s c o w .

T h e G r e a t O c t o b e r Socia l is t R e v o l u t i o n set u p en t i r e ly n e w a n d f a v o u r a b l e c o n d i t i o n s for sc ien t i f i c r e s e a r c h . U n l i m i t e d o p p o r t u n i t i e s t o exerc i se all h is c r e a t i v e ab i l i t i e s o p e n e d u p b e f o r e F e r s m a n i n s t u d y i n g a n d i n v e s t i g a t i n g t h e n a t u r a l p r o d u c t i v e fo rces of t h e c o u n t r y .

P r o f o u n d a n d p e n e t r a t i n g i n v e s t i g a t o r a s h e w a s , A . F e r s m a n w a s o n e of t h e s t a u n c h e s t a n d m o s t a r d e n t s u p p o r t e r s of a p p l i e d a c t i v i t y ; h e n e v e r ceased t o s u m m o n t h e sc ient is ts i n t o t h e f ie ld of p r a c t i c a l , n a t i o n a l - e c o n o m i c in te res t s .

I n 1919, a t t h e a g e of 35, A , F e r s m a n w a s e l ec t ed m e m b e r of t h e A c a d e m y of Sc iences of t h e U . S . S . R . a n d a t t h e s a m e t i m e a p p o i n t e d D i r e c t o r of t h e M i n e r a l o g i c a l M u s e u m of t h e A c a d e m y of Sc iences .

I n a p p r a i s i n g F e r s m a n ' s c r e a t i v e life w e c a n n o t b u t b e s u r p r i s e d a t t h e v a r i e t y of h is sc ien t i f ic a n d p r a c t i c a l in t e res t s a n d e x t r a o r d i n a r y e f f i c i ency . I n d e v e l o p -i n g t h e sc ien t i f ic p r i n c i p l e s of g e o c h e m i s t r y a n d m i n e r a l o g y h e c o n s i d e r e d f ie ld r e s e a r c h of p r i m e i m p o r t a n c e . H e t o o k a v e r y a c t i v e p a r t in e x p e d i t i o n s a n d vis i ted t h e m o s t d i v e r s e r e g i o n s of t h e c o u n t r y — t h e K h i b i n y t u n d r a o n K o l a P e n i n s u l a , flourishing F e r g h a n a V a l l e y , t h e h o t K a r a - K u m a n d K izy l -K u m s a n d s in C e n t r a l As ia , t h e vas t t a i g a s p a c e s in t h e B a i k a l a n d t h e T r a n s -Ba ika l r eg ions , t h e w o o d e d e a s t e r n s lopes of t h e U r a l s , A l t a i , t h e U k r a i n e , t h e C r i m e a , t h e N o r t h C a u c a s u s , T r a n s c a u c a s i a , e tc .

O f e x c e p t i o n a l i n t e r e s t a r e t h e t r u l y h e r o i c e x p l o r a t i o n s of K o l a P e n i n s u l a b e g u n b y A . F e r s m a n in K h i b i n y in 1920 a n d in t h e M o n c h a t u n d r a in 1930 a n d c o n t i n u i n g t o t h e v e r y e n d of his l ife.

H i s g r e a t e s t a c h i e v e m e n t w a s t h e d i s c o v e r y of a p a t i t e a n d n i c k e l - o r e depos i t s of w o r l d i m p o r t a n c e .

As a r e su l t of ex t ens ive w o r k d o n e b y A. F e r s m a n a n d o t h e r specia l i s t s K o l a P e n i n s u l a h a s g i v e n t h e c o u n t r y s o m e of t h e r i ches t depos i t s of n u m e r o u s m i n e r a l s .

I n d u s t r i a l e x p l o i t a t i o n of t h e r e s o u r c e s of K o l a P e n i n s u l a b e g a n in 1929. The r e m o t e a n d a t o n e t i m e s c a r c e l y - k n o w n w i l d e r n e s s in t h e d i s t a n t N o r t h

h a s c h a n g e d i n t o a m o s t i m p o r t a n t m i n i n g a n d i n d u s t r i a l r e g i o n . N e w cit ies, a t f irst K h i b i n o g o r s k ( n o w K i r o v s k ) a n d s o o n a f t e r w a r d s M o n c h e g o r s k a n d o t h e r s , h a v e a r i s e n in t h e u n i n h a b i t e d a r e a s as if b y m a g i c .

H e r e is w h a t A . F e r s m a n h imse l f w r o t e a b o u t t h e w o r k o n K o l a P e n i n s u l a : " I n t h e m i d s t of al l e x p e r i e n c e s of t h e p a s t , a m i d t h e v a r i o u s p i c t u r e s of

n a t u r e , m a n a n d e c o n o m y , t h e m o s t v iv id in m y life w e r e t h e i m p r e s s i o n s of t h e K h i b i n y , a w h o l e sc ien t i f i c epos w h i c h for n e a r l y t w e n t y y e a r s o c c u p i e d m y m i n d , c o n s u m e d m y e f fo r t s a n d e n e r g y , t o o k fu l l possess ion of m y b e i n g , s h a r p e n e d m y wil l , m y sc ien t i f i c t h i n k i n g , m y des i res a n d m y h o p e s . . . . O n l y b y s t u b b o r n n e s s a n d pe r s i s t ence , o n l y b y t r e m e n d o u s w o r k w e r e w e a b l e t o a c h i e v e resu l t s in this w o n d e r l a n d w h i c h r e v e a l e d its r i ches t o u s as t h o u g h

7

i n a l a i r y - t a l c . ' ' T h e K h i b i n y p e r i o d does no t o v e r s h a d o w F e r s m a n ' s o t h e r sc ien t i f i c r e s e a r c h . H e h a d e n o u g h e n e r g y for e v e r y t h i n g .

I n 1924 F e r s m a n b e g a n his w o r k in C e n t r a l As ia a n d his i n t e re s t in th i s w o r k c o n t i n u e d to t h e e n d of his life. I n 1925 h e v e n t u r e d a d a r i n g t r i p to t h e c e n t r a l K a r a K u m , b a r e l y k n o w n a t t h e t i m e , a n d s t u d i e d a r i c h d e p o s i t of n a t i v e s u l p h u r w h i c h h a s b e c o m e t h e p r o p e r t y of Sovie t i n d u s t r y . T h e s u l p h u r p l a n t b u i l t w i t h his a i d is sti l l w o r k i n g t o d a y .

B e t w e e n 1934 a n d 1939 A . F e r s m a n f in i shed his c a p i t a l f o u r - v o l u m e w o r k Geochemistry 011 t h e c h e m i s t r y of t h e e l e m e n t s of t h e e a r t h ' s c rus t , a w o r k re-m a r k a b l e for its f o r ce a n d sc ien t i f ic fo re s igh t . I n this w o r k , b a s e d on t h e l aws of phys i ca l c h e m i s t r y , w h i c h b r o u g h t A. F e r s m a n a n d , in his p e r s o n , R u s s i a n g e o c h e m i s t r y w o r l d f a m e , h e m a d e a n ex t ens ive ana lys i s of t h e r e g u l a r i t i e s of m i g r a t i o n s of a t o m s in t h e e a r t h ' s c rus t .

In 1940 F e r s m a n f in i shed his Minerals on hola Peninsula. In th is w o r k h e g a v e a b r i l l i a n t e x a m p l e of a g e o c h e m i c a l a p p r o a c h to t h e s t u d y of m i n e r a l r e sou rces a n d p r e d i c t e d t h e d i s c o v e r y of a n u m b e r of n e w m i n e r a l depos i t s .

A. F e r s m a n h a s left us a n e n o r m o u s l i t e r a r y h e r i t a g e . H e p u b l i s h e d close to i ," |00 a r t i c les , b o o k s a n d l a r g e m o n o g r a p h s . I n a d d i t i o n to t h e w o r k s on c r y s t a l l o g r a p h y , m i n e r a l o g y , geo logy , c h e m i s t r y , g e o c h e m i s t r y , g e o g r a p h y a n d ae r i a l p h o t o g r a p h y h e w r o t ' ' on a s t r o n o m y , p h i l o s o p h y , a r t , a r c h a e o l o g y , soil sc ience , b io logy , e tc .

A l e x a n d e r F e r s m a n w a s no t on ly a sc ient i s t , b u t a p u b l i c figure a n d s t a t e s m a n as wel l .

Spec ia l m e n t i o n m u s t b e m a d e of h i m as a t a l e n t e d w r i t e r a n d p o p u l a r i z e r of geo log ica l k n o w l e d g e , a " p o e t of s t o n e s , " as A. T o l s t o i ca l l ed h i m .

His r ep o r t s , l e c tu re s a n d p e r s o n a l c h a t s i n sp i r ed a n d f a s c i n a t e d his l i s teners of all ages a n d o c c u p a t i o n s , w h i l e his n u m e r o u s p o p u l a r - s c i e n c e a r t i c l e s w e r e r e a d b y all sec t ions of t h e p o p u l a t i o n .

T h e first e d i t i o n of Mineralogy jor Everyone a p p e a r e d in 1928; t h e b o o k w a s t r a n s l a t e d i n t o m a n y fo re ign l a n g u a g e s a n d h a s r u n i n to 25 ed i t ions . Recollections about a Stone was p u b l i s h e d in 1940. My 'Travels, Stories about Precious Stones a n d Geochemistry for Everyone c a m e ou t of p r i n t a f t e r A . F e r s m a n ' s d e a t h . All these books h a v e m a d e h i m v e r y p o p u l a r w i t h r e a d e r s of all ages .

S u c h books d o not c o m e i n t o b e i n g al l of a s u d d e n . T h e y a r e a resu l t of l o n g y e a r s of c r e a t i v e w o r k a n d e x p e r i e n c e ; t h e y re f lec t t h e e n t i r e life of t h e scient is t a n d his sc ient i f ic in te res t s . At the s a m e t i m e the se a r e books of a n e x p e r i e n c e d a n d t a l e n t e d t e a c h e r w h o a p p r e c i a t e s t h e p r o b l e m s of e d u c a t i n g t h e r i s ing sc ient i f ic g e n e r a t i o n . W i t h his f e rven t w o r d s of a w r i t e r a n d s p e a k e r A. F e r s m a n k i n d l e d t h e love for m i n e r a l o g y a n d g e o c h e m i s t r y in leg ions of y o u n g p e o p l e a n d led a l a r g e n u m b e r of sc ien t i f ic w o r k e r s to n e w s tud ies a n d r e s e a r c h .

F e r s m a n ' s great, love for his n a t i v e l a n d s h o u l d b e p a r t i c u l a r l y e m p h a s i z e d . T h i s love is felt in e v e r y o n e of his s t a t e m e n t s , in e a c h l ine of his w r i t i n g s . All his essays a r e h y m n s to l a b o u r , c a l l i n g to m a s t e r y a n d to c r e a t i v e t r a n s f o r m a t i o n of t h e c o u n t r y ' s n a t u r e on t h e basis of e x a c t sc ien t i f ic k n o w l e d g e .

" W e d o no t w a n t to b e p h o t o g r a p h e r s of n a t u r e , t h e e a r t h a n d its r i c h e s . " F e r s m a n used to say . " W e w a n t to b e i n v e s t i g a t o r s a n d c r e a t o r s of n e w i d e a s ;

w e w a n t t o c o n q u e r n a t u r e a n d to s u b o r d i n a t e it t o m a n , t o his c u l t u r e a n d e c o n o m y .

" W c d o n o t w a n t t o b e m e r e l y a c c u r a t e o b s e r v e r s o r i m p a s s i v e tour is t s w h o j o t d o w n t h e i r i m p r e s s i o n s in a n o t e - b o o k . W e w a n t t o ge t a d e e p in s igh t i n t o n a t u r e so t h a t o u r p r o f o u n d a n d t h o u g h t f u l i n v e s t i g a t i o n of it m a y n o t on ly g ive r ise t o i deas , b u t a lso r e su l t in d e e d s . W c c a n n o t b e m e r e l y id le a d m i r e r s of o u r vas t c o u n t r y ; w e m u s t a c t i v e l y h e l p r e s h a p e it a n d c r e a t e a n e w l i f e . "

L i fe w i t h o u t w o r k a n d sc ience h a d n o m e a n i n g t o F e r s m a n . T h e m o r e d i f f i cu l t t h e task h e f a c e d t h e g r e a t e r t h e zea l w i t h w h i c h h e t a c k l e d it .

A . F e r s m a n d i e d a f t e r a g r a v e i l lness in 1945. " T h e serv ices r e n d e r e d b y A . F e r s m a n t o sc ience a n d t o o u r c o u n t r y a r e

i m m e a s u r a b l e a n d i m m o r t a l , " s a i d A c a d e m i c i a n D . B c l y a n k i n . " T h e scope of his sc ien t i f ic i n t e r e s t s c o m b i n e d w i t h his u n t i r i n g c o n c e r n for t h e w e l l - b e i n g a n d g l o r y of o u r c o u n t r y q u i t e r e m i n d us of o u r i m m o r t a l L o m o n o s o v a n d M e n d e l e y e v . I t is n o a c c i d e n t t h a t h e h e l d t he se n a m e s so s a c r e d . "

A c a d e m i c i a n D. Shcherbakov

INTRODUCTION

Severa l yea r s a g o I w r o t e m y Mineralogy for Everyone. S ince t h e n I h a v e rece ived h u n d r e d s of le t te rs f r o m school ch i l d r en , worke r s a n d va r ious specialists. T h e le t ters s h o w so m u c h g e n u i n e a n d l ively in teres t in stones, t he i r s t u d y a n d t h e h is tory of t he i r use. S o m e of t h e c h i l d r e n ' s le t te rs d i sp l ayed a good dea l of y o u t h f u l f e rvour , v i m a n d v i g o u r . . . . T h e le t ters h a v e f a sc ina t ed m e a n d I h a v e d e c i d e d to wr i t e a n o t h e r b o o k for o u r r is ing g e n e r a t i o n .

O f l a t e I h a v e b e e n w o r k i n g in a d i f f e r en t , a m u c h h a r d e r a n d m u c h m o r e a b s t r a c t field; m y t h o u g h t s h a v e l u r e d m e a w a y i n t o a r e m a r k a b l e w o r l d , a w o r l d of inf in i te ly smal l , negl ig ib le par t i c les of w h i c h all of n a t u r e a n d m a n h imsel f a r e m a d e .

I n t h e last t w e n t y yea r s I h a v e c h a n c e d to t ake p a r t in d e v e l o p i n g a w h o l e n e w science, w h i c h w e call geochemistry. I t was n o t in c o m -f o r t a b l e s t u d y - r o o m s w i t h p e n a n d p a p e r in h a n d t h a t we d e v e l o p e d this sc ience ; it c a m e in to b e i n g as a resul t of n u m e r o u s a c c u r a t e o b s e r v a -t ions, e x p e r i m e n t s a n d m e a s u r e m e n t s ; it was b o r n in t h e s t rugg le for a n e w u n d e r s t a n d i n g of life a n d n a t u r e , a n d b e a u t i f u l , i n d e e d , w e r e t h e m o m e n t s w h e n t h e s e p a r a t e n e w c h a p t e r s of this sc ience of t h e f u t u r e w e r e b r o u g h t t o a n e n d .

B u t w h a t will I tell you a b o u t g e o c h e m i s t r y t h a t m a y e n t e r t a i n y o u ? W h a t k ind of a sc ience is i t ? A n d w h y is it n o t s imply chemis t ry , b u t geochemistry? A n d t h e n w h y is it no t a chemis t , b u t a geologist , a m ine ra log i s t a n d a c r y s t a l l o g r a p h e r w h o wr i tes a b o u t i t?

T h e r e a d e r will no t get t h e a n s w e r to his ques t ions in t h e first c h a p t e r ; h e will l e a r n a good d e a l in i t , b u t br ief ly . O n l y h e w h o r e a d s t h e book

i i

to the e n d will get a r ea l ins ight i n to g e o c h e m i s t r y a n d will a c t u a l l y en joy it.

T h e r e a d e r will t h e n say : " S o t h a t is g e o c h e m i s t r y ! W h a t a n in -teres t ing a n d d i f f icul t sc ience it is! H o w l i t t le chemis t ry , geology a n d even m i n e r a l o g y I know7 as ye t to get a real g r a s p of i t ! "

But it is w o r t h y o u r wh i l e l e a r n i n g m o r e a b o u t it because t h e f u t u r e of g e o c h e m i s t r y is m u c h m o r e i m p o r t a n t t h a n s o m e p e o p l e bel ieve, for it is precisely g e o c h e m i s t r y t h a t will, t o g e t h e r w i t h physics a n d chemis t ry , p l ace t h e g rea t resources of m a t t e r a n d e n e r g y u n d e r t h e c o m m a n d of m a n .

Before b r i n g i n g this i n t r o d u c t i o n to a n e n d I shou ld like to adv ise t he r e a d e r h o w to r e a d this book . I t is no t e n o u g h to tell w h a t to r e a d ; it is o f t en even m o r e i m p o r t a n t to tell h o w to r e a d a n d s t u d y a book in o r d e r to get t he mos t o u t of it. S o m e books a r e r e a d av id ly b e c a u s e t he in te res t ing s tory fasc ina tes t he r e a d e r a n d h e c a n n o t t e a r h imsel f a w a y f r o m it . T h a t is t h e w a y , for e x a m p l e , a d v e n t u r e stories a r e r e a d . O t h e r books m u s t b e s tud ied b e c a u s e t h e y e i the r c o n t a i n a w h o l e science or t r e a t s e p a r a t e scient if ic p r o b l e m s ; in these books scient i f ic d a t a a r e cons is tent ly p r e s e n t e d , n a t u r a l p h e n o m e n a a r e desc r ibed a n d scientif ic in fe rences a r e d r a w n . W h e n r e a d i n g such books o n e m u s t de lve in to every w o r d w i t h o u t sk ipp ing a s ingle p a g e or even l ine or w o r d .

B u t o u r book is n e i t h e r a f a sc ina t i ng novel n o r a scient if ic t rea t i se . I t is bu i l t a c c o r d i n g to a special p l a n . O n e a f t e r a n o t h e r its f ou r p a r t s pass f r o m g e n e r a l p r o b l e m s of physics a n d c h e m i s t r y to p r o b l e m s of geochemis t ry a n d its f u t u r e . T h e r e a d e r w h o is n o t well ve rsed in t he f u n d a m e n t a l s of these sciences m u s t r e a d this book slowly a n d ca re fu l ly a n d , p e r h a p s , even r e r e a d the d i f f icul t pages o r those t h a t a r e of special in teres t to h i m . Bu t if t h e r e a d e r k n o w s physics a n d chemis t ry h e m a y skip s e p a r a t e p a r t s of t he book w h i c h d e a l w i t h p r o b l e m s f a m i l i a r to h i m ; t h e a u t h o r has e n d e a v o u r e d to m a k e e a c h essay c o m p l e t e a n d as f a r as possible i n d e p e n d e n t of t he o t h e r pa r t s . T h e book is also of v a l u e to those w h o wish to get a d e e p e r ins igh t i n to chemis t ry or geology.

S t u d e n t s will find it ve ry usefu l to r e a d s e p a r a t e c h a p t e r s w h i l e s t u d y i n g a gene ra l course of c h e m i s t r y b e c a u s e e a c h of these c h a p t e r s m a y in l a rge m e a s u r e i l lus t ra te s o m e p a r t i c u l a r l y d r y pages in t h e t ex tbook of chemis t ry .

12

W h i l e s t u d y i n g t h e n o n - m e t a l s t h e r e a d e r m a y c o n c u r r e n t l y pe ruse t h e c h a p t e r on p h o s p h o r u s a n d s u l p h u r ; in inves t iga t ing t he fe r rous m e t a l s t h e s t u d e n t w o u l d d o well to f ami l i a r i ze h imse l f w i t h t he c h a p t e r on i ron a n d v a n a d i u m .

I n s t u d y i n g geology the s t u d e n t shou ld s imi lar ly m a k e use of cor-r e s p o n d i n g c h a p t e r s w h i c h t h r o w l ight o n t h e b ig c h e m i c a l p r o b l e m s of t he d i s t r i bu t i on of e l emen t s in t h e e a r t h ' s c rus t . O f p a r t i c u l a r in teres t in this respec t a r e t he c h a p t e r s d e v o t e d to t he desc r ip t i on of the e a r t h ' s c rus t , especial ly P a r t T h r e e en t i t l ed " H i s t o r y of t he A t o m in N a t u r e . "

T h o s e w h o s t u d y c h e m i s t r y will see t h a t I h a v e dea l t w i t h b u t few c h e m i c a l e l e m e n t s ; I h a v e g iven a m o r e or less de t a i l ed desc r ip t ion of on ly fifteen of t h e m . But t h e n it has neve r b e e n m y i n t e n t i o n to give a full c h e m i c a l desc r ip t ion a n d his tory of all t he c h e m i c a l e l emen t s in t h e un iverse , in t he e a r t h ' s c rus t , on t he su r face of t h e e a r t h a n d in t he h a n d s of m a n .

I w a n t e d to e l u c i d a t e on lv i n d i v i d u a l a n d mos t essential f ea tu res in t he " b e h a v i o u r " of t he mos t o r d i n a r y a n d useful e l emen t s wh ich live the i r c o m p l i c a t e d c h e m i c a l life a r o u n d us a n d a m i d the u n n o t i c e a b l e a n d c o n t i n u o u s c h e m i c a l processes of t h e e a r t h . I a m sure m a n y pages cou ld b e w r i t t e n a b o u t e a c h c h e m i c a l e l e m e n t . T h e r e a d e r h imsel f m a y wish to wr i t e t h e h is tory of some e l e m e n t a b o u t wh ich I h a v e no t said a n y t h i n g . I t seems to m e this m i g h t p r o v e a usefu l p rac t i ca l task, a n d if s o m e o n e takes a n in te res t in a l u m p of m e t a l c h r o m i u m , its fa te , its depos i t s a n d its role in i n d u s t r y , a n d p u r s u e s this course h e m a y wr i t e m a n y in t e re s t ing pages f r o m t h e h is tory of this e l e m e n t a n d shed l ight on t he b e h a v i o u r of this l i t t le m e m b e r of t he big i ron fami ly .

I can on ly adv ise t he ca re fu l r e a d e r s w h o h a v e s tud i ed this book a n d w h o a r e in te res ted in p r o b l e m s of ex tens ive analys is of n a t u r e to v e n t u r e such a task a n d to c o n t i n u e t h e pages I h a v e wr i t t en a b o u t the mos t i m p o r t a n t e l emen t s on t he e a r t h .

P A R T O N E

T H E A T O M

WHAT IS GEOCHEMISTRY?

What is geochemistry? This is the first question we must answer if we are to understand all this book is going to deal with.

We know what geology is because it teaches us about the earth, its crust, its history and the changes it undergoes; it tells us how moun-tains, rivers and seas are formed, how volcanoes and lava make their appearance and how sediments of silts and sands slowly grow on the ocean floor.

We also understand mineralogy which studies minerals. In my book Mineralogy for Everyone I wrote: "A mineral is a natural

compound of chemical elements which has formed without the inter-ference of man. It is a sort of edifice built of different quantities of certain bricks; it is not a disorderly pile of these bricks, but a structure made according to certain laws of nature. We understand very well that even by using the same bricks and in the same quantities we can put up different buildings. The same mineral may similarly be encountered in nature in most diverse forms though it essentially remains the same chemical compound.

"We count about one hundred varieties of these bricks of which all of the nature that surrounds us is built.

"These chemical elements include gases—oxygen, nitrogen and hydro-gen ; metals—sodium, magnesium, iron, mercury, gold or such substances as silicon, chlorine, bromine, etc.

"Various combinations of elements in different amounts give us what we call minerals; for example, chlorine and sodium give us common salts, two parts of oxygen and, one part of silicon yield silica or quartz, etc.

2 <7

" . . . T h r e e t h o u s a n d d i f f e r e n t m i n e r a l s ( q u a r t z , sal t , f e ld spa r , etc .) h a v e t h u s b e e n bu i l t of c o m b i n a t i o n s of va r i ous c h e m i c a l e l e m e n t s in t h e e a r t h a n d these m i n e r a l s , a c c u m u l a t i n g t o g e t h e r , f o r m w h a t w e call rock (for e x a m p l e , g r a n i t e , l imes tone , b a -sal t , s a n d , e tc . ) .

" T h e sc ience t h a t s tud ies m i n e r a l s is ca l led m i n e r a l o g y , t h e o n e t h a t descr ibes rocks is k n o w n as p e t r o g r a p h y , w h i l e g e o c h e m i s t r y inves t iga tes t h e v e r y br icks we h a v e b e e n t a lk ing a b o u t a n d t he i r w a n d e r i n g s in n a -t u r e . . . . "

G e o c h e m i s t r y is still a y o u n g sc ience a n d it has c o m e to t h e fo re m a i n l y o w i n g to t h e w o r k of Sovie t scientists.

I t s tasks consist in t r a c i n g a n d a s c e r t a i n i n g t h e f a t e a n d b e h a v i o u r of t h e c h e m i c a l e l e m e n t s in t h e e a r t h , t h e e l e m e n t s w h i c h cons t i t u t e t h e basis of s u r r o u n d i n g n a t u r e a n d w h i c h , if a r r a n g e d in a ce r t a in o r d e r , m a k e u p D . M e n d e l e y e v ' s r e m a r k a b l e p e r i o d i c sys tem.

T h e f u n d a m e n t a l u n i t of g e o c h e m i c a l r e sea r ch is t h e c h e m i c a l e l e m e n t a n d its a t o m .

As a ru le , e a c h b o x in M e n d e l e y e v ' s t a b l e c o n t a i n s o n e c h e m i c a l e l e m e n t — t h e a t o m — a n d has its o r d i n a l o r a t o m i c n u m b e r . T h e first n u m b e r be longs to t h e l ightes t e l e m e n t — h y d r o g e n , w h i l e t h e heav ies t 9 2 n d e l e m e n t is ca l led u r a n i u m a n d i t is 238 t imes as h e a v y as h y d r o g e n .

T h e a t o m s a r e ve ry smal l a n d , if w e p i c t u r e t h e m as l i t t le bal ls , e a c h a t o m will h a v e a d i a m e t e r of 0 . 0 0 0 0 0 0 1 m m . Bu t t h e a t o m s in n o w a y r e s e m b l e solid l i t t le ba l l s ; t h e y a r e a m o r e c o m p l i c a t e d sys tem consis t ing of a n a t o m i c n u c l e u s w i t h pa r t i c l e s of electricity—-e l e c t r o n s — m o v i n g a r o u n d t h e m , t h e n u m b e r of e l ec t rons v a r y i n g in d i f f e r e n t a t o m s .

I n s t r u c t u r e , t h e r e f o r e , a t o m s r a t h e r r e s e m b l e s u b - m i c r o s c o p i c so lar systems w i t h a c e n t r a l s u n — t h e n u c l e u s — a n d p l a n e t s — t h e e l e c t r o n s — m o v i n g a r o u n d i t .

Crysta ls of smoky q u a r t z in f e ld spa r

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T h e n u m b e r of e lec t rons var ies w i t h t h e d i f f e r e n t k inds of a t o m s ( c h e m i c a l e l e m e n t s ) , o w i n g to w h i c h t h e y d i f fe r i n the i r c h e m i c a l p rope r t i e s . By e x c h a n g i n g t he i r e l ec t rons t h e a t o m s c o m b i n e a n d f o r m molecu les .

M e n d e l e y e v ' s t a b l e shows a n u m b e r of n a t u r a l fami l ies of e l emen t s w h i c h a r e e n c o u n t e r e d t o g e t h e r n o t on ly i n t h e t ab le , b u t also in n a t u r e .

T h e i m p o r t a n c e of M e n d e l e y e v ' s sys tem consists precise ly in t h e f ac t t h a t i t is n o t a t heo re t i ca l s c h e m e , b u t a n express ion of t h e n a t u r a l r e l a t ionsh ips b e t w e e n t h e s e p a r a t e e l e m e n t s w h i c h d e t e r m i n e t he i r s imilar i t ies , t he i r d i f fe rences , t he i r shifts a n d t h e p a t h s of then' ' m i g r a t i o n s in t h e e a r t h . I n a w o r d , M e n d e l e y e v ' s Pe r iod i c T a b l e is also a g e o c h e m i c a l t a b l e w h i c h , as a r e l i ab le compass , he lps t h e g e o c h e m i s t in his pros-pec t i ng .

TABLE OF THE STRUCTURES OF EL.EMENTS

C r i s t a l l i n e s t r u c t u r e s of t h e c h e m i c a l e l e m e n t s as a r r a n g e d in t h e M e n d e l e y e v t a b l e . T h e a r r a n g e m e n t of t h e b a l l s s h o w s h o w t h e a t o m s a r e d i s t r i b u t e d in a s i m p l e so l id b o d y . In t h e f o r e g r o u n d ( l e f t ) w e see a d i a g r a m of d i s t r i b u t i o n of s i l icon a n d o x y g e n a t o m s in q u a r t z . ( E x p o s i t i o n a t t h e M u s e u m of t h e L e n i n g r a d M i n i n g I n s t i t u t e )

2' 19

N e w ideas a r e h o r n w h e r e v e r t h e m i n d f u l scientis t app l ies M e n -de leyev ' s L a w to t he analys is of n a t u r a l p h e n o m e n a .

Bu t w h a t is g e o c h e m i s t r y a n y w a y ? W h a t is this n e w science t h a t has la te ly a t t r a c t e d so m a n y y o u n g inves t iga to r s?

As t h e t e r m itself shows g e o c h e m i s t r y s tudies t h e c h e m i c a l processes w h i c h occu r in t h e e a r t h .

C h e m i c a l e l emen t s as i n d e p e n d e n t un i t s of n a t u r e shif t , w a n d e r a n d c o m b i n e , or , as we say, t h e y m i g r a t e in t h e e a r t h ' s c r u s t ; t h e laws g o v e r n i n g t h e c o m b i n a t i o n s of e l emen t s a n d m i n e r a l s a t d i f f e r e n t pressures a n d t e m p e r a t u r e s in va r ious po r t i ons of t h e e a r t h ' s c rus t a r e j u s t t h e p r o b l e m s o n w h i c h m o d e r n g e o c h e m i s t r y is w o r k i n g .

S o m e c h e m i c a l e l e m e n t s (for e x a m p l e , s c a n d i u m a n d h a f n i u m ) a r e i n c a p a b l e of f o r m i n g a c c u m u l a t i o n s a n d s o m e t i m e s a r e so d i spersed t h a t t he rock c o n t a i n s on ly o . o o o o o o o i p e r cen t of these c h e m i c a l e lements .

W e m i g h t call these e l e m e n t s supe r -d i spe r sed a n d w e e x t r a c t t h e m only w h e n t h e y a r e of s o m e specia l v a l u e to p rac t i ce .

W e n o w bel ieve t h a t all e l e m e n t s of M e n d e l e y e v ' s Pe r iod i c T a b l e c a n be f o u n d in every c u b i c m e t r e of rock if on ly o u r m e t h o d s of analys is de t ec t t h e m wi th suff ic ient a c c u r a c y . W e m u s t n o t fo rge t t h a t in t h e his tory of sc ience n e w m e t h o d s a r e of even g r e a t e r i m p o r t a n c e t h a n n e w theor ies .

Con t r a r iw i se , o t h e r e l emen t s (for e x a m p l e , l ead a n d i ron) in t he i r c o n t i n u o u s m i g r a t i o n m a k e a n u m b e r of stops, as it we re , f o r m c o m -p o u n d s in w h i c h t h e y easily a c c u m u l a t e a n d persist for a l ong t ime . Desp i t e t h e c o m p l e x c h a n g e s in t h e e a r t h ' s c rus t t h r o u g h o u t geological h i s tory these e l emen t s r e t a i n t h e f o r m s of t he i r a c c u m u l a t i o n , f o r m l a rge c o n c e n t r a t i o n s a n d p r o v e accessible to i n d u s t r i a l exp lo i t a -t ion.

G e o c h e m i s t r y s tudies t h e laws of d i s t r i b u t i o n a n d m i g r a t i o n of t h e e l emen t s no t on ly in t h e e a r t h a n d in t h e un ive r se as a who le , b u t also u n d e r c e r t a i n geologica l cond i t i ons a n d in c e r t a i n reg ions of t h e c o u n t r y as, for e x a m p l e , in t he C a u c a s u s a n d in t h e U r a l s , a n d ind ica tes w h e r e m i n e r a l s shou ld be p r o s p e c t e d for .

T h u s , t h e p r o f o u n d theore t i ca l p r inc ip les of m o d e r n g e o c h e m i s t r y c o m e ever closer to p r ac t i ca l p r o b l e m s , a n d o n t h e basis of a n u m b e r of g e n e r a l p r inc ip les g e o c h e m i s t r y strives to show w h e r e a c e r t a i n

20

" L e v y T a l g a r " Canyon in the Trans - I l i A l a - T a u . K a z a k h S.S.R.

c h e m i c a l e l e m e n t m a y b e f o u n d , w h e r e a n d u n d e r w h a t cond i t i ons w e m a y e x p e c t t o e n c o u n t e r a c c u m u l a t i o n s , fo r e x a m p l e , of v a n a d i u m o r t u n g s t e n , w h a t m e t a l s w o u l d " m o r e w i l l i n g l y " b e f o u n d t o g e t h e r as, for i n s t ance , b a r i u m a n d p o t a s s i u m , a n d w h a t e l emen t s will " a v o i d " e a c h o t h e r as, fo r e x a m p l e , t e l l u r i u m a n d t a n t a l u m .

G e o c h e m i s t r y s tudies t h e b e h a v i o u r of every e l e m e n t , b u t t o j u d g e this b e h a v i o u r it m u s t h a v e g o o d k n o w l e d g e of t h e p r o p e r t i e s of t h e e l e m e n t , of its pecu l ia r i t i es , of its i n c l i n a t i o n t o c o m b i n e w i t h o t h e r e l e m e n t s or , o n t h e c o n t r a r y , to s e p a r a t e f r o m t h e m .

T h e geochemis t , t hus , b e c o m e s a n e x p l o r e r a n d p r o s p e c t o r , h e suggests t h e p a r t s of t h e e a r t h ' s c rus t w h e r e i r o n or m a n g a n e s e ores c a n b e f o u n d , tells us w h e r e w e c a n d i scover depos i t s of p l a t i n u m a m i d s e r p e n t i n e s a n d exp la ins w h y ; h e advises t h e geologis t to look for a r s en i c a n d a n t i m o n y in y o u n g geologica l rocks a n d m o u n t a i n r anges , a n d p red i c t s f a i l u r e if t h e y s e a r c h for these m e t a l s w h e r e t h e cond i t i ons for t he i r c o n c e n t r a t i o n a r e l ack ing .

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But all this is possible when the "behaviour" of the chemical element has been thoroughly studied, just as by studying the behaviour of a person in life it is possible not only to explain his actions but also to predict what he will do under different circumstances.

This is where the tremendous practical importance of this new science comes in!

Geochemistry, as we see, marches shoulder to shoulder with geology and chemistry. * * *

I do not want to overburden you with a mass of facts, examples and calculations, nor am I undertaking to teach you all there is to know about geochemistry. No, I only want: you to take an interest in this new science, which was born

but very recently, so that you may convince yourselves from reading the separate essays on the wanderings of elements throughout the world that geochemistry is still a young science and that the future holds wide prospects for it, but that it must also win this future.

Like everywhere in life, progress and truth do not immediately win in the world of scientific ideas: they have to be fought for; they require a mobilization of all forces, great purposefulness and energy, a conviction of worthiness and .a faith in victory.

It is not the abstract, barren and inactive idea that wins, but the fighting idea, the idea which burns with the flame of new quests, the idea deeply rooted in life and its problems.

A vast field for research lies before the chemists of the earth in the Soviet Union.

Y o u n g geochcmis t examin ing an ou tc rop in the K a r a - S h o r Depres s ion . T u r k m e n S.S.R.

22

W e still n e e d a n e n o r m o u s n u m b e r of fac t s a n d w e n e e d t h e m , as t h e g r e a t R u s s i a n scient is t I v a n P a v l o v sa id , l ike a b i r d needs a i r t o s u p p o r t its wings .

T h e b i r d a n d t h e p l a n e , h o w e v e r , a r e k e p t in t h e a i r n o t on ly by t h e a i r itself, b u t p r i m a r i l y by t he i r o w n o n w a r d m o v e m e n t .

I t is t h e s a m e o n w a r d m o v e m e n t t h a t s u p p o r t s a n y sc ience ; t h e sc ience surv ives o n l y t h r o u g h pers i s ten t c r ea t ive w o r k a n d t h e fires of its d a r i n g ques t s s i m u l t a n e o u s l y c o m b i n e d w i t h a cool a n d sober analys is of its a c h i e v e m e n t s .

I n d u s t r y is still f a r f r o m u s i n g al l t h e e l emen t s , a n d w e m u s t c o n t i n u e to w o r k h a r d a n d pers i s ten t ly b e f o r e w e p l a c e al l t h e e l e m e n t s in M e n -de leyev ' s P e r i o d i c T a b l e a t t h e service of m a n k i n d .

WORLD OF THE INVISIBLE. THE ATOM AND THE CHEMICAL ELEMENT

L e t m e h a v e y o u r h a n d , r e a d e r , a n d I shal l t a k e y o u i n t o t h e w o r l d of v e r y sma l l t h ings w h i c h w e d o n o t u sua l l y no t i ce . H e r e is a l a b o r a t o r y of m a g n i f i c a t i o n a n d d i m i n u t i o n . L e t us go in . W e a r e e x p e c t e d t h e r e . T h i s o r d i n a r y - l o o k i n g m a n i n w o r k c lo thes is n o t ye t o ld , b u t h e is a f a m o u s i n v e n t o r . L e t us h e a r w h a t h e h a s t o say .

" L e t us g o i n t o t h e c a b i n ; i t is m a d e of m a t e r i a l t r a n s p a r e n t t o r ays of a n y w a v e - l e n g t h , i n c l u d i n g t h e shor te s t cosmic rays . I sha l l t u r n t h e lever t o t h e r i g h t a n d w e wil l b e g i n t o g r o w sma l l e r . T h i s p rocess of g r o w i n g sma l l e r is n o t v e r y p l e a s a n t ; a c c o r d i n g to t h e s top-w a t c h w e g r o w 1,000 t imes as sma l l eve ry f o u r m i n u t e s . W e shal l s top in f o u r m i n u t e s , l e ave t h e c a b i n a n d see t h e s u r r o u n d i n g w o r l d as i t is seen t h r o u g h t h e bes t mic roscopes . T h e n w e sha l l r e t u r n t o o u r c a b i n a n d t r y t o g r o w a n o t h e r 1,000 t i m e s as s m a l l . "

We l l , w e h a v e t u r n e d t h e l e v e r . . . . W e h a v e g r o w n smal le r , w e h a v e b e c o m e as sma l l as a n t s . . . . W e

h e a r t h ings d i f f e r en t l y n o w , b e c a u s e o u r e a r n o l onge r r eac t s t o t h e a i r w a v e s . . . . O n l y noises, b u z z i n g , c r a c k l i n g a n d ru s t l i ng r e a c h o u r senses. B u t w e h a v e r e t a i n e d o u r s ight b e c a u s e i n n a t u r e t h e r e a r e X - r a y s w i t h a w a v e - l e n g t h 1,000 t imes as s h o r t as t h a t of l igh t . T h e a p p e a r a n c e of t h ings h a s c h a n g e d m o s t u n e x p e c t e d l y ; m o s t b o d i e s h a v e b e c o m e v e r y t r a n s p a r e n t a n d e v e n t h e m e t a l s a r e b r i g h t l y c o l o u r e d a n d look like s t a ined g l a s s . . . . B u t t h e n glass, res in a n d a m b e r h a v e g r o w n d a r k a n d n o w look l ike me ta l s .

W e see p l a n t cells filled w i t h a p u l s a t i n g j u i c e a n d g r a i n s of s t a r c h , a n d if w e w a n t t o w e c a n p u t o u r h a n d i n t o t h e s t o m a of a l ea f ; b l o o d corpusc les as l a r g e as a f a r t h i n g float i n a d r o p of b l o o d a n d t u b e r c u l a r

2 4

baci l l i look like b e n t nai ls w i t h o u t a h e a d . . . . T h e b a c t e r i a of cho le ra r e s e m b l e smal l b e a n s w i t h fast b e a t i n g t a i l s . . . . B u t w e c a n n o t see molecu les , a n d on ly a n incessan t s h a k i n g of t h e wal ls a n d a l ight p r i c k i n g of t h e f ace by t h e a i r , as t h o u g h a w i n d w e r e b l o w i n g dus t i n to t h e face , r e m i n d us t h a t we a r e a p p r o a c h i n g t h e l imi t of divisibi l i ty of m a t t e r . . . .

W e r e t u r n t o t h e c a b i n a n d m o v e the lever o n e m o r e po in t . Eve ry -t h i n g h a s t u r n e d d a r k a r o u n d us, a n d o u r c a b i n has b e g u n to shake as i n a n e a r t h q u a k e .

As w e r e g a i n o u r senses, t h e c a b i n is still s h a k i n g a n d w e feel as if a ha i l s t o r m w e r e r a g i n g a r o u n d us ; w e a r e c o n t i n u o u s l y showered b y s o m e t h i n g like peas a n d w e ge t t h e impress ion we a r e f i red u p o n by a t h o u s a n d m a c h i n e - g u n s . . . .

O u r g u i d e s u d d e n l y speaks u p :

" W e c a n n o t l eave t h e c a b i n . W e a r e o n e mi l l ion t imes as smal l as w e w e r e ; w e n o w m e a s u r e t h o u s a n d t h s of a m i l l ime t r e , on ly o n e a n d a ha l f m i c r o n s i n fac t .

" O u r h a i r is n o w o . o o o o o o o i c e n t i m e t r e t h i c k ; this m a g n i t u d e is ca l led ' a n g s t r o m ' a n d serves t o m e a s u r e molecu le s a n d a t o m s . T h e molecu les of t h e gases of t h e a i r h a v e a d i a m e t e r of a b o u t o n e a n g s t r o m . T h e s e m o l -ecules a r e n o w t r ave l l ing a t a t r e m e n d o u s speed a n d a r e b o m b a r d i n g o u r c a b i n .

" W h e n w e le f t t h e c a b i n t h e first t i m e w e felt as if a w i n d w e r e b l o w i n g d u s t i n t o o u r faces ; th is w a s t h e a c t i o n of i n d i v i d u a l m o l -ecules . N o w t h a t w e h a v e b e c o m e sma l l e r the i r m o v e m e n t s a r e as d a n g e r o u s t o us as a shot of s a n d is to m a n .

" L o o k o u t of t h e w i n d o w a n d y o u will see a dus t p a r t i c l e o n e m i c r o n in d i a m e t e r , t h a t is n e a r l y as smal l as w e a r e ourselves . See h o w it is b u f f e t e d a b o u t b y t h e u n e q u a l b lows it receives f r o m t h e w h i r l of m o l e -cu les ! I r e g r e t w e c a n n o t see t h e m b e c a u s e t h e y m o v e too fast . . . . B u t i t is t i m e w e w e r e g o i n g b a c k : t h e u l t r a - s h o r t w a v e s i n t h e

Elec t ron ic microscope magni -fy ing u p to 500,000 t imes. T h e objec t is i l lumined by a s t ream of e lec t rons ; e lectro-magne t s serve as lenses

25

r ays of w h i c h w e a r e e x a m i n i n g t h e mo lecu l e s a r e h a r m f u l t o o u r eyes . "

A t these w o r d s o u r g u i d e t u r n s t h e l ever b a c k . . . . O f course , o u r t r i p w a s on ly i m a g i n a r y , b u t t h e p i c t u r e w e h a v e

p a i n t e d is v e r y close t o rea l i ty . E x p e r i e n c e shows t h a t w h a t e v e r w e d o to pe r f ec t t h e m e t h o d s of

analys is , as a r e su l t of a n a l y z i n g c o m p l e x bod ie s w e c o m e to a n u m b e r of s imp le subs t ances w h i c h c a n n o t b e c h e m i c a l l y d i v i d e d i n t o still s i m p l e r cons t i tuen t s .

All these s imple bodies , w h i c h c a n n o t b e d i v i d e d a n y m o r e a n d of w h i c h al l t h e bod ie s of s u r r o u n d i n g n a t u r e a r e m a d e , w e call c h e m i c a l e l emen t s .

I n c o n t i n u o u s c o n t a c t w i t h t h e v a r i o u s bod ie s of n a t u r e , l iv ing a n d d e a d , sol id, l i q u i d a n d gaseous , mare h a s a r r i v e d a t o n e o f his mos t i m p o r t a n t g e n e r a l i z a t i o n s : t h e i d e a of s u b s t a n c e , of m a t t e r . W h a t a r e t h e p r o p e r t i e s of th is m a t t e r a n d w h a t is i ts s t r u c t u r e ? T h e s e a r e t h e ques t ions t h a t a n y o n e w h o s tud ies n a t u r e m u s t ask h imself .

T h e first a n s w e r w e ge t b y d i r e c t s ensa t ion is t h e a p p a r e n t c o n t i n u i t y of s u b s t a n c e . B u t th is impres s ion is on ly a n i l lusion. By us ing a m i c r o -scope w e o f t e n d iscover a po ros i ty in s u b s t a n c e , i .e. , t h e ex i s t ence of smal l spaces invis ible t o t h e n a k e d eye.

B u t even in s u c h subs t ances as w a t e r , a l coho l a n d o t h e r l iqu ids , as wel l as gases, i n w h i c h i t w o u l d s e e m t h e r e s h o u l d b e n o pores as a m a t t e r of p r inc ip l e , w e m u s t r e cogn i ze t h e ex is tence of i n t e rva l s b e t w e e n t h e par t i c les of m a t t e r o r else w e co u l d n e v e r u n d e r s t a n d w h y subs t ances c a n c o n d e n s e u n d e r p r e s su re a n d e x p a n d b y h e a t i n g .

All m a t t e r is g r a n u l a r . T h e smal les t g r a n u l e s of s u b s t a n c e a r e ca l l ed a t o m s o r molecu les . W e h a v e m a n a g e d to ca l cu l a t e , f o r e x a m p l e , t h a t in l iqu id w a t e r t h e mo lecu l e s o c c u p y on ly a b o u t o n e - t h i r d o r o n e -f o u r t h of t h e space . T h e res t is t a k e n u p b y pores .

T o d a y w e k n o w t h a t w h e n a t o m s a p p r o a c h e a c h o t h e r c e r t a i n forces of r epu l s ion ar i se a n d t h e a t o m s c a n n o t m e r g e . A r o u n d e a c h a t o m w e c a n desc r ibe a " s p h e r e of i m p e r m e a b i l i t y " b e y o n d w h i c h n o o t h e r m a t t e r c a n p e n e t r a t e u n d e r u s u a l cond i t i ons . W e m a y , t h e r e f o r e , r e g a r d t h e a t o m s t o g e t h e r w i t h these sphe res as elast ic g lobu les i m -p e r m e a b l e t o e a c h o t h e r . E a c h e l e m e n t h a s a s p h e r e of i m p e r m e a b i l i t y t h e r a d i u s of w h i c h is expressed in a n g s t r o m s . F o r e x a m p l e , i n c a r b o n i t is 0 .19 a n g s t r o m , i n s i l i con—0.39 , i .e. , s m a l l ; in i r o n i t is 0 .83 a n d

a 6

i n c a l c i u m — 1 . 0 6 , i .e., m e d i u m ; in o x y g e n it is 1.40, i .e. , l a rge (see d i a g r a m o n p a g e 57 w h e r e t h e e l e m e n t s a r e p r e s e n t e d in t h e f o r m of circles p r o p o r t i o n a l to t h e size of t h e r ad i i of t he i r spheres ) .

B u t if w e p a c k bal ls i n t o a c o n t a i n e r (for e x a m p l e , a box) t h e d i so rde r ly p l a c e d bal ls will o c c u p y a g r e a t e r v o l u m e t h a n w h e n p a c k e d in a n o r d e r l y m a n n e r . T h e p a c k i n g w h i c h occup ies t h e smal les t v o l u m e is ca l led t h e denses t p a c k i n g . I t c a n b e o b t a i n e d , for e x a m p l e , in t h e

Model of the structure of rock salt-NaCl

Model of the structure of pyrite-FeS2

fo l lowing e x p e r i m e n t : t a k e severa l d o z e n steel bal ls ( f r o m a ba l l -b e a r i n g ) , p l ace t h e m o n a s auce r a n d t a p t h e s a u c e r l ight ly . S ince t h e bal ls will t ry to ge t to t h e c e n t r e of t h e s auce r t h e y will c r o w d e a c h o t h e r a n d will soon a r r a n g e themse lves in rows w i t h 6o° ang les in b e t w e e n . O n t h e ou t s ide t h e y will a r r a n g e themse lves a l o n g t h e sides of a r ec t i l i nea r h e x a g o n . T h i s will b e t h e denses t p a c k i n g of bal ls of o n e size on a p l a n e .

S u c h is t h e a r r a n g e m e n t of t h e a t o m s of m a n y m e t a l s — c o p p e r , go ld , e tc .

I f t h e bal ls a r e u n e q u a l (for i n s t ance , of t w o s h a r p l y d i f f e r ing sizes) it o f t e n h a p p e n s t h a t t h e l a r g e r ba l l s (for e x a m p l e , c h l o r i n e in t h e crysta ls of c o m m o n salt) yield t h e denses t p a c k i n g , w h i l e t h e sma l l e r a t o m s a r r a n g e themse lves i n t h e spaces b e t w e e n t h e l a rge bal ls .

T h u s , in c o m m o n sal t (or h a l i t e ) — N a C l — o n e a t o m of s o d i u m is s u r r o u n d e d on six sides b y a t o m s of ch lo r ine , w h i l e e a c h a t o m of ch lo r ine is s u r r o u n d e d o n six sides b y a t o m s of s o d i u m . U n d e r these cond i t i ons t h e forces of a t t r a c t i o n b e t w e e n t h e ions of s o d i u m a n d ch lo r ine a r e t h e g rea tes t .

2 7

N o w t h e n , t h e bod ies t h a t s u r r o u n d us, r ega rd less of the i r c o m -plex i ty or s impl ic i ty , consist of a c o m b i n a t i o n of m i n u t e s t par t i c les , or a t o m s , invis ible to t h e n a k e d eye, j u s t l ike a b e a u t i f u l l a rge b u i l d i n g is m a d e of s e p a r a t e smal l br icks .

T h i s t h o u g h t was b o r n in h o a r y a n t i q u i t y , a n d w e e n c o u n t e r t h e idea of " a t o m " ( indivis ible , in G r e e k ) in t h e G r e e k ma te r i a l i s t phi los-o p h y of L e u c i p p u s a n d D e m o c r i t u s w h o l ived 600-400 B. C . A c c o r d i n g to m o d e r n concep t s , t h e basis for w h i c h was la id as ea r ly as t h e 19th c e n t u r y , a c h e m i c a l e l e m e n t in a f ree s ta te a n d in t h e f o r m of a s i m p l e b o d y consists of a n a g g r e g a t e of h o m o g e n e o u s a t o m s w h i c h a r e n o l onge r divis ible a t least w i t h o u t losing t h e i n d i v i d u a l p r o p e r t i e s i n h e r e n t in t he g iven subs t ance .

T h e a t o m s of t h e s a m e c h e m i c a l e l e m e n t a r e u n i f o r m in s t r u c t u r e a n d h a v e a cha rac t e r i s t i c mass o r a n a t o m i c w e i g h t .

I n t he b e g i n n i n g of o u r c e n t u r y scientists k n e w t h e r e s h o u l d b e 92 d i f f e r en t e l e m e n t s o n e a r t h a n d , h e n c e , 92 types of d i f f e r e n t a t o m s . O f these 92 c h e m i c a l e l e m e n t s w e h a v e t hus f a r b e e n a b l e to f ind a n d

isolate f r o m n a t u r a l ob jec t s 90 c h e m i c a l e l e m e n t s a n d , c o r r e s p o n d -ingly , 90 types of a t o m s , b u t w e d o n o t d o u b t t h a t t h e u n f o u n d e l emen t s a lso exist. Al l t h e bodies of n a t u r e k n o w n to us a r e bu i l t of c o m b i n a -t ions of these 92 types of a t o m s .

U r a n i u m , t h e heav ies t of all e l e m e n t s k n o w n to us un t i l r ecen t ly , h a s n u m b e r 92.

T h e s t ructure of hydrogen , he l ium and beryl l ium a toms. T h e cir-cumferences show the orbi ts of the e lec t rons ; t he nuclei of the a toms are in the centre

28

Structure of sodium and krypton atoms

R e c e n t s tudies in d i s i n t e g r a t i o n of u r a n i u m e l e m e n t s h a v e r evea led still h e a v i e r t r a n s u r a n i u m e l e m e n t s : n e p t u n i u m 93, p l u t o n i u m 94, a m e r i c i u m 95, c u r i u m 96, b e r k e l i u m 97, c a l i f o r n i u m 98, e i n s t e i n i u m 99, f e r m i u m 100 a n d m e n d e l e -v i u m 101. T h e ex i s tence of e v e n h e a v i e r a t o m s is n o t su rp r i s ing , b u t all t hese a t o m s a r e v e r y u n s t a b l e a n d d o n o t o c c u r i n n a t u r e , b u t a r e p r o d u c e d a r t i -ficially; w e shal l n o t b e m a k i n g a n y p a r t i c u l a r m i s t a k e if in s t u d y -i n g t h e c o m p o s i t i o n of t h e n a t u r a l bod ies of t h e e a r t h w e p r o c e e d f r o m t h e c o n j e c t u r e t h a t all of t h e m a r e m a d e u p of 92 ele-m e n t s .

A t o m s of t h e s a m e e l e m e n t , l ike those of d i f f e r e n t e l ements , b y c o m b i n i n g w i t h e a c h o t h e r i n twos or m o r e , m a y f o r m molecu les of va r i ous subs tances . By c o m b i n i n g w i t h e a c h o t h e r t h e a t o m s a n d molecu le s b u i l d al l of t h e ex is t ing n a t u r a l bodies . T h e n u m b e r of a t o m s a n d molecu le s m u s t b e ve ry la rge . F o r e x a m p l e , if we t a k e 18 g r a m s of w a t e r , a so-cal led g r a m - m o l e c u l e , it will c o n t a i n 6 .06 x i o 2 3

molecu le s of w a t e r .

T h i s is a colossal n u m b e r ; it is m a n y t h o u s a n d t imes t h e n u m b e r of g r a in s of w h e a t a n d rye t h a t h a v e g r o w n o n t h e e a r t h s ince t h e ex i s tence of v e g e t a t i o n .

I n o r d e r t o ge t a n i d e a a b o u t t h e size of a m o l e c u l e let us c o m p a r e it w i t h t h e m i n u t e s t of l iv ing o rgan i sms , a b a c t e r i u m , w h i c h c a n be seen on ly t h r o u g h a m i c r o s c o p e w h e n m a g n i f i e d a b o u t a t h o u s a n d t imes . T h e size of t h e smal les t b a c t e r i a is 0 .0002 m i l l i m e t r e . A n d even this is a t h o u s a n d t imes t h e size of a w a t e r mo lecu l e , w h i c h m e a n s t h a t even t h e smal les t b a c t e r i u m c o n t a i n s m o r e t h a n t w o t h o u s a n d mi l l ion a t o m s , i. e., m o r e t h a n t h e r e a r e p e o p l e o n e a r t h .

A c h a i n of t h e w a t e r molecu le s c o n t a i n e d in t h r e e d r o p s of w a t e r w o u l d s t r e t ch f r o m t h e e a r t h t o t h e s u n a n d b a c k n e a r l y six t imes b e c a u s e it is 9 ,400 ,000 ,000 k i lomet res long .

T h e a t o m w a s o r ig ina l ly conce ived as a m i n u t e s t indiv is ib le p a r -ticle, b u t o n closer inves t iga t ion , as o u r m e t h o d s of r e s e a r c h w e r e

29

i m p r o v e d a n d r e n d e r e d m o r e a c c u r a t e , it t u r n e d o u t t o b e a ve ry c o m p l e x s t r u c t u r e . T h e n a t u r e of t h e a t o m was v iv id ly r evea l ed for t he first t i m e w h e n p e o p l e l e a r n e d of t h e p h e n o m e n a of r a d i o -ac t iv i ty a n d b e g a n to s t u d y t h e m .

E a c h a t o m c o n t a i n s a n u c l e u s w i t h a d i a m e t e r a b o u t o . o o o o i t h a t of t h e a t o m . T h e n u c l e u s p r ac t i c a l l y c o n t a i n s its e n t i r e mass . I t ca r r i e s a posi t ive e lec t r ic c h a r g e w h i c h increases as w e p r o c e e d f r o m t h e l igh te r c h e m i c a l e l emen t s to t h e h e a v i e r ones . A r o u n d this posi t ively c h a r g e d n u c l e u s revolve e lec t rons whose n u m b e r eq u a l s t h e n u m b e r of posi t ive c h a r g e s in t h e n u c l e u s so t h a t t h e a t o m as a w h o l e is e lectr i -cal ly n e u t r a l .

T h e nuc le i of t h e a t o m s of all c h e m i c a l e l e m e n t s consis t of t w o s imples t p a r t i c l e s — a p r o t o n o r h y d r o g e n a t o m n u c l e u s a n d a n e u t r o n , i. e., a pa r t i c l e w i t h a mass w h i c h a l m o s t exac t ly eq u a l s t h e mass of t h e p r o t o n b u t is devo id of a n y e lec t r ic c h a r g e . T h e p r o -tons a n d n e u t r o n s in t h e nuc le i of t h e a t o m s a r e so f i rmly b o u n d u p w i t h e a c h o t h e r t h a t t h e nuc le i of t h e a t o m s r e m a i n abso lu t e ly i n v a r i a b l e a n d s t ab le in all c h e m i c a l r eac t i ons a n d u n d e r all phys ica l forces.

Espec ia l ly s tab le is t h e c o m b i n a t i o n of t h e t w o p r o t o n s a n d t w o n e u t r o n s w h i c h f o r m t h e n u c l e u s of h e l i u m a t o m . T h e n u c l e u s of h e l i u m is so s t ab l e t h a t i n t h e a t o m s of t h e h e a v y e l e m e n t s it is, a p p a r e n t l y , c o n t a i n e d in its r e a d y - m a d e f o r m a n d flies o u t as a n a l p h a pa r t i c l e d u r i n g t h e r a d i o a c t i v e d i s i n t eg ra t i on of t h e nuc le i .

T h e c h e m i c a l p r o p e r t i e s of e l emen t s d e p e n d o n t h e s t r u c t u r e a n d p rope r t i e s of t h e e x t e r n a l shell of t h e a t o m s a n d o n t h e ab i l i ty of t h e a t o m s to lose o r g a i n e lec t rons . T h e s t r u c t u r e of t h e n u c l e u s of t h e a t o m h a r d l y a f fec ts t h e c h e m i c a l p r o p e r t i e s of t h e l a t t e r . A t o m s w h i c h h a v e t h e s a m e n u m b e r of e x t e r n a l e lec t rons , even if t h e s t r u c t u r e of the i r nuc le i a n d t he i r mass o r a t o m i c w e i g h t d i f fe r , t he re fo re , h a v e t h e s a m e c h e m i c a l p r o p e r t i e s a n d f o r m k i n d r e d g r o u p s of a t o m s as, for e x a m p l e , ch lo r ine , b r o m i n e , i o d i n e a n d t h e like.

T h e d i a g r a m s s h o w va r ious m o d e l s of a t o m i c s t r u c t u r e in w h i c h t h e r e a d e r c a n see h o w c o m p l i c a t e d t h e e l ec t ron o rb i t s b e c o m e as t he a t o m s inc rease in w e i g h t .

THE ATOMS AROUND US

L o o k a t t h e t h r e e p i c tu re s w e a r e p r i n t i n g in this c h a p t e r . A w o n d e r f u l v i ew of a m o u n t a i n l ake w i t h a b l u e mi r ro r - l ike su r face

s u r r o u n d e d b y l i m e s t o n e cliffs, d a r k - g r e e n spots of so l i ta ry trees, a n d a b o v e alJ this t h e b r i g h t s o u t h e r n s u n .

A noisy i r o n a n d steel works e n v e l o p e d in s m o k e a n d s t e a m a n d b e l c h i n g f i r e ; t r a i n l o a d s of ore , coal , flux a n d b r i ck r u n n i n g to t h e mi l l a n d r e t u r n i n g w i t h h u n d r e d s of tons of rails , b l anks , ingo ts a n d ro l led m e t a l t o t h e n e w cen t re s of i n d u s t r y .

Z I L - i i o ; a s m a r t c a r ; t h e d a r k - g r e e n v a r n i s h shines o n its f ende r s a n d y o u c a n a l m o s t h e a r t h e p u r r i n g of its m o t o r a n d t h e soft m e l o d y issuing f r o m its r ad io - r ece ive r . T h i s c a r w a s a s sembled f r o m t h o u s a n d s of p a r t s o n t h e l o n g c o n v e y e r of t h e p l a n t a n d will n o w easily r u n h u n d r e d s of t h o u s a n d s of k i lomet res .

L o o k a t these t h r e e p i c tu re s a n d tell m e f r a n k l y w h a t y o u a r e th ink-i n g a b o u t as y o u look a t t h e m , w h a t y o u h a v e t a k e n a f a n c y for a n d w h a t q u e s t i o n y o u w o u l d l ike to ask.

I a m d i v i n i n g y o u r t h o u g h t s a n d y o u r ques t ions b e c a u s e you a r e l iv ing in a n a g e of e n g i n e e r i n g a n d i n d u s t r y a n d y o u r in teres ts a r e b o u n d u p w i t h t h e m a c h i n e s t h a t c r e a t e p o w e r a n d t h e p o w e r t h a t c rea te s m a c h i n e s .

B u t I shou ld l ike t o tell y o u a b o u t s o m e t h i n g else so t h a t y o u m a y see these p i c tu re s t h r o u g h d i f f e r e n t eyes. N o w y o u l isten.

* * *

I k n o w w h a t t h e geologis t will say to m e . " J u s t t h i n k of t he r e m a r k a b l e scient i f ic geological p r o b l e m s th is l ake c o n t a i n s ! H o w was this e n o r m o u s ,

3 '

Mounta in l ake in Ta j ik i s t an

d e e p g a p f o r m e d ? W h a t forces h a v e locked these b l u e w a t e r s a m i d t h e s teep spurs of t h e T a j i k m o u n t a i n s ? T h e r e a r e b e t w e e n t w o a n d t h r e e t h o u s a n d m e t r e s f r o m t h e t o p of t h e m o u n t a i n s to t h e b o t t o m of t h e l a k e ; w h a t m i g h t y p o w e r cou ld h a v e ra ised a n d c r u m p l e d t h e layers of r o c k ? "

T h e mine ra log i s t will s a y : " W h a t w o n d e r f u l l imes tone is f o r m e d b y these cliffs a n d m o u n t a i n s ! I t m u s t h a v e t a k e n scores a n d h u n d r e d s of m i l l e n n i u m s for this p o w e r f u l s e d i m e n t of silt, shells a n d tes tae to a c c u m u l a t e on t h e o c e a n floor a n d b e c o m p r e s s e d i n t o d e n s e l imes tone , a l m o s t i n t o m a r b l e ! T a k e a n o r d i n a r y m i n e r a l o g i c a l m a g n i f y i n g glass w h i c h magn i f i e s t en t imes a n d y o u will h a r d l y d i sce rn t h e ind i -v i d u a l sh iny crysta ls of l i m e s p a r of w h i c h the rock is m a d e . "

" H o w w h i t e a n d p u r e this l imes tone i s ! " t h e c h e m i c a l t echno log i s t will i n t e r r u p t h i m . " T h i s is exce l len t r a w m a t e r i a l fo r t h e c e m e n t i n d u s t r y a n d for r oa s t i ng i n t o l i m e ; it is a l m o s t p u r e c a l c i u m ca r -b o n a t e , a c o m b i n a t i o n of a t o m s of c a l c i u m , o x y g e n a n d c a r b o n d iox ide . Look , I shal l dissolve it in a w e a k a c i d ; t h e c a l c i u m will dissolve a n d t h e c a r b o n d iox ide will c o m e off w i t h a h iss ."

32

" B u t w e cou ld p e r f o r m even m o r e exac t e x p e r i m e n t s , " t h e geo-c h e m i s t will say. " W e c a n p r o v e w i t h t h e a id of a spec t roscope t h a t this l imes tone c o n t a i n s o t h e r a t o m s as wel l ; it h a s s t r o n t i u m , b a r i u m , a l u m i n i u m a n d si l icon. A n d if we m a k e a super -p rec i s ion analys is a n d t ry to f ind t h e ra res t a t o m s of w h i c h t h e r e is less t h a n one -mi l l i on th of o n e p e r c e n t h e r e we shal l b e a b l e to d i scover even z inc a n d lead in this l imes tone .

" A n d d o n ' t t h i n k this is a specif ic f e a t u r e of o u r l imes tone because e x p e r i e n c e d chemis t s will find 35 d i f f e r e n t types of a t o m s even in t h e w o r l d ' s pu re s t m a r b l e .

" N o w w e a r e even inc l ined to bel ieve t h a t we shou ld be a b l e to find all t he e l emen t s of t h e M e n d e l e y e v Per iod ic T a b l e in every c u b i c m e t r e of s tone - g r a n i t e o r basa l t , l imes tone o r c l a y — o n l y the a m o u n t of s o m e of these will b e one- t r i l l ion th t h a t of c a l c i u m or c a r b o n . "

T h e w o r d s of t h e geologist , mine ra log i s t , chemis t a n d geochemis t wil l impress you so m u c h t h a t in s t ead of s imp le greyish l imes tone y o u will see m o u n t a i n s of some mys te r ious s tone a n d you will w a n t to ge t a d e e p e r ins ight i n to its n a t u r e a n d d i scover t he secret of its o r ig in a n d be ing .

* * *

N o w let 11s t u r n to t he works . W h a t s t r a n g e bu i ld ings , u n u s u a l in size a n d s h a p e ! G i a n t towers filled wi th ore , coal a n d l imes tone ; e n o r m o u s p ipes lead to these towers a n d feed t h e m compres sed ho t a i r . W h a t fo r? W h y is m e t a l s m e l t e d in t h e m , w h y is coal b u r n e d a n d w h y d o c louds of h e a l e d gases f la re u p as they leave these towers?

Y o u will p r o b a b l y be su rp r i sed if I tell you t h a t this is a l a b o r a t o r y ol a t o m s ; in t he o r e t he a t o m s of i ron a r e very f i rmly t ied to each o t h e r by l a rge r balls oxygen a t o m s -which d o not let t he i ron a t o m s get closer to each o t h e r a n d g ive us t h e heavv m a l l e a b l e me ta l we call i ron . . . . I r o n o r e possesses n o n e of t h e p rope r t i e s of this me ta l t h o u g h it con t a in s 70 per cent of it. W e mus t , t he re fo re , d r ive t he oxygen ou t . But this is not so easy to d o .

D o you r e m e m b e r , clear r e a d e r , t he Russ i an fa i ry- ta le a b o u t the litt le girl A l y o n u s h k a w h o h a d to pick ou t all t he g ra ins ol" s a n d ou t ol a pile of corn ? D o you r e m e m b e r tha t she ca l led on he r l i t t le f r iends , t he an t s , a n d tha t they succeeded wi th this t ask? But t h e n those were

.1

gra ins of sand wi th a d i a m e t e r a mi l l ion t imes t h a t of (he oxygen a t o m ! I k n o w von will s ay : " T h i s is a h a r d job a n d 1 scarcely bel ieve it r a n IK- d o n e . " T o be sure , it took a lot of work a n d h u m a n ene rgy (o solve this b r a in - t ea se r .

But it was solved j u s t t h e s a m e ! I n this case t he h u m a n gen ius d id no t call u p o n an ts , b u t on a t o m s

of o t h e r subs tances . A n d in a l l i ance wi th t he n a t u r a l e lements - - - l i re a n d w i n d it m a d e these a t o m s t ake t h e oxygen a w a y f r o m the i r on a n d b r ing it wi th t h e ho t a i r to t h e su r f ace of t he m e t a l boi l ing in t he f u r n a c e .

Bu t w h o a r e these a t o m i c f r i ends t h a t h a v e v a n q u i s h e d o x y g e n ? T h e r e a r c t w o of t h e m — s i l i c o n a n d c a r b o n . Bo th of t h e m seize oxygen , ho ld it m u c h faster t h a n i ron a n d bu i ld very s t rong s t ruc tu re s wi th it . A n d they h e l p o n e a n o t h e r . W h i l e b u r n i n g , c a r b o n takes tin- oxygen a w a y f rom t h e i ron a n d deve lops a t r e m e n d o u s t e m p e r a t u r e ; it cou ld n o t d o t he w h o l e j o b by itself, h o w e v e r , because t h e h a r d i ron o re is r e f r ac to ry a n d no t very mob i l e , a n d the a t o m s of c a r b o n c a n n o t p e n e t r a t e in to t h e d e n s e l u m p s of ore .

T h i s is w h e n silicon comes to the a i d : small a n d t enac ious it yields fusible slags, dissolves t he ore , takes a w a y the oxygen a n d h a n d s it over to t h e c a r b o n . P a r t of t he c a r b o n dissolves in t he i ron a n d m a k e s it m o b i l e a n d fusible .

A t this t i m e t h e e l e m e n t s s tep i n : t h e (ire increases t he mobi l i ty of t he i ron, all t h a t is l ight rises to the su r face t o g e t h e r wi th t he gases, all t h a t is heavy settles to t he b o t t o m , a n d beho ld t he m i r a c l e : the a t o m s h a v e separa ted— the iron wi th the dissolved c a r b o n takes its p l ace a t the b o t t o m of t he f u r n a c e , whi le t he l ight slags wh ich h a v e ca r r i ed olf all of t he ore ' s oxygen f loat on t he su r face of t he me l t ed m e t a l a n d can be easily t h r o w n ou t .

I m a g i n e t he k n o w l e d g e t h a t h a d to be a c c u m u l a t e d , t he ins ight in to the hab i t s a n d w h i m s of each a t o m t h a t h a d to be a c q u i r e d for m a n to be ab l e u n m i s t a k a b l y to sort the a t o m s a t will on so g r a n d a scale!

* * *

Let us n o w take a look a t t he th i rd p i c tu re the Sovie t a u t o m o b i l e X I L - i 10. It is also a c o m b i n a t i o n ol a t o m s p icked for a s ingle p u r p o s e , i.e., to p r o d u c e an u n t i r i n g , power fu l , noiseless a n d fast ca r .

Meta l lu rg ica l p lan t

T h o u s a n d s of p a r t s m a d e of 65 k inds of a t o m s a n d a t least 100 g r a d e s of m e t a l t h a t ' s w h a t Z I L - 1 1 0 is! I t has a lot of i ron , b u t i r on w h o s e p rope r t i e s h a v e b e e n c h a n g e d 100 d i f f e r e n t w a y s ; h e r e is p i g i r on , a n i r on a l loy c o n t a i n i n g 4 pe r cen t c a r b o n ; this is t h e i ron f r o m w h i c h t h e b o d y of t h e m o t o r was eas t . B u t h e r e is a n i ron in w h i c h less c a r b o n was left , a n d the resul t is a h a r d a n d e las t ic steel . N o w s o m e a t o m s of m a n g a n e s e , n ickel , c o b a l t a n d m o l y b d e n u m , w h i c h resemble ' i ron , w e r e a d d e d to it a n d the steel has b e c o m e elast ic , d u r a b l e a n d shock-proof . T h e n s o m e v a n a d i u m was a d d e d a n d t h e steel h a s b e c o m e as p l i ab le as a w h i p ; tireless spr ings a r e m a d e of this steel .

I t is n o l onge r c o p p e r , b u t a l u m i n i u m t h a t n o w holds second p l ace in t h e c a r ; t he pis tons a n d knobs , t he g r a c e f u l bodies , t h e p l a t i n g a n d b a n d s — a l l t h a t c a n b e m a d e l ight is m a d e of a l u m i n i u m o r its al loys wi th c o p p e r , si l icon, z inc a n d m a g n e s i u m .

A n d h o w a b o u t t h e best po rce l a in used in t he m a n u f a c t u r e of a u t o -m o b i l e s p a r k p l u g s ? A n d w h a t a b o u t t he va rn i sh t h a t fears n o r a i n or co ld , t h e wool lens , t h e c o p p e r in t he wi r ing , the lead a n d s u l p h u r in t he ba t t e r i e s? E n o u g h , o r we shal l n o t find a s ingle e l e m e n t t h a t

ZII.-110 passenger car bui l t by the Moscow L ikhachov M o t o r W o r k s

36

does not t ravel wi th t he ea r . C o m b i n i n g wi th each o t h e r they fo rm m o r e t h a n 250 d i f f e r en t subs tances a n d m a t e r i a l s wh ich a r e d i r ec t ly o r ind i rec t ly used in the a u t o m o b i l e i ndus t ry .

It shou ld be e m p h a s i z e d t h a t he r e m a n d i s r ega rds the n a t u r a l p roc-esses, b r e a k s t h e m a n d s u b o r d i n a t e s t h e m to his o w n will. Is it a t

all n a t u r a l fo r a l u m i n i u m to be f r e e ? N o , a t h o u s a n d t imes n o ; a n d if it w e r e n o t for t he gen ius of m a n this w o u l d neve r h a p p e n even if t h e e a r t h existed m a n y m o r e mi l l ions of years .

H a v i n g u n d e r s t o o d a n d l e a r n e d the p r o p e r t i e s of a t o m s m a n has t a k e n a d v a n t a g e of his k n o w l e d g e a n d shifts t he e l emen t s as h e sees

37

Weight content of elements in the earth's crust (down to a depth of [6 km.)

(it. T h e l ight e l e m e n t s a r e t h e mos t w i d e s p r e a d in t he e a r t h ; five of t h e m oxygen , sil icon, a l u m i n i u m , i ron a n d c a l c i u m - m a k e u p 90 .03 per cent of t h e e a r t h ' s c rus t . I f we a d d seven m o r e - s o d i u m , p o t a s s i u m , m a g n e s i u m , h y d r o g e n , t i t a n i u m , c a r b o n a n d ch lo r ine - these twelve e l emen t s will cons t i t u t e 99 .29 p e r cen t . The . ' r e m a i n i n g 80 e l e m e n t s h a r d l y m a k e u p 0.7 p e r cen t by we igh t . Bu t this d i s t r i b u t i o n does n o t sui t m a n w h o s t u b b o r n l y searches for t he r a r e e l emen t s , ex t rac t s t h e m f r o m t h e e a r t h , a t t imes wi th i nc red ib l e diff icul t ies , m a k e s a n a l l - r o u n d s t u d y of the i r p r o p e r t i e s a n d uses t h e m w h e r e v e r necessary a n d e x p e d i e n t . T h a t ' s w h y we f ind nickel (of w h i c h the e a r t h con t a in s 0.02 per cen t ) , coba l t (wh ich fo rms 0.001 pe r c e n t ) , m o l y b d e n u m (less t h a n 0.001 pe r cen t ) a n d even p l a t i n u m (wh ich cons t i tu tes 0 . 0 0 0 0 0 0 0 1 2 per cen t of t h e e l emen t s ) in t he a u t o m o b i l e .

T h e a t o m s a r e all a r o u n d , a n d m a n is the i r mas t e r . H e takes t h e m wi th his mas t e r fu l h a n d , mixes t h e m , casts a w a y t h e ones he has n o use for a n d c o m b i n e s those h e needs;, t h o u g h w i t h o u t h i m these ele-m e n t s shou ld neve r m e e t . A n d whi l e t h e m o u n t a i n l ake in T a j i k i s t a n glorifies t he p o w e r f u l n a t u r a l e l e m e n t s w h i c h h a v e ra ised t h e cliffs a n d c r e a t e d t h e gaps , t he mill a n d a u t o m o b i l e a r e a n i n d u s t r i a l sym-p h o n y a b o u t t h e m i g h t of the h u m a n genius , a b o u t h u m a n l a b o u r a n d k n o w l e d g e .

ItlKTH AND BEHAVIOUR OF TIIE ATOM IN THE UNIVERSE

I r c inc i i ihc r a lovely a n d q u i e t n i g h t in t he C r i m e a . It seemed all n a t u r e h a d g o n e to s leep a n d n o t h i n g d i s t u r b e d the s m o o t h surface ol t he p lac id sea. Even the s tars d id no t twink le in t he b lack sou the rn sky, b u t shone b r igh t ly . S i lence re igned all a r o u n d a n d it seemed the wor ld h a d ceased m o v i n g a n d stood still in t he inf in i te cairn ol the s o u t h e r n n igh t .

Bu t h o w fa r this p i c t u r e is f r o m rea l i ty a n d h o w decep t ive t he peace a n d q u i e t of s u r r o u n d i n g n a t u r e !

Suff ice it to beg in d i a l i ng a r ad io - r ece ive r to f ind t h a t t he wor ld is p ie rced by m y r i a d s of e l e c t r o m a g n e t i c waves. N o w several met res , n o w t h o u s a n d s of k i lomet res long, t he s t o r m y waves of wor ld e the r rise to t he he igh t of t he ozone s t r a t a a n d p o u n c e u p o n the ea r th a g a i n . P i l ing u p on t o p of each o t h e r t h e v fill t he wor ld with osc i l la t ions i m p e r c e p t i b l e to t h e u n a i d e d ea r .

A n d the s tars wh ich a p p e a r so i m m o v a b l e in t he f i r m a m e n t rush t h r o u g h wor ld space a t t h e te r r i f ic speed of h u n d r e d s a n d t h o u s a n d s of k i lomet res pe r second . O n e sun-s t a r h e a d s in o n e d i r ec t i on of the ga l axy c a r r y i n g a w a y s t r e a m s of bodies invisible to t h e eye ; o the r s whi r l a t a n even fas te r r a t e a n d c r e a t e e n o r m o u s n e b u l a e ; still o thers speed i n t o u n k n o w n reg ions of t he un iverse .

V a p o u r s of i n c a n d e s c e n t subs tances rush t h r o u g h t h e s te l lar a tmos -p h e r e w i t h a veloci ty of t h o u s a n d s of k i lomet res p e r second , a n d it takes on ly several m i n u t e s for i m m e n s e gaseous c louds m e a s u r i n g t h o u s a n d s of k i lomet res to a p p e a r a n d to f o r m g l i t t e r ing p r o m i n e n c e s in t he c o r o n a of t h e sun .

T h e m e l t is bo i l ing in t h e i m m e a s u r a b l e d e p t h s of t h e d i s t an t s tars . T h e t e m p e r a t u r e t h e r e r u n s as h i g h as scores of mil l ions

Evening on the Crimean seashore near Alupka

BflftMS

of deg rees ; i n d i v i d u a l par t ic les b r e a k a w a y f r o m o n e a n o t h e r , t he nuc le i of t h e a t o m s bu r s t , s t r e a m s of e lec t rons r u s h t o t h e u p p e r layers of t h e s te l lar a t m o s p h e r e s , w h i l e p o w e r f u l e l e c t r o m a g n e t i c s to rms t r ave l t h o u s a n d s of mi l l ions of k i lomet res , r e a c h o u r e a r t h a n d d i s t u r b t h e c a l m of its a t m o s p h e r e .

T h e cosmos is filled w i t h osci l lat ions, a n d L u c r e t i u s C a r u s , o n e of t h e g rea tes t scientists of t h e pas t , b e a u t i f u l l y said a l m o s t o n e h u n d r e d years B. C . :

" . . . n o rest , w e m a y b e sure , is a l lowed to t he first-bodies m o v i n g t h r o u g h t h e d e e p vo id , b u t r a t h e r p l i ed wi th u n c e a s i n g , d iverse m o t i o n , some w h e n t h e y h a v e d a s h e d t o g e t h e r l e a p b a c k a t g r e a t s p a c e a p a r t , o the r s t oo a r e t h r u s t b u t a shor t w a y f r o m t h e b l o w . "

O u r e a r t h is also l iv ing its life. I t s q u i e t a n d seeming ly s i lent su r f ace is real ly r ep l e t e w i t h v i ta l ac t iv i ty . Mi l l ions of m i n u t e s t b a c t e r i a p o p u l a t e e a c h c u b i c c e n t i m e t r e of t h e soil. E x t e n d i n g t h e possibil i t ies of r e sea r ch t h e mic roscope reveals n e w w o r l d s of even sma l l e r l iving be ings , t h e cons t an t ly m o v i n g viruses, a n d t h e ques t i on n o w is w h e t h e r t h e y

t P E K E T S H S

shou ld b e cons ide red l iving be ings o r r e m a r k a b l e molecu les ol i n a n i m a t e n a t u r e .

T h e molecu les shif t e t e rna l ly in t h e t h e r m a l m o v e m e n t s of t h e sea, a n d scient if ic analys is shows t h a t e a c h osci l la t ion i n s e a - w a t e r t ravels a l ong a n d c o m p l i c a t e d course a t speeds m e a s u r e d in k i lomet res pe r m i n u t e .

T h e a i r a n d the e a r t h e t e rna l ly e x c h a n g e a t o m s . A t o m s of h e l i u m v a p o r i z e f r o m t h e d e p t h s of t h e e a r t h ' s c rus t i n t o t h e a i r ; t h e ve loc i ty of the i r m o v e m e n t is so h i g h t h a t t h e y o v e r c o m e g r a v i t y a n d fly a w a y i n t o i n t e r p l a n e t a r y space .

T h e m o b i l e a t o m s of o x y g e n e n t e r t h e o r g a n i s m s f r o m t h e a i r ; mo lecu le s of c a r b o n d i o x i d e a r e b r o k e n u p b y p l a n t s t hus c r e a t i n g a c o n t i n u o u s c a r b o n cycle, w h i l e m o l t e n h e a v y rocks a r e still bo i l ing i n t h e in t e r io r of t h e e a r t h a n d a r e t r y i n g to b r e a k t h r o u g h to t h e su r face .

A c l ea r a n d t r a n s p a r e n t crys ta l lies be fo re us h a r d a n d mot ionless . I t w o u l d seem t h a t t h e i n d i v i d u a l a toms-of t h e s u b s t a n c e w e r e d i s t r i b u t e d t h r o u g h s t r ic t ly fixed un i t s of some i n v a r i a b l y s t r o n g la t t ice . B u t th is is on ly a p p a r e n t : t h e a t o m s a r e i n c o n s t a n t m o t i o n , r evo lv ing a r o u n d t he i r po in t s of e q u i l i b r i u m , c o n t i n u o u s l y e x c h a n g i n g the i r e lec t rons n o w f r e e as in t h e a t o m s of a m e t a l a n d n o w b o u n d ; a n d t h e y m o v e a l o n g c o m p l e x l y r e c u r r i n g orb i t s .

E v e r y t h i n g is a l ive a r o u n d us. T h e p i c t u r e of t h e q u i e t e v e n i n g in t h e C r i m e a is decep t ive , a n d the m o r e o u r sc ience m a s t e r s n a t u r e t h e w i d e r t he r e a l p i c t u r e of all t h e m o v e m e n t s of t h e w o r l d s u b s t a n c e

Pro tube rances on the sun d u r i n g the eclipse of M a y 28, 1900. W h i t e circle shows size of the ear th on the s ame scale; its d i a m e t e r is 12,750 km.

41

tha t s u r r o u n d s us o p e n s u p b e f o r e us. A n d w h e n science l e a r n e d to m e a s u r e mo t ion w h i c h occurs in mi l l ion ths of a second , w h e n it b e g a n wi th its n e w R o e n t g e n " h a n d s " to m e a s u r e mi l l ion ths of a c e n t i m e t r e wi th a n a c c u r a c y wi th w h i c h we c a n n o t even use o u r ya rds t i ck , a n d w h e n it l e a rned to m a g n i f y the p ic tu res of n a t u r e 200 ,000 a n d 300 ,000 t imes a n d b r o u g h t w i th in m a n ' s vision "not on ly t h e m i n u t e s t viruses, bu t even ind iv idua l molecules of subs t ance , it d a w n e d on us t h a t t he re was n o ca lm in t he w o r l d , b u t only a chaos of c o n s t a n t m o v e m e n t s wh ich seek the i r t e m p o r a r y e q u i l i b r i u m .

O n c e u p o n a t ime , very long ago , even be fo re t he h e y d a y of a n c i e n t Cireece, t he re lived a r e m a r k a b l e p h i l o s o p h e r whose, n a m e was H c r a c l i -tus. Wil l i his pe rsp icac ious m i n d he was ab l e to p e n e t r a t e in to t h e vcrv d e p t h s of t he un iverse , a n d he said t h e w o r d s w h i c h H e r z e n ca l led the mos t b r i l l i an t w o r d s in h u m a n his tory .

H e r a c l i t u s s a id : " E v e r y t h i n g is f l u i d , " a n d m a d e the idea of e t e r n a l m o t i o n the basis of his wor ld sys tem. W i t h this i dea h u m a n i t y has gone t h r o u g h all t h e stages of its h is tory . It was on this idea t h a t L u -cre t ius C a r u s bu i l t his ph i lo sophy in t he r e m a r k a b l e p o e m on t h e n a t u r e of th ings a n d the his tory of t h e w o r l d . T h e b r i l l i an t R u s s i a n scientist M i k h a i l L o m o n o s o v bu i l t his physics wi th r a r e pe r sp icac i ty on this idea , say ing t h a t each po in t in n a t u r e has t h r e e m o v e m e n t s : t r ans l a t i ona l , r o t a t o r y a n d osci l la tory. A n d n o w t h a t t he n e w ach ieve-m e n t s of science h a v e c o n f i r m e d this old ph i losoph ic i dea we m u s t t ake a n e w view of t he s u r r o u n d i n g wor ld a n d t h e laws of m a t -ter.

T h e laws of d i s t r i bu t i on of a t o m s will be for us t h e laws of t he inf ini tely c o m p l e x m o v e m e n t s of d i f f e r e n t velocit ies, d i f f e r e n t d i rec -t ions a n d d i f f e r en t scales w h i c h d e t e r m i n e t he m u l t i f o r m i t y of t he s u r r o u n d i n g wor ld , t he d ivers i ty of its restless a t o m s . T o d a y w e a r e b e g i n n i n g to get a n e w ins ight i n t o space .

T h e p a r t of t he un ive r se accessible to o u r obse rva t ion is colossal . It c a n n o t be m e a s u r e d in k i lomet res , fo r this is too smal l a un i t . E v e n the d i s t ance of 150 mi l l ion k i lomet res be tween the sun a n d the e a r t h , wh ich l ight t raverses in e igh t a n d o n e - t h i r d minu te s , is a lso too smal l a un i t , t h o u g h l ight c a n t r ave l seven a n d a hal f t imes a r o u n d t h e ea r th in o n e second . Scient is ts h a v e i n v e n t e d a n e w un i t , t h e " l i g h t y e a r , " i. e., t he d i s t ance l ight t raverses in o n e yea r . T h e best te lescopes c a n m a k e ou t s tars f r o m w h i c h it t akes l ight mi l l ions of yea r s to r e a c h

4 2

vis. T h e cosmos is real ly inf in i te , h u t as fa r as vvc a r e c o n c e r n e d its l imits a r c set by t he resolving p o w e r of o u r telescopes.

Clus te rs of s te l lar m a t t e r in spacc fo rm local c o n d e n s a t i o n s a n d give rise to w h a t we call t he visible w o r l d . The re a r e a p p r o x i m a t e l y o n e h u n d r e d t h o u s a n d mi l l ion of these wor lds . E a c h of these wor lds also con t a in s a b o u t o n e h u n d r e d t h o u s a n d mi l l ion s tars a n d each s t a r is m a d e u p of I a n d 57 n o u g h t s (if)5 7) of p ro t o n s a n d neu t rons , i.e., t he m i n u t e s t par t ic les of w h i c h t h e w h o l e wor ld is composed , no t c o u n t i n g t h e even sma l l e r pa r t i c les of e lectr ic i ty , t he nega t ive ly c h a r g e d e lec t rons .

H y d r o g e n is t h e m o s t a b u n d a n t e l e m e n t in t he universe . W e know a l a rge n u m b e r of cosmic n e b u l a e c o m p o s e d a lmos t en t i re ly of h y d r o g e n . T h e a t o m s of h y d r o g e n a c c u m u l a t e a t t r a c t e d b y g r a v i t a t i o n a n d impe l l ed by specif ic i n t e r a t o m i c forces, t h e s t u d y of wh ich has only-j u s t b e g u n . P o w e r f u l c lusters cons is t ing of a n u m b e r of a t o m s expressed b y a figure of 56 digi ts ar ise a n d a n e w s ta r m a k e s its a p p e a r a n c e . Bu t t he d imens ions of t he un ive r se a r e inf in i te ly g r e a t c o m p a r e d wi th t h e v o l u m e of t h e a t o m s w h i c h h a v e c o m e in to be ing . W e k n o w t h a t t he g r e a t e r p a r t of t h e un ive r se is a c t u a l l y a sort of vo id c o n t a i n i n g on ly f r o m 10 to 100 par t ic les , i .e., a t o m s of subs t ance , pe r c u b i c m e t r e , a n d this c o r r e s p o n d s to a r a r e f a c t i o n w h i c h is 10 27 t h a t of t h e n o r m a l a t m o s p h e r i c p ressure on e a r t h . H e r e r a r e f i ed spaces a r e f o u n d side b y side wi th abso lu t e ly u n p r e c e d e n t e d c o n d e n s a t i o n s p r o d u c e d by p res su re in t he in te r io rs of s tars w h e r e t h o u s a n d s of mil l ions of a t m o s -p h e r e s a r e c o m b i n e d w i t h scores or h u n d r e d s of mi l l ions of degrees of h e a t ; this is t he n a t u r a l l a b o r a t o r y w h e r e h y d r o g e n gives rise to n e w a n d h e a v i e r a t o m s , p r i m a r i l y h e l i u m .

I n t h e s tars s h i n i n g w i t h a d a z z l i n g w h i t e l ight as, for e x a m p l e , t he f a m o u s sate l l i te of Sirius, t he s u b s t a n c e is so dense t h a t it is a t h o u s a n d t imes as h e a v y as go ld a n d p l a t i n u m . W e c a n even h a r d l y i m a g i n e w h a t this s u b s t a n c e is a n d w h a t p rope r t i e s it has .

O n the o n e h a n d , we h a v e in f in i te i n t e r p l a n e t a r y spaces t raversed by t h e f ree ly flying single a t o m s . H e r e w o r l d rest is in d ia lec t ica l un i ty w i t h p r e c i p i t a t e m o v e m e n t , a n d a t e m p e r a t u r e of a lmos t abso lu t e ze ro re igns .

O n the o t h e r h a n d , w e h a v e t h e c e n t r a l regions of t h e s tars w h e r e mi l l ions of degrees of h e a t a r e c o m b i n e d w i t h pressures of mi l l ions of a t m o s p h e r e s a n d w h e r e t he a toms , h a v i n g o v e r c o m e the repu l s ion

43

of the electrons, are knitted into a single dense mass of substances never seen on earth. Under these conditions the evolution of chemical elements takes place, and the elements are the heavier and denser the greater the mass of the star and the higher the pressure and tem-perature in its interior.

The chemical element which comes into being is the first step in the struggle against chaos. Heavier nuclei may be formed from free protons and electrons at enormous temperatures and pressures.

Various structures, which we call chemical elements, thus gradually arise in different places. Some of them are heavier and have more energy,

N e b u l a M - i o i in the constel la t ion of the Big D i p p e r

others are light and consist of only a few protons and neutrons. These lighter elements are carried away in streams to the periphery of the stars, into their atmospheres or combine into immense world nebulae. Others, which are less mobile, remain on the surface of incan-descent or molten bodies.

Powerful radiations destroy some structures and build, others; some elements disintegrate while others are created anew until the ready-made atoms find themselves where there are 110 forces strong enough to destroy their stable nuclei. This is when the history of the wanderings of individual atoms through the universe begins. Some of them fill the interplanetary spaces as, for example, the atoms of calcium and sodium, which in their free flight traverse the entire

4 4

universe . O t h e r s , w h i c h a r e h e a v i e r a n d s tab le r , a c c u m u l a t e in va r ious p a r t s of t h e n e b u l a e . T e m p e r a t u r e s d r o p , e lect r ica l fields of a t o m s c o m b i n e wi th e a c h o t h e r a n d molecu les of s imp le ch emi ca l c o m p o u n d s a r e f o r m e d ; these i n c l u d e ca rb ides , h y d r o c a r b o n s , par t ic les of ace ty l ene a n d s o m e subs tances u n k n o w n on e a r t h wh ich the as t rophys ic is t s obse rve 011 the i n c a n d e s c e n t sur faces of d i s t an t s tars as t he first p r o d -uc t of atomic, c o m b i n a t i o n s . These s imple free molecules g r a d u a l l y give rise to m o r e a n d m o r e h a r m o n i o u s systems. At low t e m p e r a t u r e s , ou t s ide t he des t ruc t ive fields a n d cosmic d e p t h s , t he second s tep in t h e wor ld o r d e r the crysta l is f inally b o r n . A crystal is a r e m a r k a b l e s t r u c t u r e w h e r e the a t o m s a r e a r r a n g e d in a ce r t a in o rde r ly re la t ion to each o t h e r , like bu i ld ing-b locks in a box. T h e b i r th of a crysta l is t h e nex t s tage in the process of t he e m e r g e n c e of m a t t e r f r om chaos . i o ~ i n d i v i d u a l a t o m s c o m b i n e to lo rm a c u b i c c e n t i m e t r e of crys-ta l l ine subs t ance . N e w proper t i es , t he p rope r t i e s of crystals , m a k e the i r a p p e a r a n c e . N o w it is n o longer t he laws of t he e l e c t r o m a g n e t i c c lus ters of wh ich they a r e c o m p o s e d , not t he yet u n k n o w n laws of n u c l e a r ene rgy t h a t gove rn , but n e w laws of m a t t e r , the laws of chemis t ry .

I shall not c o n t i n u e t he desc r ip t ion of this p i c tu re . I on ly w a n t e d to show tha t we h a v e very litt le k n o w l e d g e of t he wor ld tha t s u r r o u n d s us, t h a t this wor ld is u n c o m m o n l y c o m p l e x a n d its c a l m is only a p p a r e n t because it is rep le te wi th m o t i o n ; m a i l e r as we know it he r e on e a r t h , as we see it in h a r d s tone in s u r r o u n d i n g n a t u r e , c o m e s in to the wor ld in a whir l of m o t i o n . M u c h of wha t I h a v e said has a l r e a d y been d e m o n s t r a t e d by m o d e r n science, bu t a good deal of how first t h e a t o m a n d then the crystal c o m e in to be ing f rom wor ld chaos is as yet a mys te ry to us.

And still, h o w beau t i fu l ly this p i c t u r e was p a i n t e d by Luc re t iu s C a m s , t he R o m a n ph i lo sophe r , t w o t h o u s a n d years a g o ! Let us recall a few lines f rom his p o e m :

"Hut on ly a sort of I resh- fbr ined s t o r m , a mass g a t h e r e d t o g e t h e r of l i rs t -begi i inings of every k ind , whose d iscord was w a g i n g w a r a n d c o n f o u n d i n g in te rspaces , pa ths , in te r lac ings , weights , blows, mee t ings , a n d mot ions , because o w i n g to the i r unl ike forms a n d diverse shapes ,

> all th ings were u n a b l e to r e m a i n in un ion , as they d o now, a n d to give a n d receive h a r m o n i o u s mot ions , f r o m this mass pa r l s began lo llv oil' h i the r a n d th i the r , a n d like th ings l<> un i t e w i fh like, a n d

so to un fo ld a w o r l d , a n d to s u n d e r its m e m b e r s a n d dispose its g r e a t pa r t s . . . . "

A n d so t he re is n o rest in n a t u r e ; e v e r y t h i n g c h a n g e s even if a t d i f f e r en t ra tes . S tone , t he s y m b o l of d u r a b i l i t y , also c h a n g e s because t he a t o m s of w h i c h it is c o m p o s e d a r e in e t e rna l m o t i o n . T o us it a p p e a r s f i rm a n d mot ion less on ly b e c a u s e we d o no t see this m o t i o n t h e results of w h i c h b e c o m e p e r c e p t i b l e a long t i m e a f t e r w a r d s , w h e r e a s we ourselves c h a n g e m u c h fas ter .

It was long bel ieved t h a t on ly t he a t o m was indivis ible , i n v a r i a b l e a n d indi lTerent t o e t e r n a l c h a n g e . Bu t lo a n d b e h o l d ! a t o m s , too, a r e heed fu l of t ime . S o m e of t h e m , we call t h e m r a d i o a c t i v e , c h a n g e fas t ; o the r s c h a n g e slowly. M o r e o v e r , we k n o w n o w t h a t a t o m s also evolve, t h a t t hey a r e c r e a t e d in t he h e a t of t h e stars, t h a t t h e y d e v e l o p a n d die . . . .

A n d the h u m a n m i n d reflects t h e s a m e e t e rna l m o t i o n a n d d e v e l o p -m e n t : a t first i n c o m p r e h e n s i o n , c h a o s a n d lack of o r d e r . T h e n t h e types of c o n n e c t i o n s b e t w e e n all p a r t s of t he wor ld beg in to g r o w c lear , t he m o v e m e n t s p r o v e sub jec t lo laws, a n d a h a r m o n i o u s p i c t u r e of a n indivis ible un ive r se p resen t s itself to m a n . S u c h is t h e w o r l d as m o d e r n science reveals it to us.

HOW MENDELEYEV DISCOVERED HIS LAW

I n t he old b u i l d i n g of t he chemica l l a b o r a t o r y of Pe t e r sbu rg U n i -vers i ty sa l a y o u n g t h o u g h a l r e a d y we l l -known professor . It was D m i t r y M e n d e l e y e v . H e h a d just been a p p o i n t e d h e a d of t he d e p a r t m e n t of gene ra l c h e m i s t r y a t t he univers i ty a n d was busy d r a w i n g u p a s tudy p l a n for his s t uden t s . H e was t h i n k i n g of h o w he migh t most conven i en t l y set for th the laws of chemis t ry , desc r ibe the his tory of t he s e p a r a t e e l emen t s a n d p roceed wi th t he course ol s tudy . l i e was w o n d e r i n g how he m i g h t c o n n e c t his stories a b o u t po ta s s ium, s o d i u m , l i t h i u m , i ron, m a n g a n e s e , nickel , etc. I le a l r e a d y h a d a feel ing the s e p a r a t e chem ica l a t o m s were in some w a y re la ted to each o t h e r t h o u g h these re la t ions were no t c lea r as yet .

In o r d e r lo f ind t he best possible a r r a n g e m e n t he took s e p a r a t e c a rd s a n d w r o t e in big let ters the n a m e of a n e l e m e n t , its a t o m i c we igh t a n d some of its chief p rope r t i e s on each c a r d . T h e n he began lo a r r a n g e these ca rd s by g r o u p i n g the e l emen t s a c c o r d i n g to the i r p roper t i e s a b o u t till' w a y o u r g r a n d m o t h e r s used to a r r a n g e the i r c a rd s w h e n p l ay ing pa t i ence .

S u d d e n l y the professor observed a r e m a r k a b l e r egu la r i t y . l i e h a d a r r a n g e d his chemica l e l e m e n t s o n e a f t e r a n o t h e r in t he o r d e r ol increas-ing a t o m i c weights a n d d iscovered t h a t wi th but few excep t ions the p rope r t i e s ol the e l emen t s r e c u r r e d a t ce r t a in in tervals . l i e then began to lay out m o r e ca rd s be low the first row a n d a l t e r p l a c i n g seven ele-m e n t s s t a l l ed on the th i rd row.

In this row he h a d lo put a l r e a d y seven teen e l emen t s in o r d e r that the e l emen t s s h o w i n g a n y s imi lar i t ies be a r r a n g e d one be low a n o t h e r , but s o m e h o w it d id not c o m e out q u i t e right a n d lie h a d to leave gaps . Seven teen m o r e ca rd s m a d e a n o t h e r row. 11 was ge t t i ng m o r e compl i -

•17

cated; several atoms just would not fit though the recurrence of properties was clearly observed.

All the e lements k n o w n to D . M e n d e l c y e v were , thus , a r r a n g e d in the fo rm of a t ab le a n d wi th b u t few except ions they all fol lowed each o ther in hor i zon ta l rows in t h e o rde r of the i r increas ing a t o m i c weights , while the s imi lar e lements f o u n d themselves a r r a n g e d in ver t ica l co lumns .

I n M a r c h 1869, D . M e n d e l e y e v sent t he first brief r epor t 011 his law to the Phys ico-Chcmica l Society in Pe te rsburg . T h e n , sensing the e n o r m o u s i m p o r t a n c e of his discovery, he b e g a n work ing persistently, co r rec t ing his t ab le a n d m a k i n g it m o r e exact . H e soon f o u n d b lanks in the table .

" N e w substances will soon be found for these b l ank spaces fo l lowing silicon, bo ron a n d a l u m i n i u m , " he would say. His predic t ions soon c a m e t rue a n d the newly discovered e lements n a m e d ga l l ium, ger-m a n i u m a n d s c a n d i u m were p laced in the v a c a n t squares of t he table .

O n e of the greates t discoveries in the history of chemis t ry was, thus , m a d e by the Russ ian chemis t 1). Mende leyev . Hut d o n ' t th ink it is so s imple, my f r i ends ; t ha t all you have to d o is t ake cards , wri te n a m e s on them, a r r a n g e t hem in a cer ta in o r d e r a n d the th ing is done . T h i s s implici ty , this c h a n c e discovery, as it were , is only a p p a r e n t . O n l y 62 e l emen t s w e r e k n o w n a t tha t t ime. The a t o m i c w eights were d e t e r m i n e d inaccura te ly , some of t h e m wrongly , a n d the proper t ies of t he a t o m s were but little k n o w n . M a n had to get a n insight in to the n a t u r e of each chemica l subs tance , g rasp the similari t ies be tween some of the e lements , d iv ine the course of each e l emen t ' s migra t ions , the " f r i e n d -s h i p " or "hos t i l i t y " of the e lements in the ea r th itself.

I). Mende leyev succeeded in kn i t t ing in to a single whole all t ha t had been known of the chemis t ry of the e a r t h before h im.

T o be sure, the re were also o the r scientists w h o not iced a re la t ion-ship between the e lements t hough the i r ideas abou t it were still v a g u e a n d imperfec t .

Hut most scientists ol t ha t l ime though t the idea of kinship be tween the e lements ab su rd . Thus, when the English chemist N e w l a n d s , one ol the f ighters lor the f r eedom of I taly in ( i a r i b a l d i ' s a r m v , sub-mi t t ed to the press a p a p e r on the r ecu r r ence ol the p roper t i es ol cer la i i^ e lements with an increase in their a t o m i c weights his p a p e r was re jec ted by the Chemica l Society a n d one of the chemists tried lo r id icule

,|8

Newlands by saying he might have arrived at an even more interesting conclusion if he had arranged all the elements in alphabetic order.

But all these were only particulars. Science still needed a lot more: ii had to draw up a single plan, a funda-mental law- of the universe, and show by facts that this law was valid everywhere, that all the properties of each element were governed by this law, were subject to it and had their source in it.

This required intuition of a genius, ability to see what was common to the elements, despite the discrepancies, and persistence in investigating concrete facts. D. Mendeleyev proved equal to the task.

He was able to show the inter-relations of all the atoms in nature so clearly, distinctly and simply that nobody could disprove his system. The order had been found. True enough, the bonds which linked these elements with each other were still a mystery, but the order was so obvious that it enabled Mendeleyev to speak of a new natural law—the Periodic Law of chemical elements.

Many years have elapsed since then. D. Mendeleyev worked on this law for nearly 40 years penetrating into the deepest mysteries of chemistry.

In the Chamber of Weights and Measures, which he headed, he studied and measured the various properties of metals, by most accu-rate methods, finding ever more confirmation of his discovery.

He travelled through the Urals studying its resources and devoted many years to the problem of oil and its origin; everywhere, in the laboratory and in nature, he found confirmation of his Periodic Law. In the profoundest theories and in industry this law was being transformed into a guiding compass which directed the searches of scien-tists and men of practice like a compass guides the seafarers at sea.

D . M e n d e l e y e v . Pho tog raph m a d e in 1869

4 49

D. Mendeleyev

n

Tlic periodic system of elements . T h e original table produced hy I) . Mendeleyev in 1869

I). Mende l eyev correc ted a n d improved his lit t le t ab ic of 1869 unt i l the very last days of his life; h u n d r e d s of chemists , fol lowing in his footsteps, discovered new e lements a n d n e w c o m p o u n d s g r a d u a l l y d iv in ing the p ro found inne r m e a n i n g of Mende l eyev ' s table .

T o d a y we see it in a n ent i re ly new l ight . I). Mende leyev ' s Periodic. T ab le p roved an excel lent gu ide to the s tudy

of the regular i t ies of the s t ruc tures of a t o m i c spect ra . W h i l e s tudy ing the spect ra of e lements a r r a n g e d in the o r d e r of Mendeleyev's Per iodic T a b l e I leriry Moseley, young British physicist, qu i t e unexpec ted ly discovered one more regular i ty in Mende leyev ' s Per iodic T a b l e in 1913, a n d ascer ta ined the. i m p o r t a n t role of the a t o m i c n u m b e r s of e lements .

j<>

EXPERIMENT IN THE SISTEM OF ELEMENTS

Based on The i r A tomic Weights and

Chemical S i m i l a r i t i e s

H e p r o v e d t h a t t h e mos t i m p o r t a n t p a r t of t h e e l e m e n t w a s t h e c h a r g e on t h e cen t r a l nuc l eus w h i c h exac t ly eq u a l s t h e e l e m e n t ' s a t o m i c n u m b e r . I t e q u a l s o n e in h y d r o g e n , t w o in h e l i u m , t h i r t y in z inc a n d n i n e t y - t w o in u r a n i u m ; j u s t as m a n y e lec t rons a r e t ied by these c h a r g e s to t he nuc l eus a n d rush a r o u n d t h e l a t t e r in t he i r orb i t s .

I n every a t o m the n u m b e r of e l ec t rons s u r r o u n d i n g t h e n u c l e u s e q u a l s t h e a t o m i c n u m b e r of t he e l e m e n t . All e l ec t rons a r c ve ry def in i te ly a r r a n g e d in s e p a r a t e layers . L a y e r K , first a n d closest to t h e nuc leus , c o n t a i n s f ine e l ec t ron in h y d r o g e n a n d t w o e lec t rons in all t h e o t h e r e l e m e n t s . T h e second l aye r L c o n t a i n s e ight e l ec t rons in mos t a t o m s . L a y e r M m a y h a v e u p to 18 e lec t rons , l aye r N u p to 32.

T h e c h e m i c a l p r o p e r t i e s of a t o m s a r e d e t e r m i n e d m a i n l y by t h e s t r u c t u r e of t he o u t e r m o s t e l ec t ron l ayer w h i c h is p a r t i c u l a r l y s t a b l e wl fcn t h e n u m b e r of e lec t rons in it r e a c h e s e igh t . The a t o m s w i t h o n e o r t w o e lec t rons in the i r o u t e r m o s t l ayer easily give t h e m u p a n d c h a n g e to ions. F o r e x a m p l e , s o d i u m , p o t a s s i u m a n d r u b i d i u m h a v e o n e e lec t ron each in the i r o u t e r m o s t layers . T h e y lose t h e m ve ry easily a n d c h a n g e to u n i v a l e n t posi t ively c h a r g e d ions. U n d e r t h e c i r c u m -s tances t h e nex t e lec t ron l ayer b e c o m e s t h e o u t e r layer . T h i s layer c o n t a i n s 8 e lec t rons wh ich ensures t he s tab i l i ty of t h e i o n - a t o m .

T h e a t o m s of c a l c i u m , b a r i u m a n d o t h e r a l k a l i n e - e a r t h m e t a l s h a v e t w o e lec t rons in the i r o u t e r m o s t layers e a c h , u p o n losing w h i c h they b e c o m e s t ab l e b i v a l e n t posi t ive ions. T h e a t o m s of b r o m i n e , c h l o r i n e a n d o t h e r ha logens h a v e seven e lec t rons in the i r o u t e r m o s t layers . T h e y g reed i ly c a p t u r e e lec t rons f r o m t h e o u t e r m o s t layers of o t h e r a t o m s a n d by r e p l c t i n g the i r o w n o u t e r m o s t layers to e ight e l ec t rons b e c o m e s tab le n e g a t i v e ions.

T h e e l e m e n t s wi th th ree , f ou r a n d live e lec t rons in t he i r o u t e r m o s t layers d i sp lay a lesser t e n d e n c y to f o r m ions in c h e m i c a l reac t ions .

The w e i g h t of t he a t o m a n d t h e f r e q u e n c y of its o c c u r r e n c e in n a t u r e d e p e n d on the s t r u c t u r e of its nuc leus , wh i l e its c h e m i c a l p r o p e r t i e s a n d s p e c t r u m a r e d e p e n d e n t on t h e n u m b e r of its e l ec t rons a n d a r e e x t r a o r d i n a r i l y s imi la r in e l e m e n t s w i t h like s t r u c t u r e s of t h e o u t e r m o s t e l ec t ron layers .

S u c h is t h e mys te ry of t h e a t o m . S ince this mys t e ry was r evea led chemis t s a n d physicists, gcochcmis l s a n d a s t r o n o m e r s , t e chn i c i ans a n d technologis t s h a v e recogn ized M e n d e l e y e v ' s Pe r iod i c L a w as o n e of the p r o l o u n d e s t laws ol n a t u r e .

D . I . M E N D E L E Y E V ' S P E R I O D I C

PERIODS SERIES E L E M E N T

PERIODS SERIES I (1 m IV V 1 I H 1

1 . 0 0 8 0 •

2 II Li 3

6 . 9 4 0 2

Be 4

9 . 0 1 3 2

5 B 1 1 0 . 8 2

6 C 2 12.011

7 N 2 1 4 . 0 0 8

3 III Na n , 2 2 . 9 9 1 2

M g 1 2 2

2 4 . 3 2 2

3 13 Al

2 2 6 . 9 8

j 14 Si 2 2 8 . 0 9

5 1 3 P 2 3 0 . 9 7 5

4 IV K

19 J 8

3 9 . 1 0 0 2

Ca20 ! 8

4 0 . 0 8 2

Sc 21 i 8

4 4 . 9 6 2

Ti 22 ,zo 4 7 . 9 0 2

V 23 ?, 8

5 0 . 9 5 2

4 V i

29 Cu ! 6 3 . 5 4

,S 30 Zn 2 6 5 . 3 8

31 Ga 2 6 9 . 7 2

.1 32 Ge 2 7 2 . 6 0

33 As 2 7 4 . 9 1

5 VI

37 < Kb « 8 5 . 4 8 2

38 I c 8 br is 8

8 7 . 6 3 2

Y 39 1 8

8 8 . 9 2 2

__ 4 0 2

Zr 3 9 1 . 2 2 2

41 1

Nb \l 8

9 2 . 9 1 2 5 VII

1 4 7 . S A? 2 1 0 7 . 8 8 0

s 48 Cd 8 2 112.41

3 4 9

s In 2 114 .76

4 50 _ 1! Sn 2 118.70

s 51 Sb 2 121 .76

6 VIII

5 5 1

Cs | 132.91 2

5 6 2

Ba 3 1 3 7 . 3 6 2

5 7 2

La * i s

1 3 8 . 9 2 2

72 2

Hf 3 8

1 7 8 . 6 2

73 2

Ta % 8

1 8 0 . 9 5 2 6 IX

i 79

?! Au 2 1 9 7 . 0

2 8 0

i H ^ ! 2 0 0 . 6 1

3 81 18

fs T1 2 2 0 4 . 3 9

4 82 <8

if Pb 8 2 2 0 7 . 2 1

5 83 18

% Bi a 2 2 0 9 . 0 0

7 X 87 ;

_ 18 Fr 32 1 1 18

[ 2 2 3 ] \

88 2

Ra S 18 2 2 6 . 0 5 i

89 2

i 18 Ac ** ^ 2 2 7 2

(Th) (Pa)

* L A N T H A 5 8 |

Ce S 140.13 2

5 9 »

Pr i 140.92 '

6 0 2

Nd £ 144.27 ®

61 2

Pm ?! [145] 2

6 2 2

Sm i 150.43 2

6 3 |

EU ft 152.0 2

6 4 J

Gd 5 156.9 2

* • A C T I 9 0 2

10 m. ii Th 232 .05 •

91 2 9 20 Pa » 231 S

92 2 9 U S 238.07 '

9 3 2

Np 1 [237] 5

94 2 8 24

Pu S [242] S

95 2

Am 1 [ 2 4 3 ] 2

9 6 2

Cm 1 [245] 1

Figures in square brackets are mass numbers of stablest isotopes

T A B L E O F E L E M E N T S G R O U P S

VI VII VIII 0

( H ) H e 2

4.003 2

8 0

I I6

9 F

Z 1 9 . 0 0

N e 1 0

2 0 . 1 8 3 2

. 1 6 S

2 3 2 . 0 6 6

7 1 7 C I

2 3 5 . 4 5 7

A r 1 8 i

3 9 . 9 4 4 2

2 4 , Cr IJ

5 2 . 0 1 2

* * 2 5 2 M n IS

5 4 . 9 4 2

F e 2 6 \

5 5 . 8 5 2

2 7 z C o 15

5 8 . 9 4 2

X T - 2 8 2

N l <|

5 8 . 6 9 2

, 1 5 4 S e

! 7 8 . 9 6 i W B r

2 7 9 . 9 1 6

K r 3 6 4

8 3 . 8 0 2

42 1 M o ! i

8 9 5 . 9 5 2

T c I j

[ 9 9 ] 2

4 4 1

R u I I 8

101.1 2

4 5 1

R h I ! 8

102 .91 2

4 6 0

Pd s 8

106 .7 2

<! 5 2 S T e

2 1 2 7 . 6 1

1 5 3 18 - I 18 ' 1

2 126 .91

5 4 X e 18

8 I 3 I . 3 2

7 4 2

w S 8

1 8 3 . 9 2 2

7 5 , 5

R e n 8

1 8 6 . 3 1 2

7 6 2 14

O s fi 8

1 9 0 . 2 2

7 7 2 15

I r S 8

1 9 2 . 2 2

7 8 1

p t 5 8

1 9 5 . 2 3 2

6 8 4 18

8 PO 8 2 2 1 0

1 8 5 18

18 A t

2 [ 2 1 0 ]

8 6 8 18

R n 8 8

2 2 2 2

(U)

N I D E S

65 2

T b ? !

1 5 8 . 9 3 2

66 2

D y S

1 6 2 . 4 8 2

6 7 2

H o ? ! 8

1 6 4 . 9 4 I

6 8 2

E r £ 8

1 6 7 . 2 2

6 9 2

T u ?S 1 6 8 . 9 4 2

7 0 2

Y b 5 8

1 7 3 . 0 4 2

7 1 I

L U S 8

1 7 4 . 9 9 2

n i d e s

9 7

BK [ 2 4 5 ]

9 8

Cf [ 2 4 8 ]

2 99 2 A 100 28 32 18 EN

23 32 <T FM 8 2 [253] 1 2 [255]

101"

M V [256]X

-Atomic number

"Electron layers

Atomic might Symbol

MENDELEYEVS PERIODIC SYSTEM OF ELEMENTS I N O U R D A Y S

Investigators have proposed many different methods whereby the characteristic, features of'Mcndelcyev's Periodic Table might IK: revealed as clearly and distinctly as possible.

Some illustrations in this book show how Mcndelcyev's great law was represented at different times, now as bands and columns now as a twisted spiral on a plane, and now as a complicated pattern of lines and arcs.

We shall come back to the attempt at setting the table forth in the form of a grand spiral later, but now we shall present it as it is presented bv modern science.

Let us look into this table and try to make out what it really means. In the first place we see a big number of squares or boxes which are

arranged in seven horizontal rows (or periods) and in eighteen vertical columns or, as the chemists call them, groups. Incidentally, let us imme-diately observe that in most textbooks this table is given in a somewhat different form (the, rows appear doubled, as it were), but we shall find it more convenient to analyze it the way it is.

The first period contains only two elements—-hydrogen (H) and helium (He); the second and third periods contain eight chemical elements each; there arc 18 chemical elements in each of the fourth, fifth and sixth periods. The boxes of these six periods should be occupied by 72 elements; it turns out, however, that 14 elements similar to lanthanum, so-called lanthanidcs, are inserted between box 57 and box 72. Finally, the last period contains, apparently like the preceding one, 32 boxes but only some of them arc occupied as yet.

.VI

T h e M e n d e l e y e v ' s per iod ic system of e lements as r ep resen ted by Soddy (1914). Hor i -zontal lines show series of e lements wi th similar chemical proper t ies . Big per iods arc shown in the fo rm of eights (8). W h i t e circles contain meta ls , black c i rc les -meta l lo ids . Grev circles show neut ra l e l emen t s (noble gases and e l emen t s y ie ld ing ampho te r i c oxides)

It is hard to conceive the existence of any chemical elements arranged before the first square occupied by hydrogen because the proton and neutron, which form the nucleus of hydrogen, are the fundamental bricks of which the nuclei of all the other elements are built; hydrogen, no doubt, rightly stands at the head of Mendeleyev's Periodic Table. The question about the end of the table is much more complicated. The last place had ' l ong been occupied by uranium.

However, t ransuranium elements have been obtained in some experiments. Consequently, uranium does not terminate Mendeleyev's table. Nine more boxes have been occupied so far beyond uranium; these elements are: neptunium (No. 93), plutonium (No. 94), americ-ium (No. 95), curium (No. 96), berkelium (No. .97), californium (No. 98), einsteinium (No. 99), fermium (No. 100) and mendelevium (No. 101).

As the figures at the top of each box show, each box is numbered. T,he numbers run one after another from one on. They are called the atomic numbers of chemical elements; they are related to

55

the number of electric particles contained in the elements and are, therefore, very important and inalienable properties of each box, each element.

For example, atomic number 30 in the square occupied by zinc w ith an atomic weight of 65.38 is. on the one hand, the ordinal number of the square and shows, 011 the other hand, that the atom of zinc consists of a nucleus with 30 electric particles, called electrons, revolving around it.

Chemists made many vain attempts to find elements Xo. 43, Xo. 61. Xo. 85 and 87 in nature; they analyzed various minerals and s a l t s and tried to discover some as yet unknown lines in their spectra. They made many mistakes, published bombastic articles about dis-coveries of elements, but these four elements have not been found either on the stars or on earth. It has now been possible, however, to prepare them artificially.

One of them, Xo. 43, is supposed to have properties similar to those of manganese. D. Mendelevev named it ekamanganese.

This element has now been synthesized and named technetium. The second element is located below iodine and is designated

bv Xo. 85. It is supposed to have some fabulous properties and be even more volatile than iodine. D. Mendelevev gave it the name of ekaiodine. It has also been synthesized and given the name of astatine.

The third element, which had also been mvsterious for a long time, is shown in our table under X6?' 87. It was predicted by Mendelevev who named it ekacesium. It has been synthesized and named fran-cium.

Finally, the fourth element, which has not been found either 011 the stars or on earth, is Xo. 61. It is one of the rare-earth metals. It has been svnthesized and is now known as promethium.

Today the table of elements is much more complete than it was at the time D. Mendelevev had to make out the complicated picture of nature and draw up his first draft of the table.

As we have already mentioned, each box with a definite number is occupied by one chemical element. Physicists have demonstrated, however, that it is really a much more complicated affair. Thus, accord-ing to the chemical properties, box Xo. 17 contains only one atom of the gas known as chlorine with a small nucleus and seventeen

D. Mcnde!e \ e \ p e r i o d i c sv-tem nf e lements in the f ^ m i ot tirdcN -.ph'-n^ I : c d iamete r s of the iirrle circle^ represent the m/c- of the at^nis and ion-. I r . 1 \\ i: by Y. Biiibin in 194s

electrons which, like planets, surround it on all sides. Meantime, physicists indicate that there are two chlorines: one heavier, and the other—lighter. But since their proportion is equal everywhere t h e i r

mean weight is always 35.46. And here is another example. The familiar box No. 30 is occupied

by zinc. But here, too, physicists point out there are different zincs, some heavier, some lighter, six different kinds in all. It. thus, turns out that though each box contains one chemical element with

5 7

d e f i n i t e n a t u r a l p r o p e r t i e s l l i e r e m a y lie s e v e r a l k i n d s o r " i s o t o p e s "

ol t h i s e l e m e n t . I n s o m e e a s e s t h e r e is o n l y o n e . in o t h e r s the re - a r e

e v e n t e n .

N a t u r a l l y , t h e g e o c h e m i s t s b e c a m e e x t r e m e l y i n t e r e s t e d in t h i s

p h e n o m e n o n . W h y s h o u l d a l l t h e s e i s o t o p e s h e e n c o u n t e r e d in v e r y

d e f i n i t e a m o u n t s a n d w h y a r e t h e r e n o t m o r e of t h e h e a v y e l e m e n t

in s o m e p l a c e s a n d ol t h e l i g h t e l e m e n t in o t h e r p l a c e s . ' C h e m i s t s

w e n t t o w o r k e h e i l ; i hg o n t h i s fac t, l o r a n a l y s i s t h e y t o o k s a l t s of

d i f f e r e n t o r i g i n : c o m m o n s a l t f r o m t h e s e a a n d f r o m v a r i o u s l a k e s ,

ro i k - s a l t a n d s a l t f r o m C e n t r a l A f r i c a ; f r o m e a c h k i n d o f s a l t t h e y

i s o l a t e d I h e c h l o r i n e a n d u n e x p e c t e d l y o b t a i n e d t h e s a m e n u m b e r s

l o r t h e a t o m i c w e i g h t . T h e y e v e n l o o k c h l o r i n e f r o m t h e r o c k s t h a i ,

h a d f a l l e n f r o m t h e s k v , b u t t h e c o m p o s i t i o n of c h l o r i n e p r o v e d a b s o -

l u t e l y t h e s a m e . A n d w h a t w e c a l l a t o m i c w e i g h t r e m a i n e d i n v a r i a b l e ,

n o m a t t e r w h e r e t h e e l e m e n t , c a m e . f r o m .

H u t t h e t r i u m p h of t h e c h e m i s t s d i d n o t l a s t l o n g . O t h e r i n v e s t i g a t o r s

t r i e d t o s e p a r a t e t h e s e h e a v v a n d l i g h t i s o t o p e s o f t h e a t o m in t h e

l a b o r a t o r y . A f t e r c o m p l i c a t e d a n d l e n g t h y d i s t i l l a t i o n of c h l o r i n e

g a s t h e y m a n a g e d t o o b t a i n o n e g a s c o m p o s e d o f l i g h t e r a t o m s o f

c h l o r i n e a n d a n o t h e r m a d e u p o f h e a v i e r a t o m s . B o t h t h e s e c h l o r i n e s

a r e c h e m i c a l l y a b s o l u t e l y t h e s a m e , b u t t h e i r w e i g h t s d i f f e r .

T h i s d i s c o v e r y o f i s o t o p e s o f e a c h e l e m e n t h a s r e n d e r e d M e n d e -

l e y e v ' s t a b l e m o r e c o m p l i c a t e d . I t s e e m e d s o s i m p l e : b e f o r e : <)2 b o x e s

w i t h o n e c h e m i c a l e l e m e n t in e a c h . T h e n u m b e r d e n o t e d h o w m a n y

e l e c t r o n s t h e r e w e r e a r o u n d t h e n u c l e u s . E v e r y t h i n g w a s so s i m p l e ,

so c l e a r a n d so c e r t a i n ! A n d s u d d e n l y i t h a d a l l t u r n e d o u t w r o n g !

I n s t e a d of o n e o x y g e n t h e r e a r e T H R K E o f t h e m a n d t h e i r w e i g h t s

a r e e x a c t l y 15, 1 () a n d 18. H u t the: m o s t r e m a r k a b l e t h i n g is t h a t h y d r o g e n

a l s o h a s T H R K K k i n d s o f a t o m s , o n e w i t h t h e w e i g h t o f I , t h e s e c o n d

w i t h t h e w e i g h t o f 2 , a n d t h e t h i r d w i t h t h e w e i g h t o f 3 . T h e s e c o n d

k i n d h a s b e e n g i v e n a s p e c i a l n a m e d e u t e r i u m .

C h e m i c a l l y it is l i k e o r d i n a r y h y d r o g e n , b u t i t h a s t w i c e t h e w e i g h t

of t h e u s u a l h y d r o g e n . A t l a rge , p l a n t s w h e r e w a t e r is d e c o m p o s e d

b y m e a n s o f e l e c t r i c i t y it h a s b e e n p o s s i b l e t o o b t a i n p u r e d e u t e r i u m

a n d f r o m t h e l a t t e r s p e c i a l w a t e r w h i c h c o n t a i n s h e a v y h y d r o g e n

i n s t e a d o f t h e l i g h t v a r i e t y . I t a p p e a r s t h a t h e a v y w a t e r p o s s e s s e s

s p e c i f i c p r o p e r t i e s : i t d e s t r o y s l i f e ' v e r y s t r o n g l y a f f e c t s l i v i n g c e l l s , .

I n a w o r d , it ' " b e h a v e s " in a v e r v s p e c i f i c m a n n e r .

F o l l o w i n g tills a c h i e v e m e n t of t h e chcmis t s t h e geochemis t s took u p t h e s a m e p r o b l e m in r e l a t i o n t o n a t u r a l bodies . T h e y t h o u g h t t h a t s ince it was possible t o d iv ide t h e a t o m s of h y d r o g e n i n t o va r ious k inds in t h e r e t o r t n a t u r e was p r o b a b l y d o i n g t h e s a m e . O n l y in n a t u r e all c h e m i c a l processes a r c ve ry restless a n d t h e n a t u r a l condi t ions ' of t h e m o l t e n m a g m a s in t he e a r t h ' s i n t e r i o r o r o n its su r f ace c h a n g e so o f t e n t h a t we c a n h a r d l y e x p e c t t h e a c c u m u l a t i o n of p u r e iso-topes w h i c h we h a v e b e e n a b l e t o o b t a i n a t fac tor ies a n d in re -s e a r c h ins t i tu tes . As a m a t t e r of f ac t it has t u r n e d o u t t h a t t h e w a t e r of t h e seas a n d oceans c o n t a i n s a l i t t le m o r e h e a v y w a t e r t h a n d o r ivers a n d t h e r a i n . C e r t a i n m i n e r a l s c o n t a i n even m o r e h e a v y w a t e r . A w h o l e n e w w o r l d , f o r m e r l y inaccess ib le to t h e mine ra log i s t a n d geochemis t , o p e n e d u p b e f o r e us.

T h e d i f f e r e n c e b e t w e e n these c o m p o u n d s is so negl ig ib le in n a t u r e t h a t it r e q u i r e s t h e sub t les t m e t h o d s of c h e m i c a l a n d phys ica l ana lys is to d i scover i t .

T h e mi l l i on ths a n d even t h o u s a n d t h s of a g r a m a n d c e n t i m e t r e a r e i m p e r c e p t i b l e to a mine ra log i s t a n d geochemis t w h e n h e s tudies t h e s tones, t he w a t e r s a n d t h e e a r t h s of s u r r o u n d i n g n a t u r e . W e m a y even fo rge t t h a t t h e r e a r e t h r e e oxygens , six z incs a n d t w o po ta s s iums since t h e d i f f e rences b e t w e e n t h e m a r e so negl ig ib le a n d , f r a n k l y speak ing , o u r m e t h o d s of inves t iga t ion a r e still so c r u d e .

O n l y t h e chemis t s a n d physicists h a v e l e a r n e d to d iv ide t he e l e m e n t s i n to d i f f e r en t isotopes by the i r precise inves t iga t ions a n d t h e r e c a n b e n o d o u b t t h a t w h e n t h e y m a s t e r all of o u r n a t u r e b y the i r mos t a c c u r a t e m e t h o d s they will d iscover t h e

59

Por t r a i t of D . M e n d c l e y c v pa in ted by his w i f e A. M e n d e l e y e v a

greatest laws o f geochemistry of which we cannot even dream as yet.

Meanwhile you and I may forget about isotopes. As far as we are concerned each box in Mcndelcyev's Periodic Table contains only one definite and invariable chemical element. For us, box Xo. 50 contains only one tin which is always and everywhere the same and which yields the same chemical reactions all over, is encountered in nature in the same crystals and has an atomic weight of 118.7 wherever it may be found.

Mcndelcyev's Periodic Table is none the worse for this greatest discovery of isotopes; it has only become more complicated in its minutest details while remaining essentially as dear , simple and distinct a picture of nature as it was painted for us by Mendelevev who foresaw its tremendous importance.

Let us go deeper into this tabic and see of what significance it is for the investigators ot nature, the mineralogists and the geochemists.

Let us first take a look at each column of boxes from top to bottom.

Here is the first column—lithium, sodium, potassium, rubidium, cesium and fnincium. These are all metals and we call them the alkali metals. In nature they occur together except artificially obtained franciurn. We know their compounds well: for sodium—com-mon salt which you use with your food, and for potassium—saltpetre with which fireworks are made.

Then come very rare alkali metals which are now used in intricate electric appliances. But whatever the differences among all these elements they are very much alike chemically.

And here is the second vertical column in which we find the alkaline-earth metals from beryllium, the lightest, to the famous radium. These also resemble each other forming, as it were, one family.

Then comes the third column with boron, aluminium, scandium, yttrium, a box with fifteen rare-earth elements and, finally, actinium. Only the first two elements—boron and aluminium—which play an important part in nature are well known to us from everyday life. The first of these forms part of boric acid and borax which is used in soldering. Aluminium is a constituent of nephcline, feldspar, corundum and bauxite, while in its pure form we can see it in metal wares, pots and pans. This is a rather complex group.

( jo

Aluminium may be considered a real metal, but boron is more like a non-metal because it forms salts (such as borax) with typical metals.

We go on to the fourth column containing carbon, silicon, titanium, zirconium, hafnium and, finally, thorium. The first two are among the most important chemical elements in nature; carbon forms the entire mass of organic nature and is a constituent ot all limestones, while silicon is an element about which you will read a special chapter.

We now come to the fifth, sixth and seventh columns. In these columns we have onlv special metals which are very highly valued in the metallurgy of iron and which are added to steel to improve its qualities.

And here is the remarkable middle of Mendeleyev's Periodic Table consisting of the eighth, ninth and tenth columns. The most curious feature of this part of the table is that the neighbouring metals are very much alike. Iron, cobalt and nickel greatly resemble each other and in nature arc always encountered together; they are also hard to separate in chemical analysis. Ruthenium, rhodium and palladium (the light platinum metals), as well as osmium, iridium and platinum (the heavy platinum metals) resemble each other no less.

The centre of the table is followed by four vertical columns occupied by so-called heavy metals. These include copper, zinc, tin and lead which are familiar to us Irom our everyday experience.

Now comes column fifteen. It begins with the gas known as nitrogen. This is followed bv volatile phosphorus and arsenic, semi-metallic antimony and, finally, by the rather typical metal, bismuth. This column marks, as it were, a sharp transition to the next part ol Mende-leyev's Periodic Table where we shall no longer encounter any metals with metallic lustre and other familiar properties. There we find sub-stances which chemists have named non-metals and which are gaseous, liquid or solid.

The sixteenth column contains oxygen, sulphur, selenium, tellurium and the mvstcrious polonium; this is followed bv the seventeenth column of volatile substances, first gases hydrogen, lluorine and chlorine, then liquid bromine, and, finally, solid but also volatile

(M

crystals ol iodine. Chemists have given this group of elements (except hydrogen) the name of halogens because they form salts with alkalis. I his is denoted by the meaning of the Creek word: halogen means

salt-producing. And here is the last column, the eighteenth, in which we find the rare or noble gases. These do not combine with anything but impregnate the entire earth, all minerals, everything that surrounds us in nature. They begin with light helium, the gas of the sun, and end with the remarkable gas called radon whose: atoms live only a lew days.

MENDELEYEV'S PERIODIC SYSTEM OF ELEMENTS IN GEOCHEMISTRY

f l o w a r e the- c h e m i c a l e l e m e n t s d is t r i b u t e c l in t h e e a r t h a n d a l l

t h r o u g h n a t u r e ? T h i s h a s l o n g b e e n a q u e s t i o n of g r e a t i m p o r t a n c e

t o m a n .

T h i s q u e s t i o n h a s a l w a y s c o m e t o t h e l o r e s p o n t a n e o u s l y , a r i s i n g

f r o m t h e n e e d s of d a y - t o - d a y h i e . P r i m i t i v e m a n n e e d e d m a t e r i a l s

f o r h i s w o r k - t o o l s a n d f o r h u n t i n g w e a p o n s a r i d s h a p e d t h e m I r o m

h a r d (l int or f r o m s i m i l a r l y h a r d , h u t s t r o n g e r , n e p h r i t e . I t is c l e a r

t h a t t h e s c a n h for m i n e r a l s b e g a n m a n y t h o u s a n d s of y e a r s b e f o r e

o u r l i m e w h e n p r i m i t i v e m a n s t a r t e d p a y i n g a t t e n t i o n t o s p a r k l e t s

o f g o l d in r i v e r s a n d s a n d t o the. b e a u t y o r w e i g h t ol d i f f e r e n t s t o n e s

t h a t , a t t r a c t e d h i m .

I n t h i s w a y m a n first f o u n d o u t a b o u t , a n d t h e n l e a r n e d t o

e x t r a c t a n d p r o c e s s c u p p e r , t i n , g o l d a n d , f i n a l l y , i r o n , l i e g r a d u a l l y

a c c u m u l a t e d d a t a a n d e x p e r i e n c e . T h e r e g i o n s w h e r e m a n w a s t o

s e a r c h l o r c o p p e r a r i d c o b a l t m i n e r a l s t o m a n u f a c t u r e b l u e d y e s , a n d

l a t ' r t o f i n d i r o n (or b r o w n or l i r e , c l a y l o r s t a t u e t t e s a n d t u r q u o i s e

f o r t h e s a c r e d s c a r a b s w e r e a l r e a d y k n o w n in a n c i e n t I ' . g y p t .

I . i t t l e b y l i t t l e m a n l e a r n e d t in t s i m p l e n a t u r a l l a w s . Il t u r n e d o u t

t h a t s o m e m e t a l s w e r e o l t e n e n c o u n t e r e d t o g e t h e r , a s , f o r e x a m p l e ,

t i n , c o p p e r a n d z i n c ; in i t s t i m e t h i s s u g g e s t e d t o m a n t h e i d e a ol a l l o y i n g

t l i e m a n d p r o d u < i n g b r o n z e , ( i o l d a n d p r e c i o u s s t o n e s w e r e l o u n d

t o g e t h e r in o t h e r p l a c e s , c l a y a n d f e l d s p a r s , f r o m w h i c h p o r c e l a i n

a n d f a i e n c e c a n be: m a d e , in s t i l l c i t h e r p l a c e s .

M a n h a s , t h u s , g r a d u a l l y d i s r o v e r e d t h e f u n d a m e n t a l l a w s of g e o -

c h e m i s t r y . A n d I l ie a l c h e m i s t s , w h o in t h e M id d i e A g e s I rice I t o pr oclue e

g o l d a r i d the. p h i l o s o p h e r ' s s tone , i n t h e m y s t e r i o u s q u i e t o l t h e i r

l a b o r a t o r i e s , a l s o c o n t r i b u t e d a g o o d d e a l t o t h e a c c u m u l a t i o n o f

n a t u r a l f a c t s .

A l r e a d y t h e a l c h e m i s t s k n e w w e l l t h a t c e r t a i n m e t a l s h a v e a n a f f i n i t y

l o r e a c h o t h e r a n d a r e e n c o u n t e r e d t o g e t h e r : t h u s s p a r k l i n g c r y s t a l s

o f g a l e n a a r e a l w a y s a c c o m p a n i e d i n t h e e a r t h b y z i n c - b l e n d e , s i l v e r

i o l l o w s g o l d , w h i l e c o p p e r is o f t e n f o u n d t o g e t h e r w i t h a r s e n i c .

W h e n m i n i n g d e v e l o p e d i n E u r o p e t h e g c o c h e m i e a l r e g u l a r i t i e s

b e c a m e c l e a r e r a n d m o r e d i s t i n c t . T h e f u n d a m e n t a l p r i n c i p l e s o f t h e

n e w s c i e n c e ol g e o c h e m i s t r y w e r e c o m i n g i n t o b e i n g i n t h e d e e p m i n e s

ol S a x o n y . S w e d e n a n d t h e C a r p a t h i a n s ; it w a s a s c e r t a i n e d w h a t s u b -

s t a n c e s w e r e f o u n d i n n a t u r e t o g e t h e r a n d u n d e r w h a t c o n d i t i o n s ,

a n d w h a t l a w s l o r c e d s o m e e l e m e n t s t o a c c u m u l a t e i n c e r t a i n p a r t s

o f t h e e a r t h a n d d i s p e r s e i n o t h e r s .

T h e s e w e r e t h e m o s t u r g e n t q u e s t i o n s i n m i n i n g , w h i c h r e q u i r e d

t h e a b i l i t y t o f i n d p l a c e s w h e r e t h e i n d u s t r i a l l y i m p o r t a n t m e t a l s —

i r o n . g o l d . e t c . a c c u m u l a t e d i n l a r g e q u a n t i t i e s .

T o d a v w e k n o w t h a t t h e c o m m o n o c c u r r e n c e o f e l e m e n t s a n d

t h e i r b e h a v i o u r a r e s u b j e c t t o v e r v d e f i n i t e l a w s a n d t h a t t h e s e

l a w s h e l p i n p r o s p e c t i n g l o r m i n e r a l s .

W e k n o w v e r v w e l l I r o m o u r o w n d a i l v p r a c t i c e t h a t s u c h n a t u r a l

e l e m e n t s a s n i t r o g e n , o x y g e n a n d t h e r a r e , n o b l e g a s e s a r e f o u n d p r i n -

c i p a l l y in t h e a t m o s p h e r e . W e a l s o k n o w t h a t i n s a l t - l a k e s o r i n sa l t

m i n e s t h e s a l t s ol c h l o r i n e , b r o m i n e a n d i o d i n e a r e f o u n d t o g e t h e r

111 c o m b i n a t i o n w i t h t h e m e t a l s — p o t a s s i u m , s o d i u m , m a g n e s i u m a n d

c a l c i u m .

I n g r a n i t e s , t h e s e l i g h t c r y s t a l l i n e r o c k s w h i c h h a v e r e s u l t e d f r o m t h e

c o o l i n g o f m o l t e n m a g m a s , w e f i n d t h e i r ow n d e f i n i t e c h e m i c a l e l e m e n t s .

T h c v a r e c o n n e c t e d w i t h p r e c i o u s s t o n e s w h i c h c o n t a i n a t o m s o f b o r o n ,

b e r y l l i u m , l i t h i u m a n d l l u o r i n e . T h e y a l s o i n c l u d e a c c u m u l a t i o n s o f

i m p o r t a n t a n d r a r e m e t a l s t u n g s t e n , n i o b i u m a n d t a n t a l u m .

l ! n l i k e t h e g r a n i t e s , in t h e h e a v y b a s a l t r o c k s w h i c h h a v e s t r e a m e d

o u t o t t h e e a r t h ' s i n t e r i o r w e find t o g e t h e r t h e m i n e r a l s o f c h r o m i u m ,

n i c k e l , c o p p e r , i r o n a n d p l a t i n u m . I n t h e c o m p l e x l y r a m i f i e d s y s t e m s

ol l o d e s b r a n c h i n g o u t ol i m m e n s e u n d e r g r o u n d l a k e s o f m o l t e n m a g m a

w h i c h r i s e s t o t h e e a r t h ' s su i ' l . i c e t h e p r o s p e c t o r finds z i n c a n d

l e a d , g o l d a n d s i l v e r , a r s e n i c a n d m e r c u r y .

1 h e m o r e o u r s c i e n c e d e v e l o p s t h e c l e a r e r a n d m o r e c e r t a i n b e c o m e

t h e l a w s w h i c h w e r e l o n g i n c o m p r e h e n s i b l e .

I ' l

M e a n w h i l e , let us t ake a look a t M e n d e l e y e v ' s Pe r iod ic T a b l e . D o n ' t you t h i n k it is t he s a m e c o m p a s s for us sea rcher s for stones a n d m e t a l s as it is for t h e chemis t s?

T h e c e n t r e of M e n d e l e y e v ' s Pe r iod ic T a b l e is o c c u p i e d by n ine m e t a l s : i ron , coba l t , nickel a n d six m e t a l s of t h e p l a t i n u m g r o u p . W e know the i r depos i t s lie d e e p in t h e en t ra i l s of t h e e a r t h . If tall m o u n t a i n r a n g e s a r e e r o d e d over mi l l ions of years a lmos t to t he level of plains, as is t he case in t he Ura l s , these g r e e n P l u t o n i c rocks, t he beare r s of i ron a n d p l a t i n u m , a r e la id b a r e .

Y o u see t h a t these e l emen t s a r e no t on ly t he f o u n d a t i o n of ou r m o u n -ta in r anges , b u t t h a t t h e y also o c c u p y the cen t r a l p l ace in M e n d e l e y e v ' s Pe r iod i c T a b l e .

Le t us t u r n to t h e me ta l s w h i c h we call h e a v y a n d wh ich t ake u p c o n s i d e r a b l e space to t h e r igh t of nickel a n d p l a t i n u m . T h e s e a r c c o p p e r a n d zinc, si lver a n d gold , lead a n d b i s m u t h , m e r c u r y a n d arsenic . H a v e w e n o t j u s t said these m e t a l s were a lways e n c o u n t e r e d t o g e t h e r ? M i n e r s look for t h e m in lodes wh ich cu t t h r o u g h t h e e a r t h ' s crust .

N o w let us go left of t he c e n t r e of t he t a b l e w h e r e we obse rve a s imi la r field. T h e s e a r e t h e f a m i l i a r m e t a l s w h i c h f o r m t h e p rec ious stones, t h e c o m p o u n d s of b e r y l l i u m a n d l i t h i u m ; they a r e t h e r a r e a n d u l t r a -r a r e e l e m e n t s w h i c h a c c u m u l a t e in t he o u t e r m o s t ex t rus ions of g r a n i t e massifs, in l a rge g r a n i t e pegma t i t e s .

Le t us go f a r t h e r left a n d r igh t in o u r t ab le . W e m u s t no t forget , h o w e v e r , t h a t its long rows close in in a c o m m o n spira l a n d t h a t t h e e x t r e m e left a n d r igh t g r o u p s a r e con t iguous . H e r e we see t he ve ry f a m i l i a r e l e m e n t s of sal t depos i t s : sal t- lakes, seas a n d oceans , a n d extens ive a c c u m u l a t i o n s of rock-sa l t . T h e s e a r e t he e l emen t s t h a t f o r m t h e salts of ch lo r ine , b r o m i n e , iod ine , s o d i u m , po ta s s ium a n d c a l c i u m .

A n d n o w look ca re fu l ly a t t h e t o p r i g h t - h a n d c o r n e r of t h e t a b l e ; he r e you will find t h e chief e l e m e n t s of t he a t m o s p h e r e — n i t r o g e n , oxygen , h y d r o g e n , h e l i u m a n d o t h e r n o b l e gases ; a t t h e t o p l e f t - h a n d c o r n e r you will see l i t h i u m , b e r y l l i u m a n d b o r o n . D o n ' t t h e y r e m i n d you of t h e vo la t i l e p a r t s of t h e g r a n i t e massifs w h e r e t h e b e a u t i f u l p rec ious s tones— t h e p i n k a n d g r e e n t o u r m a l i n e s , t h e b r i g h t - g r e e n e m e r a l d s a n d violet kunz i t e s a r e f o r m e d ? As y o u see, M e n d e l e y e v ' s 'Per iodic T a b l e itself suggests t h e g r o u p s of e l e m e n t s e n c o u n t e r e d in n a t u r e a n d real ly a n d t ru ly serves as a c o m p a s s for t h e s e a r c h of mine ra l s .

65

In order to confirm the regularities mentioned by an example let us recall the chief minerals found in the Urals.

The Urals appears before us as an enormous Mendeleyev's Peri-odic Table spreading across the rocks. The axis of the range and of the table passes through the heavy green rocks of platinum de-posits. Its extreme groups are in the salt zone of famous Solikamsk and in the regions of the Emba.

Is it not a marvellous con-firmation of the profoundest and most abstract ideas? I believe you have already guessed that in Mendeleyev's table the elements are not arranged fortuitously but according to the similarities of their properties. And the greater the similarities between the ele-ments the closer to each other they are found in the Periodic Table.

It is the same in nature. The signs showing various minerals on our geological maps have not been put there by mere accident, as it is no accident that osmium, iridium and platinum or antimony and arsenic are encountered in nature together.

The same laws of similarity, of chemical affinity of the atoms determine the behaviour of the elements in the earth's entrails. The Periodic Table is really the most important instrument with the aid of which man discovers the resources of the earth's interior, finds useful metals and employs them in developing his economy and industry.

Let us recall the distant past of the Urals. Heavy molten magmas consisting of dark, black and green Plutonic rocks rich in magnesium and iron rose from the interior of the earth. They received an admixture of chromium, titanium, cobalt and nickel ores; to these were added

Cliffs on the banks of the Chusovaya River (Sverdlovsk Reg ion)

66

t he m e t a l s of t h e p l a t i n u m g r o u p — r u t h e n i u m , r h o d i u m , p a l l a d i u m , o s m i u m , i r i d i u m arid p l a t i n u m .

T h u s b e g a n t h e first s t age in t he h is tory of t h e Ura l s , t h e deep ly i m b e d d e d c h a i n of d u n i t e a n d s e r p e n t i n e rocks t h a t f o r m t h e cen t r a l f r a m e of t h e U r a l s R a n g e w h i c h s t re tches to t h e Arc t i c is lands in t h e N o r t h a n d is b u r i e d u n d e r t h e f ea the r -g rass s teppes of K a z a k h -s t an in t h e S o u t h . I n M e n d e l e y e v ' s Pe r iod i c T a b l e it is t h e cen t ra l p a r t .

I n t he process of s e p a r a t i o n of mel t s t h e l igh te r vola t i le subs t ances a r e evo lved , a n d in t he c o m p l e x c h a n g e of rocks w h i c h f o r m the p r e sen t -d a y U r a l s l i gh t - co lou red g ran i t e s c rys ta l l ized ou t in t h e i n t e r io r a t t he e n d of its vo l can i c act ivi ty- I t is t h e g rey g r a n i t e so f ami l i a r to all w h o live in t h e U r a l s , especial ly a l o n g its e a s t e rn slopes. W h i t e veins of p u r e q u a r t z p ie rce t h e g r a n i t e a n d th ick p e g m a t i t e veins b r a n c h i n t o its e x t e r n a l sec t ions a n d p e n e t r a t e i n t o t h e l a t e r a l rocks. T h e s e processes l e ad to t h e a c c u m u l a t i o n of t h e vo la t i l e e l emen t s bo ron , fluorine, l i t h i u m a n d b e r y l l i u m a n d t h e r a r e e a r t h s a n d to t he f o r m a t i o n of t h e p rec ious s tones a n d r a r e - m e t a l ores of t he U r a l s .

I n M e n d e l e y e v ' s pe r iod i c sys tem it is t h e left field of t he t ab le . B u t h o t so lu t ions rose to t he su r f ace b o t h a t t h e s a m e t i m e a n d l a t e r .

T h e y b o r e t h e low-mel t ing , m o b i l e a n d h igh ly so luble c o m p o u n d s of z inc , l ead , c o p p e r , a n t i m o n y a n d a rsen ic , a n d w i t h t h e m ca r r i ed silver a n d go ld .

T h e s e o r e depos i t s r u n in a l ong c h a i n a l o n g t h e eas t e rn slopes of t h e U r a l s , n o w f o r m i n g l a rge concen t r a t i ons—lenses , n o w b r a n c h i n g lodes a n d c lus ters of lodes .

I n M e n d e l e y e v ' s Pe r iod i c T a b l e it is t h e r i g h t field of o re e lements . Bu t t h e n t h e vo l can i c ac t iv i ty c a m e to a n e n d a n d t h e pressures , w h i c h

ra ised t h e U r a l s , sh i f ted its r idges f r o m Eas t to W e s t a n d o p e n e d he r e a n d t h e r e a n ou t l e t for vo lcan ic rock a n d for t h e ho t w a t e r s of t he veins , ceased .

T h e n a l e n g t h y pe r iod of d e s t r u c t i o n b e g a n . F o r h u n d r e d s of mi l l ions of yea r s t h e U r a l s M o u n t a i n s e r o d e d , the i r rocks b e i n g w e a t h e r e d a w a y . All t h a t was h a r d to dissolve r e m a i n e d , t he rest was dissolved a n d c a r r i e d a w a y b y w a t e r to t h e seas a n d lakes. T h e G r e a t P e r m i a n Sea w h i c h w a s h e d t h e wes te rn s lope of t he U r a l s a c c u m u l a t e d these subs tances . T h e sea b e g a n d r y i n g o u t ; bays , lakes a n d firths were d e t a c h e d f r o m it a n d t h e salts se t t led to t h e b o t t o m .

5 6 7

I t was, thus , t h a t t h e salts of s o d i u m , p o t a s s i u m , m a g n e s i u m , ch lo r ine , b r o m i n e , b o r o n a n d r u b i d i u m a c c u m u l a t e d .

I n M e n d e l e y e v ' s Pe r iod i c T a b l e t h e y o c c u p y t h e u p p e r a n d t h e le f t -h a n d boxes.

A n d only w h a t d id no t yield to t h e c h e m i c a l a c t i o n of w a t e r n o w r e m a i n s w h e r e o n c e t h e r e w e r e t h e m o u n t a i n peaks of t h e U r a l s .

A crus t of d i s i n t e g r a t e d rock g r e w for scores of mi l l ions of yea r s in t h e t rop ica l c l i m a t e of t h e Mesozo ic e r a . A c c u m u l a t i n g in this c rus t i ron , nickel , c h r o m i u m a n d c o b a l t f o r m e d t h e r i ch depos i t s of b r o w n h e m a t i t e w h i c h la id t h e f o u n d a t i o n for t h e nickel i n d u s t r y in t h e S o u t h Ura l s .

Q u a r t z depos i t s a c c u m u l a t e d in t h e reg ions of g r a n i t e d i s i n t eg ra t i on . G o l d , t u n g s t e n a n d p rec ious s tones w e r e r e t a i n e d a n d c o n c e n t r a t e d in these depos i t s a n d in sands .

T h u s , t h e U r a l s g r a d u a l l y d i e d cove r ing u p w i t h soil, a n d on ly n o w a n d t h e n w a t e r s r u s h e d in f r o m t h e Eas t e r o d i n g its a l r e a d y ove r -g r o w n hills a n d d e p o s i t i n g m a n g a n e s e a n d i ron ores a l o n g t h e shores .

VVe find M e n d e l e y e v ' s Pe r iod ic T a b l e h i d d e n u n d e r t h e t a i g a of t he po la r U r a l s a n d u n d e r t h e f ea the r -g ra s s s t eppes of K a z a k h s t a n . Sovie t p e o p l e a r e n o w d i scover ing v a r i o u s e l e m e n t s o f th is t a b l e a n d a r e u t i l iz ing t h e m for i n d u s t r i a l pu rposes .

THE ATOM DISINTEGRATES. URANIUM AND RADIUM

T h e p r e c e d i n g c h a p t e r s to ld us t h a t t h e a t o m , w h i c h in G r e e k m e a n s " i n d i v i s i b l e , " f o rms t h e basis of t h e sc ience of g e o c h e m i s t r y . All of t h e s u r r o u n d i n g n a t u r e is c o m p o s e d of a c o m b i n a t i o n of 101 var ie t ies of a t o m s w h i c h c o r r e s p o n d to 101 d i f f e r e n t e l emen t s .

B u t w h a t is th is m i n u t e s t " i n d i v i s i b l e " pa r t i c l e of m a t t e r ? Is it real ly " i n d i v i s i b l e " ? D o t h e 101 var ie t ies of a t o m s a c t u a l l y exist i n d e p e n d e n t l y of e a c h o t h e r w i t h o u t d i sp l ay ing a n y u n i t y of s t r u c t u r e ?

T h e i d e a of t h e a t o m as a m a t e r i a l l y indiv is ib le g lobu l e f o r m e d t h e f o u n d a t i o n of c h e m i s t r y a n d physics . T h e " i n d i v i s i b l e " a t o m q u i t e e x p l a i n e d t h e phys ica l a n d c h e m i c a l p r o p e r t i e s of m a t t e r , a n d for this r e a s o n chemis t s a n d physicis ts w e r e n o t p a r t i c u l a r l y anx ious t o d iscover t h e c o m p l e x s t r u c t u r e of t h e a t o m t h o u g h they suspect -ed it .

A n d on ly w h e n the f a m o u s F r e n c h physic is t B e c q u e r e l d i scovered in 1896 t h e p h e n o m e n o n of some invis ible r a d i a t i o n b y u r a n i u m u n -k n o w n un t i l t h e n a n d t h e C u r i e s f o u n d t h e n e w e l e m e n t k n o w n as r a d i u m , in w h i c h this p h e n o m e n o n was m u c h m o r e p r o n o u n c e d , it b e c a m e c l ea r t h a t t h e a t o m h a d a ve ry c o m p l e x s t r u c t u r e . N o w , a f t e r t h e b r i l l i an t w o r k of M a r i e C u r i e - S k l o d o w s k a , t h e Cur ie - Jo l io t s , R u t h e r f o r d , R o z h d e s t v e n s k y , B o h r et al , t h e p i c t u r e of t h e a t o m ' s s t r u c t u r e is suf f ic ient ly c lear . W e k n o w n o t on ly t he s imples t pa r t i c l e s of w h i c h t h e a t o m is c o m p o s e d , b u t a lso t he i r sizes, we igh t s , m u t u a l l oca t ion a n d t h e forces t h a t b i n d t h e m .

W e h a v e a l r e a d y sa id t h a t t h e a t o m of e a c h c h e m i c a l e l e m e n t desp i te its neg l ig ib le size (it h a s a d i a m e t e r of 0 .00000001 c e n t i m e t r e ) r ep resen t s a ve ry c o m p l e x s t r u c t u r e bu i l t like o u r so lar sys tem.

6 9

The atom is composed of a nucleus (its diameter is o.ooooi that of the atom and corresponds to about 1' 12 cm) in which the bulk of the atom is concentrated.

The nucleus of the atom carries a positive electric charge. The number of the positive particles in the nucleus increases with the tran-sition from the atoms of the light chemical elements to the heavy ones and corresponds numerically to the number of the box the element occupies in the Periodic Table.

Electrons, each carrying a nega-tive charge, revolve around the nucleus at various distances from it. The number of electrons equals that of the positive charges on the nucleus, so that the atom as a whole is an electrically neutral structure.

The nuclei of the atoms of all chemical elements are built of two simplest particles- a proton, or hydrogen atom nucleus, and a neutron. The proton lias a mass nearly equal to that of the hydrogen atom and carries one positive charge. The neutron is a material particle with a mass similar to that of the proton but without any electric charge.

The protons and neutrons in the nuclei of atoms cohere so firmly that in all chemical reactions the nuclei of the atoms are perfectly stable and remain unchanged.

If we gradually pass from the lighter to the heavier chemical elements in Mendeleyev's periodic system we will find that the nuclei of the atoms of the light elements are composed of an approximately equal number of protons and neutrons (this is easy to see from the fact that the atomic weight of the elements in the beginning of the Periodic Table is either numerically equal or close to the doubled atomic number of the element).

With a transition to the heavier chemical elements the number

M a r i e Cur i e -Sk lodowska in h e r Par i s l abora to ry

of n e u t r o n s in t h e nuc l e i of t h e a t o m s beg ins t o exceed t h a t of t h e p r o t o n s . F ina l ly , t h e n u m b e r of n e u t r o n s c o n s i d e r a b l y exceeds t h a t of t h e p r o t o n s a n d t h e nuc l e i of t h e a t o m s b e c o m e u n s t a b l e . Begin-n i n g w i t h t h e 81 st a t o m i c n u m b e r w e e n c o u n t e r u n s t a b l e , as well as s tab le , va r ie t i es of a t o m s of c h e m i c a l e l emen t s . T h e nuc le i of t he a t o m s of t h e u n s t a b l e e l e m e n t s s p o n t a n e o u s l y d i s i n t eg ra t e l i b e r a t i n g l a r g e a m o u n t s of e n e r g y a n d c h a n g e to a t o m s of o t h e r ch emi ca l e l emen t s .

F r o m a t o m i c n u m b e r 86 on all nuc le i of a t o m s of c h e m i c a l e l e m e n t s r e p r e s e n t u n s t a b l e s t r u c t u r e s a n d t h e c o r r e s p o n d i n g e l emen t s a r e r a d i o a c t i v e .

R a d i o a c t i v i t y is a p r o p e r t y of t h e a t o m to d i s i n t e g r a t e s p o n t a n e o u s l y c h a n g i n g to a t o m s of o t h e r e l e m e n t s w i t h a l i b e r a t i o n of l a rge a m o u n t s of e n e r g y in t h e f o r m of d i f f e r e n t r a d i a t i o n s . T h e l a t t e r h a v e b e e n d i v i d e d i n t o t h r e e g r o u p s .

T h e first is t h e a l p h a rays o r a s t r e a m of fast t r ave l l ing m a t e r i a l pa r t i c les w i t h a d o u b l e pos i t ive e lec t r ic c h a r g e ; e a c h a l p h a pa r t i c l e h a s a mass f o u r t imes t h a t of t h e h y d r o g e n a t o m a n d is a c t u a l l y a n u c l e u s of t h e h e l i u m a t o m .

T h e second is t h e b e t a r ays or a s t r e a m of e lec t rons t r ave l l ing a t a n e n o r m o u s r a t e . E a c h e l ec t ron car r ies o n e n e g a t i v e c h a r g e , t h e smal les t of t h e exis t ing cha rges , a n d has a mass 1/1,840 t h a t of t he h y d r o g e n a t o m .

T h e t h i r d g r o u p is f o r m e d by g a m m a rays w h i c h r e p r e s e n t a r a d i a t i o n r e s e m b l i n g X - r a y s , b u t w i t h a s h o r t e r w a v e - l e n g t h .

I f we p u t a b o u t a g r a m of a r a d i u m salt i n t o a smal l glass t u b e , so lder th is t u b e a n d w a t c h it , w e shal l b e a b l e to obse rve all t he p r i n c i p a l p h e n o m e n a t h a t a t t e n d r a d i o a c t i v e d i s i n t e g r a t i o n .

I n t h e first p lace , if w e use a n i n s t r u m e n t sensi t ive e n o u g h to m e a s u r e s l ight d i f f e rences in t e m p e r a t u r e , w e shal l easily d i scover t h a t t he t e m p e r a t u r e of t h e t u b e c o n t a i n i n g r a d i u m sal t is s o m e w h a t h i g h e r t h a n t h a t of t h e e n v i r o n m e n t .

Y o u ge t t h e impress ion t h e r e is a n ef f ic ient h e a t i n g dev ice h i d d e n in t h e r a d i u m salt . O n t h e basis of this o b s e r v a t i o n we c a n d r a w a n i m p o r t a n t conc lus ion t h a t r a d i o a c t i v e d i s i n t e g r a t i o n o r t h e process of b r e a k - u p of t h e a t o m i c nuc le i is a t t e n d e d by a c o n t i n u o u s p r o d u c t i o n of l a rge a m o u n t s of ene rgy . E x p e r i e n c e shows t h a t in " b r e a k i n g u p ' ' CM o n e g r a m of r a d i u m p r o d u c e s 140 smal l ca lor ies of h e a t pe r h o u r

7 i

whi le in c h a n g i n g c o m p l e t e l y to l ead ( w h i c h takes a b o u t 20 ,000 years) it will p r o d u c e 2.9 mi l l ion l a r g e ca lor ies of h e a t , i .e., as m u c h as is p r o d u c e d b y t h e b u r n i n g of ha l f a t o n of coal .

N o w let us t ake a sma l l p u m p a n d p u m p t h e a i r o u t of t h e t u b e c o n t a i n i n g r a d i u m i n t o a n o t h e r t u b e f r o m w h i c h t h e a i r w a s p u m p e d o u t b e f o r e h a n d . Le t us so lder this n e w t u b e . W e will soon find t h a t in t he d a r k this t u b e emi t s a g reen i sh -b lu i sh l ight j u s t l ike t h e t u b e w i t h t h e r a d i u m salt .

T h i s s e c o n d a r y r a d i o a c t i v i t y is d u e to t h e a p p e a r a n c e of a n e w r a d i o a c t i v e s u b s t a n c e b o r n of r a d i u m . T h i s s u b s t a n c e is a gas. I t has b e e n n a m e d r a d o n ( R n ) .

T h e a m o u n t of r a d o n in t he t u b e increases for a pe r iod of fo r tv d a y s a f t e r w h i c h it b e c o m e s c o n s t a n t b e c a u s e t h e r a t e of d i s i n t e g r a t i o n of r a d o n t h e n equa l s t he r a t e of its emiss ion. W e c a n obse rve r ad io -ac t iv i ty by h o l d i n g t h e t u b e s u p to a c h a r g e d e lec t roscope . R a d i o a c t i v e r a d i a t i o n ionizes t he a i r m a k i n g it a c o n d u c t o r of e lec t r ic i ty a n d t h e e lec t roscope r u n s d o w n .

If we w a t c h t h e effect of t h e t u b e c o n t a i n i n g r a d o n on a c h a r g e d e lec t roscope d a y a f t e r d a y w e shal l easily obse rve t h a t in t h e cou r se of t i m e this e f fec t weakens . W i t h i n 3 .8 days t h e ef fec t will b e ha l f lost, a n d if t h e t u b e is b r o u g h t close to a c h a r g e d e lec t roscope 40 d a y s l a t e r it will fail to p r o d u c e a n y effec t . Bu t if we pass a n e lec t r ic d i s c h a r g e t h r o u g h o n e of these " m a t u r e " t u b e s a n d obse rve t h e l u m i n e s c e n c e of this gas p r o d u c e d by t h e d i s cha rge in a spec t roscope w e shal l d i scover t h e a p p e a r a n c e of t he s p e c t r u m of a n e w g a s — h e l i u m . F ina l ly , if w e t h o r o u g h l y r e m o v e t h e r a d i u m sal t f r o m t h e t u b e a f t e r k e e p i n g it in t h e l a t t e r for m a n y years a n d t h e n by sensi t ive m e t h o d s of ana lys i s test t he su r face of its i n n e r wal ls for t h e p re sence of fo re ign c h e m i c a l e l emen t s we will be a b l e to find m i n u t e s t t r aces of l ead in t h e e m p t y t u b e .

I n o n e y e a r t h e d i s in t eg ra t ion of t he a t o m s of o n e g r a m of me ta l l i c r a d i u m p r o d u c e s 4 .00 X t o - 4 g r a m s of lead w i t h a mass n u m b e r of 206 a n d 172 c u b i c mi l l ime t r e s of gaseous h e l i u m .

T h u s , r a d i o a c t i v e d i s i n t eg ra t i on of r a d i u m resul ts in o n e n e w r a d i o -ac t ive e l e m e n t a f t e r a n o t h e r w i t h t h e final f o r m a t i o n of n o n - r a d i o a c t i v e lead . A t this s tage t r a n s f o r m a t i o n ceases. R a d i u m is itself on ly a n i n t e r m e d i a t e l ink in a long c h a i n of p r o d u c t s of u r a n i u m t rans fo r -m a t i o n .

7 2

The series of elements produced as a result of disintegration of radio-active elements is known as the radioactive series.

All the nuclei of each radioactive element are unstable and are equally probable to disintegrate in a given period of time. Thus, a sufficiently large sample of radioactive substance containing many millions of atoms always disintegrates at the same constant rate re-gardless of any chemical or physical influences.

It has been demonstrated that no external physical influences produce any effect on the decay of a radioactive substance, be it a temperature of liquid helium, which is close to absolute zero, or temperatures of several thousand degrees, pressures of several thousand atmospheres or high-voltage electric discharges.

The rate at which a radioactive substance disintegrates, or is trans-formed, is usually expressed by the half-life period 7" or the time required for half the initially present atoms of the substance to disin-tegrate. This value is, apparently, characteristic of and constant for each variety of unstable atoms, i .e. , for each given radioactive ele-ment.

The half-life periods of radioactive elements vary very widely— from a fraction of a second for the most unstable atomic nuclei to thou-sands of millions of years for the slightly unstable elements which include, for example, uranium and thorium. Like its radioactive "parent" the "daughter" nucleus is frequently itself an unstable radioactive substance and decays further until a stable nucleus is formed after several successive generations of nuclei.

Three such natural radioactive series or families are known today: the uranium-radium series beginning with the isotope of uranium with a mass number of 238, the uranium-actinium series beginning with another isotope of uranium with a mass of 235 and the thorium series. The nuclei of the atoms of lead isotopes with mass numbers of 206, 207 and 208 respectively are the stable and no longer disinte-grating end-products of each of these series formed after ten to twelve successive transformations. In addition to lead the alpha particles, which have lost their kinetic energy and charge and have become atoms of helium, are stable products of transformations in each of the above radioactive series.

During the incessant radioactive disintegration of the uranium, thorium and radium atoms on earth heat is continuously produced.

73

If we calculate the amount of heat produced by all the aforesaid elements during their decay we shall find that, without the least suspect-ing it. we have long been using this heat because the latter noticeably heats our earth.

It happens very similarly that the helium gas used in filling dirigibles and barrage balloons is formed by the radioactive decay of the atoms

t w o pictures ot a h u m a n h a n d : l e f t - i n the rays of r a d i u m , r i g h t - t a k e n with the aid of X-rays. Meta l s a re no t t r a n s p a r e n t

of uranium, thorium and radium found in the earth. It has been com-puted that enormous amounts of helium gas constituting many hundreds of millions of cubic metres have thus formed in the earth since its existence.

The continuous disintegration of the atoms of uranium, thorium and radium contained in tlx- earth is of interest to us not only as a source of constant heat and of formation of industrial reserves of chemical elements, but also as a natural timepiece by which we can tell the time that has elapsed since the formation of any particular rock and of the very earth as a solid body.

But how can we use the atoms of uranium, thorium and radium as a timepiece for telling geological time? Here is how. We see that the rate at which disintegration of radioactive atoms takes place is

74

not subject to any chemical or physical influences and remains strictly constant. On the other hand, during radioactive decay stable and no longer changing atoms of the elements helium and lead are formed and, as time wears on, their amounts will increase more and more.

Since we know the amount of helium and lead formed as a result of radioactive decay of the atoms of one gram of uranium or thorium in one year we determine the amount of uranium or thorium contained in a particular mineral and the amount of helium and lead in the same mineral, and by taking the ratio of helium to uranium and thorium, on the one hand, and the ratio of lead to uranium and thorium, on the other, we get the time in years that has passed since the moment this mineral was formed.

As a matter of fact, when the mineral was formed it contained only atoms of uranium and thorium and had no atoms of helium or lead; then through the disintegration of the atoms of uranium and thorium atoms of helium and lead began to appear and gradually to accumulate in the mineral.

A mineral containing atoms of uranium and thorium may be likened to a sand-glass, and you have probably all seen how it works. Let me remind you how it is made. It consists of two intercommunicating vessels one of which contains a certain amount of sand. As the sand-glass is put in operation it is fastened and the sand is allowed to pour slowly from the upper vessel into the lower by force of gravity.

Des t ruc t i on of n i t rogen nuclei u n d e r the act ion of a lpha part icles. Long- r ange pro tons are l ibe ra ted

75

T h e a m o u n t ol" s a n d is usua l ly p u t in t he sand-glass w i t h t h e i d e a t h a t it e m p t y i n t o t he lower vessel in a de f in i t e pe r iod of t ime , say, 10 or 15 m i n u t e s . I n p r a c t i c e a sand-glass is used to m e a s u r e c o n s t a n t pe r iods of t i m e t h o u g h it cou ld b e used to m e a s u r e a n y pe r iods of t ime . Fo r this we w o u l d e i t he r h a v e to weigh the a m o u n t of sand o r to m a r k off e q u a l v o l u m e s in t h e vessels a n d m e a s u r e t h e v o l u m e s of s a n d p o u r e d in . S ince s a n d flows a t a de f in i t e r a t e u n d e r t he ac t i on of g r av i ty we can d e t e r m i n e by v o l u m e t h e a m o u n t of sand p o u r i n g f r o m the u p p e r vessel i n to t h e lower p e r m i n u t e a n d tell t h e n u m b e r of m i n u t e s t h a t h a v e e lapsed f r o m t h e t i m e we p u t t h e sand-glass in o p e r a t i o n by the v o l u m e of s a n d w e find in t he lower vessel.

S o m e t h i n g like this is h a p p e n i n g to t he m i n e r a l in w h i c h a t o m s of u r a n i u m a n d t h o r i u m a r e f o u n d . I t r e sembles t h e u p p e r vessel t h a t con t a in s a ce r t a in a m o u n t of s a n d , on ly t h e p a r t of t he s a n d g r a i n s is p l ayed by the a t o m s of u r a n i u m a n d t h o r i u m . T h e y a r e also t r a n s -f o r m e d in to a t o m s of h e l i u m a n d l ead a t a de f in i t e r a t e a n d , as is t h e case wi th t h e sand-glass , t h e a t o m s of d i s in t eg ra t ion a c c u m u l a t e in d i rec t p r o p o r t i o n to the t i m e t h a t h a s e lapsed s ince t h e exis tence of t h e r a d i o a c t i v e m i n e r a l .

W e d e t e r m i n e t h e a m o u n t of r e m a i n i n g u r a n i u m by d i r ec t ana lys is a n d e s t ima te t he n u m b e r of d i s i n t eg ra t ed a t o m s of u r a n i u m a n d t h o r i u m by the a m o u n t of h e l i u m a n d lead t h a t h a v e f o r m e d f r o m t h e m . T h e s e d a t a m a k e it possible to find t he r a t i o of u r a n i u m to t he a m o u n t of t h e lead a n d h e l i u m p r o d u c e d a n d , c o n s e q u e n t l y , to e s t i m a t e t he t i m e d u r i n g w h i c h t h e d e c a y took p lace . I n this m a n n e r scientists h a v e b e e n a b l e to d e t e r m i n e t h a t t h e r e a r e m i n e r a l s o n e a r t h s ince t h e f o r m a t i o n of w h i c h nea r ly t w o t h o u s a n d mi l l ion yea r s h a v e passed . T h u s , w e n o w k n o w t h a t o u r e a r t h is a ve ry old o ld - l adv a n d t h a t she is cons ider -ab ly o lde r t h a n t w o t h o u s a n d mi l l ion years .

T o c o n c l u d e this c h a p t e r I shou ld l ike to tell y o u a b o u t o n e m o r e p h e n o m e n o n w h i c h was d i scovered very r ecen t ly a n d w h i c h is p r o b -a b l y des t ined to p l a y a n i m p o r t a n t p a r t in t he life of peop le . W e h a v e seen t h a t b e g i n n i n g wi th a t o m i c n u m b e r 81 in M e n d e l e y e v ' s pe r iod ic system the a t o m s of t h e h e a v y c h e m i c a l e l e m e n t s h a v e n o t on ly s table , b u t also u n s t a b l e nucle i , t he l a t t e r possessing t h e p r o p e r t y of r ad ioac t iv i ty . I t also t u r n s ou t t h a t t he nuc l eus of a n a t o m becomes u n s t a b l e if a ce r t a in de f in i t e p r o p o r t i o n b e t w e e n the p r o t o n s a n d n e u t r o n s is g r e a t l y d i s t u r b e d . W i t h t h e n u m b e r of n e u t r o n s g r e a t l y

7 6

e x c e e d i n g t h a t of t h e p r o t o n s in t h e nuc l eus t he l a t t e r b e c o m e s un-s tab le .

As soon as scientists no t i ced this p r o p e r t y of t h e nuc le i of c h e m i c a l e l e m e n t s t h e y f o u n d a m e a n s of a r t i f ic ia l ly c h a n g i n g t h e p r o p o r t i o n b e t w e e n t h e p r o t o n s a n d n e u t r o n s in t h e nuc le i a n d , thus , to t r a n s f o r m t h e s t ab le var ie t ies of a t o m i c nuc le i i n to u n s t a b l e ones a n d to m a k e c h e m i c a l e l e m e n t s ar t i f ic ia l ly r a d i o a c t i v e a t t he i r will . H o w c a n this b e d o n e ?

T o d o this w e h a v e to f ind s o m e sort of p ro jec t i l e n o t l a r g e r t h a n t h e nuc l eus of t h e a t o m , i m p a r t a g r e a t d e a l of e n e r g y to it a n d fire it i n to t h e n u c l e u s of t h e a t o m .

T h e a l p h a par t ic les e m i t t e d b y r a d i o a c t i v e subs tances a r e j u s t t he pro jec t i l es of a t o m i c size w i t h a v e r y g r e a t a m o u n t of ene rgy . T h e y w e r e t h e first to b e e m p l o y e d b y scientists for t h e p u r p o s e of ar t i f ic ia l ly b r e a k i n g u p t h e n u c l e u s of t h e a t o m . E rnes t R u t h e r f o r d , f a m o u s Bri t ish physic is t , was t h e first to succeed w i t h i t ; wh i l e a c t i n g on t h e nuc l e i of n i t r o g e n a t o m s w i t h a l p h a rays in 1919, h e d i scovered t h a t these a t o m s e m i t t e d p r o t o n s .

F i f t e en years la te r , in 1934, t h e y o u n g F r e n c h scientists. I r £ n e C u r i e -J o l i o t a n d F r e d e r i c J o l i o t by a c t i n g o n a l u m i n i u m w i t h t h e a l p h a par t i c les of p o l o n i u m d i scovered t h a t u n d e r t h e ac t i on of t h e a l p h a rays a l u m i n i u m no t on ly e m a n a t e d rays c o n t a i n i n g n e u t r o n s , bu t r e t a i n e d its r a d i o a c t i v e p rope r t i e s a n d c o n t i n u e d to e m i t b e t a rays for s o m e t i m e a f t e r t h e e n d of i r r a d i a t i o n b y a l p h a par t ic les .

By c h e m i c a l ana lys is t h e J o l i o t - C u r i e s a s c e r t a i n e d t h a t it was no t t h e a l u m i n i u m itself t h a t b e c a m e ar t i f ic ia l ly r a d i o a c t i v e b u t t h e p h o s p h o r u s a t o m s f o r m e d f r o m t h e a t o m s of a l u m i n i u m u n d e r t he a c t i o n of t h e a l p h a par t ic les .

T h u s , t h e first a r t i f ic ia l ly r a d i o a c t i v e e l e m e n t s w e r e o b t a i n e d a n d a r t i f i c ia l r a d i o a c t i v i t y w a s d i scovered . A f t e r t r y i n g v a r i o u s m e t h o d s t o o b t a i n ar t i f ic ia l ly r a d i o a c t i v e e l e m e n t s scientists soon b e g a n a c t i n g o n t h e nuc le i of c h e m i c a l e l e m e n t s b y n e u t r o n s i n s t ead of a l p h a par t ic les s ince t h e f o r m e r p e n e t r a t e i n t o t h e a t o m i c nuc le i m o r e easily t h a n the l a t t e r w h i c h h a v e a posi t ive c h a r g e a n d a r e , t he r e fo re , r epe l l ed by t h e nuc l eus as t h e y a p p r o a c h t h e a t o m .

T h e s e repe l l ing forces a r e so g r e a t in t h e nuc le i of t h e a t o m s of t h e h e a v y c h e m i c a l e l e m e n t s t h a t t h e e n e r g y of a l p h a par t ic les does no t suffice to o v e r c o m e t h e m a n d t h e a l p h a pa r t i c l e s c a n n o t r e a c h t h e

77

nuc leus of t he a t o m . S ince n e u t r o n s d o no t c a r r y a n y e lec t r ic c h a r g e they a r e no t repe l l ed b y t h e nuc le i a n d easily p e n e t r a t e i n t o t h e m . As a m a t t e r of f ac t , it h a s b e e n possible t o o b t a i n a r t i f ic ia l ly r a d i o a c t i v e u n s t a b l e var ie t ies of a t o m i c nuc l e i for all t h e c h e m i c a l e l emen t s by a c t i n g o n these e l e m e n t s w i t h n e u t r o n s .

I n 1939 it was d i scovered t h a t w h e n u r a n i u m , t h e heavies t c h e m i c a l e l e m e n t , was a c t e d u p o n b y n e u t r o n s of low ene rgy , t he a t o m s of u r a n i u m suf fe red A' n e w , f o r m e r l y u n k n o w n , t y p e of d i s i n t eg ra t i on in w h i c h t h e n u c l e u s of t h e a t o m spli t u p i n t o t w o a p p r o x i m a t e l y e q u a l ha lves . T h e s e ha lves a r e themse lves u n s t a b l e var ie t ies of t h e a t o m i c nuc le i of f a m i l i a r chemica l e l e m e n t s f o u n d in t h e m i d d l e of M e n -de leyev ' s Pe r iod ic T a b l e .

O n e y e a r l a t e r , in 1940, K . P e t r z h a k a n d G . F le rov , y o u n g Sovie t physicists, d i scovered t h a t this n e w t y p e of d i s i n t eg ra t i on o r n e w t y p e of r ad ioac t iv i ty of u r a n i u m , also o c c u r r e d in n a t u r e , b u t t h a t it was e n c o u n t e r e d m u c h m o r e r a r e l y t h a n t h e u sua l d i s i n t eg ra t i on of u r a n i u m .

I f it takes ha l f of al l t h e a t o m s c o n t a i n e d b y u r a n i u m 4 ,500 mi l l ion years to b r e a k u p in o r d i n a r y r a d i o a c t i v e d e c a y , d i s i n t e g r a t i o n by divis ion of t h e a t o m s in ha lves takes 4 4 X 1 0 1 5 years . C o n s e q u e n t l y ,

this s econd t y p e of d i s i n t eg ra t i on occurs t en mi l l ion t imes as s lowly, b u t is a c c o m p a n i e d by a m u c h g r e a t e r l i be r a t i on of e n e r g y t h a n t h e usua l r a d i o a c t i v e d i s in t eg ra t i on .

As scientists d e m o n s t r a t e d in 1946, c e r t a i n s t ab le nuc le i of e l e m e n t s a r e f o r m e d in t h e new-t y p e of r a d i o a c t i v i t y of u r a n i u m as we l l ; t hese con t i nuous ly a c c u m u l a t e in n a t u r e a l o n g w i t h t h e f o r m a t i o n of u n s t a b l e a n d f u r t h e r d i s i n t e g r a t i n g nuc le i .

W h e r e a s t h e u sua l r a d i o a c t i v e d i s i n t e g r a t i o n is a t t e n d e d b y a f o r m a t i o n a n d g r a d u a l a c c u -m u l a t i o n of t h e a t o m s of h e l i u m t h e n e w t y p e of r ad ioac t i v i t y of u r a n i u m resul ts i n t h e for -m a t i o n a n d g r a d u a l c o n c e n t r a t i o n of t h e a t o m s of x e n o n or k r y p t o n .

By b o m b a r d i n g the- i so topes of u r a n i u m it has b e e n possible to o b t a i n a n u m b e r of n e w t r a n s -u r a n i u m e l e m e n t s — n e p t u n i u m w i t h t h e a t o m i c

7»

Uranium 255

Destruct ion of a ura-nium atom by a .slow-neutron

Barium Krypton

Neutron

n u m b e r of 93, p l u t o n i u m — 9 4 , a m e r i c i u m — 9 5 , c u r i u m — 9 6 , be r -k e l i u m — 9 7 , c a l i f o r n i u m — 9 8 , e i n s t e i n i u m — 9 9 , f e r m i u m — 1 0 0 a n d m e n d e l e v i u m — 1 0 1 ; t h e y h a v e all f o u n d the i r p laces in M e n d e l e y e v ' s Pe r iod i c T a b l e .

T h e mos t in te res t ing , t h o u g h , is t h e fac t t h a t by this n e w type of d i s i n t e g r a t i o n it has b e c o m e possible to d i r ec t a n d a c c e l e r a t e or s low it d o w n a t will. I f this process b e g r e a t l y a c c e l e r a t e d a n d t h e a t o m s c o n t a i n e d in o n e k i l o g r a m of u r a n i u m b e m a d e to b r e a k u p in this m a n n e r a t o n c e t h e e n e r g y a n d h e a t l i b e r a t e d as a resu l t will e q u a l t h a t p r o d u c e d by t h e c o m b u s t i o n of 2 ,000 tons of coal a n d a t r e m e n d o u s explos ion will occu r .

A f t e r , t h e explos ion t h e f r a g m e n t s themse lves will seek n e w fo rms of e q u i l i b r i u m un t i l t h e y l i b e r a t e t h e s u r p l u s e n e r g y a n d c h a n g e to m o r e s t ab l e a n d slowly d i s i n t e g r a t i n g a t o m s of d i f f e r e n t meta l s .

T h e r e m a r k a b l e p a r t of this d i scovery is t h a t h u m a n e n g i n e e r i n g n o t on ly p r o d u c e s these s t o r m y reac t ions w h i c h l i be r a t e t r e m e n d o u s ene rgy , b u t c a n also in f luence , r e t a r d o r a c c e l e r a t e t h e m a n d r e p l a c e t h e s t o r m y explos ions by a s lower a n d q u i e t e r l i be r a t i on of p o w e r f u l e n e r g y over a p e r i o d of t h o u s a n d s of years . A n d t h e b r i l l i an t t h o u g h t a b o u t n u c l e a r e n e r g y w h i c h was on ly a r i s ing a t t h e e n d of t h e 90 's in t h e m i n d of P i e r r e C u r i e , w h o j o i n t l y wi th his wife d i scovered r a d i u m , t h e t h o u g h t t h a t on ly few scientists d a r e d express o n t h e th re sho ld of t h e n e w c e n t u r y , is n o w b e c o m i n g rea l i ty .

W h e n in 1903 t h e scientists p a i n t e d a p i c t u r e of a h a p p y f u t u r e of h u -m a n i t y possessing endless reserves of t h e ene rgy i t n e e d e d , this i d e a seemed only a b e a u t i f u l f a n t a s y a n d d id n o t f ind c o n f i r m a -t ion e i the r in r ea l fac ts of n a t u r e or in t h e a c h i e v e -m e n t s of t h e e n g i n e e r i n g of t h e t ime . A n d n o w this d r e a m is c o m i n g t rue .

S m a l l w o n d e r t h a t u r a -n i u m has la te ly b e c o m e

m,

D i a g r a m of self-sustained chain reaction in the nuclei of uranium atoms - 2 ^

79

Neutron

Uranium 215

Fragments of nucleus Nucleus in the

process of division

the object of exceptional attention in all countries. Formerly it was only a waste product of radium production. The radium concerns in Belgium, Canada, the United States and other countries tried to find application for this by-product at large radium plants. But they could find no real use for it; it was low-priced and was utilized in dyeing porcelain and tile and in the production of cheap green glass.

The situation has changed of late; having become the centre of attention it is now uranium and not radium that is being searched and prospected for.

Even if it still requires a lot of effort to master this problem, even if this power is more expensive in the beginning than the power we get. from steam-boilers, grand opportunities for utilizing these practically eternal engines open up before humanity.

Man has a new form of energy more powerful than any-thing ever known before.

The scientists the world over are now doing their best to master this great new force as soon as possible.

It is a matter of regret that the warmongers are trying to utilize this energy primarily for destruction. But the forces that are capable of frustrating the plans of the handful of im-perialists and of making this new power serve all of working hu-manity have already matured. In the Soviet Union atomic energy is already being used for the production of electric power.

When the time comes that atomic energy is a commonplace

U r a n i u m reactor . This is the n a m e given to the device in which the chain nuclear react ion of u ran ium takes place. I t is an enormous tank filled with u r a n i u m and graphi te , which dece le ra tes the react ion. On the outs ide the reac tor is su r rounded by a subs tance which reflects neu t rons

80

thing we shall have electric stations fitting in a suit-case, motors of several horse power the size of a pocket watch, jet propulsion with a reserve of energy lasting several years and planes capable of flying for months on end without refuelling.

The age of atomic energy, the age of unprecedented might of man is in the offing.

And in the light of the new ideas about the structure of the atom D. Mendeleyev's Periodic Law has retained its significance.

Moreover, it will serve as the same guiding star in cognizing the intra-atomic phenomena as it has served in learning the chemical relations between the atoms.

We (7re beginning a m'w oge of

uranium and (iforrnc : energy

85

THE ATOM AND TIME

It is hard to conceive a simpler and at the same time a more complex idea than lime. An old Finnish proverb says: "There is nothing more remarkable, more complex and more invincible in the world than time." Aristotle, one of the greatest philosophers of the ancient world, wrote, four centuries B.C.. that amid the unknown in surrounding nature the most unknown was time because nobody knew what time was nor how to control it.

Kven at the early stages of culture man wondered about the be-ginning of time, about the end of tW world, about how surrounding nature was created, about the age ,of the earth, the planets and the stars and about how long the sun would shine in the sky.

•According to ancient Persian legends the world has existed only i 2,000 years.

The astrologers of Babylon who told fortunes by the stars believed the world was very old, that it was moi'f than two million years old, while the Bible taught it was onlv six thousand years since the will of God had created the world in six days and six nights.

The greatest minds continued studving the problem of time for many thousands of vears, and the ancient legends and fantasies of astrologers were gradually replaced by exact methods of estimating the age of our earth.

The astronomer Galileo was the first to at tempt an estimate of the earth's age in 1615; he was followed by Lord Kelvin in i8b'J. The latter calculated the age of the earth on the basis of the theory of its cooling and arrived at a figure which appeared enormous at the time -lorty million years.

Then geological methods came into use. In Switzerland, Britain, Sweden, Russia and America geologists began estimating the time our earth required to form the sedimentary rocks which are over one hundred kilometres thick.

It appears that rivers annually carry away at least 10 million tons of substance which they erode from the continents so that every 25,000 years our continents lose a layer of earth on the average one metre thick. Thus, by gradua' ly studying the activity of water and glaciers, the sediments on the earth and in the oceans and the striated glacial clays geologists have come to the conclusion that 40 million years could not cover the history of the earth's crust. In 1899 the British geophysicist Joly estimated the age of our earth at 300 million years.

But these estimates did not satisfy either the physicists or the chemists or even the geologists themselves.

The destruction of the continents did not at all proceed as regularly as Joly believed. The periods of sedimentation were followed by stormy explosions of volcanoes, earthquakes and rises of mountain ranges. The sediments already accumulated were melted and eroded.

Joly's estimate did not satisfy the exact investigators who wanted to find a real timepiece to tell the time of the past, a reliable gauge to estimate the age of the earth's crust.

And then chemists and physicists came to take the place of the geologists. They, finally, found a timepiece, a perpetual and eternal timepiece. This timepiece was not made by a skilled workman, it has no springs to make it run and does not need winding. This time-piece is the disintegrating atom of radioactive elements.

We have already learned in the preceding essay that the whole world is filled with disintegrating atoms and that the atoms of uranium and thorium, radium and polonium, actinium and many dozens of other elements break up in the unnoticeable but great process. This disintegration proceeds at a constant rate and, as before stated, cannot be accelerated or slowed down either by high temperatures of thousands of degrees or by the lowest temperatures approximating absolute zero, or yet by enormous pressures. No usual means can alter this definite and invariable process of disintegration of certain atoms which takes place in nature.

True, modern engineering has managed to find powerful means by which it is able to destroy and create atoms. But there are no such

6' 83

conditions in nature and the invariable rate of disintegration of the heavy elements is maintained for millions and thousands of millions of years.

The atoms of uranium, radium and thorium break up and certain amounts of atoms of helium and stable, lifeless atoms of lead are simul-taneously formed always and everywhere in the universe. These two natural elements—helium and lead—have created a new timepiece. And now, for the first time in human history, it has become possible to measure time by a real world standard of an eternal character.

What a striking picture which is at the same time so difficult of comprehension! Several hundred different atoms fill the universe with their complex electromagnetic systems. While radiating energy, they change by leaps from one form into another: some of the newly created systems are viable and are stubbornly preserved (the enor-mous length of the period of their transformations is, apparently, inaccessible to us); others exist thousands of millions of years slowly emitting energy and going through complex series of disintegration; still others live for years, days or hours; others yet exist seconds and even fractions of seconds.

Obeying the laws which govern the transformation of atomic systems the elements fill nature, but time regulates their quantitative dispersion, time distributes them through the universe and creates the complexity of life on our earth and in the universe.

Universal processes run slowly and eternally; the rapidly disintegrat-ing heavy atoms die, others break up under the action of alpha particles, still other and stabler universal bricks are created, and non-radio-active elements, the end-products of disintegration, gradually accu-mulate.

It has already been established that elements stable against alpha rays prevail in the sun; 90 per cent of the earth's surface consists of elements with an even number of electrons or a number divisible by four, i. e., precisely the elements most stable against the destructive action of gamma rays and cosmic rays. The stablest of these, simply and densely built, form our inorganic world; the less stable (as potassium and rubidium) take part in the vital processes and by their disinte-gration help the organisms to fight for their lives. The rapidly disin-tegrating elements (radon and radium) destroy this life by destroying themselves. In some stellar systems the process of disintegration is

« 4

AGE OF THE E A R T H

Million years

o

200

250

300

350

<i50

500

Periods Quaternary

Tertian/

Cretaceous

Jurassic

Triassic

Permian

Carboni-ferous

Devonian

Silurian

Orctovichian

Cambrian

Phases of mountain

formation

Alpine phase

only developing, as is the case in the rather mature system of our sun: in other systems in stellar nebulae— it is only beginning; in still others- in the dark extinguished bodies—the fading processes of disintegration are now taking place infinitely slowly. Time determines the composition, nature and combination of elements in the course of cosmic history.

Phvsicists and chemists have figured (nit that 1,000 grams ol uranium will vield 13 grams of lead and 2 grams of helium in 100 million years.

In 2,000 million years the amount of lead will already reach 22;, grams, i.e., one quarter of the uranium will change to lead, and 35 grams of volatile helium will accumulate. But the process continues and in 4,000 million years there will be 400 grams of lead and (>o grams ol helium with only half, 500 grams, of the primary uranium remaining.

Let us go on with our reasoning: let us take 100,000 million years rather than only 4,000 million; by that time most of the uranium will disintegrate and change to lead and helium. There will be hardly any uranium left on earth; heavy atoms of lead will be dispersed every-where in nature instead and the atmosphere will be enriched by-helium, the gas of the sun.

And so on the basis of these data geochemists and geophysicists have recently drawn up an absolute chronological scale of the geological evolution of the earth.

This new timepiece tells us that the age of our planet probably exceeds 3 to 4 thousand million years, i.e., 3 to 4 thousand million years must have elapsed since the moment in cosmic history when the planets of our solar system in-cluding the earth were formed. ^re-cambrian

ttera/nian phase

Caledonian phase

50

100

150

Charnian phase

More than 2,000 million years separate us from the appearance of the earth's hard crust, this second most important moment in the history of the earth, the beginning of its geological history. At least 1,000 million years has passed since the beginning of life. The famous Cambrian blue clay found in the environs of Leningrad began to be deposited about 500 million years ago.

" T i m e p i e c e " measur ing the ape of the ear th . If we t ake the dura t ion of the ea r th ' s his tory f r o m the beginning of the most ancient archaic e ra to our clays as 24 hours and cor respondingly reduce the dura t ion of all eras e s t ima ted by the r ad ioac t ive process, our t imepiece will show seventeen hours for the p r e - C a m b r i a n era , four hours for the Pa leozoic era, two hours for the Mesozoic e ra and one hour for the Cainozoic era . M a n a p p e a r s only five minutes b e f o r e midn igh t

During the first epoch, i.e., three-fourths of the entire geological history of the earth, molten masses repeatedly broke out of the interior to the surface and disturbed the calm of the first, still thin, but hard shell of the earth. The molten masses poured out on to its surface,

impregnated it with their hot breath and solutions, bent and lifted it in the form of mountains. Our geochemists and geologists have already found the oldest mountain ranges on earth (Belomorids in Karelia and the oldest granites in the state of Manitoba, Canada) . These ranges are about 1,700,000,000 years old.*

Then the long history of the development of the organic world began. The diagram on page 86 shows the duration of each geological epoch.

About 500 million years ago the mighty ranges of Caledonia rose in the north of Europe; the ranges of the Urals and Tien Shan were formed 200 to 300 million years ago; the formation of the Alps lasted about 25 to 50 million years, while the last paroxysms of the Caucasian volcanoes were being extinguished and the mountain peaks of the Himalayas were rising.

Then came prehistoric t ime; the glacial epochs began one million years ago; the first man appeared 800,000 years ago; the last glacial epoch ended 25,000 years ago; the Egyptian and Babylonian cultures began 10,000 to 8,000 years ago; bur chronology started 1,958 years ago.

It will be many more years before scientists accurately verify their remarkable timepiece. But the method has been found. One of the riddles of time has been solved and there can be 110 doubt- tha t the chemist will soon be able to tell the age of each individual sample of stone, will be able to determine the time that has elapsed since it was formed.

Mr. Chemist, we no longer believe your atoms are invariable; everything is fluid, everything changes, everything disintegrates and is recreated, one tiling dies and another comes into being; such is the history of the world's chemical processes in time. But man has been able to transform even the death of the atom into an instrument "v? of cognizing the world and into a standard measure of time. ^

* S o m e A m e r i c a n a u t h o r s e s t i m a t e t h e a g e of t h e M a n i t o b a g r a n i t e s a t 3 ,100 mi l l i on yea r s , b u t Sovie t sc ient is ts c o n s i d e r these f igu res e x a g g e r a t e d . Ed.

P A R T T W O

C H E M I C A L E L E M E N T S IN N A T U R E

SILICON—BASIS OF THE EARTH'S CRUST

One of Zhukovsky's ballads tells us about a foreigner who came to Amsterdam and to his questions about who owned the stores, the houses, the ships and the lands received the invariable answer: "Kan met verstaan." " H o w rich he must be ," the foreigner thought envying the man, unawares that in Dutch these words meant " I cannot under-stand."

I recall this story whenever I am told about quartz. I am shown most diverse objects: a transparent sphere glittering in the sun with the clearness of cold spring water, a beautiful agate of a variegated

D r u s e of rock crystal , the pures t and mos t t r a n s p a r e n t var ie ty of qua r t z

9 1

S f | 28.06

pattern, a multi-coloured sparkling opal, pure sand on the seashore, a thread of molten quartz as thin as a silk fibre, or fireproof pottery made of the same quartz, beautifully faceted piles of rock crystal, a mysterious pattern of fantastic jasper, a petrified tree turned into Hint, a crudely formed arrow-head of primitive man; and whatever my question I am told: all this is made of quartz or of minerals with a very similar composition. It is all the same chemical compound of silicon and oxygen.

Si is the symbol for silicon, the second most abundant element in nature (oxygen is the first). I t never occurs in the free state; it always forms a compound with oxygen—Si02 , which is known as silica, or silicon dioxide.

S I L I C O N A N D S I L I C A

Granite contains about 80 per cent silica or 40 per cent silicon. Most hard rocks are built of its compounds. The porphyry of the mausoleum in Red Square, the beautiful granites in the revetment of the Moskva Hotel and the dark-blue sparkling labradorite feeing the ground floor of some houses in Dzerzhinsky Street in Moscow, in a word, all the hard and strong rock of the earth is composed of more than one-third silicon.

Silicon is the chief constituent of ordinary clay. The common sand found on river banks, the sandstones and shales are essentially also silicon. No wonder, therefore, that about 30 per cent by weight of the entire earth's crust consists of this element and that down to the depth of 16 kilometres about 65 per cent of the crust is formed of its main compound with oxygen which chemists call silica or SiO, and which we most frequently refer to as quartz. We know more than two hundred different varieties of natural silica, while mineralogists and geologists use more than one hundred different names when enumerating various kinds of this most important mineral.

We speak of silicon dioxide when we name flint, quartz, rock crystal and mean the same when we admire the beauty of violet amethyst, of variegated opal or red sard, black onyx or grey chalcedony; it also includes the beautiful varieties of jasper, whetstone and ordinary

9 2

sand. Most diverse names are given to the individual varieties and it prob-ably requires a whole science to make out the compounds of this remarkable element.

But in nature we even encounter many more compounds in which our silica is combined with oxides of other metals and, thus, gives rise to thousands of new mineral varieties called silicates.

M a n makes use of these in his con-struction and in general economy; the most important of them are clays and feldspars used in the manufacture of various kinds of glass, porcelain and pottery; they are used in the produc-tion of window-panes, cut-glass and concrete, which is as strong as armour and which forms one of the chief materials in the construction of high-ways, bridges and reinforced concrete flooring and roofing of plants and factories, theatres, houses, etc.

Is there anything in the world that can compare in strength and diversity of its properties with silicon and its compounds in the hands of man?

N a t u r a l p i l l a r s - ind iv idua l struc-tures of volcanic rock-basa l t . Rovno Region, Ukrainian S.S.R,

S I L I C O N I N A N I M A L S A N D P L A N T S

But even long before ingenious man learned to use silicon dioxide for his needs nature had made extensive use of it in the life of plants and animals. Wherever it was necessary to build a strong stalk or a firm straw of an ear the content of silica increased, and we know what a great deal of it is contained in the ash of ordinary straw and especially in the strong stems of such plants as horse-tail which grew in the distant geological carboniferous epochs rising from marshy lowlands for dozens of metres like the bamboo tubes rich in silica now rise in the gardens of Sukhumi and Batumi. In these plants nature was able to combine

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the law of mechanical strength with the strength of the material itself.

But the strength of the stem is of enormous practical importance not only to the ears of cereals, which it prevents from falling under the blows of wind or rain, but also to other plants.

Flowers and decorative plants are transported by planes every day; in order to prevent the flowers from crumpling and to keep their stems intact it is necessary to add readily soluble silicon salts to their soil. The plants absorb silica with water and their stems grow strong and durable.

But it is not only the stems that need the strength of silicon and its compounds. The minutest plants, diatomaceous seaweeds build their skeletons from silica, and we now know that one cubic centimetre of rock formed from the testae of these seaweeds requires about 5,000,000 of these small organisms. Particularly remarkable are the structures in which silica is used by animals to build their skeletons. Animals found various solutions for

the problem of strength in the different epochs of the development of life. In some cases they protected their bodies with an ex-ternal calcareous shell; in others they built this shell from calcium phosphate; in still other cases a hard skeleton instead of the shell formed the foundation of the animal, this skeleton being made of most diverse but strong materials. Sometimes these were calcium phosphates like the substance of which our bones are built; sometimes they were fine, delicate needles of bar ium and strontium sulphates; finally, some groups of animals made use of

Radio la r i a . P s e u d o p o d i a of the liv-ing cell p r o t r u d e f r o m the openings in the e legan t flint skeleton

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Flint skeleton of a "g lass" sponge about 50 cm. long

strong silica of which they built their structures. Thus, the families of radiolarians constructed their delicate skeletons from fine silicious needles.

Some sponges also form their hard parts from silicious needles— spiculae.

Nature contrives to use silica in hundreds of different ways to give the soft, changeable cells firm support.

W H Y A R E S I L I C I O U S C O M P O U N D S S O S T R O N G ?

Our scientists have been trying for some time to solve the riddle of the remarkable strength that silicon imparts to the skeletons of animals and plants, to thousands of minerals and rocks, and to the finest industrial commodities.

And when the eyes of our roentgenologists penetrated into the interior of silicious compounds they beheld remarkable pictures that revealed the reason for their strength and the riddle of their struc-ture.

It appears that silicon contained in them is in the form of charged atoms—ions 0.000,000,004 cm. in size. These small charged globules are united with similar but larger charged globules of oxygen. As a result, four globules of oxygen, touching each other, very closely

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Arrangement of atoms of silicon (white balls) and oxygen (black) in a cry stal of quartz. The atoms of oxy-gen always bind the a toms of silicon. I ' ramc structure

arrange themselves around each of these silicon globules and form a special geometrical figure which we call a tetrahedron.

The tetrahedrons combine with each other according to different laws and give rise to large and complex structures which it is hard to compress or bend and in which it is uncommonly difficult to break an atom of oxygen away from the central atom of silicon.

Modern science has found that these tetrahedrons may form thou-sands of combinations.

Other charged particles some-times arrange themselves among them; in some cases our tetrahe-

drons combine into separate bands or films forming clays and talcs, but combinations of tetrahedrons are always the basis of their structures.

And as carbon and hydrogen form hundreds of thousands of different compounds in organic chemistry, silicon and oxygen form thousands of structures in inorganic chemistry; the complexity of these structures has been revealed by X-rays.

Silica is not only difficult to destroy mechanically; it is not only so hard that a sharp steel knife cannot cut into the compound, but it is also stable chemically because not a single acid except hydrofluoric acid can destroy or dissolve it and only a very strong alkali dissolves silica* transforming it into new compounds. It is very hard to melt and begins to pass into the liquid state only at 1,600 to i ,700° C.

No wonder, therefore, that silicon and its various compounds form the basis of inorganic chemistry. In our time a whole science of chem-

* S i l i ca is ea s i ly f u s e d w i t h s o d a ; in t h i s c a s e t h e c a r b o n d i o x i d e of" t h e s o d a is v e r v v i o l e n t l y l i b e r a t e d a n d a t r a n s p a r e n t g l o b u l e of s o d i u m s i l i ca t e , w h i c h d i s so lves in w a t e r , is f o r m e d . T h i s is w h y w e ca l l it s o l u b l e g lass .

96

We two form thousands

of structures

istry of silicon has come into being, and the paths of geology, mineralogy, engineering and construction are interlaced with the history of this element at each step.

HISTORY OF SILICON IN THE EARTH'S CRUST

Let us now take several examples in order to trace the fate of silicon in the earth's crust. With metals it forms the basis of the molten magma in the interior of the earth's crust. When this molten magma hardens in the interior forming crystalline rock—granites and gabbro, or pours out to the surface in the form of lava streams, basalt and other rock, complicated compounds of silicon, called silicates, are formed. If there is a surplus of silicon pure quartz makes its appearance.

Here they are, the short crystals of quartz in granite porphyries or the dense smoky crystals in pegmatite veins, the last remnants of the melts of this earth's interior. If you carefully bake a piece of this "smoky topaz"* in bread or heat it to 300 or 4003 C. you will get "golden topaz" with which you can make a bead or a brooch.

Here are quartz veins with white compact quartz. We know that some of them are hundreds of kilometres long. Immense quartz veins stand out like beacons on the slopes of the Urals. Veins with cavities filled with transparent rock crystal stretch for many hundreds of kilo-metres here. These are the pure transparent varieties of quartz de-scribed by the Greek philosopher Aristotle who gave them the name "crystal" and who connected the origin of rock crystal with petri-fied ice. This is the rock crystal which as far back as the 17th century was mined in the natural "cellars" of the Swiss Alps with individ-ual cavities yielding up to 500 tons, i.e., up to 30 carloads, of rock crystal.

Individual crystals are sometimes enormously large. A crystal of rock crystal 8 metres in circumference was found on Madagascar. The Japanese turned an immense sphere more than one metre in diameter and weighing nearly 1.5 tons from Burmese transparent rock crystal.

* T h e n a m e d o e s n o t q u i t e fit s i nce in c o m p o s i t i o n " s m o k y t o p a z " is m e r e l y a q u a r t z ( S i O , ) a n d n o t a r e a l t o p a z w h o s e c o m p o s i t i o n is m o r e c o m p l e x ; it i n c l u d e s s i l icon , a l u m i n i u m a n d fluorine w i t h o x y g e n — A l 2 F 2 ( S i 0 4 ) .

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Another type of silica, which exter-nally in no way resembles the variety we have just discussed, is precipitated from molten lava when hot silica-laden steams deposit immense masses of silicious nodules and geodes ih separate veins or gas cavities. And as the rock disintegrates into clay gruss enormous balls up to one metre in diameter roll, as it were, out of it.

In the State of Oregon (U.S.A.) they are known by the name of "giant eggs." They are broken up into pieces and then sawed up into thin plates to produce beautiful laminated agates, i. e., raw material for the "rubies" of watches and other pre-cision instruments, for the knife-edges of balances and for mortars used in chemical laboratories. Even after the

cessation of volcanic activity, silica is sometimes brought out to the earth's surface by hot springs due to the presence of cooling extruded masses. Such, for example, is the origin of the "base opal" deposited by geysers in Iceland and in Yellowstone National Park in the U.S.A.

Let us take a look at the snow-white sands of the dunes on the coast of the Baltic and of the northern seas and at the millions of square kilometres of sandy deserts in Central Asia and Kazakhstan; it is sand that determines the nature of sea coasts and deserts: quartz sand now with a red film of ferric oxide, now with a prevalence of black flint and now pure white, cleaned by the sea-waves.

And here are fancy wares made of rock crystal. With the aid of various scrapers and emery powder a skilful Chinese craftsman has made fantastic articles from quartz crystals.

Wonder how many decades he spent on turning this little vase or on making this monstrous dragon, or on hollowing out this little bottle for rose oil?

Remains of quar tz veins p rese rved as the mos t d u r a b l e par t s of the ea r th ' s crust du r ing wea the r ing . H e i g h t 30 met res

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D e p o s i t s of g e y s e r i t e - b a s e o p a l - f o r m te r races of silicious tuff

There is an agate plate dyed different colours. Ingenious man has learned to impregnate it with different solutions, thus changing the grey, unattractive agate into brightly coloured plates to be used in the manufacture of various wares.

But here we see even more wonderful pictures: entire petrified forests in Arizona, stone tree-trunks of pure silica- agate in the Western regions of the Ukraine and amid the Permian deposits on the Western slopes of the South Urals.

Here is a sparkling stone resembling the light in a cat's or a tiger's eye. Here we have mysterious crystals inside which we see, "phantom-like," what appears to be other crystals of the same quartz. And here reddish-yellow sharp needles—"Cupid's Arrows"—of the mineral rutile pierce rock crystal in every direction. Here is golden felt— "Venus ' Hai r . " Here we see a remarkable stone with a cavity inside nearly completely filled with water. The water plays and sparkles inside the silicious shell.

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Here we have an incredibly tor-tuous tube, a result of the action of lightning on quartz sand, alloyed ful-gurites, "arrows from the sky" or " thunderbol ts" as the people call them. And there are stones from the sky. Singular meteorites of green or brown glass rich in silica are found in various sections of the vast zone which stretches across Australia, Indo-China and the Philippines.

T o think of the controversies these mysterious formations gave rise to! Some thought these were remains of molten glass of ancient man ; others believed them to be molten particles of terrestrial dust; still others con-sidered them to be products of sands

which melted when masses of meteor iron fell into them; but most scientists are inclined to believe they are real particles from other worlds.

F L I N T A N D Q U A R T Z I N T H E H I S T O R Y O F C U L T U R E

A N D E N G I N E E R I N G

In the preceding pages I tried to paint for the reader a picture of the complex history of quartz, silica and their varieties. From the hot molten materials to the cold surface of the earth, from the cosmic regions to the sand that is strewn on our icy sidewalks, we encounter silicon and silica everywhere; we find quartz all over as one of the most remarkable and most abundant minerals in the world.

I could finish my story of quartz right here, but I want to tell you about the tremendous importance of quartz in the history of culture and engineering. It is no mere accident that primitive man made his first tools from flint or jasper. It is not without reason that the earliest decorations in the ancient Egyptian structures and in the remains of the Shumerian Culture in Mesopotamia were made pre-

Sea sand of fine crystalline grains of quartz. T h e purest sand is used for the manufac tu re of quar tz glass

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cisely from quartz. I t is not in vain that as early as 12 centuries B. C. the peoples of the East learned to melt sand with soda and produce glass.

Rock crystal found most extensive application with the Persians, Arabs, Indians and Egyptians, and we have information that quartz was processed five and a half thousand years before our time. For many centuries the ancient Greeks believed rock crystal to be petrified ice turned into stone by divine providence.

Many fantastic stories are connected with this stone. Enormous importance was attached to it in biblical legends. In the construction of Solomon's Temple in Jerusalem this mineral played a very im-portant part under different names: agate, amethyst, chalcedony, onyx, sard, etc.

The first industry for processing this stone was organized in the middle of the 15th century. Man learned to cut, grind, colour and widely utilize it for decorative purposes. But this was all individual attempts of handicraftsmen and was not done on a mass scale until the new engineering made greater demands on it. Rock crystal is now extensively used in industry and in radio-engineering where supersonic waves are picked up and transformed into electric oscilla-

Crystal chande l ie r s a t t he S ta te Ph i lha rmon ic Society in L e n i n g r a d

l o t

t ions b y m e a n s of p iezo-q u a r t z p la tes . R o c k crys ta l h a s b e c o m e o n e of t h e m o s t i m p o r t a n t f o r m s of r a w m a t e r i a l fo r o u r in -dus t ry .

I n a d d i t i o n to t h e f l u t e t u r n e d f r o m rock c rys ta l ( V i e n n a A r t M u s e u m ) a n d t h e t r a n s p a r e n t s a m o v a r ( A r m o u r y M u s e u m in M o s -cow) w e n o w h a v e smal l q u a r t z p la t e s for t h e r a d i o ; these smal l p la tes a r e re-spons ib le for t h e success of o n e of t h e g rea t e s t dis-cover ies of m a n — l o n g -d i s t a n c e t r ansmis s ion of e l e c t r o m a g n e t i c waves .

Bu t q u a r t z , i .e. , p u r e

rock crvs ta l , will soon b e Every th ing in this p ic ture is m a d e of q u a r t , glass m a d e , j y c h e m i s t s C r y s t a l s

of this m i n e r a l — s m a l l p u r e p la te s for t h e r a d i o a n d ,

m a y b e , for o u r w i n d o w - p a n e s a n d c r o c k e r y wi l l b e g r o w n o n f ine silver w i r e a t a h i g h t e m p e r a t u r e a n d u n d e r g r e a t p re s su re in l a r g e a i r t i g h t vessels filled w i t h l i qu id glass.

T h e n t h e l i fe-giving u l t r a -v io l e t r ays of t h e sun , r e t a i n e d b y o r d i n a r y w i n d o w - p a n e s , will fill o u r rooms . W e shal l h a v e c rocke ry m a d e of m o l t e n q u a r t z a n d shal l b e ab l e to d i p in co ld w a t e r q u a r t z cups , h e a t e d on a stove, w i t h o u t a n y misg iv ing .

M o s t de l ica te fabr ics wil l b e w o v e n f r o m v e r y f ine q u a r t z t h r e a d s , so fine in f ac t t h a t five h u n d r e d of t h e m p u t t o g e t h e r will b e n o th i cke r t h a n a m a t c h s t ick; a n d silica will be t h e m a t e r i a l n o t on ly for b u i l d i n g t h e skeletons of t h e m i n u t e s t r a d i o l a r i a n s , b u t also for t h e c lo thes of m a n .

R o c k crys ta l has b e c o m e t h e basis of n e w e n g i n e e r i n g ; n o t on ly t h e geochemis t uses it as a t h e r m o m e t e r for t a k i n g t h e t e m p e r a t u r e

10a

of t h e t e r res t r i a l processes ,* a n d n o t on ly t h e physicis t d e t e r m i n e s t he l e n g t h of e l e c t r o m a g n e t i c w a v e s w i t h t h e a id of q u a r t z ; q u a r t z offers n e w a n d t e m p t i n g p rospec t s in v a r i o u s b r a n c h e s of i n d u s t r y a n d will soon f o r m p a r t a n d p a r c e l of o u r d a y - t o - d a y life.

T h e m o r e pers i s ten t ly chemis t s a n d physicists m a s t e r t he a t o m s of sil icon t h e soone r t h e y will wr i t e o n e of t h e m o s t r e m a r k a b l e pages i n t h e h i s to ry of sc ience a n d eng inee r ing , as well as in t he h is tory of t h e e a r t h itself.

* ] f rock c rys ta l c rys ta l l i zes a t a t e m p e r a t u r e a b o v e 5 7 5 ° C . it f o r m s c rys ta l s of a spec ia l a p p e a r a n c e , i .e . , h e x a g o n a l d i p y r a m i d s . If it f o r m s f r o m so lu t ions a t t e m p e r a t u r e s b e l o w 5 7 5 ° C . t h e s h a p e of its c rys ta l s is d i f f e r e n t ; t h e c rys ta l s a r c e l o n g a t e d in t h e f o r m of h e x a g o n a l p r i s m s . — Ed.

CARBON—BASIS OF ALL LIFE

c6 12.010

Is t h e r e a n y o n e w h o h a s neve r seen a p rec ious i r idescen t d i a m o n d , or g rey g r a p h i t e , o r o r d i n a r y b lack c o a l ? All these a r e on ly d i f f e r e n t fo rms in w h i c h the s a m e e l e m e n t — c a r b o n — i s f o u n d in n a t u r e .

T h e r e is re la t ive ly l i t t le c a r b o n 011 e a r t h ; its a m o u n t cons t i tu tes o n e pe r cen t of t he w e i g h t of t h e e a r t h ' s c rus t , b u t it p lays a n e n o r -m o u s ro le in t h e c h e m i s t r y of t h e e a r t h : w i t h o u t it life w o u l d b e i m -possible.

T h e to ta l a m o u n t of c a r b o n in t h e e a r t h ' s c rus t is 4 ,584 ,200 ,000 mi l l ion tons. C a r b o n is d i s t r i b u t e d t h r o u g h t h e e a r t h ' s c rus t as fol lows:

W e m u s t a d d to this 2 ,200 ,000 mi l l ion tons in t h e a t m o s p h e r e a n d 184,000,000 mi l l ion tons in t h e w a t e r of t h e oceans .

Le t us look i n t o t h e h is tory of c a r b o n , t h e e l e m e n t of w h i c h l iv ing m a t t e r is bu i l t a n d w h i c h is s t u d i e d b y a specia l b r a n c h of c h e m i s t r y . A good d e a l of its m i g r a t i o n t h r o u g h t h e e a r t h ' s c rus t is still m y s t e r i o u s a n d v a g u e .

A t t h e earl iest s tages of its ex is tence accessible to o u r r e sea rch w e e n c o u n t e r this e l e m e n t in m o l t e n m a g m a s . I t f o r m s p a r t of d i f f e r e n t rocks w h i c h h a v e h a r d e n e d in t he i n t e r i o r a n d in t h e ve ins of m o l t e n

I n l i v i n g s u b s t a n c e . I n soi ls I n p e a t I n b r o w n c o a l I n c o a l I n a n t h r a c i t e

4 0 0 , 0 0 0 m i l l i o n t o n s 1 , 2 0 0 , 0 0 0 m i l l i o n t o n s 2 , 1 0 0 , 0 0 0 m i l l i o n t o n s 3 , 2 0 0 , 0 0 0 m i l l i o n t o n s

7 0 0 , 0 0 0 m i l l i o n t o n s

6 0 0 . 0 0 0 m i l l i o n t o n s I n s e d i m e n t a r y r o c k s . . . 4 , 5 7 6 . 0 0 0 , 0 0 0 m i l l i o n t o n s

1 0 4

Vegeta t ion of the C a r b o n i f e r o u s pe r iod , f r o m which coal was f o r m e d

masses n o w in t h e f o r m of l i t t le leaves o r g l o b u l a r c lusters of g r a p h i t e ancl n o w in t h e s h a p e of crysta ls of p rec ious d i a m o n d s . B u t t h e mos t of t he c a r b o n escapes t h e h a r d e n i n g massifs ; it rises a l o n g veins as vo la t i l e h y d r o c a r b o n s a n d c a r b i d e s a n d p r o d u c e s a c c u m u l a t i o n s of g r a p h i t e (for e x a m p l e , o n Cey lon) o r c o m b i n e s w i t h oxygen a n d rushes u p w a r d in t h e f o r m of c a r b o n d iox ide .

W e k n o w t h a t in t h e i n t e r io r t he o m n i p o t e n t si l icon d iox ide p r even t s this gas f r o m f o r m i n g sal ts ; as a m a t t e r of f ac t we d o n o t k n o w a single m o r e o r less i m p o r t a n t m i n e r a l c o n t a i n i n g c a r b o n d iox ide in igneous rock. Bu t t h e s a m e rocks r e t a i n it m e c h a n i c a l l y in the i r cavi t ies ( jus t as t h e y r e t a i n e d so lu t ions of c h l o r i n e sal ts) , a n d these gas inclus ions a c c u m u l a t e 5 t o 6 t imes as m u c h c a r b o n d iox ide as we h a v e in o u r a t m o s p h e r e .

I n t h e reg ions of vo lcanoes , n o t on ly ac t ive b u t a l r e a d y long ex t inc t , this gas b r o k e o u t i n t o t h e a t m o s p h e r e as ea r ly as t h e t e r t i a r y p e r i o d , n o w co l lec t ing i n s e p a r a t e gas s t r e a m s t o g e t h e r w i t h

1 0 5

T o p : d i a m o n d and g raph i t e consist of ca rbon a toms bu t the a toms a r r a n g e themse lves in these minera l s d i f fe rent ly . In the d i a m o n d (right) each a tom is su r rounded equid is tan t ly by fou r a toms of carbon ( t e t r ahedrons ) . In g raph i t e the a toms a re a r r a n g e d in l ayers ; the a tomic b o n d s b e t w e e n the layers a re w e a k

o t h e r vo la t i l e c o m p o u n d s a n d n o w m i x i n g w i t h w a t e r a n d f o r m i n g n a r s a n s ( m i n e r a l w a t e r s ) .

M a n h a s m a d e use of these w a t e r s for t h e r a p e u t i c p u r -poses a n d h a s bu i l t s a n a t o r i a a n d h y d r o p a t h i c es tabl i sh-m e n t s n e a r t h e m , for e x a m -ple , i n t h e C a u c a s u s . T h e w a t e r in t h e m is so over -s a t u r a t e d w i t h c a r b o n d i o x i d e t h a t t h e b u b b l e s c o n s t a n t l y r is ing t o t h e su r f ace c r e a t e t h e impress ion t h a t t h e w a t e r is bo i l ing .

If y o u visit t h e U r a l s , h o w e v e r , y o u will n o t f ind a n y such w a r m c a r b o n d iox ide spr ings . G e o c h e m i s t r y exp la ins this d i f f e r e n c e in t h e compos i t i on of t h e w a t e r s of t he U r a l s a n d t h e C a u c a s u s b y t h e f a c t t h a t t h e U r a l s a rose m u c h ea r l i e r t h a n t h e C a u c a s i a n M o u n t a i n s a n d t h e u n d e r g r o u n d rocks h a d a l r e a d y cooled h e r e d u r i n g t h e pe -r iod of m o u n t a i n f o r m a t i o n .

Bu t in t he C a u c a s u s a focus of h e a t h a s b e e n r e t a i n e d d e e p u n d e r t he m o u n t a i n s . T h e rocks l oca t ed n e a r this focus a n d c o n t a i n i n g c a r b o n d iox ide (cha lk a n d l imes tones ) p a r t l y d e c o m p o s e u n d e r t h e i n f l u e n c e of t he h e a t a n d l i b e r a t e gaseous c a r b o n d iox ide . T h i s c a r b o n d iox ide rises a l o n g cracks to t h e su r face t o g e t h e r w i t h t h e m i n -era l ized w a t e r .

W e k n o w cases w h e n t h e u n d e r g r o u n d s t r e a m s of c a r b o n d iox ide a r e so p o w e r f u l a n d a r e e jec ted u n d e r such h i g h p ressure t h a t o w i n g to t he i r e v a p o r a t i o n a fog a n d " s n o w " a r e f o r m e d of t h e solid c a r b o n d iox ide n e a r ^ „ „ „ , , , . . . , s t e l l a t e crystals of g raph i t e in igneous rock. t he po in t s of t he i r exit on t h e [)men Mountains in the South Urals

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su r face of t h e e a r t h . T h i s solid c a r b o n d iox ide f r o m the n a t u r a l s t r e a m s is used for t e c h n i c a l p u r p o s e s as d r y ice.

T h e r e w e r e pe r iods in t h e h i s to ry of t h e e a r t h ' s c rus t w h e n inc reased vo l can i c ac t iv i ty e x t r u d e d t r e m e n d o u s a m o u n t s of c a r b o n d iox ide i n t o t he a t m o s p h e r e ; t h e r e - w e r e also t imes w h e n l u x u r i a n t t ropica l v e g e t a t i o n r e t u r n e d a lot of c a r b o n to its n a t i v e s ta te . T h e role of m a n w i t h his i ndus t r i a l ac t iv i ty pa les b e f o r e these processes.

E n o r m o u s a m o u n t s of c a r b o n d iox ide a r e n o w t h r o w n ou t by ac t ive vo lcanoes , for e x a m p l e , Vesuv ius , E t n a , K a t i n a i in Alaska , etc. T h e gases e jec ted by vo lcanoes consist m a i n l y of c a r b o n d iox ide .

C a r b o n i c ac id beg ins its de s t ruc t ive ac t i on on the su r face of the e a r t h as a p o w e r f u l f a c t o r of c h e m i c a l t r a n s f o r m a t i o n s ; un l ike t he i n t e r io r he r e it is c a r b o n i c a n d no t silicic acid t h a t is m a s t e r of the s i t u a t i o n ; it des t roys igneous rock , ex t rac t s me ta l s , c o m b i n e s wi th c a l c i u m a n d m a g n e s i u m a c c u m u l a t i n g in t he f o r m of l imes tones a n d d o l o m i t e s ; its salts collect in w a t e r bas ins in i m m e n s e a m o u n t s , a n d it is f r o m these salts t h a t o r g a n i s m s m a k e the i r shells a n d corals bu i ld the i r m i g h t y s t ruc tu re s .

W e c a n n o t suff ic ient ly a p p r e c i a t e t h e s ign i f icance of these slow t r a n s f o r m a t i o n s of c a r b o n on the e a r t h ' s su r f ace s ince they no t on ly i n f l uence t h e c l i m a t e on t h e sur face , bu t also d e t e r m i n e t h e c h a n g e s in t h e d e v e l o p m e n t of t he en t i r e o r g a n i c w o r l d .

J u s t i m a g i n e for a second w h a t t h e e a r t h w o u l d look like w i t h o u t c a r b o n . I t m e a n s t h e r e w o u l d no t be a s ingle t ree , or g reen leaf or b l a d e of grass. N o r w o u l d t he re be a n y a n i m a l s . O n l y b a r e cliffs of va r i ous rocks w o u l d j u t o u t a m i d the lifeless s ands a n d si lent deser ts of the e a r t h . T h e r e wou ld be n o m a r b l e a n d n o l imes tones wh ich d e c o r a t e o u r l a n d s c a p e s wi th the i r w h i t e co lour . T h e r e w o u l d be n e i t h e r coal n o r oil. W i t h o u t c a r b o n d iox ide t he c l i m a t e of t he ea r th wou ld be m o r e severe a n d co lde r s ince t h e c a r b o n d iox ide in t he a tmos -p h e r e p r o m o t e s a b s o r p t i o n of t h e l u m i n o u s e n e r g y of the sun .

T h e wa te r s , too, w o u l d b e lifeless. T h e c h e m i c a l p r o p e r t i e s of c a r b o n a r e very p e c u l i a r . I t is the on ly

e l e m e n t t h a t yields a n u n l i m i t e d n u m b e r of c o m p o u n d s wi th oxygen , h y d r o g e n , n i t r o g e n a n d o t h e r c h e m i c a l e l emen t s . M a n y of these c a r b o n or o r g a n i c c o m p o u n d s themse lves cons t i t u t e va r i ous c o m p l e x pro te ins , fats, c a r b o h y d r a t e s , v i t a m i n s a n d m a n v o t h e r c o m p o u n d s wh ich fo rm p a r t of t he tissues a n d cells of l iving o rgan i sms .

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G e o c h e m i c a l cycle of c a r b o n

The very name "organic compounds" indicates that man learned about carbon compounds when he began isolating them from the tissues of plants and animals as, for example, sugar and starch, later learning to produce manv artificial compounds. Today organic chem-istry which studies carbon and its compounds, their synthesis and analysis, numbers more than one million organic compounds. We may point out for comparison that our laboratories produce more than 30,000 inorganic compounds and that there are less than 3,000 natural inorganic compounds or minerals.

There are so many organic compounds that we have to give them ever longer and more complicated names; for example, acrichm. the well-known medicine for malaria, has the following full n a m e - -<kmethoxychlorodieth\iamin()methvll)utylaminoacrichin."

The capacity of carbon to yield numerous compounds is responsible for the wealth and diversity of species of plants and animals of which there are at least several million.

But this does not mean that carbon forms the main mass in the living organisms, or living substance, as we sav in geochemistry. They only contain 10 per cent carbon; they arc composed mainly of water (up to 80 per cent), the rest being other chemical elements.

Owing to the ability of organisms to nourish, develop and reproduce themselves, enormous masses of carbon pass through living substance

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STABLE F O R M S

/fydrocarbons Living substance Carbon dioxide Carbonates

Carbon dioxide Carbonates Graphite

Carbon dioxide ? (graphite)

Diamond Carbides Fe, Mi, etc.

REGIONS OF THE INTERIOR

Earth's surface (biosphere)

Region of mefamorphism

Piatomc region

Carbonates '(Sand- stones)

Carbonates (marbles)

Carbon-sil/cafes

8ifuminous shales, coals

oils, tars

Carbides Diamond

Living substance -

&asei

in t he process of life. Y o u m u s t h a v e seen man}- t imes h o w a p o n d begins to b e o v e r g r o w n w i t h a g r e e n film of seaweeds a n d o t h e r p lan t s o n t h e su r face in t he sp r ing , h o w these p l an t s ful ly m a t u r e in t he s u m m e r a n d h o w t h e y g r o w b r o w n a n d set t le to t he b o t t o m in t he a u t u m n f o r m i n g g r o u n d silt r ich in o r g a n i c m a t t e r . T h e y serve as t h e source , as w e shal l see la te r , of coals a n d vege t ab l e s i l t s — " s a p r o p c l s " —-from wh ich syn the t i c b e n z i n e c a n be o b t a i n e d .

A n i m a l s give off a lot of c a r b o n d iox ide d u r i n g r e sp i r a t i on . T h u s , for e x a m p l e , the su r face of all p u l m o n a r y alveoli in m a n

cons t i tu tes a b o u t 50 s q u a r e me t res , a n d in 24 h o u r s m a n expi res a n a v e r a g e of 1.3 k i l og rams of c a r b o n d iox ide .

All of m a n k i n d a n n u a l l y expi res a b o u t 1,000 mi l l ion tons of c a r b o n d iox ide i n to t h e a t m o s p h e r e of t he e a r t h .

"F ina l l y , t h e r e is a n even g r e a t e r reserve of b o u n d c a r b o n d iox ide u n d e r g r o u n d in t h e f o r m of l imestones , c h a l k , m a r b l e a n d o the r mine ra l s , f o r m i n g layers h u n d r e d s a n d even t h o u s a n d s of met res th ick . If w e cou ld r e t u r n t he en t i r e a m o u n t of c a r b o n d ioxide b o u n d u p in t h e m as c a l c i u m c a r b o n a t e a n d m a g n e s i u m c a r b o n a t e to t h e a t m o s p h e r e t h e a i r w o u l d c o n t a i n 25 ,000 t imes as muc.l. c a r b o n d iox ide .

T h e c a r b o n d iox ide of t he a t m o s p h e r e p a r t l y dissolves in the wate i of t h e w o r l d o c e a n . F r o m t h e a i r a n d t h e w a t e r c a r b o n d iox ide is a b s o r b e d by p l an t s . As t he a m o u n t of c a r b o n d iox ide in the w a t e r of t h e o c e a n decreases n e w q u a n t i t i e s of it c o m e f r o m the a i r . T h e vas t su r f ace of t h e o c e a n ac ts as a g r e a t p u m p a b s o r b i n g a n d a s p i r a t i n g c a r b o n d iox ide .

P l a n t s a r e t h e first to d r a w c a r b o n d iox ide i n to t he cycle of l iv ing subs t ance . T h e leaves of g r e e n p l a n t s c a p t u r e c a r b o n d iox ide in t h e l ight a n d t r a n s f o r m it i n to c o m p l e x o r g a n i c c o m p o u n d s . T h i s process is ca l led pho tosyn thes i s a n d involves l ight a n d ch lo rophy l l , t h e g r e e n s u b s t a n c e of p l an t s . T h e e n o r m o u s i m p o r t a n c e of p h o t o -synthesis in n a t u r e was first es tab l i shed a n d s tud i ed in de ta i l by t h e R u s s i a n scientis t K l i m e n t T i m i r y a z e v . I n t he course of a yea r l a rge a m o u n t s of a t m o s p h e r i c c a r b o n d iox ide go t h r o u g h the p lan t s . B u t this s h o r t a g e of c a r b o n d iox ide in t h e a t m o s p h e r e is con t inuous ly r ep l en i shed b y the l i be r a t i on of c a r b o n d iox ide f r o m w a t e r reservoirs a n d a n i m a l o r g a n i s m s .

E n o r m o u s masses of o r g a n i c subs t ance—t i s sues of p l a n t s — a r e f o r m e d

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i

O p e n cast mining of b r o w n coal

as a resu l t of pho tosyn thes i s . P l an t s serve as food for a n i m a l s t hus e n s u r i n g t he i r ex is tence a n d d e v e l o p -m e n t . I f w e a d d to this t h a t oils a n d coals a r e f o r m e d f r o m d e a d o r g a n i s m s it wil l b e c o m e c lea r h o w i m p o r t a n t t h e a b s o r p t i o n of c a r b o n d iox ide b y p l a n t s is to g e o c h e m i s t r y . T h e r e is n o r e a c t i o n m o r e i m p o r -t a n t in its g e o c h e m i c a l e f fec t t h a n t h e r e a c t i o n of pho tosyn thes i s i n p l an t s .

As p rev ious ly s t a t e d , t h e c a r b o n cycle does n o t e n d w i t h t h e f o r m a t i o n of o r g a n i c c o m p o u n d s f r o m c a r b o n d iox ide in p l a n t s a n d l a t e r in a n i m a l s . O r g a n i s m s die . T h e i r bod ie s a n d tissues a c c u m u l a t e i n l a rge a m o u n t s in t he f o r m of depos i t s o n t h e b o t t o m s of p o n d s , lakes a n d seas a n d as depos i t s of p e a t . T h e s e r e m a i n s of o r g a n i s m s a r e s u b j e c t e d t o t he a c t i o n of w a t e r , processes of f e r m e n t a t i o n a n d p u t r e f a c t i o n . Bac te r i a s h a r p l y a l t e r t h e c o m p o s i t i o n of t h e tissues of t h e o rgan i sms . Cel lulose , t h e l ign in of p l an t s , persists m o s t s t u b b o r n l y .

T h e o r g a n i c r e m a i n s a r e cove red u p b y a h e a v y l aye r of s a n d a n d c lay .

T h e n u n d e r t h e i n f l u e n c e of h e a t , p ressure a n d c o m p l e x c h e m i c a l processes coa l o r oil g r a d u a l l y b e g i n to b e f o r m e d d e p e n d i n g on t h e n a t u r e of these r e m a i n s a n d t h e cond i t i ons for t he i r p r e s e r v a t i o n .

T h e solid o r g a n i c c a r b o n w h i c h arises as a resu l t of t h e process of p l a n t d e c o m p o s i t i o n occurs i n t h r e e f o r m s : a n t h r a c i t e , coal a n d l igni te .

A n t h r a c i t e is t h e r iches t in c a r b o n . S tud ie s u n d e r t h e m i c r o s c o p e c o n f i r m t h e v e g e t a b l e o r ig in of coal a n d l igni te . T h e s e coals a r e schistous, a n d i m p r i n t s of leaves, spores a n d seeds c a n b e o b s e r v e d b e t w e e n the layers even w i t h t h e n a k e d eye. E a c h p iece of coal is p a r t of t h e c a r b o n a t o n e t i m e a b s o r b e d b y a cell of a p l a n t as c a r b o n d iox ide w i t h t h e a id of t h e e n e r g y of solar r ays a n d c h l o r o p h y l l .

" A c a p t u r e d so lar r a y " is t h e w a y coa l is r e f e r r ed to . As a m a t t e r of fac t , e a c h smal l p i ece of coal has r e t a i n e d t h e so lar r a y c a p t u r e d by t h e p l a n t a n d first t r a n s f o r m e d i n t o c o m p l e x v e g e t a b l e t issue a n d t h e n c h a n g e d in t h e process of s low d e c o m p o s i t i o n . I t hea t s t h e boi l-

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ers of mills, fac tor ies a n d s eago ing sh ips ; i ts e n e r g y dr ives g igan t i c m a c h i n e r y a n d its o u t p u t d e t e r m i n e s t h e i m m e n s e d e v e l o p m e n t of m o d e r n i n d u s t r y .

T h e a n n u a l p r o d u c t i o n of coal is expressed b y t h e e n o r m o u s figure of m o r e t h a n 1,000 mi l l ion tons w h i c h b y f a r exceeds t h e o u t p u t of a n y o t h e r m i n e r a l . I n k n o w n coa l reserves t h e U . S . S . R . ho lds second p l ace in t h e w o r l d , b u t w i t h t h e g r o w t h of t h e c o u n t r y ' s i n d u s t r y these e n o r m o u s reserves will on ly last f r o m 100 to 200 years .

W e m u s t exp lo re t h e i n t e r io r of o u r e a r t h in o r d e r to inc rease t h e r ea l reserves of th is v a l u a b l e subs t ance . Bu t coal yields n o t on ly hea t . M a n ex t rac t s f r o m it v a l u a b l e p r o d u c t s w h i c h h a v e la id t h e basis fo r t h e c h e m i c a l i n d u s t r y of coal . F r o m o r d i n a r y coal m a n h a s l e a r n e d to p r o d u c e a n i l i n e dyes, a sp i r in a n d s t r ep toc ide .

W h i l e coa l was f o r m e d m a i n l y f r o m p l a n t cells a n d tissues, such a l i q u i d o r g a n i c s u b s t a n c e as oil was f o r m e d f r o m o t h e r p r o t o z o a a n d t he i r spores ; h e n c e , th is l iqu id fue l , w h i c h is e v e n m o r e v a l u a b l e t h a n coal , is also a sort of " c a p t u r e d solar r a y . " M o d e r n fast ships, p l a n e s a n d a u t o m o b i l e t r a n s p o r t c a n exist on ly o n oil pu r i f i ed a n d r e f i ned i n t o p u r e g r a d e s of gasol ine . M a n has l e a r n e d to p r o d u c e ar t i f ic ia l b e n z i n e f r o m c e r t a i n g r a d e s of coal , b u t t h e r e is no t v e r y m u c h coa l fit fo r this p u r p o s e , t h e y ie ld of l iqu id p r o d u c t s is low a n d t h e q u a l i t y of ar t i f ic ia l gaso l ine is lower . I n ques t of oil m a n dri l ls wells m o r e t h a n f o u r k i lomet res d e e p a n d e x t r a c t s . this v a l u a b l e l i q u i d , t h e " b l a c k b lood of t h e e a r t h , " f r o m t h e e a r t h ' s ent ra i l s .

T h e well , t h r o u g h w h i c h oil is e x t r a c t e d , o p e r a t e s for several years . C o m p l e x s t r u c t u r e s — d e r r i c k s 37 t o 4 3 m e t r e s t a l l — a r e p u t u p o n t h e su r face . T h e forest of oil de r r i cks looks v e r y ef fec t ive f r o m a f a r . O n e c a n see such oilfields in t h e C a u c a s u s o n the w e s t e r n slopes of t h e U r a l s (Bashk i r i a ) , i n C e n t r a l Asia a n d o n S a k h a l i n . T h e r e a r e also c o n s i d e r a b l e oil depos i t s in I r a n , M e s o p o t a m i a a n d in o t h e r coun t r i e s .

Oi l foun ta in which f o r m e d an oil lake in the Baku fields. T h e foun ta in gushed for th ree years on end

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T h u s , this e l e m e n t c o m e s f r o m t h e i n t e r io r to t h e su r f ace a g a i n ; this t i m e it is b r o u g h t o u t b y m a n h imse l f ; a n d i n t h e c o n t i n u o u s s t rugg le for exis tence, fo r t h e possession of t he n a t u r a l e n e r g y reserves, m a n a n n u a l l y b u r n s m o r e t h a n 700 mi l l ion tons of coa l .

I n o r d e r to ge t h e a t m a n c h a n g e s e v e r y t h i n g in to c a r b o n d iox ide a n d w a t e r a g a i n .

Agen t s of d i f f e r e n t o rde r s a n d d i f f e r e n t s igni f icance , t hus , s t rugg le w i t h e a c h o t h e r n o w ox id iz ing c a r b o n a n d n o w r e d u c i n g it to its n a t i v e s ta te .

But , as p rev ious ly s t a t ed , in a d d i t i o n to coal t h e r e a r e t w o m o r e in t e re s t ing var ie t ies of p u r e c a r b o n — d i a m o n d a n d g r a p h i t e . H o w d i f f e r en t t h e s p a r k l i n g d i a m o n d is f r o m t h e o r d i n a r y g rey g r a p h i t e w i t h w h i c h w e w r i t e ! W e a lways a t t r i b u t e d i f f e rences in t h e p r o p -ert ies of bodies to t h e d i f f e rences in t he i r c o m p o s i t i o n . I n th is case, h o w e v e r , t h e d i f f e r e n t p rope r t i e s a r e d u e to d i f f e r e n t a r r a n g e m e n t of t h e a t o m s in t h e crystals .

I n t he d i a m o n d crys ta l t h e a t o m s lie ve ry close to e a c h o the r . T h i s a c c o u n t s for its c o n s i d e r a b l e specif ic g r a v i t y a n d h a r d n e s s , w h i c h

Fores t of oil derr icks in a Baku oilfield

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exceeds t h e h a r d n e s s of all t h e o t h e r m i n e r a l s , as wel l as for its excep t ion -al ly h i g h r e f r a c t i o n i ndex .

D i a m o n d c a n f o r m f r o m m o l t e n rock on ly u n d e r ve ry h i g h pressures of 30 a n d , p e r h a p s , even 60 t h o u s a n d a t m o s p h e r e s .

S u c h pressures exist o n l y a t a d e p t h of 60 to 100 k i lomet res . R o c k s very s e l d o m c o m e to t h e su r f ace f r o m such d e p t h s , a n d this m a y b e t h e r e a s o n w h y d i a m o n d s a r e e n c o u n t e r e d e x t r e m e l y ra re ly . F o r its h a r d n e s s a n d spa rk l e t h e d i a m o n d is ve ry h igh ly v a l u e d as a first-class p rec ious s tone .

I n d i a h a s l ong b e e n k n o w n fo r h e r d i a m o n d s m i n e d in p l a c e r deposi ts . D i a m o n d fields w e r e d i scovered i n Brazi l (1727) , in A f r i c a (1867) a n d i n t h e Sovie t U n i o n . T h e g r e a t e r p a r t of w o r l d ' s d i a m o n d s is n o w m i n e d a t t h e A f r i c a n depos i t s d i scovered i n t h e va l ley of t h e V a a l R i v e r , t h e r igh t t r i b u t a r y of t h e O r a n g e R i v e r .

A t first t h e y w e r e m i n e d in r ive r c lay p l a c e r deposi ts , b u t it was soon d i scovered t h a t t h e y w e r e also t o b e f o u n d in t h e b l u e c lay on t h e gen t l y s lop ing hills a w a y f r o m t h e r ive r . T h e b lue c lay b e g a n to b e w o r k e d a n d a " d i a m o n d r u s h " s t a r t e d ; p lots of b l u e c l ay t h r e e m e t r e s s q u a r e w e r e b o u g h t a t a mi l l i on t imes t he i r p r i ce a n d v e r y d e e p holes w e r e d u g . P e o p l e s w a r m e d l ike an t s i n these holes a n d d u g t h e rock . Suspens ion ways w e r e bu i l t i n o r d e r to r e m o v e t h e p rec ious c lay .

I t was n o t v e r y d e e p , h o w e v e r , b e f o r e t h e c lay d i s a p p e a r e d a n d h a r d g r e e n rock k n o w n as k i m b e r l i t e c a m e i n t o v iew. I t a lso c o n t a i n e d d i a m o n d s , b u t t h e y w e r e ve ry

O p e n cast w o r k in d i a m o n d - b e a r i n g pits in the env i rons of K i m b e r l e y in 1830. T h e pic-tu re shows n u m e r o u s ropes used by the owner s of smal l p lo ts f o r hois t ing the ore

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h a r d t o e x t r a c t a n d t h e s m a l l o w n e r s h a d t o g i v e u p t h e i r c o s t l y a n d

i n e f f i c i e n t e f f o r t s . A l t e r a p e r i o d o f i n a c t i v i t y a l a r g e s t o c k c o m p a n y

r e s u m e d w o r k , h u t t h i s t i m e it s a n k m i n e s .

T h e d i a m o n d - h e a r i n g r o c k g o e s d o w n i n t o t h e i n t e r i o r t o i n a c c e s -

s i b l e d e p t h s . I t f i l l s t h e p i p e s f o r m e d d u r i n g v o l c a n i c e x p l o s i o n s .

f i f t e e n c r a t e r s p r o d u c e d b y t h e s e e x p l o s i o n s a r e k n o w n ; t h e l a r g e s t

o f t h e m is 3 5 0 m e t r e s i n d i a m e t e r , t h e r e s t m e a s u r e f r o m 3 0 t o t o o

m e t r e s .

K i m b e r l i i e is s p r i n k l e d w i t h v c r v s m a l l d i a m o n d g r a i n s w e i g h i n g

less t h a n 1 0 0 m i l l i g r a m s ' o r h a l f a c a r a t ) . L a r g e s t o n e s a r e a l s o e n -

c o u n t e r e d s o m e t i m e s . T h e " E x c e l s i o r ' " w e i g h i n g 9 7 2 c a r a t s o r i<)4 g r a m s

w a s t h e l a r g e s t f o r a l o n g t i m e . A n e v e n l a r g e r d i a m o n d n a m e d

" C u l l m a n " a n d w e i g h i n g 3 , 0 2 5 c a r a t s o r 6 0 5 g r a m s w a s f o u n d i n

K)o( i . S t o n e s w e i g h i n g m o r e t h a n 10 c a r a t s a r e r a r e a n d e x p e n s i v e .

T h e m o s t f a m o u s d i a m o n d s w e i g h f r o m 4 0 t o 2 0 0 c a r a t s . T h e o r d i n a r y

d i a m o n d s c r u m b s , a s w e l l a s t h e b l a c k v a r i e t y - - ' " c a r b o n a d o " o r t h e

d i a m o n d d r o p s ( d i a m o n d f r a g m e n t s ) a r e a l s o v e r y v a l u a b l e b e c a u s e

I he u n r l j , L'rc.uu-t lii.imomiN: ;rop row* "(ocar \1or:u! ' \\ L-i':hcd -80 carars nn I ' l u u s , Or I o v -wc iuh t 104 carats, " Reecnr ' - 1 c a r a t > ; (bottom row " I• lorcntine 14. carals, oM anil new :;rim!inu of the " K o h - i - \ o r " d iamom: (ittO 106 t : ' '

1 14

they are used in engineering for drilling and boring hard rock. The drawing machines which produce tungsten filament threads for electric light bulbs require rather large stones.

Graphite is the same carbon, but how its properties differ from those of diamonds, though!

Its atoms easily separate from each other along planes. This soft mineral with a metallic lustre is not transparent, easily breaks up into small sheets and leaves a trace on paper. Graphite very poorly combines with oxygen and can stand very high temperature being a sort of fireproof material.

I t is of dual origin: it is formed either by the decomposition of carbon dioxide liberated from the magma during the formation of igneous rock or by the metamor-phosis of coal. A famous deposit of the first type is in Siberia. Lenses of very pure graphite are found here amid the cooled igneous rock—-nephelitic syenite. Enor-mous deposits of gra-phite occur in the basin ' of the Yenisei River. This graphite originated from coal and is high in ash content.

Or ig ina l f o r m s of na t ive d i amonds , sketched by A . Fers inan in 1911

For the manufacture of lead pencils graphite is mixed with purified clay and the hardness of the pencil depends on the amount of the latter; little clay is used for soft pencils and vice versa. The cylinders are then pressed and glued into wood. But only 5 per cent of the total graphite produced goes into lead pencils. Most of it is used to manufacture fireproof crucibles for melting the highest grades of steel,

8» 115

Whenever we write in pencil we use graphite.

Carbon tetrachloride

tar fire extinguishers

Solvents for lacquers

Hydrogen for dirigidtes and /he cfiemical industry

/fW materials for explosives

fiaw materials for aniline dyes

^ _ Rav materials for Acetylene for welding ftaw ma ferials for ff>e mam/facta re and catting metals the production at rubber ofplastics

Use of oil in vn r io j s branches of industry. The picture shows only a small part of the different substances produced by chemical processing of oil

e l e c t r i c f u r n a c e e l e c t r o d e s , a n d f o r l u b r i c a t i n g f r i c t i o n p a r t s i n h e a v y

m a c h i n e r y ( f o r e x a m p l e , b l o o m i n g s ' ) ; a s a p o w d e r i t is u s e d f o r

s p r i n k l i n g t h e c l a y m o u l d s e m p l o y e d i n c a s t i n g m e t a l m a c h i n e

p a r t s .

W e s h o u l d n o w r e c a l l t h e f a t e o f t h e c a r b o n d i o x i d e t h a t w a s

r e t a i n e d i n l a y e r s o f t h e e a r t h i n t h e f o r m o f l i m e s t o n e s , c h a l k

a n d m a r b l e .

T o b e g i n w i t h , h o w w a s .it f o r m e d ? T h i s is e a s y t o a n s w e r ;

s u f f i c e it t o e x a m i n e a l i t t l e c h a l k p o w d e r u n d e r t h e m i c r o s c o p e .

W e s h a l l f i n d in it a w h o l e w o r l d o f m i c r o s c o p i c f o s s i l s . W e s h a l l

s e e n u m e r o u s c i r c l e s , l i t t l e r o d s a n d c r y s t a l s n o t i n f r e q u e n t l y o f a

fine a n d b e a u t i f u l p a t t e r n . T h e s e a r e r e m a i n s o f t h e l i m e s k e l e t o n s

Artificial fats for soap

li/dricafion for machinery

Benzine for motors Fuel for engines

of mic roscop ic o r g a n i s m s — r h i z o p o d s . S o m e of the i r species a r e still f o u n d in t h e w a r m seas. T h e skele tons of r h i z o p o d s a r e m a d e of c a l c i u m c a r b o n a t e , a n d m y r i a d s of such skeletons f o r m e d the rock a f t e r t he d e a t h of t he o rgan i sms . B u t t he f o r m a t i o n of rock involves no t on ly t h e lower mic roscop ic a n i m a l s ; t h e skele tons of m a n v o t h e r m a r i n e a n i m a l s a n d p l a n t s a r e m a d e of c a l c i u m c a r b o n a t e .

These skeletons a r e also e n c o u n t e r e d in l imestones . By the r e m a i n s of t he o rgan i sms scientists c a n tell t he t i m e the

l imes tones were f o r m e d . The latest g e o c h e m i c a l r e sea rch m a k e s it possible to d e t e r m i n e

t he r e l a t ion b e t w e e n coal a n d oil a n d tlie to ta l a m o u n t of l imestones in t he wor ld .

C o n s e q u e n t l y , t he a b u n d a n c e of l imes tone in each geological epoch enab les us to e s t ima te t he a m o u n t s of coal a n d oil wh ich were t h e n f o r m e d . T h e s e g e o c h e m i c a l conc lus ions a r e of g r e a t i m p o r t a n c e even if t he p rac t i ca l e s t ima tes p r o v e i n a c c u r a t e .

M a n y of t he a n c i e n t l imes tones c h a n g e to m a r b l e u n d e r t he in f luence of p ressure a n d lose all t races of o r g a n i c life. T h e c a r b o n d iox ide a c c u m u l a t e d in t h e m over a pe r iod of mil l ions of years has left its cycle. O n l y if m o u n t a i n - f o r m i n g or vo lcan ic processes should occur a n y w h e r e n e a r t h e m a r b l e s they m a y a g a i n release c a r b o n d ioxide u n d e r t he i n f l uence of h e a t a n d give rise to its n e w cycle.

T h u s n a t u r e itself m a i n t a i n s a b a l a n c e in t he e t e rna l cycle of ch emi ca l processes.

PHOSPHORUS—ELEMENT OF LIFE AND THOUGHT

I n o r d e r t o m a k e t h e h i s t o r y o f t h i s r e m a r k a b l e n a t u r a l e l e m e n t

m o r e i n t e l l i g i b l e I s h a l l t e l l y o u t w o s t o r i e s . O n e o f t h e m wi l l d a t e

f r o m d i s t a n t t i m e s , i . e . , t h e e n d o f t h e 1 7 t h c e n t u r v , t h e o t h e r w i l l

r e f e r t o o u r o w n d a v s . T h e n I s h a l l t r y t o d r a w c o n c l u s i o n s f r o m t h e s e

t w o s t o r i e s a n d se t f o r t h t h e f a b u l o u s h i s t o r y ol p h o s p h o r u s w i t h o u t

w h i c h t h e r e c a n b e n e i t h e r l i f e n o r t h o u g h t .

* * *

A d a r k b a s e m e n t w e a k l y l i g h t e d b y a g r a t e d w i n d o w , l o c a t e d h i g h

in t h e w a l l . A f u r n a c e \Vi th h e a r t h s a n d a l a r g e b e l l o w s , l a r g e r e t o r t s

a n d c l o u d s o f s m o k e . . . . T h e w a l l s a r e c o v e r e d w i t h v a r i o u s i n s c r i p t i o n s ,

A r a b i c d i c t a , p e n t a g r a m s , a s t r o n o m i c c a l c u l a t i o n s a n d a p i c t u r e ol

a s t a r r y s k y a n d t h e h e a v e n l y b o d i e s . A n c i e n t v o l u m e s w i t h h e a v v

l e a t h e r c o v e r s a n d s o m e m y s t e r i o u s s i g n s a r c l a i d o u t o n t h e t a b l e s

a n d o n t h e f l o o r . O n t h e floor t h e r e a r e a l s o l a r g e b o w l s f o r g r i n d i n g

s a l t s , p i l e s o f s a n d a n d h u m a n b o n e s , v e s s e l s w i t h t h e " w a t e r of y o u t h " :

t h e t a b l e is c r o w d e d w i t h s p a r k l i n g d r o p s o f m e r c u r y , f i n e g l a s s e s ,

r e t o r t s , a n d y e l l o w , b r o w n , r e d a n d g r e e n s o l u t i o n s .

A g a i n s t t h i s b a c k g r o u n d o f a n o l d a l c h e m i c a l l a b o r a t o r y w e b e h o l d

t h e f i g u r e o f a g r e y - h a i r e d a l c h e m i s t w h o in h i s l o n g v o l u n t a r y s e c l u s i o n

h a s b e e n t r v i n g t o c h a n g e s i l v e r t o g o l d a n d t o u t i l i z e t h e m y s t e r i o u s

p o w e r o f c o m b u s t i o n t o t r a n s f o r m o n e m e t a l i n t o a n o t h e r .

H e h a s b e e n d i s s o l v i n g p o w d e r s a n d h u m a n b o n e s i n a t h o u s a n d

d i f f e r e n t w a v s , e v a p o r a t i n g t h e u r i n e o f m a n a n d v a r i o u s a n i m a l s ;

h e h a s b e e n s e a r c h i n g f o r t h e p h i l o s o p h e r ' s s t o n e w h i c h w o u l d m a k e

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M e d i e v a l a lchemis t in his l a b o r a t o r y

old people young and would teach man to produce costly gold from ordinary metal.

I t was under these mysterious and complex conditions that the alchemists of the i 7th century were trying to work out the problems of chemistry. But the attempts to produce gold from mercury or to obtain the philosopher's stone from human bones proved futile. Time wore on and the experiments brought no results. The alchemists sur-rounded their laboratories with ever greater mystery and hid their recipes and the thick volumes of their notes.

In 1669 Lady Fortune finally visited one of the alchemists working in Hamburg. In search of the precious stone he took fresh urine, evap-orated it dry and annealed the black residue. At first he heated this residue gently, then more and more strongly; a white wax-like substance began to collect at the top of the tube, and the alchemist noticed, much to his surprise, that the substance was luminescent.

Hennig Brandt (that was the alchemist's name) long kept his dis-covery absolutely secret. Other alchemists vainly tried to gain access

119

to his laboratory. The powers that be came to Hamburg in an endeav-our to buy his secret. T h e discovery created a tremendous impression; the greatest minds of the 17th century took an interest in it believing that the philosopher's stone had been found. This stone shed a cold, quiet light; it was given the name of "cold light," while the substance itself was named "phosphorus" (which means "l ight-bearing" in Greek).

Robert Boyle and Leibniz took considerable interest in Brandt 's discovery. Very soon one of Boyle's pupils and assistants in London attained such wonderful results that he even advertised in a newspaper: Hankwitz, London chemist, address so and so, prepares all sorts of medicines. In addition he informs all those who are curious that he is the only one in London capable of producing all varieties of phos-phorus at 3 pound sterling per ounce.

And still the production of phosphorus remained a secret of the alchemists until 1737. Their attempts to utilize this remarkable element were fruitless. Believing they had discovered the "philosopher's stone

G e n e r a l v iew of apa t i t e depos i t s

1 2 0

R.Boy le

they vainly tried to use this luminescent white phosphorus in changing silver to gold. The philosopher's stone would not reveal its secret properties, while the explosions which sometimes occurred during experiments only frightened the investigators. Phosphorus remained a mysterious substance and found no application for itself. It took nearly two centuries before Liebig, a chemist, discovered in his modest chemical laboratory one more mystery—the significance of phosphorus and phosphoric acid in the life of plants. It became clear that phosphoric compounds were the basis of life in the fields, and the idea that compounds of the "cold light" should be strewn over the fields to improve the crops was voiced for the first time in this laboratory.

We know the mistrust with which these words of Liebig were treated. His attempts to fertilize the soil with saltpetre were useless, and the cargo of this salt brought by ships from South America found no buyers and was dumped into the sea. The possibility of using the salts of the "cold light" for the purpose of increasing the yield of rye and wheat and for developing the stem of the valuable fibrous p l a n t - flax—was long considered a mere fantasy. It took years of persistent scientific work again before phosphorus became one of the most important chemical elements in agriculture.

My second story deals with 1939. In the U.S.S.R., apatite, a light green stone and very valuable mineral, is mined on a large scale on the slopes of snow-covered mountains in the north. It is produced in tremendous quantities and its output vies with that of the phosphorite extracted on the Mediterranean Coast, in Africa and in Florida. Apatite goes to large concentration plants where it is pulverized and separated from harmful constituents; the result is a pure white powder, as soft and friable as flour. Then it is loaded into railway trucks and dozens of trainloads of it are sent from the distant Arctic regions to factories in Leningrad, Moscow, Odessa, Vinnitsa, Donets Basin, Perm and Kuibyshev where it is treated with sulphuric acid and transformed into a new substance, another white powder—a soluble phosphate fertilizer. Millions of tons of these phosphates are strewn by special machines over the fields of our country doubling the yield of flax, increasing the sugar content of sugar-beets, multiplying the number of cotton bolls and improving the vegetable crops.

121

W e h a v e p a i n t e d t w o p i c tu re s f r o m the h i s to ry of p h o s p h o r u s : its d iscovery a n d its u t i l i za t ion in o u r days . M o r e t h a n t en mi l l ion tons of p h o s p h a t e fer t i l izer is a n n u a l l y p r o d u c e d in t h e w o r l d ; of these two mi l l ion tons a r e s t r e w n over t h e fields.

Bu t p h o s p h o r u s is u sed n o t on ly for fer t i l izer . T h e i m p o r t a n c e of this s u b s t a n c e increases w i t h e a c h pass ing yea r . A t t h e p re sen t t i m e this " c o l d l i g h t " is used i n a t least 120 b r a n c h e s of i n d u s t r y .

I n t h e first p l ace p h o s p h o r u s is t h e s u b s t a n c e of life a n d t h o u g h t ; t he c o n t e n t of p h o s p h o r u s in t h e bones d e t e r m i n e s t h e g r o w t h a n d n o r m a l

Dispersed over t h e fields t h e m i n u t e s t a t o m s of p h o s p h o r u s ge t i n to t h e b r e a d , vege t ab l e s a n d o t h e r foods we c o n s u m e . C a l c u l a t i o n s s h o w t h a t in e a c h piece of b r e a d w e i g h i n g 100 g r a m s we c o n s u m e u p to 10 ,000 ,000 ,000 ,000 ,000 ,000 ,000 a t o m s of p h o s p h o r u s , i .e. , a figure so e n o r m o u s t h a t i t is h a r d to cal l it in o r d i n a r y l a n g u a g e .

W e h a v e to ld y o u a b o u t t h e c o u n t r y ' s m a i n source of p h o s p h a t e s , t h e a p a t i t e of t h e K h i b i n y M o u n t a i n s . Bu t i m m e n s e as t h e m i n e s o n K o l a Pen in su l a a r e they c a n n o t a l one p r o v i d e e n o u g h phos-p h a t e for t h e vas t fields of t h e Soviet U n i o n b e c a u s e of t r a n s p o r t l imi ta t ions . T h e n u m b e r of t r a i n l o a d s of p rec ious a p a t i t e t h a t r e a c h S ibe r ia , K a z a k h s t a n a n d C e n t r a l Asia does n o t suffice a n d h e r e n e w l y d i scovered depos i t s c o m e to

the a id . Phospho r i t e s a r e n o w v igorous ly m i n e d in m a n y sect ions of t he E u r o p e a n p a r t of t he Soviet U n i o n ; 110 less i m p o r t a n t depos i t s a r e n o w k n o w n in S ibe r i a a n d in C e n t r a l Asia . N e w depos i t s a r e b e i n g p ro spec t ed for a n d w o r k e d in va r ious p a r t s of t h e c o u n t r y . T h e p h o s p h o r i t e deposi ts m a k e it possible to secu re scores of mi l l ions of tons of p h o s p h a t e fer t i l izer w h i c h b r i n g s its l i fe-giving force t o t h e c o u n t r y ' s s t a te a n d co l l ec t ive - fa rm fields a n d fu l ly i m p r e g n a t e s t h e g ra ins in t h e ears a n d t h e s tems of t h e p l a n t s w i t h its v iv i fy ing a toms .

Blas t - fu rnace for subl imat ion of phosphorus

122

d e v e l o p m e n t of t he cells of t he b o n e m a r r o w a n d is, in t he long r u n , respons ib le for t he s t r e n g t h of t he l iving o rgan i sms . T h e h i g h c o n t e n t of p h o s p h o r u s in t h e ce reb ra l m a t t e r i nd ica te s its essential role in the work of t h e b r a i n . P h o s p h o r u s def ic iency in t h e food leads to a weaken ing of t he en t i r e o r g a n i s m . T h e exis tence of a n u m b e r of d i f f e r en t medicinc--a n d p h a r m a c e u t i c a l p r e p a r a t i o n s c o n t a i n i n g p h o s p h o r u s for the weak a n d the conva lescen t s is no m e r e a c c i d e n t . N o t only m a n needs phos-p h o r u s ; p l a n t s a n d a n i m a l s also r e q u i r e e n o r m o u s q u a n t i t i e s oi it. M a n has l e a r n e d to fer t i l ize w i t h p h o s p h o r u s not on ly t he l and bu t t he sea as well . Fe r t i l i za t ion of s ea -wa te r w i th p h o s p h o r u s in enclosed bays a n d gulfs r a p i d l y increases t h e r e p r o d u c t i o n a n d g r o w t h of sea-w e e d s a n d o t h e r m i c r o s c o p i c o r g a n i s m s wh ich leads to a n increased r e p r o d u c t i o n of fish. W e h a v e pe r sona l ly witnessed e x p e r i m e n t s in w h i c h p h o s p h o r u s was i n t r o d u c e d in to p o n d s n e a r L e n i n g r a d as a resul t of w h i c h the fish grew to twice the i r f o r m e r size. P h o s p h o r u s has latelv p l a y e d a verv i m p o r t a n t p a r t in t he p r e p a r a t i o n of va r ious foods a n d , especial ly , m i n e r a l wa te r s . H i g h g r a d e s of m i n e r a l wa te r s a r e o b t a i n e d wi th t he a id of p h o s p h o r i c ac id . P h o s p h a t e s , especial ly those of m a n g a n e s e a n d i ron , p r o d u c e s t rong a n d d u r a b l e coa t ings . W e k n o w t h a t h i g h - q u a l i t v wa re s of stainless steel a r e m a d e by a specia l m e t h o d of c o a t i n g wi th p h o s p h a t e s . T h e sur faces of p lanes c a n be r e n d e r e d stainless wi th t he a id of such p h o s p h a t e coa t ings . T h e " c o l d l i g h t " of p h o s p h o r u s c r e a t e d in its t i m e o n e of the largest b r a n c h e s of i ndus t ry , n a m e l y , the m a t c h i n d u s t r y . O u r y o u n g r e a d e r s d o no t k n o w the p h o s p h o r u s m a t c h e s used be fo re t he m a t c h e s of o u r t ime were i nven t ed . I still r e m e m b e r since m y c h i l d h o o d the boxes of p h o s p h o r u s m a t c h e s w h i c h were m a d e wi th red h e a d s * a n d l igh ted by r u b b i n g aga ins t some ob jec t . Peop le p a r t i c u l a r l y liked to l ight these m a t c h e s aga ins t t h e soles of the i r shoes. H o w e v e r , t he d a n g e r o u s p rope r t i e s ol phos-p h o r u s necess i ta ted t he i n v e n t i o n of o t h e r m a t c h e s , t h e ones we a r c us ing t o d a y .

T h e use of p h o s p h o r u s in m a t c h e s sugges ted t h e i dea of u t i l iz ing this s u b s t a n c e for a cold fog r a t h e r t h a n for a cold l ight . W h e n burning-p h o s p h o r u s c h a n g e s to p h o s p h o r i c ac id w h i c h dr i f t s in t he a i r for a long-t i m e in t he f o r m of a mis t .

M i l i t a r y e n g i n e e r i n g has m a d e use of this pecu l i a r i t y of p h o s p h o r i c ac id for c r e a t i n g smoke-screens . I n c e n d i a r y b o m b s c o n t a i n a cons ider -a b l e a m o u n t of p h o s p h o r u s , a n d in m o d e r n w a r f a r e p h o s p h o r i c b o m b s

1 2 3

Manufacture of flares

Smoke shells

I 'sc of phosphorus in dif ferent branches of industry

s p r e a d i n g a w h i t e cold fog h a v e b e c o m e o n e of t he m e a n s of a t t a c k a n d des t ruc t i on .

W e shall no t w e a r y you w i t h t h e c o m p l e x c h e m i c a l course t rave l led by p h o s p h o r u s in n a t u r e , f r o m the mel t s d e e p i n t he in t e r io r of t h e e a r t h to t he fine a p a t i t e needles a n d t h e l iv ing filters (mic ro -o rgan i sms) wh ich a b s o r b p h o s p h o r u s f r o m its w e a k solut ions in s ea -wa te r .

T h e his tory of m i g r a t i o n of p h o s p h o r u s in t h e e a r t h ' s c rus t is u n -c o m m o n l y in te res t ing . T h e fa te of p h o s p h o r u s is b o u n d u p w i t h t he c o m p l e x process of life a n d d e a t h . B u t p h o s p h o r u s a c c u m u l a t e s w h e r e o r g a n i c life t e r m i n a t e s a n d a n i m a l s die en masse , a t t he j u n c t i o n of s ea -cu r ren t s w h e r e s u b m a r i n e cemete r i e s a r e f o r m e d . I n t h e e a r t h p h o s p h o r u s a c c u m u l a t e s in t w o w a y s : e i the r in t he d e e p depos i t s of a p a t i t e s e p a r a t e d f r o m the ho t m o l t e n m a g m a or in t h e r e m a i n s of t he skeletal p a r t s of a n i m a l s . T h e a t o m of p h o s p h o r u s goes t h r o u g h a c o m p l e x cycle in t he h is tory of t he e a r t h . S e p a r a t e l inks of its m i g r a t i o n s h a v e been d i scovered b y chemis ts , geochemis t s a n d technologis t s . I t s pas t f a te is lost in t h e d e e p in t e r io r of t he e a r t h ; its f u t u r e is in w o r l d i ndus t ry .

Manufacture of matches Fertilizer

Manufacture of plastics

Medical -preparations

P/iofographu

• Chemical reagents

incenaiary nhpi i.t P

SULPHUR—BASIS OF THE CHEMICAL INDUSTRY

S u l p h u r is o n e of t h e first c h e m i c a l e l emen t s k n o w n to m a n . I t was e n c o u n t e r e d in m a n y p laces a l o n g t h e M e d i t e r r a n e a n Coas t a n d co u l d n o t e scape t h e a t t e n t i o n of t h e a n c i e n t p e o p l e s — t h e Greeks a n d R o -m a n s . V o l c a n i c e r u p t i o n s i n v a r i a b l y b r o u g h t a lot of s u l p h u r to t h e s u r f a c e ; t h e o d o u r of s u l p h u r d iox ide a n d h y d r o g e n s u l p h i d e was cons ide r ed a sign of t h e ac t iv i ty of V u l c a n , t he u n d e r g r o u n d god . T h e c lear , t r a n s p a r e n t crysta ls of s u l p h u r in t he l a rge Sic i l ian depos i t s w e r e no t i ced m a n y c e n t u r i e s B .C . T h e ab i l i ty of this s tone to l i be r a t e a s p h y x i a n t gases a t t r a c t e d specia l a t t e n t i o n . I t was precise ly because of th is u n u s u a l p r o p e r t y t h a t s u l p h u r was cons ide r ed o n e of t h e bas ic e l e m e n t s i n t h e w o r l d a t t h a t t ime .

N o w o n d e r , t he re fo re , t h a t to t h e m i n d s of a n c i e n t na tu ra l i s t s a n d especia l ly a lchemis t s s u l p h u r a lways p l a y e d a n e x c e p t i o n a l ro le in t h e processes of vo l can i c ac t iv i ty or for -m a t i o n of m o u n t a i n r a n g e s a n d lodes.

A t t h e s a m e t i m e it a p p e a r e d to t h e a l chemis t s t h a t s u l p h u r possessed a mys te r ious p r o p e r t y of l i b e r a t i n g n e w subs t ances d u r i n g c o m b u s t i o n a n d shou ld , t he re fo re , h a v e b e e n t h e miss ing c o n s t i t u e n t of t h e p h i l o s o p h e r ' s s tone w h i c h t h e y so v a i n l y t r i ed t o find i n o r d e r to b e a b l e to p r o d u c e a r t i f i c ia l go ld .

T h e i d e a of t h e e x c e p t i o n a l ro le of s u l p h u r i n n a t u r e is exce l len t ly c o n -

P h o s p h o r u s smel t ing in the M i d d l e Ages

125

O l d engrav ing of Vesuvius

veyed in t h e f a m o u s t rea t i se of t h e R u s s i a n scientist L o m o n o s o v en t i t l ed " O n T e r r e s t r i a l L a y e r s " a n d p u b l i s h e d in 1763. T h e fo l lowing a r e a few q u o t a t i o n s f r o m t h e t r ea t i s e :

" I n cons ide r ing t h e g r e a t d e a l of u n d e r g r o u n d fire t h e m i n d i m -m e d i a t e l y t u r n s t o cogn i t i on of t h e m a t t e r w h i c h it c o n t a i n s . " . . . " I s t h e r e a n y t h i n g t h a t c a n b u r n b e t t e r t h a n s u l p h u r ? W h a t c a n k e e p u p a n d feed a fire w i t h g r e a t e r fo rce t h a n s u l p h u r ? " " W h a t c o m b u s -

I t ib le m a t t e r comes m o r e a b u n d a n t l y t h a n s u l p h u r ou t of t h e e a r t h ' s i n t e r i o r ? "

"Because it is n o t on ly from t h e j a w s of fire-breathing m o u n t a i n s t h a t it be lches fo r th , a n d i n h o t sp r ings t h a t s p u r t o u t of t h e e a r t h a n d in d r y u n d e r g r o u n d ven t s t h a t it a c c u m u l a t e s i n g r e a t a m o u n t s ,

1 2 6

Sulphur hills in the K a r a K u m s . T u r k m e n S.S.R.

b u t b e c a u s e t h e r e is n o t a s ing le o r e a n d h a r d l y a s t o n e w h i c h b y m u t u a l f r i c t i o n w i t h a n o t h e r d o e s n o t g i v e off" a s u l p h u r o u s sme l l t h u s a n n o u n c -i n g i ts p r e s e n c e . . . . T a k i n g f i re i n t h e e n t r a i l s of t h e e a r t h a n d e x p a n d i n g t h e h e a v y a i r i n t h e abysses it presses a g a i n s t t h e e a r t h l y i n g a b o v e , l if ts i t a n d b y m o v i n g i t i n d i f f e r e n t d i r e c t i o n s a n d i n d i f f e r e n t a m o u n t s , p r o d u c e s d i f f e r e n t q u a k e s a n d p r i m a r i l y b r e a k s t h r o u g h w h e r e v e r i t f i n d s t h e l eas t r e s i s t ance , s h o o t i n g i n t h e a i r t h e l i g h t p a r t s of t h e d e -s t r o y e d e a r t h ' s s u r f a c e w h i c h i n f a l l i n g t a k e u p t h e n e a r - b y fields, w h i l e t h e o t h e r s , b e c a u s e of t h e i r e n o r m i t y , o v e r c o m e t h e fire b y t h e i r g r a v i t y a n d c o m i n g d o w n f o r m m o u n t a i n s .

" W e h a v e o b s e r v e d a g r e a t d e a l of fire i n t h e b o w e l s of t h e e a r t h a n d a n a b u n d a n c e of s u l p h u r w h i c h i t r e q u i r e s f o r b u r n i n g a n d w h i c h suff ices f 6 r e a r t h q u a k e s a n d fo r p r o d u c i n g g r e a t a l t e r a t i o n s — c a l a m i t o u s b u t a lso u s e f u l , t e r r i b l e b u t a lso b r i n g i n g d e l i g h t . "

T r u e e n o u g h , t h e e a r t h ' s i n t e r i o r c o n t a i n s a lot of s u l p h u r a n d in c o o l i n g i t g ives of f m a n y v o l a t i l e c o m p o u n d s of v a r i o u s m e t a l s i n c o m -b i n a t i o n w i t h s u l p h u r , a r s e n i c , c h l o r i n e , b r o m i n e a n d i o d i n e . W e c a n j u d g e a b o u t th i s n o t o n l y b y t h e o d o u r t y p i c a l of v o l c a n i c e r u p t i o n s , of a s p h y x i a n t soffioni i n S o u t h I t a l y o r of t h e c l o u d s of s u l p h u r d i o x i d e of t h e K a m c h a t k a e r u p t i o n s ; s u l p h u r is a lso b r o u g h t o u t i n

27

solut ions a n d it f o r m s lodes. T o g e t h e r w i t h a r s en i c a n d a n t i m o n y , its f r i ends a n d fe l low- t rave l le rs in these h o t vo la t i l e fluids, it f o rms the m i n e r a l s f r o m w h i c h m a n h a s o b t a i n e d z inc a n d l ead , si lver a n d gold since t i m e i m m e m o r i a l .

Bu t on t h e e a r t h ' s su r f ace these d a r k , o p a q u e , l u s t rous po ly-me ta l l i c ores a n d va r ious g lances a n d pyr i t es a r e s u b j e c t e d t o t h e ac t i on of a t m o s p h e r i c o x y g e n a n d of w a t e r ; t h e l a t t e r d e c o m p o s e t h e su lph ides i n to n e w c o m p o u n d s , ox id iz ing t h e s u l p h u r i n t o su l -p h u r d iox ide . W e k n o w this gas by t h e o d o u r of s u l p h u r m a t c h e s . W i t h w a t e r it f o rms s u l p h u r o u s a n d s u l p h u r i c acids .

S u l p h u r a n d its p r o d u c t s a r e s imi la r ly l i b e r a t e d d u r i n g o x i d a t i o n of l a rge p y r i t e lenses, t h e y des t roy t h e s u r r o u n d i n g rocks a n d , c o m b i n i n g w i t h s t ab le r e l ements , f ina l ly yie ld g y p s u m or o t h e r m ine ra l s . I t will b e n o t e d t h a t s u l p h u r i c ac id , w h i c h is f o r m e d in p y r i t e depos i t s a n d w h e r e n a t i v e s u l p h u r is m i n e d , possesses d e s t r u c t i v e p rope r t i e s .

I reca l l t h e M e d n o g o r s k M i n e in t h e S o u t h U r a l s w h e r e so m u c h s u l p h u r i c ac id is l i b e r a t e d d u r i n g t h e o x i d a t i o n of p y r i t e t h a t it is abso lu te ly imposs ib le t o g u a r d oneself a g a i n s t its po i sonous ac t iv i ty a n d the w o r k e r s ' c lo thes d o no t las t l ong b e c a u s e t h e ac id eats holes in t h e m .

W h e n we w o r k e d in t h e K a r a - K u m s a n d s ( T u r k m e n S .S .R . ) we d id n o t k n o w this p r o p e r t y of s u l p h u r deposi ts , a n d w h e n o u r s ample s of s u l p h u r ore n e a t l y w r a p p e d in p a p e r c a m e to L e n i n g r a d w e f o u n d t h a t t h e p a p e r was en t i re ly e a t e n a w a y , t h a t on ly sc raps of t h e labels r e m a i n e d a n d t h a t even t h e boxes w e r e d a m a g e d . W e h a d

to desc r ibe t h e h e r o of these c a l a m -ities, t h e n a t u r a l s u l p h u r i c ac id , as a n e w i n d e p e n d e n t l iqu id m i n e r a l .

T h e K a r a - K u m o re is n o t e d for t h e fac t t h a t it consists of a m i x t u r e of s a n d a n d s u l p h u r . T o o b t a i n p u r e s u l p h u r P. V o l k o v , Sovie t c h e m i c a l e n g i n e e r , p r o p o s e d a n i n g e n i o u s m e t h o d . F i n e o r e is p u t i n to a bo i le r w o r k i n g u n d e r h i g h p ressure , w a t e r is a d d e d , t h e boi le r is h e r m e t i c a l l y sea led a n d s t e a m u n d e r a p r e s su re

D u n e s of gypsum sand o f 5 t o 6 a t m o s p h e r e s i s p a s s e d

1 2 8

t h r o u g h it. T h e t e m p e r a t u r e in t h e a u t o c l a v e rises to a b o u t 140° C. , t h e s u l p h u r mel t s a n d collects in t h e lower p a r t of t h e boi ler wh i l e t he c lay a n d s a n d a r e s t i r red u p by t h e s t e a m a n d ca r r i ed to t h e top . A t a p is o p e n e d some t i m e l a t e r a n d the s u l p h u r qu ie t ly flows i n t o specia l t rays . T h e en t i r e process of m e l t i n g takes a b o u t t w o hour s . Sovie t eng inee r s solved t h e p r o b l e m of p u r i f y i n g K a r a - K u m s u l p h u r as s imp ly as all t h a t .

S u l p h u r does n o t k e e p its in i t i a l f o r m l o n g : it soon c o m b i n e s w i t h va r ious m e t a l s a n d in vo l can i c reg ions f o r m s a c c u m u l a t i o n s of a l u n i t e w h i c h is d i spersed a r o u n d ac t ive vo lcanoes in w h i t e spots or b a n d s .

S o m e a s t r o n o m e r s be l ieve t h a t a l u n i t e is r espons ib le for t h e w h i t e ha loes a n d t h e w h i t e r ays w h i c h s u r r o u n d t h e c ra te r s of t he l u n a r m o u n t a i n s .

A l a r g e a m o u n t of ox id ized s u l p h u r is in c o m b i n a t i o n w i t h c a l c i u m . T h e resu l t ing c o m p o u n d is r a t h e r h a r d t o dissolve i n t he l a b o r a t o r y b u t it is a suff ic ient ly m o b i l e c o m p o u n d in t h e e a r t h . T h i s c o m p o u n d , w h i c h w e call g y p s u m , is depos i t ed in l a rge q u a n t i t i e s as th ick layers in sa l t - lakes a n d i n d r y i n g sea bas ins .

B u t t h e h i s to ry of s u l p h u r o n t h e e a r t h ' s su r f ace does no t e n d w i t h this . P a r t of t h e s u l p h u r i c ac id c h a n g e s i n to a gas a g a i n ; a n u m b e r of m i c r o - o r g a n i s m s r e d u c e s u l p h u r ; h y d r o g e n s u l p h i d e a n d vo la t i l e gases a r e f o r m e d f r o m t h e so lu t ions of its salts a n d a r e b r o u g h t ou t to t h e su r face in ve ry l a rge a m o u n t s b y o i l - bea r ing w a t e r s ; t h e y s a t u r a t e t h e a i r in m a r s h y l o w l a n d s a n d in a n u m b e r of firths a n d lakes f o r m a b l ack silty mass w h i c h is ca l led c u r a t i v e m u d a n d is ex tens ive ly used for t h e r a p e u -t ic p u r p o s e s in t h e C r i m e a a n d t h e C a u c a s u s .

A ve ry g r e a t p a r t of t h e s u l p h u r volat i l izes as h y d r o g e n su lph ide , t hus , r e t u r n i n g to a m o b i l e f o r m . T h i s ends o n e of t h e pe r iods in t h e c o m p l e x cycle of this e l e m e n t in g e o -logical h is tory .

Bu t m a n h a s s h a r p l y Explos ion of p o w d e r

1 2 9

c h a n g e d t h e p a t h s w h i c h sul-p h u r t rave l s on e a r t h , a n d it h a s b e c o m e o n e of i n d u s t r y ' s m o s t v a l u a b l e ma te r i a l s . O n l y a mi l l ion tons of i t , i s m i n e d a n n u a l l y i n its p u r e s ta te , b u t i n i r on c o m p o u n d s f r o m w h i c h s u l p h u r is o b t a i n e d for ac id it is m i n e d in scores of mi l l ions of tons a n -n u a l l y .

S u l p h u r h a s b e c o m e t h e basis of t h e c h e m i c a l i n d u s t r y a n d w e s h o u l d be h a r d p u t to

it to n a m e all t h e b r a n c h e s of i n d u s t r i a l e n g i n e e r i n g for w h i c h it is i nd i spensab le . I shal l m e n t i o n on ly t h e m a i n b r a n c h e s , b u t these e x a m p l e s a r e e n o u g h to s h o w t h a t i n d u s t r y c a n n o t exist w i t h o u t s u l p h u r .

S u l p h u r is r e q u i r e d for t h e p r o d u c t i o n of p a p e r , ce l lu loid , pa in t s , mos t med ic ines , m a t c h e s , fo r t h e p u r i f i c a t i o n of b e n z i n e , e t h e r a n d oils, a n d for t h e m a n u f a c t u r e of p h o s p h a t e fer t i l izers , vi t r iols , a l u m , soda , glass, b r o m i n e a n d iod ine . W i t h o u t it it is h a r d to p r o d u c e ni t r ic , h y d r o c h l o r i c a n d ace t i c ac ids ; h e n c e , it is c l ea r w h y s u l p h u r has p l a y e d a n e n o r m o u s p a r t in t h e d e v e l o p m e n t of i n d u s t r y s ince t h e b e g i n n i n g of t he 19th c e n t u r y . As s u l p h u r i c a c i d w e n e e d it for t h e p r o d u c t i o n of d y n a m i t e , wh i l e its use in g u n p o w d e r h a s m a d e it abso -lu te ly i n d i s p e n s a b l e to fire-arms.

T h e s t rugg le fo r s u l p h u r s t a n d s o u t , t he r e fo re , al l t h r o u g h t h e h is tory of t he 18th c e n t u r y , Sicily was l o n g t h e o n l y s u p p l i e r of s u l p h u r . I t was p a r t of t h e I t a l i a n k i n g d o m a n d s ince t h e b e g i n n i n g of t h e 18th c e n t u r y Bri t ish f r iga tes h a d r e p e a t e d l y b o m b a r d e d t h e Sic i l ian coas t in a n e n d e a v o u r to c a p t u r e this w e a l t h . T h e n t h e S w e d e s d i scovered a m e t h o d of p r o d u c i n g s u l p h u r a n d s u l p h u r i c ac id f r o m pyr i tes . T h e vast S p a n i s h p y r i t e depos i t s b e c a m e t h e c e n t r e of a t t e n t i o n of all E u r o p e a n s ta tes a n d the Bri t ish f r iga tes a p p e a r e d a t t h e S p a n i s h coas t in o r d e r to seize this sou rce of s u l p h u r a n d s u l p h u r i c ac id , as well . T h e Sici l ian depos i t s w e r e neg l ec t ed a n d all a t t e n t i o n was focused on S p a i n .

A t a match fac tory . Matchcs b e f o r e packing

1 3 0

Compressed air Liquid sulphur

Sulphur-contaimng

calcite

Compressed air

Sulphur in native bed

Anhydride

T h e n t h e first a n d e x t r e m e l y r i ch s u l p h u r deposi ts w e r e d i scovered i n F l o r i d a .

I n p u r s u i t of h i g h e r p r o -d u c t i v i t y a seeming ly i n c r e d -ib le m e t h o d was p r o p o s e d : s u p e r h e a t e d s t e a m was p u m p e d u n d e r g r o u n d ; o w i n g to t h e low m e l t i n g t e m p e r a -t u r e of s u l p h u r ( i i 9 ° C . ) t h e s t e a m m e l t e d it u n d e r g r o u n d a n d fo rced it to t h e su r f ace i n a l iqu id s ta te .

T h e first i n s t a l l a t ion for p u m p i n g ou t m o l t e n s u l p h u r w a s bu i l t a n d t h e s u l p h u r was e j ec t ed to t h e s u r f a c e w h e r e it sol idif ied i n to l a r g e hills.

T h i s m e t h o d is ve ry p r o -d u c t i v e a n d e n o r m o u s a m o u n t s of s u l p h u r w e r e o b t a i n e d by it in A m e r i c a . T h e I t a l i a n a n d S p a n i s h depos i t s r e c e d e d i n t o t h e b a c k g r o u n d . O n c e a g a i n a b r i l l i an t idea o c c u r r e d to t h e Swedes in t h e p o l a r c o u n t r y of s u l p h u r o u s ores. O n e of t he p l a n t s b e g a n to p r o d u c e s u l p h u r as a b y -p r o d u c t w h i l e p rocess ing py r i t i c ores.

A g a i n a m e t a l s u l p h i d e h a s b e c o m e t h e source of s u l p h u r a n d a g a i n t h e l a t e of s u l p h u r i c ac id h a s c h a n g e d .

I a m te l l ing y o u this to s h o w y o u h o w in t r i ca t e ly c r ea t ive ideas s o m e t i m e s c h a n g e t h e use of a s u b s t a n c e in i n d u s t r y . T h e s e n e w m e t h o d s will r e m a i n in t h e h i s to ry of sc icnce ; they h a v e r ad ica l ly c h a n g e d

;!r-nrk

Free (loose sedimentary rocks)

salt Roc*

I n s t a l l a t i o n fo r s u l p h u r e x t r a c t i o n f r o m a d e e p b o r e - h o l e . S u p e r h e a t e d s t eam and c o m p r e s s e d a i r a r c p u m p e d t h r o u g h d o u b l e p ipes in to l i m e s t o n e s , wh ich con ta in s u l p h u r , a n d m e l t t h e l a t t e r . L i q u i d s u l p h u r r i ses a l o n g r i ng s p a c e in t h e p ipes a n d p o u r s o u t to the sur-f a c e w h e r e it h a r d e n s in t h e f o r m of e n o r -m o u s r e c t a n g u l a r m o n o l i t h s

q

Faner •Jvim

Use of sulphur in various branches of industry

the techniques of sulphur extraction and have influenced certain pro-duction relations. It is. not without reason that one of the I tal ian journals wrote that the new methods "ki l led" the populat ion of Sicily forcing it to starve by growing oranges on its poor plantations and grazing goats in its parched mountain pastures.

fertilizer

drugs .'•latches

Insecticides

CALCIUM—SYMBOL OF DURABILITY

One day, as I was passing through Xovorossiisk, I was askec! bv a group of engineers and technicians working at the large cement plants located near the city to lecture at their club on limestones and marls which are the principal raw materials for cement.

I had to tell them that I did not know anv-thing about the subject. I knew very well that various kinds of limestones formed the basis of lime and cement; I also knew how valuable good lime and cement were: 1 told them how hard it was to get these two necessarv products for the construction jobs in the North.

Simple lime w as usuallv ordered from the Valdai Hills fifteen hundred kilometres awav from the construction sites, while cement came from Xovorossiisk in a roundabout way, across the Black, Aegean and Mediterranean seas, and the Atlantic and Arctic oceans: I told them that that was why I vcrv well understood how terribly important lime was to life and construction, but that personally I never had any-thing to do with limestones and knew nothing about them.

" Then tell us about calcium," one of the engineers said, thus empha-sizing that the metal known as calcium was the basis of all limestones. "Tell us about this metal from the point of view of geochemistry, its properties, its fate, where and how it accumulates, and why it is precisely this element that creates the beautv of marbles and imparts such valuable technical properties to limestones and cement marls."

I gave them a lecture on this subject, and this is how the story of calcium atoms in the universe, which 1 am going to tell vou, came about.

I to ld t h e m t h a t s ince t h e y w e r e w o r k i n g in t h e c e m e n t i n d u s t r y , t he i ndus t ry of b i n d i n g subs tances , o n e of t h e mos t i m p o r t a n t b r a n c h e s of t he b u i l d i n g i n d u s t r y , t h e h is tory of c a l c i u m a t o m s s h o u l d b e of special in te res t to t h e m .

Chemis t s a n d physicists say t h a t in M e n d e l e y e v ' s sys tem c a l c i u m occup ies a ve ry specif ic p l a c e u n d e r n u m b e r 20. T h i s m e a n s t h a t it consists of a nuc leus , i .e., m i n u t e s t p a r t i c l e s — p r o t o n s a n d n e u -t rons , a n d t w e n t y f r ee nega t i ve ly c h a r g e d par t i c les k n o w n as elec-t rons .

N u m b e r 40 d e n o t e s t h e a t o m i c w e i g h t of this e l e m e n t l oca t ed in t he f o u r t h series of t he second g r o u p of M e n d e l e y e v ' s sys tem. T o f o r m s tab le molecu le s in its c o m p o u n d s it r e q u i r e s t w o n e g a t i v e charges . As t h e chemis t s say, it has a v a l en ce of t w o .

Y o u m u s t h a v e no t i ced t h a t in w h a t I said I used figures w h i c h a r e mul t ip l i e s of four . I n g e o c h e m i s t r y these a r e v e r y i m p o r t a n t n u m b e r s . W e k n o w t h a t in life, too , w h e n w e w a n t to m a k e s o m e t h i n g s t ab l e we a lways use these n u m b e r s ; fo r e x a m p l e , a

G e n e r a l v iew of a cement p lan t

134

t ab l e has lour legs. A s tab le body , a n y s t r u c t u r e , is usual!) sym-met r i ca l so t h a t t he r ight a n d the left ha lves a r e s imi la r .

T h e n u m b e r s 2, 4, 20 a n d 40 tell us t h a t c a l c i u m a t o m s a r e ex-cep t iona l ly s tab le , a n d we d o no t k n o w yet h o w m a n y h u n d r e d s ol mil l ions of degrees it w o u l d t ake to des t roy this d u r a b l e s t r u c t u r e of the small nuc leus a n d the g r o u p of t h e t w e n t y nega t i ve p lane t s speed ing a r o u n d it. A n d as t he as t rophysic is ts begin to u n d e r s t a n d the s t r u c t u r e of the en t i r e w o r l d t he e n o r m o u s p a r t t he c a l c i u m a t o m s h a v e p l aved in the un ive r se comes increas ing ly to the lore.

Mere is t he c o r o n a d u r i n g a so lar eclipse. Even the n a k e d eye c a n see t he i m m e n s e p r o m i n e n c e s , the ex t rus ion of r e d - h o t speed ing p a n i c l e s of me ta l s for a d i s t a n c e of h u n d r e d s of t h o u s a n d s ol k i lomet res : c a l c i u m plays the p r inc ipa l p a r t a m o n g these. Per fec t m e t h o d s h a v e n o w e n a b l e d o u r a s t r o n o m e r s to find ou t w h a t fills the i n t e r p l a n e t a r y spaces. The en t i r e space a m i d the d ispersed s te l lar n e b u l a e is p ie rced by speed ing l ight a t o m s of ce r t a in chemica l e l ements , a n d it is aga in c a l c i u m which a l o n g wi th s o d i u m plavs a b ig p a r t a m o n g t h e m .

A n d t h e n o b e v i n g the laws of g r av i ty ce r t a in speed ing par t ic les ol the universe t rave l l ing the i r i n t r i ca t e rou tes c o m e (lying to ou r e a r t h . T h e v fall in the fo rm ol me teor i t e s , a n d a g a i n ca l c ium plays a t r e m e n d o u s pa r t in t h e m .

O n o u r e a r t h , too, we could h a r d l y t h ink of a n y m e t a l of g r e a t e r i m p o r t a n c e to t he f o r m a t i o n of the e a r t h ' s crus t a n d the c rea t ion of life a n d t echn ica l progress .

As f a r back as t he t ime w h e n the m o l t e n masses boi led on the sur lace of the e a r t h , w h e n the heavy v a p o u r s g r a d u a l l y s e p a r a t e d out a n d the a t m o s p h e r e f o r m e d , a n d w h e n the first d r o p s of w a t e r c o n d e n s e d a n d c r e a t e d the g rea t oceans a n d seas, c a l c i u m , t o g e t h e r wi th its f r iend m a g n e s i u m , wh ich is as dense a n d s t r o n g a n d as e v e n - n u m b e r e d .in e l e m e n t (its n u m b e r is 12), is one of t he most i m p o r t a n t me ta l s on e a r t h .

In t he d i f fe ren t rocks, wh ich p o u r e d out to the sur lace or h a r d e n e d in the in te r ior , t he a t o m s of c a l c i u m a n d m a g n e s i u m p l a y e d a special p a r t . T h e floor of the l a rge oceans , especial ly the Pacif ic , a r e still paved wi th basal t in wh ich c a l c i u m a t o m s a r e verv i m p o r t a n t , a n d we know tha t ou r c o n t i n e n t s float on this basal t bed wh ich fo rms a sort ol th in , h a r d crust 011 the mel ts ol the in te r io r .

( i e o c h e m i s t s h a v e ev e n e s t i m a t e d t h a t t h e c o m p o s i t i o n ol t h e e a r t h ' s

e r u s t i n c l u d e s | p e r c e n t c a l c i u m a n d 2 p e r c e n t m a g n e s i u m b y

M a r b l e qua r ry

weight. They have linked the laws of calcium dispersion with the re-markable properties of the calcium atom itself, with the even number of its electrons and with the wonderful stability of this beautiful and perfect structure.

Immediately after the formation of the earth's crust these atoms began their complicated migrations.

At that time of the distant past volcanic eruptions'brought out large masses of carbon dioxide to the exterior. The heavy clouds of the atmosphere saturated with vapours of water and carbon dioxide sur-rounded the earth and destroyed the earth's surface removing the still hot masses of the earth in the wild primary storms. Thus, the most interesting stage in the history of migrations of calcium atoms began.

With carbon dioxide calcium yielded strong, stable compounds. In a surplus of carbon dioxide the calcium carbonate was transported by water; with a loss of carbon dioxide it was deposited in the form of a white crystalline powder.

Tha t is how the thick layers of limestones were formed. Wherever the sediments on the surface of the earth accumulated the remains of clays, layers of marls were deposited. The stormy movements of the molten underground masses, which broke into the layers of limestone, roasted them with their vapours at a temperature of thousands of degrees and transformed them into the snow-white mountains of marble whose proud peaks blend with the snow.

And then out of some complex clusters of carbon compounds came the first lumps of organic matter. These jelly-like colloid masses re-sembling the medusas of our Black Sea gradually grew more complex and new properties, properties of the living cells, arose. The great laws of evolution, the struggle for existence and for the further development of the genus ren-dered these molecules more complex, led them to new combinations and

37

Cora l polyps in the ocean

new properties arose on the basis of the' great laws of the organic world. Life was gradually taking form, first as simple cells in the hot seas and oceans, then as more complex multi-cellular organisms all the way up to man, the most perfect organism on earth. This gradual complication in the growth of each organism always reflected the struggle for the creation of a strong and stable body. In a number of cases the soft and clastic body of an animal could not resist its enemies who tore it to pieces and destroyed it at each step. In the process of gradual evolution organic substance in-creasingly strove to protect itself. Wha t was required was either some impenetrable shell around the soft body to hide the animal,

t.t r , • „ , • or a strong internal frame, the thing we Nes t s of whi te a n t s - t e r m i t e s - & ' bui l t of calcium ca rbona te . call a skeleton, so that the soft body might A f r i c a hold firmly on the hard bones. And the

history of1 life shows us that in this search for a hard and durable material calcium has played a very specific part. Calcium phosphate was the first to be drawn into the shells and the first shells encountered in the earth's crust were made of the mineral known as apatite.

It was not the best way, however. Phosphorus is needed for life itself and its reserves are not everywhere so large as to enable the animal to build a strong shell. The history of the development of the animal and plant world has shown that it is of greater advantage to build the strong parts from other insoluble compounds—opal, bar ium sulphate and strontium sulphate, but calcium carbonate proved the most suitable

1 3 8

material. True, phosphorus proved no less

necessary, and as various types of molluscs and crawfish, as well as unicellular organisms started to make extensive use of calcium carbonate for their pretty shells the

Shell of a ' f r e sh -wa te r mol lusc used fo r m a n u f a c t u r e of bu t tons

skeletal p a r t s of t e r res t r ia l a n i m a l s b e g a n to b e bu i l t of p h o s p h a t e s . T h e b o n e s of m a n o r of l a r g e a n i m a l s a r e m a d e of c a l c i u m p h o s p h a t e w h i c h in its n a t u r e v e r y m u c h r e semble s o u r m i n e r a l a p a t i t e . Bu t in t h e f o r m e r , as wel l as in t he l a t t e r case, c a l c i u m h a s p l a y e d a n a p p r e c i a b l e p a r t . T h e on ly d i f f e r e n c e is t h a t t h e ske le ton of m a n was b e i n g bu i l t of t he p h o s p h a t e of this m e t a l , w h i l e t he shells w e r e bu i l t m a i n l y of i ts c a r b o n a t e .

I t is h a r d to t h i n k of a m o r e re -m a r k a b l e p i c t u r e t h a n t h e o n e t h a t p resen t s itself to a n a t u r a l i s t as h e c o m e s to t he coast of, say, t h e M e d -i t e r r a n e a n .

I r e m e m b e r w h e n as a y o u n g geologis t I f o u n d myself fo r t he first t i m e o n t h e rocky sho re of N e r v i , n e a r G e n o a . I w a s a m a z e d a t t h e b e a u t y a n d m u l t i f o r m i t y of shells, p a r t i - c o l o u r e d seaweeds , h e r m i t c r a b s w i t h t he i r b e a u t i f u l l i t t le l imes tone h o m e s , v a r i o u s molluscs , w h o l e colonies of sea-mosses a n d va r ious l imes tone corals .

I w a s c o m p l e t e l y i m m e r s e d in this w o n d e r f u l w o r l d of t r a n s p a r e n t b lu i sh w a t e r t h r o u g h w h i c h I cou ld see i r r idescen t c o m p o u n d s of t he s a m e c a l c i u m c a r b o n a t e . Bu t m y rever ies in this n e w w o r l d w e r e in t e r -r u p t e d b y a n e n o r m o u s oc topus , w h i c h c a m e u p to o u r rock u n n o t i c e d , a n d I b e g a n to tease it w i t h a st ick.

C a l c i u m a c c u m u l a t e d in shells a n d skele tons o n t h e floors of sea bas ins in h u n d r e d s of t h o u s a n d s of fo rms . T h e r e t h e i n t r i c a t e r e m a i n s of d e a d o r g a n i s m s f o r m e d w h o l e ceme te r i e s of c a l c i u m c a r b o n a t e , t h e f o u n d a t i o n of n e w rock , e n t i r e f u t u r e m o u n t a i n ranges .

A n d n o w w h e n w e a d m i r e t h e m u l t i f o r m i t y of m a r b l e co lours w h i c h d e c o r a t e o u r a r c h i t e c t u r a l s t ruc tu re s , o r de l igh t a t t h e b e a u t i f u l g rey or w h i t e m a r b l e of t he s w i t c h b o a r d at a n e lec t r ic s t a t ion , or go d o w n t h e s tairs of o u r M e t r o w i t h the i r y e l l o w - b r o w n steps m a d e of t he S h e v a r d i n o m a r b l e - l i k e l imes tone f o u n d n e a r M o s c o w , w e m u s t n o t

Shells of molluscs a rc ex t rac ted f r o m the sea by dragging . Used in the cement indust ry as pure CaCC>3 and for the m a n u f a c t u r e of bu t tons

39

fo rge t t h a t t h e basis for al l these e n o r m o u s a c c u m u l a t i o n s of l i m e s t o n e was laid b y a smal l l iv ing cell a n d b y t h e c o m p l e x c h e m i c a l r e a c t i o n w h i c h ca t ches t h e d i spersed c a l c i u m a t o m s in s ea -wa t e r , c h a n g e s t h e m i n t o h a r d c rys ta l l ine skele tons a n d fibres of c a l c i u m m i n e r a l s t h a t w e r e g iven t h e n a m e s of ca lc i te a n d a r a g o n i t e .

Bu t w e k n o w t h a t t h e m i g r a t i o n s of c a l c i u m a t o m s d o no t e n d w i t h t h a t .

T h e w a t e r s dissolve t h e c a l c i u m a g a i n a n d its spher i ca l ions r e s u m e the i r m i g r a t i o n s in t he e a r t h ' s c rus t in c o m p l e x a q u e o u s so lu t ions n o w f o r m i n g so-cal led h a r d , c a l c i u m - r i c h wa te r s , n o w p r e c i p i t a t i n g t o g e t h e r w i t h s u l p h u r in t he f o r m of g y p s u m a n d n o w crys ta l l iz ing i n t o s ta lac t i tes a n d s t a lagmi tes , t h e c o m p l e x f an t a s t i c f o r m a t i o n s in l imes tone caves.

T h e n beg ins t h e last s tage in t he h is tory of c a l c i u m - a t o m m i g r a t i o n s : m a n takes possession of c a l c i u m . H e no t on ly uses m a r b l e s a n d l imes tones

T h e M a r b l e Palace , L e n i n g r a d branch of the Lenin M u s e u m . W i t h the except ion of the g round f loor (bui l t of gran i te ) cons t ruc ted ent i re ly f r o m Russian m a r b l e

140

i n t he i r p u r e f o r m , b u t in t he l a rge f u r n a c e s of t h e c e m e n t p l a n t s a n d in t h e l ime kilns he releases c a l c i u m f r o m the p o w e r of c a r b o n d iox ide a n d c rea te s l a r g e a m o u n t s of c e m e n t a n d l i m e w i t h o u t w h i c h w e w o u l d h a v e n o i n d u s t r y .

I n t h e mos t c o m p l e x processes of p h a r m a c e u t i c a l , o r g a n i c a n d i n o r g a n i c c h e m i s t r y c a l c i u m plays a n e n o r m o u s p a r t a n d d e t e r m i n e s these processes in t h e l a b o -ra to r i e s of chemis ts , t echnologis t s a n d meta l lu rg i s t s . B u t even this n o l onge r satisfies m a n . T h e r e is t oo m u c h c a l c i u m a r o u n d us a n d this s t ab le a t o m c a n b e used for even f ine r c h e m i c a l r e a c t i o n s ; m a n spends scores of t h o u s a n d s of k i lowat t s of e lec t r ic p o w e r o n i t : h e no t on ly frees t h e c a l c i u m a t o m s in l imes tone f r o m t h e c a r b o n d iox ide , b u t also severs its b o n d w i t h o x y g e n a n d p r o d u c e s it in its p u r e f o r m , i.e., in t h e f o r m of a sh iny , spa rk l ing , soft a n d resi l ient m e t a l w h i c h b u r n s in t he a i r a n d covers itself w i t h a w h i t e film of t h e s a m e l ime .

A n d it is precise ly this a f f in i ty for oxygen , this close a n d s t rong b o n d w h i c h is es tab l i shed b e t w e e n t h e a t o m s of t h e ca l c ium, m e t a l a n d t h e a t o m s of o x y g e n t h a t m a n m a k e s use of. H e i n t r o d u c e s t h e me ta l l i c a t o m s of c a l c i u m i n t o m o l t e n i r on a n d in s t ead of us ing va r ious o t h e r c o m p l e x deoxid izers a n d a n u m b e r of m e t h o d s of p u r i f y i n g p ig i ron a n d steel f r o m h a r m f u l gases h e m a k e s t h e m e t a l l i c a t o m s of c a l c i u m d o this w o r k b y u t i l i z ing t h e m in o p e n - h e a r t h a n d blas t -f u r n a c e s .

T h u s t h e m i g r a t i o n of this e l e m e n t is r e s u m e d ; its me ta l l i c pa r t i c les d o no t spa rk le l ong for t h e y a r e a g a i n t r a n s f o r m e d i n t o c o m p l e x o x y g e n c o m p o u n d s m o r e s t ab le o n tfye su r f ace of o u r e a r t h .

As y o u see, t h e h i s to ry of c a l c i u m a t o m s is m u c h m o r e c o m p l i c a t e d

Sculpture of a girl. M a d e of whi te Ura l s m a r b l e by S. K o n e n k o v

141

Kaluzhskaya Stat ion of the Moscow U n d e r g r o u n d . T h e wal l s a re f a t e d with wh i t e

Ura l s m a r b l e

Ryelorusskaya Stat ion of the Moscow U n d e r g r o u n d . T h e co lumns a re m a d e of whi te marb le , the wal ls and the mosaic f loor a rc la id ou t of mul t i -co loured domes t i c marb l e s

t h a n we t h i n k ; it w o u l d be diff icul t to f ind a n o t h e r ch emi ca l e l e m e n t w h i c h t ravels such i n t r i c a t e rou tes in space a n d w h i c h d e t e r m i n e s m o r e i m p o r t a n t m o m e n t s in the or ig in of o u r wor lds a n d in ou r in-dus t r i a l life.

W e mus t not forget t h a t c a l c i u m is o n e of t he mos t v igorous a n d m o b i l e a t o m s in t he universe , t h a t it has u n l i m i t e d possibilit ies of c o m b i n i n g in to c rys ta l l ine s t r u c t u r e s a n d t h a t m a n will m a k e m a n y n e w discover ies in wh ich he will b e ab l e to use these m o b i l e g lobules for d e v e l o p i n g n e w m a t e r i a l s for b u i l d i n g a n d i n d u s t r y p e r h a p s never be fo re equa l l ed in s t r e n g t h .

But this still r equ i r e s a lot of work a n d a g r e a t e r insight i n to t he n a t u r e of this a t o m . T o m a k e a good geochein is t a n d be a b l e to c h a r t a n e w course in geology o n e m u s t b e a t h o u g h t f u l chemis t a n d physicist a n d a n e x p e r t in geology. T o b e a good technolog is t a n d u n d e r s t a n d t h e n e w ways of i ndus t ry , t he p a t h s w h i c h will lead to br i l l ian t victories ove r n a t u r e a n d to t h e wides t possible u t i l i za t ion of t h e most a b u n d a n t e l e m e n t s of t he e a r t h , o n e h a s to m a s t e r t he sciences of chemis t ry , physics, geology a n d g e o c h e m i s t r y .

POTASSIUM—BASIS OF PLANT LIFE

Po ta s s ium is a cha rac t e r i s t i c a lka l i e l e m e n t w h i c h occup ies a r a t h e r low p l ace in t h e first g r o u p of M e n d e l e y e v ' s Pe r iod i c T a b l e . I t is a typ ica l o d d e l e m e n t b e c a u s e its cha rac t e r i s t i c ind ices a r e o d d ; its a t o m i c n u m b e r , i.e., t h e n u m b e r of e lec t rons c o n s t i t u t i n g its e lec t ron shell is 19 a n d its a t o m i c we igh t is 39. I t f o rms s t r o n g b o n d s only wi th o n e a t o m of a ha lo id , for e x a m p l e , c h l o r i n e ; it is, as w e say, u n i v a l e n t . As a n o d d e l e m e n t p o t a s s i u m is a t t h e s a m e t i m e c h a r a c t e r i z e d by the cons ide rab l e size of its c h a r g e d sphe r i ca l pa r t i c les a n d this t o g e t h e r w i t h the i r o d d n u m b e r is respons ib le for the i r c o n s t a n t t e n d e n c y to m i g r a t i o n a n d the i r specia l mob i l i t y .

N o w o n d e r , t he re fo re , t h a t t h e en t i r e h i s tory of p o t a s s i u m in t he e a r t h is c o n n e c t e d , like t h e fa te of its f r i end s o d i u m , w i t h excep t iona l mobi l i ty a n d c o m p l e x t r a n s f o r m a t i o n s . I t f o rms m o r e t h a n o n e h u n d r e d m i n e r a l s in t h e e a r t h ' s crus t a n d , in smal l a m o u n t s , p a r t of a h u n d r e d o the r m i n e r a l species. I ts a v e r a g e c o n t e n t in t h e e a r t h ' s c rus t is close to 2.5 per cen t . T h i s is a l a rge figure a n d it shows t h a t a l o n g w i t h s o d i u m a n d c a l c i u m p o t a s s i u m be longs to t he e l emen t s w h i c h preva i l in t he e a r t h .

T h e his tory of po t a s s ium in t h e c o m p l e x geological pas t of o u r p l a n e t is very in te res t ing . I t has been s tud i ed in de ta i l a n d we c a n n o w t r a c e t he en t i r e course t r aversed by p o t a s s i u m a t o m s un t i l t hey c o m p l e t e the i r c o m p l e x life cycle a n d r e t u r n to t h e b e g i n n i n g of the i r m i g r a t i o n s .

W h e n the m o l t e n m a g m a s h a r d e n in t h e in te r io r of t he e a r t h a n d i n d i v i d u a l e l emen t s a r e d i s t r i bu t ed a c c o r d i n g to the i r mobi l i ty , a c c o r d i n g to the i r ab i l i ty to m i g r a t e , to f o r m vola t i le gases or m o b i l e fus ib le par t ic les we find p o t a s s i u m a m o n g t h e m . I t does no t p r e c i p i t a t e in

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t he first crysta ls w h i c h a r e f o r m e d b e f o r e o the r s in t h e in t e r io r of o u r e a r t h ; w e scarce ly e n c o u n t e r it i n g r e e n o l i v i n e - c o n t a i n i n g P l u t o n i c rocks w h i c h m a k e u p c o n t i n u o u s zones of t h e e a r t h ' s i n t e r i o r . E v e n in t h e b a s a l t masses w h i c h f o r m t h e o c e a n floor w e e n c o u n t e r n o m o r e t h a n 0 .3 p e r cen t p o t a s s i u m .

I n t h e course of t h e c o m p l e x c rys ta l l i za t ion of m o l t e n m a g m a s t h e m o r e m o b i l e a t o m s of t h e e a r t h a c c u m u l a t e in t he i r u p p e r p a r t s ; h e r e w e find m o r e of t h e sma l l h e a v i l y - c h a r g e d ions of sil icon a n d a lu -m i n i u m ; h e r e w e also h a v e m a n y o d d a t o m s of t h e alkal is p o t a s s i u m a n d s o d i u m a n d vola t i le w a t e r c o m p o u n d s . T h e rocks w e call g r an i t e s a r e f o r m e d f r o m these m o l t e n r e m a i n s . T h e y cover vas t sect ions of t h e e a r t h ' s su r f ace r e p r e s e n t i n g t h e c o n t i n e n t s floating o n basal ts .

T h e g r a n i t e s h a r d e n in t h e i n t e r i o r of t h e e a r t h ' s c rus t a n d p o t a s s i u m a c c u m u l a t e s in t h e m in a m o u n t s c o n s t i t u t i n g n e a r l y t w o p e r cen t , a n d m a i n l y f o r m s p a r t of t h e m i n e r a l w e call f e l d s p a r or o r thoc lase . P o t a s s i u m is also a c o n s t i t u e n t of t h e w e l l - k n o w n b l ack a n d w h i t e m i c a s ; in s o m e p laces it a c c u m u l a t e s in even g r e a t e r a m o u n t s f o r m i n g

Lake- sa l t in the poo l of the K a r a k o l sal t works , T a j i k S.S.R.

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l a rge crysta ls of a w h i t e m i n e r a l , ca l led leuc i te , of w h i c h p a r t i c u l a r l y b ig q u a n t i t i e s a r e c o n t a i n e d i n t h e p o t a s s i u m - r i c h lavas in I t a l y w h e r e it is m i n e d for t h e p u r p o s e of p r o -d u c i n g p o t a s s i u m a n d a l u m i n i u m .

T h e g ran i t e s a n d ac id lavas of i gneous rock a r e t h u s t h e c r a d l e of p o t a s s i u m a t o m s o n e a r t h .

W e k n o w h o w t h e y a r e des t royed on t h e su r f ace of t h e e a r t h b y w a t e r , a i r a n d t h e c a r b o n d iox ide w i t h w h i c h t h e a t m o s p h e r e a n d t h e w a t e r

a r e s a t u r a t e d , a n d h o w roots of p l a n t s g r o w t h r o u g h t h e m c o r r o d i n g i n d i v i d u a l m i n e r a l s b y t h e ac ids t h e y l i be ra t e .

T h o s e w h o h a v e ever b e e n in t h e env i rons of L e n i n g r a d m u s t h a v e seen h o w easily g r a n i t e s d i s i n t e g r a t e a t t he i r o u t c r o p s a n d in bou lde r s , h o w the i r m i n e r a l s a r e w e a t h e r e d , t h e rock loses its lus t re a n d p u r e q u a r t z s ands a c c u m u l a t e in t h e f o r m of d u n e s as r e m a i n s of t h e o n c e p o w e r f u l g r a n i t e massifs. F e l d s p a r d i s in t eg ra t e s a t t h e s a m e t ime . T h e p o t e n t agen t s of t h e e a r t h ' s s u r f a c e e x t r a c t t h e s o d i u m a n d p o t a s s i u m a t o m s f r o m it a n d l eave a p e c u l i a r ske le ton of l a m i n a t e d m i n e r a l f o r m i n g c o m p l e x rocks w h i c h w e call c lay .

A t this m o m e n t o u r t w o f r i e n d s — p o t a s s i u m a n d s o d i u m — b e g i n the i r n e w m i g r a t i o n s . I n c i d e n t a l l y , t h e y a r e f r i ends o n l y un t i l this m o m e n t b e c a u s e a f t e r t h e d e s t r u c t i o n of t h e g r a n i t e e a c h of t h e m begins l iv ing its o w n life. S o d i u m is easily w a s h e d o u t b y w a t e r ; t h e r e is n o t h i n g to r e t a i n its ions in t h e s u r r o u n d i n g s i l t - con ta in ing c lays a n d sed imen t s . T h e s e ions a r e ca r r i ed a w a y b y s t r e a m s a n d r ivers i n to l a rge seas w h e r e they f o r m t h e s o d i u m c h l o r i d e w h i c h w e call c o m m o n sal t a n d w h i c h is t h e p r i n c i p a l in i t ia l p r o d u c t of o u r e n t i r e c h e m i c a l i n d u s t r y .

Bu t p o t a s s i u m has a d i f f e r e n t f a te . I n sea -wa te r s w e find it on ly in smal l quan t i t i e s . T h e r e is a b o u t t h e s a m e n u m b e r of s o d i u m a n d po-tass ium a t o m s in rocks, b u t of o n e t h o u s a n d p o t a s s i u m a t o m s o n l y t w o r e a c h the sea-bas ins , wh i l e t h e o t h e r 998 a r e a b s o r b e d b y t h e soil a n d r e m a i n in silts a n d in t h e s e d i m e n t s of m a r s h e s a n d r ivers . T h e soil a b s o r b s p o t a s s i u m a n d this cons t i tu tes its m i r a c u l o u s force .

Across the salt bed of L a k e Baskunchak

1 4 6

A c a d e m i c i a n K . G e d r o i t z , w e l l - k n o w n soil scient is t , w a s t h e first to d i v i n e t h e g e o c h e m i c a l n a t u r e of t h e soil. H e f o u n d in it t h e p a r t i -cles w h i c h r e t a i n d i f f e r e n t me ta l s , especia l ly p o t a s s i u m , arid d e m o n -s t r a t e d t h a t t h e fe r t i l i ty of t h e soil i n l a r g e m e a s u r e d e p e n d e d o n t h e p o t a s s i u m a t o m s w h i c h a r e so l igh t ly a n d so loosely c o n n e c t e d w i t h i t t h a t e a c h p l a n t cell cou ld a b s o r b these a t o m s a n d m a k e use of t h e m for its o w n life. A n d i t is b y a b s o r b i n g these l i g h t l y - b o u n d , s eeming ly f r e e - h a n g i n g , p o t a s s i u m a t o m s t h a t t h e p l a n t deve lops its sp rou t s .

R e s e a r c h h a s s h o w n t h a t t h e roo ts of p l a n t s r e a d i l y e x t r a c t p o t a s s i u m t o g e t h e r w i t h s o d i u m a n d c a l c i u m .

P l an t s c a n n o t l ive w i t h o u t p o t a s s i u m . W e d o n o t k n o w ye t w h y t h e y c a n n o t n o r w h a t p a r t p o t a s s i u m p lays in t h e p l a n t o r g a n i s m , b u t e x p e r i m e n t s h a v e s h o w n t h a t w i t h o u t p o t a s s i u m t h e p l a n t s w i t h e r a w a y a n d die .

I n c i d e n t a l l y , i t is n o t on ly p l a n t s t h a t n e e d p o t a s s i u m ; t h e l a t t e r a lso f o r m s a n essent ia l p a r t of a n i m a l o rgan i sms . T h u s , fo r e x a m p l e , t h e musc le s of m a n c o n t a i n m o r e p o t a s s i u m t h a n s o d i u m . Espec ia l ly l a r g e a m o u n t s of p o t a s s i u m a r e c o n t a i n e d i n t h e b r a i n , t h e l iver , t he h e a r t a n d t h e k idneys . I t will b e n o t e d t h a t p o t a s s i u m is p a r t i c u l a r l y i m p o r t a n t d u r i n g t h e g r o w t h a n d d e v e l o p m e n t of t h e o r g a n i s m . T h e h u m a n a d u l t r e q u i r e s m u c h less p o t a s s i u m .

P o t a s s i u m beg ins o n e of t h e cycles in its m i g r a t i o n s f r o m t h e soil. I t is e x t r a c t e d f r o m t h e soil b y t h e roo ts of p l an t s , is a c c u m u l a t e d in t he i r d e a d r e m a i n s , p a r t l y passes i n t o t h e o r g a n i s m of m a n or a n i m a l s a n d is a g a i n r e t u r n e d w i t h t h e h u m u s to t h e soil f r o m w h i c h i t w a s e x t r a c t e d b y a l iv ing cell .

T h e g r e a t e r p a r t of p o t a s -s i u m t rave l s prec ise ly th i s r o u t e , b u t i n d i v i d u a l a t o m s m a n a g e to r e a c h l a r g e o c e a n s a n d t o g e t h e r w i t h o t h e r salts t o d e t e r m i n e t h e sa l in i ty of s e a - w a t e r , t h o u g h t h e

E v a p o r a t i n g pools a t t he Saki Sa l t -Works in the Cr imea . T h e br ine rich in potass ium and b romine is e v a p o r a t e d he re

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l a t t e r con t a in s 40 t imes as m a n y a t o m s of s o d i u m as p o t a s s i u m . H e r e is w h e r e t h e s econd cycle of t h e m i g r a t i o n s of p o t a s s i u m a t o m s

begins . W h e n l a rge reg ions of oceans b e g i n to d r y o u t b e c a u s e of t h e m o v e -

m e n t s of t h e e a r t h ' s c rus t t h e y g ive rise to s e p a r a t e sha l low seas, lakes, firths, l agoons a n d bays , a n d f o r m sa l t - lakes l ike L a k e Sak i or t h e lakes n e a r Y e v p a t o r i y a on t h e Black Sea coas t . O n h o t s u m m e r d a y s w a t e r e v a p o r a t e s so g r e a t l y t h a t t h e sal t p rec ip i t a t e s , is c a r r i e d a s h o r e b y waves a n d s o m e t i m e s a c c u m u l a t e s o n t h e b o t t o m of abso lu t e ly d r y lakes in t h e f o r m of a g l i t t e r ing w h i t e sheet . I t will b e obse rved t h a t t h e salts p r e c i p i t a t e in a c e r t a i n s e q u e n c e : c a l c i u m c a r b o n a t e crystal l izes first a n d is fo l lowed b y g y p s u m (ca l c ium s u l p h a t e ) a n d s o d i u m ch lo r ide , i .e. , c o m m o n sal t . A b r i n e w h i c h is g r e a t l y s a t u r a t e d w i t h salts a n d w h i c h is k n o w n as " r a p a " in t h e S o u t h of t h e U . S . S . R .

V

Harves t i ng in fields fer t i l ized by po tass ium, phosphorus , and ni t rogen salts

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r e m a i n s ; this b r i n e c o n t a i n s scores of p e r cen t of va r i ous salts a n d , especial ly , salts of p o t a s s i u m a n d m a g n e s i u m .

P o t a s s i u m h a p p e n s to b e even m o r e m o b i l e t h a n s o d i u m ; t h e p r o p -er t ies of its l a rge sphe r i ca l a t o m s m a n i f e s t themse lves a n d it con t i nues its m i g r a t i o n s un t i l a n even h o t t e r s u n e v a p o r a t e s t he lakes to t h e ve ry e n d , un t i l w h i t e a n d r ed p o t a s s i u m salts a r e p r e c i p i t a t e d o n t h e su r f ace of sal t depos i t s ; it is in th is m a n n e r t h a t p o t a s s i u m depos i t s a r e f o r m e d .

V e r y l a rge a c c u m u l a t i o n s of p o t a s s i u m salts, w h i c h m a n so b a d l y needs for i n d u s t r y , s o m e t i m e s f o r m in t h e e a r t h ' s c rus t . H e r e it is n o l o n g e r t h e mys t e r ious forces of t h e soil a n d n o t p l a n t s t h a t d e t e r m i n e t h e r o u t e to b e t r ave l l ed by p o t a s s i u m ; n o r is it t h e s o u t h e r n s u n t h a t a c c u m u l a t e s it on t h e shores of sa l t - lakes ; h e r e in i n d u s t r y i t is m a n h imse l f w h o is t h e a g e n t of t h e n e w a n d e n o r m o u s cycle in t he m i g r a t i o n s of its a t o m s .

S t u d y i n g t h e ro le of p o t a s s i u m a n d p h o s p h o r u s in p l a n t s J u s t u s L ieb ig , o n e of t h e g rea tes t G e r m a n chemis ts , u t t e r e d t he fo l lowing w i n g e d w o r d s a b o u t 100 yea r s a g o : " O u r fields c a n n o t b e fer t i le w i t h o u t these t w o e l e m e n t s . " A n idea , f an t a s t i c for its t ime , crossed his m i n d ; i t o c c u r r e d to h i m p e o p l e shou ld fer t i l ize t he i r fields b y ar t i f ic ia l ly i n t r o d u c i n g va r ious s a l t s — p o t a s s i u m , n i t r o g e n a n d p h o s p h o r u s — i n t o t h e soil a f t e r e s t i m a t i n g t h e a m o u n t s t h e p l a n t s cou ld ut i l ize.

H i s i dea was m e t w i t h d i s t rus t by t h e f a r m i n g p e o p l e of t h e m i d d l e of last c e n t u r y ; it was cons ide red a "sc ien t i s t ' s f a n c y , " especial ly s ince t h e sa l tpe t r e , w h i c h was b r o u g h t b y sa i l ing vessels f r o m S o u t h A m e r i c a a n d w h i c h h e p r o p o s e d for u t i l i za t ion as fer t i l izer , was ex-cessively expens ive a n d f o u n d n o m a r k e t . Sources of p h o s p h o r u s w e r e u n k n o w n , w h i l e t he g r i n d i n g of b o n e s p r o p o s e d by L i e b i g y ie lded e x t r e m e l y costly fer t i l izer . P e o p l e d i d n o t k n o w h o w to m a k e use of p o t a s s i u m a n d on ly r a r e ly col lec ted t h e ashes of p l a n t s a n d s t r ewed t h e m over t h e fields. T h e f a r m e r s of t h e U k r a i n e h a v e l ong b e e n b u r n i n g t h e r e m a i n s of m a i z e stalks a n d s c a t t e r i n g t h e ashes, t hus o b t a i n e d , a b o u t t h e f ie lds; t he s ign i f icance of these ashes t o t h e c rops o c c u r r e d to t h e m s p o n t a n e o u s l y w i t h o u t t h e a id of science.

M a n y yea r s h a v e passed s ince t h e n a n d p r o b l e m s of fe r t i l i za t ion h a v e a c q u i r e d g r e a t i m p o r t a n c e i n all c o u n t r i e s ; fer t i l i ty of t h e soil n o w la rge ly d e p e n d s o n w h e t h e r m a n is a b l e to i n t r o d u c e i n t o t h e soil suff ic ient a m o u n t s of t h e subs t ances w h i c h t h e p l a n t s h a v e e x t r a c t e d

4 9

f r o m it a n d w h i c h m a n has t a k e n a w a y f r o m t h e fields in the f o r m of g r a in , s t r a w a n d f ru i t . I t n o w a p p e a r s t h a t p o t a s s i u m h a s b e c o m e o n e of t he mos t necessary e l e m e n t s of f a r m i n g .

Suff ice i t t o say t h a t in 1940 such c o u n t r i e s as H o l l a n d used u p to 42 tons of p o t a s s i u m o x i d e p e r h e c t a r e . T r u e , this figure is m u c h lower in o t h e r c o u n t r i e s ; on ly a b o u t f ou r tons p e r h e c t a r e is used in A m e r i c a .

A n d m a n k i n d has f aced t h e p r o b l e m of finding l a r g e depos i t s of p o t a s s i u m salts, of l e a r n i n g to e x t r a c t t h e m a n d to m a n u f a c t u r e fer t i l izer f r o m t h e m .

G e r m a n y long o w n e d the w o r l d ' s p o t a s s i u m i n d u s t r y . Depos i t s of t he f a m o u s S tass fu r t salts w e r e d i scovered o n t h e eas t e rn slopes of t h e H a r z M o u n t a i n s a n d h u n d r e d s of t h o u s a n d s of t r a i n l o a d s of p o t a s s i u m salts w e r e t r a n s p o r t e d f r o m N o r t h G e r m a n y to all coun t r i e s .

T h e o t h e r count r i es , for w h i c h f a r m i n g was a q u e s t i o n of v i ta l i m -p o r t a n c e , cou ld n o t p u t u p w i t h it . N o r t h A m e r i c a s p e n t a lot of t i m e a n d e n e r g y b e f o r e it f o u n d a sma l l p o t a s s i u m depos i t . T h e F r e n c h m a d e some h e a d w a y b y d i s cove r ing p o t a s s i u m in t h e R h i n e V a l l e y ; w h i l e p o t a s s i u m was b e i n g s e a r c h e d for t h e p o t a s s i u m m i n e r a l s of t h e igneous rock f o u n d in I t a l y w e r e m a d e use of. B u t al l this was in -s igni f icant c o m p a r e d w i t h t he a m o u n t s r e q u i r e d b y t h e e x h a u s t e d soils.

R u s s i a n exp lo re r s t r i ed for m a n y yea r s t o find p o t a s s i u m depos i t s in Russ ia . I n d i v i d u a l c o n j e c t u r e s p r o v e d frui t less u n t i l t h e pers i s ten t w o r k of a w h o l e school of y o u n g chemis t s supe rv i sed b y A c a d e m i c i a n N . K u r n a k o v resu l ted in t h e d i scovery of t h e w o r l d ' s l a rges t p o t a s s i u m deposi ts . T h e d i scovery was a c c i d e n t a l , b u t a c c i d e n t s in sc ience a r e usua l ly t he resu l t of l ong a n d l abo r ious p r e p a r a t i o n , wh i l e t h e " a c c i d e n t a l d i s c o v e r y " is nea r ly a lways m e r e l y t h e last s t ep in t h e l e n g t h y s t rugg le for t h e e f f e c t u a t i o n of a de f in i t e i d e a a n d a r e w a r d fo r a p r o t r a c t e d a n d pers i s ten t s ea rch .

T h i s also ho lds t r u e of t h e d i scovery of p o t a s s i u m . A c a d e m i c i a n K u r n a k o v h a d s tud i ed t h e c o u n t r y ' s sa l t - lakes for m a n y d e c a d e s a n d his m i n d pers i s ten t ly s e a r c h e d for t h e r e m a i n s of t he a n c i e n t p o t a s s i u m lakes. W h i l e w o r k i n g in t he l a b o r a t o r y on t h e c o m p o s i t i o n of sal t f r o m old P e r m i a n sa l t -works N iko l a i K u r n a k o v n o t i c e d in s o m e cases a h i g h p o t a s s i u m c o n t e n t .

O n a visit to o n e of t h e sa l t -works h e o b s e r v e d a smal l p iece of b r o w n -red m i n e r a l w h i c h r e m i n d e d h i m of t h e r e d p o t a s s i u m salts, t h e ca r -

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nallites of the German deposits. True, the personnel of the salt-works were not sure where this piece had come from and whether it had not been from the collection of the salts they had received from Germany. But Academician Kurnakov took the piece, put it in his pocket and went to Leningrad. Upon analysis he found much to everybody's surprise that the piece was potassium chloride.

The first strike was made, but that was not enough; it was still necessary to prove that this piece of potassium had come from the entrails of the Solikamsk earth and that there were large deposits there. A hole had to be bored, some salt extracted under the difficult condi-tions of the twenties and its com-position studied.

P. Preobrazhensky, one of the most prominent geologists of the Geological Committee, undertook to do the work. He pointed out the necessity of boring deep holes, and soon these holes reached thick layers of potassium salts, thus opening a new era in the history of potassium over the entire surface of the earth.

Now that several decades have passed since this discovery the pic-ture of distribution of the potassium reserves among all countries of the world has completely changed. We find the greater part of these reserves in the Soviet Union; in terms of potassium oxide Germany owns only 2,500 million tons, Spain—350 million, France—285 million, while America and the other countries have very little potassium. Not all of the potassium deposits in the Soviet Union have been studied, however.

I t is quite probable that the U.S.S.R. will soon increase its reserves and new pictures of potassium migration in the ancient Permian seas 300 to 400 million years ago will be revealed.

* ^ m

A c a d c m i c i a n N i k o l a i K u r n a k o v (1860-1941)

This distant past in the geological history of our country is now pictured as follows: The an-cient Permian Sea covered the entire East of the European part of the Soviet Union. This sea was the shallow southern portion of the ocean that spread over the country from the North. Its separate bays and gulfs reached Arkhangelsk on the White Sea and Novgorod. In the East the sea bordered on the Urals, while in the southwest its arms stretched as far as the Donets Basin and Kharkov. In the south-east it reached far south to the regions of the Caspian. Some scien-tists even believed that in the

Geolog i s t P. P reob razhensky (1874-1944) beginning of its existence our Russian Permian Sea merged with the great Thetis Ocean which

engirded the earth in the distant past of the Permian epoch. This large ocean gradually grew shallow forming separate lakes along its coast, while the humid climate was replaced by the winds and the sun of the deserts.

The young Urals Mountains were being destroyed by powerful hot winds; everything was being moved to the shores of the dying Permian Sea. The sea was receding to the south. Gypsum and common salt were accumulating in the lakes and firths in the north, while the content of potassium and magnesium salts was increasing in the south. The brine which man obtains artificially in the sedimentary basins, for example the Saki Lake, was accumulating in the southeast. Separate shallow seas and lakes saturated with residual salts of potassium and magnesium were thus gradually formed.

Deposits of potassium salts began to accumulate. Separate potas-sium deposits hidden under the soil stretch from Solikamsk to the south-east Urals. Everywhere the bore holes run into powerful underground lenses of common salt overlaid by potassium salts.

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Sylvini te , a rock consist ing of layers of sylvite a n d ha l i te . Sol ikamsk depos i t

A small piece of brown-red salt noticed by the keen eye of a scientist in the laboratory of the works thus led to the solution of one of the greatest problems, the problem of potassium. The country was now in a position not only fully to provide the fields with fertilizer and to increase their yield, but also to create a new potassium industry and to produce the most diverse potassium salts so indispensable to chemical production. These are potassium hydroxide, carbonate, nitrate, perchlorate, chromate and other diverse compounds increasingly used in the national economy. Large amounts of magnesium are obtained as "waste products" along with potassium; a lustrous light metal is isolated from these waste products by electrolysis, while one of its alloys, known as "electron,"* opens a new page in the field of railway and aircraft construction.

* The alloy electron should not be confused with the electron which is a particle of negative electricity; this is only an accidental coincidence of terms.

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j T h e c o u n t r y ' s a g r o c h e m i s t s a r e n o w r e a l i z i n g t he i r d r e a m of p r o -m i c i n g e n o u g h p o t a s s i u m o x i d e i n o r d e r fu l ly t o p r o v i d e o u r fields w i t h this v a l u a b l e s u b s t a n c e a n d to i nc rea se t he i r y ie ld .

S u c h is t h e h i s to ry of p o t a s s i u m in t h e e a r t h a n d in t h e h a n d s of m a n .

B u t this e l e m e n t h a s a n o t h e r sma l l f e a t u r e t o w h i c h w e s h o u l d t u r n o u r a t t e n t i o n . C u r i o u s l y e n o u g h o n e of t h e i so topes of p o t a s s i u m possesses r a d i o a c t i v e p r o p e r t i e s (very w e a k , to b e su re ) , i .e., i t is u n s t a b l e ; th is i so tope emi t s v a r i o u s r ays a n d c h a n g e s to a t o m s of a n o t h e r s u b s t a n c e , w h i c h in s u b s e q u e n t g r o u p i n g s f o r m s a t o m s of c a l c i u m .

T h i s p h e n o m e n o n cou ld n o t b e d e m o n s t r a t e d for a l o n g t ime , b u t it t u r n e d o u t l a t e r t h a t this v e r y p o t a s s i u m - 4 0 rea l ly p l a y e d a n i m -p o r t a n t p a r t in t h e life of t h e e a r t h b e c a u s e c o n s i d e r a b l e a m o u n t s of h e a t w e r e l i b e r a t e d d u r i n g t h e t r a n s f o r m a t i o n of t h e u n s t a b l e po tas -s i u m a t o m s in to a t o m s of c a l c i u m . Sovie t rad io logis t s h a v e e s t i m a t e d t h a t a t least 20 p e r c e n t of t h e h e a t f o r m e d in t h e e a r t h u n d e r t h e in f luence of a t o m i c d i s i n t e g r a t i o n is p r o d u c e d b y t h e salts of p o t a s s i u m a n d , hence , t h e e n o r m o u s ro le p l a y e d b y t h e d i s i n t e g r a t i o n of t h e p o t a s s i u m a t o m s in t h e t h e r m a l resources of t h e e a r t h .

N a t u r a l l y , biologists a n d physiologis ts t r i ed to find o u t t h e i m -p o r t a n c e of these p r o p e r t i e s t o t h e life of t h e p l a n t itself a n d g a v e express ion t o t h e i dea t h a t t h e m i r a c u l o u s a n d as ye t i n c o m p r e h e n s i b l e love of t he p l a n t s for p o t a s s i u m was d u e to t h e fac t t h a t b y t he i r r a -d ia t ions t h e a t o m s of p o t a s s i u m exe r t ed s o m e specia l i n f l u e n c e o n t h e life a n d g r o w t h of t h e cell.

M a n y e x p e r i m e n t s w e r e c o n d u c t e d in th is d i r e c t i o n b u t so f a r t h e y h a v e fa i led to p r o d u c e a n y de f in i t e resul ts . T h e s e d i s i n t e g r a t i n g a t o m s of p o t a s s i u m a n d t he i r r a d i a t i o n s i n al l p r o b a b i l i t y p l a y a s ign i f ican t p a r t a n d a r e respons ib le for a n u m b e r of pecu l i a r i t i e s in t h e g r o w t h a n d d e v e l o p m e n t of t h e l iv ing cell a n d of t h e w h o l e o r g a n i s m .

S u c h a r e t h e pages f r o m t h e g e o c h e m i s t r y of p o t a s s i u m , this o d d , m i g r a t i n g c h e m i c a l e l e m e n t . S u c h is t h e h i s to ry of its m i g r a t i o n s a n d cycle o n e a r t h .

A s imi la r s to ry of m i g r a t i o n s in t h e i n t e r io r of t h e e a r t h , o n its su r -face a n d in i n d u s t r y c a n b e to ld a b o u t eve ry c h e m i c a l e l e m e n t , b u t for m a n y of t h e m i n d i v i d u a l s tages in t he i r h i s to ry still e scape t h e

154

s c r u t i n y of t h e i n v e s t i g a t o r ; on ly s e p a r a t e h is tor ica l exce rp t s c a n n o w b e w r i t t e n for m a n y e l emen t s , a n d it is u p t o t h e geochemis t of t h e f u t u r e to c o m b i n e t h e m i n t o a h a r m o n i o u s a n d cons is ten t s tory. T h e h i s to ry of p o t a s s i u m is m o r e obv ious b e c a u s e al l t h e epochs in t h e life of this i m p o r t a n t e l e m e n t a r e c lea r t o us.

N o t on ly d o w e k n o w its h i s to ry , b u t w e also h a v e in o u r h a n d s a p o w e r f u l i n s t r u m e n t for f i n d i n g its depos i t s a n d for t h e t e c h n o l o g y of its u se ; t h e on ly t h i n g t h a t is still mys t e r ious t o us is t h e ro le it p l ays in t h e l iv ing o r g a n i s m , p e r h a p s t h e m o s t i n t e r e s t i ng a n d mos t i m p o r t a n t p a g e in its h i s tory .

IRON AND THE IRON AGE

I r o n is no t on ly t h e m a i n m e t a l in n a t u r e ; it is t h e basis of c u l t u r e a n d i ndus t ry , t he i n s t r u m e n t of w a r a n d of peace fu l l a b o u r . I t w o u l d be h a r d to find in M e n d e l e v e v ' s P e r i o d i c T a b l e a n o t h e r e l e m e n t so b o u n d u p w i t h t h e pas t , p r e s e n t a n d f u t u r e f o r t u n e s of m a n . P l iny the E l d e r , o n e of t he first mihe ra log i s t s of a n c i e n t R o m e , w h o d i ed in 79 A . D . d u r i n g t h e e r u p t i o n of Vesuv ius , s m o t h e r e d b y " t h e ashes a n d dus t e r u p t e d by a firir-breathing m o u n t a i n " as t h e R u s s i a n m i n e r -alogist Vas i ly Seve rg in w r o t e a b o u t h i m m o r e t h a n 100 yea r s ago , expressed h imsel f v e r y b e a u t i f u l l y a b o u t i ron .

I n his fine t r a n s l a t i o n w e r e a d some b r i l l i an t pages f r o m t h e h i s to ry of i r on as it o c c u r r e d to P l i n y : " I r o n ores give m a n a n exce l len t a n d a t t h e s a m e t i m e a mos t h a r m f u l i n s t r u m e n t . I t is by m e a n s of this i n s t r u m e n t t h a t we till t h e e a r t h , p l a n t bushes , cu l t i va t e f r u i t - b e a r i n g o r c h a r d s a n d by s h e a r i n g wi ld v ines m a k e t h e m g r o w y o u n g e r w i t h e a c h pass ing yea r . I t is also w i t h this i n s t r u m e n t t h a t we bu i ld houses , c rush s tones a n d use i r on for m a n y s imi la r pu rposes . Bu t it is w i t h t he s a m e i ron t h a t w e fight ba t t l e s a n d loo t ; a n d w e use it n o t on ly close-by, b u t also t h r o w it by s t r o n g h a n d o r shoo t it in t h e form of f e a t h e r e d a r r o w s . T h e c o n t r i v a n c e s of t h e h u m a n m i n d a re , in m y o p i n i o n , t h e m o s t vic ious t h i n g . I n Alchemical symbol for iron used

in the M i d d l e Ages

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Picture of an old iron works (19th century)

o r d e r t h a t m a n b e ki l led t h e sooner , d e a t h h a s b e e n g iven wings a n d f e a t h e r s h a v e b e e n a t t a c h e d to i ron . M a n a l o n e a n d n o t n a t u r e is t o b l a m e for t h i s . "

S i n c e a b o u t t h e f o u r t h m i l l e n n i u m B. G., w h e n m a n first m a s t e r e d th is m e t a l , t h e s t rugg le for i r on has n e v e r ceased i n t h e h i s to ry of m a n . I n t h e b e g i n n i n g m a n m a y h a v e p i c k e d u p t h e s tones t h a t fell f r o m t h e sky (meteor i t es ) a n d m a d e his w a r e s f r o m t h e m , l ike t h e Aztecs of M e x i c o , t h e I n d i a n s of N o r t h A m e r i c a , t h e Esk imos i n G r e e n l a n d a n d t h e i n h a b i t a n t s of t h e N e a r Eas t . I t is n o t w i t h o u t r e a s o n t h a t t h e a n c i e n t A r a b l e g e n d tells us t h a t i r on is of celest ial o r ig in . I n t h e l a n g u a g e of t h e C o p t s i t is even ca l led " s k y - s t o n e " ; r e i t e r a t i n g t h e a n c i e n t E g y p t i a n l e g e n d s t h e A r a b s used to say t h a t d r o p s of go ld fell f r o m t h e sky to t h e A r a b i a n D e s e r t ; o n e a r t h this go ld c h a n g e d to silver a n d t h e n to b l ack i r o n as p u n i s h m e n t t o t h e t r ibes t h a t f o u g h t for t h e possession of t h e h e a v e n l y g i f t .

I t w a s a l ong t i m e b e f o r e i r o n cou ld b e ex tens ive ly used b e c a u s e it was d i f f icu l t t o sme l t it o u t of t h e ores a n d t h e r e w e r e ve ry f ew stones, i . e . , me teo r i t e s , f a l l i ng f r o m t h e sky.

5 7

O n l y in t he first m i l l e n n i u m A. D . d id m a n l e a r n to sme l t i r o n ores a n d t h e b r o n z e a g e was r e p l a c e d b y t h e i r on a g e w h i c h in t h e h i s to ry of c u l t u r e h a s las ted t o - d a t e .

I n t h e c o m p l e x h i s to ry of t h e peop les t h e s t rugg le for i r on , as also for gold , h a s a l w a y s p l a y e d a n e n o r m o u s ro le , b u t n e i t h e r t h e m e d i e v a l me ta l lu rg i s t s n o r t h e a l chemis t s cou ld g a i n r e a l m a s t e r y over t h e m e t a l ; m a n b e g a n to m a s t e r i r o n on ly i n t h e 19th c e n t u r y , a n d it g r a d u a l l y b e c a m e o n e of t h e m o s t i m p o r t a n t m e t a l s in i n d u s t r y . As m e t a l l u r g y d e v e l o p e d , t h e smal l p r i m i t i v e i r o n - s m e l t i n g f u r n a c e s w e r e r e p l a c e d b y b l a s t - f u r n a c e s w h i c h g a v e rise t o g i a n t m e t a l l u r g i c a l p l a n t s w i t h a c a p a c i t y of t h o u s a n d s of tons .

T h e i r o n - o r e depos i t s h a v e b e c o m e t h e basis of t h e w e a l t h of i nd i -v i d u a l coun t r i e s . T h e e n o r m o u s i r o n reserves of severa l t h o u s a n d mi l l ion tons in L o r r a i n e w e r e t h e r e a s o n for t h e s t rugg le a m o n g t h e capi ta l i s ts . W e k n o w t h a t in t h e sevent ies of last c e n t u r y F r a n c e a n d G e r m a n y f o u g h t for t h e possession of t h e vas t o r e reserves of t h e R h i n e deposi ts .

W e wi tnessed t h e episodes i n t h e s t rugg le b e t w e e n E n g l a n d a n d G e r m a n y fo r K i i r u n a v a a r a , this r e m a r k a b l e m i n e i u P o l a r S w e d e n t h a t a n n u a l l y yields u p to 10 mi l l i on tons of exce l len t i r o n

ores . W e k n o w h o w R u s s i a g r a d u a l l y d i scovered a n d m a s -t e r ed h e r i r o n resources b e -g i n n i n g w i t h K r i v o i R o g a n d t h e U r a l s a n d a l l t h e w a y u p to t h e l a r g e i r o n reserves i n t h e depos i t s of t h e K u r s k A n o m a l y .

T h e n u m e r o u s depos i t s i n t h e Sovie t U n i o n c r e a t e t h e m i g h t of t h e c o u n t r y ' s i n d u s t r y b y s u p -p l y i n g it w i th m e t a l f o r rai ls , b r idges , locomot ives , a g r i c u l t u r a l m a c h i n e r y a n d o t h e r tools f o r p e a c e f u l l a b o u r . T h e figures of a n n u a l p i g i r on a n d steel p r o d u c t i o n n o w r u n i n t o m a n y

A blast-furnace at the Magnitogorsk Plant m i l l i o n s o f t o n s .

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I n t h e s t rugg le for m e t a l n e w w a y s for t h e d e v e l o p m e n t of m o d e r n m e t a l -l u r gy c a n a l r e a d y b e d i s ce rned .

I r o n a n d steel a r e o f t e n r e p l a c e d b y n e w var ie t i es of h i g h - g r a d e steel, a n d t h e r a r e m e t a l s — c h r o m i u m , nickel , v a n a d i u m , t u n g s t e n a n d n io -b i u m — a d d e d to t h e al loys in a m o u n t s of t e n t h s of o n e p e r cen t e n h a n c e t h e p r o p e r t i e s of t h e m e t a l m a k i n g i t h a r d , u n y i e l d i n g a n d s tab le .

I n a n e f fo r t t o i m p r o v e t h e p r o p e r -ties of m e t a l a n d to o b t a i n n e w c h e m i c a l r e a c t i o n s in t h e e n o r m o u s b l a s t - f u r n a c e s a n d f o u n d r i e s m a n is so lv ing o n e of his bas ic p r o b l e m s in t h e fight fo r i ron . I r o n is s l i pp ing f r o m t h e h a n d s of m a n ; i t is n o t go ld t h a t a c c u m u l a t e s in t h e safes a n d b a n k s a n d on ly a n ins ign i f i can t p a r t of w h i c h is lost. I r o n is u n s t a b l e on t h e su r f ace of t h e e a r t h , in o u r s u r r o u n d i n g s ; w e k n o w ourselves h o w easily it rusts . Suff ice it t o l eave a p iece of w e t i r on i n t h e o p e n a n d w e soon find it c o v e r e d w i t h r u s t y spots ; s h o u l d w e fai l to cove r a n i r o n roof w i t h a coa t of oil p a i n t , r u s t will e a t o u t b ig holes in t h e i r o n ins ide of a yea r . I n t h e e a r t h w e find i r o n tools of t h e old ages t r a n s f o r m e d i n t o b r o w n h y d r o u s ox ides ; spears , a r r o w s a n d a r m o u r a r e al l r u i n e d , sub j ec t t o t h e g r e a t c h e m i c a l l a w of i r o n o x i d a t i o n u n d e r t h e i n f l u e n c e of t h e o x y g e n c o n t a i n e d in t h e a i r . M a n is n o w f a c i n g a task of e x c e p t i o n a l i m p o r t a n c e , t h e task of safe-g u a r d i n g his i ron .

M a n n o t on ly i m p r o v e s t h e qua l i t i e s of m e t a l b y t h e a d d i t i o n s I m e n t i o n e d , b u t a lso covers i r on w i t h a c o a t i n g of z inc o r t in , c h a n g i n g i t to w h i t e m e t a l ; m a n c h r o m i u m - p l a t e s a n d n icke l -p la tes va r i ous p a r t s of m a c h i n e s , covers t h e m e t a l w i t h d i f f e r e n t p a i n t s a n d t r ea t s i t w i t h p h o s p h a t e s . M a n uses v a r i o u s m e t h o d s to p r e v e n t t h e i r o n f r o m o x i d a t i o n b y t h e m o i s t u r e a n d o x y g e n in o u r s u r r o u n d i n g s . A n d w e m u s t say th is is n o easy m a t t e r ; h e i n v e n t s n e w m e t h o d s us ing

Geode of limonite (brown hema-tite) from the Bakal Mine in the South Urals. It was formed by dis-integration of iron carbonate (side-rite). Collection of the Sverdlovsk Mining Institute Museum

159

zinc and cadmium and replaces tin by other metals. But the natural chemical processes occur spontaneously and the more iron man extracts from the entrails of the earth, the more he develops his ferrous metallurgy, the greater will be the need for safeguarding this metal.

How strange it seems to speak about safeguarding iron when there is so much of it around. Meanwhile, geological congresses were held recently and having estimated the iron reserves geologists pointed at the impending iron shortage; they predicted the exhaustion of the world deposits in 50 to 70 years and said man would have to replace this metal by another. They said concrete, clay and sand would replace iron in building, industry and life. However, time marches on, the date set for the exhaustion of the iron reserves should be drawing close, but the geologists are discovering ever new iron deposits. The iron-ore resources in the Soviet Union fully satisfy the needs of industry and there seems to be no end to the discoveries of new iron deposits.

Iron is one of the most important metals in the universe. We see its lines in all cosmic bodies; they sparkle in the atmospheres of the hot stars; we see atoms of iron stormily moving across the solar surface;

I ron min ing in the V y s o k a y a G o r a I ron M i n e near N i z h n y Tagi l in the Ura l s (Sverd-lovsk Reg ion)

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Pour ing steel a t a m o d e r n meta l lu rg ica l p lan t

every y e a r t h e y c o m e fa l l ing d o w n on e a r t h in t h e f o r m of fine cosmic dus t a n d i ron me teo r i t e s . L a r g e masses of n a t i v e i r on fell in t h e S t a t e of A r i z o n a , in S o u t h A f r i c a a n d i n t h e ba s in of t h e P o d k a m e n n a y a T u n g u s k a ( U . S . S . R . ) . Geophys ic i s t s asser t t h a t t h e e n t i r e c e n t r e of t he e a r t h consists of a mass of n icke l i fe r rous i r o n a n d t h a t o u r e a r t h ' s c rus t is a scale s imi la r to t h e glassy slags w h i c h r u n o u t of a b las t -f u r n a c e d u r i n g t h e s m e l t i n g of p ig i ron .

B u t t h e e n o r m o u s reserves of i r o n f o u n d in t h e cosmos o r t h e deposi ts c o n t a i n e d i n t h e i n t e r i o r of o u r p l a n e t a r e as ye t inaccess ib le to in-d u s t r y ; w e a r e l iv ing a n d w o r k i n g o n a t h i n film of e a r t h , a n d m e t -a l l u rgy m u s t d e p e n d on ly u p o n t h e few- h u n d r e d m e t r e s b e l o w t h e su r f ace f r o m w h i c h m o d e r n m i n i n g is a b l e to e x t r a c t i r on ores.

M e a n w h i l e geochemis t s r evea l t h e h i s to ry of i ron . T h e y say t h a t e v e n t h e e a r t h ' s c rus t c o n t a i n s 4 .5 p e r c e n t i r on a n d t h a t t h e on ly m e t a l of w h i c h t h e r e is m o r e t h a n i r o n i n s u r r o u n d i n g n a t u r e is a lu -m i n i u m . W e k n o w t h a t i t is a c o n s t i t u e n t of t h e m o l t e n masses

1 6 1

Cristalline sima

D i a g r a m of the structure of the ear th . S ia l - rocks rich in silicon and aluminium (grani te type). Sima—rocks rich in silicon, magnesium, and iron (basal t type). T h e ore shell and the iron core are located in the centrc of the earth

w h i c h h a r d e n in t h e i n t e r i o r of t h e e a r t h in t h e f o r m of ol ivinic a n d basa l t rocks, as t h e heav ies t a n d p r i m o r d i a l rock ( s ima) .

W e k n o w t h a t re la t ive ly l i t t le i r on r e m a i n s in g r a n i t e rocks (sial) wh ich is e v i d e n t f r o m the i r light: co lours wh i t e , p i n k a n d g r e e n . A n d still, c o m p l e x c h e m i c a l r eac t i ons a c c u m u l a t e e n o r m o u s reserves of i r o n o r e o n t h e su r face of t h e e a r t h . S o m e of t h e m a r e f o r m e d in t h e s u b -t ropics w h e r e t h e pe r iods of t rop ica l r a i n s a r e fo l lowed b y b r i g h t s u n n y d a y s of ho t s u m m e r s . E v e r y t h i n g so lub le t h e r e is w a s h e d o u t of t h e rock a n d l a rge a c c u m u l a t i o n s — c r u s t s of i ron a n d a l u m i n i u m ores -a r c f o r m e d .

W e k n o w h o w r u s h i n g w a t e r s c o n t a i n i n g o r g a n i c s u b s t a n c e b r i n g t r e m e n d o u s a m o u n t s of i r on f r o m var ious , j ocks a n d depos i t t h e m o n t h e floors of n o r t h e r n lakes, for e x a m p l e in K a r e l i a ; p ieces of i ron as smal l as p i n - h e a d s o r w h o l e layers of it a r e depos i t ed on (lie floors

6 2

. Sial Sial.

M a g n e t i c A n o m a l y were , in all p r o b a b i l i t y , also f o r m e d s imi la r ly .

T h e ores of these t w o last depos i t s w e r e f o r m e d by t h e w a t e r s of a n c i e n t seas so long a g o t h a t the ho t b r e a t h of t he e a r t h ' s i n t e r i o r h a s b e e n a b l e to c h a n g e t he i r s t r u c t u r e , a n d ins t ead of t he b r o w n h e m a t i t e we find in K e r c h , w e see h e r e a l t e r e d b lack i ron ores cons is t ing of h e m a t i t e a n d m a g n e t i t e .

T h e m i g r a t i o n s of i r on o n t h e e a r t h ' s su r f ace n e v e r cease. T r u e , ve ry l i t t le of it a c c u m u l a t e s in s e a - w a t e r a n d it is r i gh t ly said t h a t this w a t e r c o n t a i n s p r ac t i c a l l y n o i ron a t all. H o w e v e r , u n d e r special , e x c e p t i o n a l cond i t i ons f e r r u g i n o u s s ed imen t s , even en t i r e i ron -o re deposi ts , w h i c h a r e e n c o u n t e r e d in a n u m b e r of a n c i e n t sea layers , a r e f o r m e d in t h e sea a n d in sha l low bays . O u r f a m o u s i r o n - o r e deposi ts n e a r K h o p e r a n d K e r c h in t h e U k r a i n e a n d n e a r A y a t y in t h e U r a l s w e r e t h u s f o r m e d . B u t i r on is m i g r a t i n g e v e r y w h e r e — i n s t reams , r ivers , lakes a n d m a r s h e s — a n d p l a n t s a l w a y s f m d this i m p o r t a n t c h e m i c a l e l e m e n t w i t h o u t w h i c h t h e y c a n n o t live.

T r y a n d d e p r i v e a p o t of f lowers of its i ron a n d y o u will soon see t h a t t h e f lowers lose t he i r co lours a n d o d o u r , a n d t h a t the i r leaves t u r n ye l low a n d b e g i n to w i t h e r a w a y . T h e l i fe-giving ch lo rophy l l , w h i c h i m p a r t s t h e p o w e r t o t h e l iv ing cell a n d w h i c h ex t rac t s t h e c a r b o n f r o m c a r b o n d iox ide b y g iv ing u p t h e o x y g e n to t he a i r , c a n -n o t exist w i t h o u t i r on b e c a u s e it c a n n o t b e f o r m e d w i t h o u t i t .

T h e cycle of i r on o n e a r t h is, thus , c o m p l e t e d in p l a n t s a n d in o t h e r liv-i n g systems, a n d the r ed corpusc les in t he b lood of m a n a r c o n e of t he last s tages in t he m i g r a t i o n s of this m e t a l w i t h o u t w h i c h t h e r e c a n be n o life.

O l d engrav ing da t ing f rom 1497. Magne t i c iron clilfs pidl the nails out of the ship, and the ship sinks

II

of t h e lakes i n to w h i c h t h e w a t e r s f low, i n v o l v i n g specia l i ron b a c t e r i a . I r o n ores h a v e t h u s a c c u m u l a t e d in m a r s h e s a n d 011 t h e b o t t o m of seas all t h r o u g h t h e l ong geologica l h i s to ry of t h e e a r t h , a n d t h e r e is n o d o u b t t h a t in a n u m b e r of cases a n i m a l a n d p l a n t life h a s exe r t ed its i n f l u e n c e 011 t h e f o r m a t i o n of these deposi ts .

T h i s is t he w a y t h e l a rge K e r c h deposi ts w e r e f o r m e d ; t h e e n o r m o u s reserves of i ron

STRONTIUM—METAL OF RED LIGHTS

Is t h e r e a n y o n e w h o has n e v e r seen b e a u t i f u l f i r eworks w i t h t he i r red sparks w h i c h slowly f a d e in t h e a i r a n d a r e r e p l a c e d b y s imi la r ly b r i l l i an t g r e e n l igh t s?

T h o u s a n d s of b r i g h t r e d , g r e e n , ye l low a n d w h i t e l ights , r e v o l v i n g suns a n d hiss ing rocke ts of t h e f i r eworks let off d u r i n g o u r m a j o r ho l i -days , p l a y i n t h e a i r a n d s ca t t e r t h e d a r k n e s s of t h e n i g h t . S i m i l a r

Salute in L e n i n g r a d

1 6 4

r e d flares go u p in t h e a i r f r o m ships a t t imes of g r a v e d a n g e r ; t hey a r e d r o p p e d f r o m p l anes for n i g h t s igna l i za t ion a n d t h e y ta lk w i t h e a c h o t h e r in the i r c o d e d l a n g u a g e d u r i n g p r e p a r a t i o n s for n i g h t a t t a c k s a n d b o m b i n g s .

V e r y few p e o p l e k n o w h o w these b r i g h t " B e n g a l " l ights , w h i c h h a v e go t t he i r n a m e f r o m I n d i a , .-re m a d e ; t he r e , w h i l e c o n d u c t i n g re l ig ious services, t h e pr ies ts i n sp i r ed f e a r in t h e w o r s h i p p e r s b y sud-d e n l y l i gh t ing mys t e r ious g h a s t l y - g r e e n o r b l o o d - r e d l ights in t he s emi -da rknes s of t he i r t e m p l e s a n d houses of p r a y e r .

N o t e v e r y b o d y k n o w s t h a t these l ights a r e o b t a i n e d f r o m t h e salts of s t r o n t i u m a n d b a r i u m , t h e t w o p e c u l i a r h e a v y e a r t h s t h a t cou ld no t b e to ld a p a r t for a l ong t i m e un t i l it was obse rved t h a t in fire o n e of t h e m shed a b r i g h t r ed l ight a n d t h e o t h e r a g reen i sh-ye l low. Soon a f t e r w a r d s m a n l e a r n e d to p r o d u c e vo la t i l e salts of these t w o meta l s , m i x t h e m w i t h p o t a s s i u m c h l o r a t e , coal a n d s u l p h u r , a n d f r o m this m i x t u r e to press l i t t le bal ls , cy l inders a n d p y r a m i d s w i t h w h i c h the sky-rockets a n d t h e t u b e s of t h e fireworks a r e filled.

S u c h is o n e of t h e last p a g e s in t h e l ong a n d i n t r i c a t e h is tory of these t w o e l emen t s . I shou ld p r o b a b l y b o r e you if I to ld you i n de t a i l a b o u t t h e l o n g r o u t e t r ave l l ed b y t h e a t o m s of s t r o n t i u m a n d b a r i u m f r o m t h e m o l t e n g r a n i t e s a n d a lka l ine m a g m a s in t he e a r t h ' s c rus t al l t h e w a y to t h e i n d u s t r i a l en te rp r i ses w h i c h re f ine s u g a r , p r o d u c e d e f e n c e e q u i p m e n t , m a k e m e t a l or m a n u f a c t u r e fireworks.

I m u s t tell y o u t h a t I r e a d a r e m a r k a b l e s to ry a b o u t t h e m i n e r a l s of s t r o n t i u m w r i t t e n by a K a z a n scientis t a n d p u b l i s h e d in a V o l g a n e w s p a p e r wh i l e I w a s still a s t u d e n t of M o s c o w Un ive r s i t y . T h i s t a l e n t e d mine ra log i s t de sc r ibed h o w h e a n d o n e of his f r i ends col lec ted b e a u t i f u l b l u e crysta ls of celest i te o n t h e b a n k s of t h e V o l g a . H e r e l a t e d h o w d ispersed a t o m s g a v e rise to these b l u e crysta ls in t h e P e r m i a n l imes tone , w h a t p r o p e r t i e s t h e y h a d a n d w h a t t he i r uses w e r e ; this s to ry i m p r i n t e d itself u p o n m y m e m o r y so v iv id ly t h a t I r e m e m b e r e d for m a n y l o n g years t h e b l u e m i n e r a l celest i te w h i c h h a d go t its n a m e f r o m t h e L a t i n w o r d caelum, m e a n i n g sky, fo r its b e a u t i f u l sky-b lue co lour .

T o find this s tone was m y che r i shed d r e a m for a l o n g t i m e ; in 1938 I was , finally, lucky e n o u g h to find it w h e n I least e x p e c t e d it a n d I r eca l l ed this r e m a r k a b l e s tory .

65

I was conva le sc ing in Kis lovodsk ( N o r t h C a u c a s u s ) . A f t e r m y ser ious illness I was still u n a b l e to c l i m b m o u n t a i n s t h o u g h I was i r resis t ibly d r a w n to rocks, q u a r r i e s a n d cliffs.

A b e a u t i f u l b u i l d i n g of a n e w h o l i d a y h o m e was b e i n g e r ec t ed n e a r o u r s a n a t o r i u m . I t was b e i n g d e c o r a t e d by p ink vo l can i c tu f f b r o u g h t f r o m the vi l lage of Ar t i k ( A r m e n i a ) a n d . the re fo re , n a m e d Ar t ik tu f f . T h e fence a n d g a t e w a y w e r e b e i n g m a d e of a yel lowish d o l o m i t e in w h i c h lovelv p a t t e r n s a n d o r n a m e n t s w e r e h e w n .

I fell i n t o t he h a b i t of vis i t ing t h e b u i l d i n g a n d w a t c h i n g the w o r k -m e n skilfully h e w t h e soft d o l o m i t e s tone a n d knock off s e p a r a t e h a r d pieces. " I n this s tone we s o m e t i m e s find h a r m f u l h a r d n o d u l e s . " said one of t h e workers . " W e call t h e m s tone disease b e c a u s e t h e y get in t he w a y of h e w i n g ; we b r e a k t h e m off a n d t h r o w t h e m in to t h a t pi le t h e r e . "

I w e n t over to t he pi le a n d in o n e of t he b r o k e n n o d u l e s s aw a smal l b lue c rvs ta l ; w h y , t h a t was r ea l celest i te! I t was a lovely t r a n s p a r e n t b lue needle , l ike a l ight s a p p h i r e f r o m Cey lon , like a l ight s u n - f a d e d co rn f lower .

I b o r r o w e d a h a m m e r f r o m o n e of t he workers , b r o k e u p severa l nodu le s a n d was s t ruck d u m b w i t h de l igh t . Before m e w e r e crystals of celest i tc. Blue b r u s h e s of t h e m l ined the cavi t ies ins ide t h e n o d u l e s . A m o n g t h e m w e r e w h i t e t r a n s p a r e n t crysta ls of calc i te , wh i l e t h e n o d u l e itself was f o r m e d b y q u a r t z a n d g rey c h a l c e d o n y , a d e n s e a n d s t rong se t t ing for t h e celest i te neck lace .

I asked the worke r s w h e r e t h e d o l o m i t e for t h e b u i l d i n g was q u a r r i e d a n d was s h o w n t h e w a y to t h e q u a r r y . E a r l y in t h e m o r n i n g t w o d a y s l a t e r we d r o v e a l o n g a dus ty r o a d to t h e d o l o m i t e q u a r r y . O u r r o u t e r a n a l o n g the s t o r m v l i t t le A l i k o n o v k a R i v e r , pas t t he b e a u t i f u l b u i l d -ing of t he " C a s t l e of L o v e a n d P e r f i d y . " T h e va l ley g r e w n a r r o w a n d c h a n g e d to a go rge w i t h s teep cliffs of l imes tone a n d do lomi t e s h a n g i n g like cornices over o u r heads . S o o n we pe rce ived t h e q u a r r y w i t h e n o r m o u s b o u l d e r s a n d f r a g m e n t s of l a t e r a l rock .

W e h a d n o luck a t first. T h e l a rge nodu les , we s p a r e d n o e f fo r t to b r e a k u p , c o n t a i n e d smal l crysta ls of ca lc i te a n d rock crysta l o r s t a l agmi t i c masses of w h i t e a n d grey o p a l a n d s e m i - t r a n s p a r e n t cha l -c e d o n v ; finally, we h i t t h e r igh t p lace . O n e a f t e r a n o t h e r we sor ted out ores of b r i g h t - b l u e celest i te. ca re fu l lv c a r r i e d t h e m d o w n , w r a p p e d t h e m in p a p e r a n d a g a i n c r a w l e d over t he d u m p s col lec t ing t h e w o n -

11>6

d e r f u l s amples . P r o u d l y w e b r o u g h t o u r s ample s b a c k to t he sana -t o r i u m , a r r a n g e d a n d w a s h e d t h e m , b u t felt w e d id n o t h a v e e n o u g h . I n a few days we w e r e off in o u r l i t t le c a r t a g a i n in ques t of celest i te.

O u r r o o m was filled w i t h b o u l d e r s of d o l o m i t e c o n t a i n i n g b lue eyes ; t h e d i r ec to r of t h e s a n a t o r i u m w a t c h e d us r e p r o a c h f u l l y , b u t w e k e p t b r i n g i n g ever n e w samples . O u r b e h a v i o u r i n t r i g u e d some of o u r s a n a t o r i u m n e i g h b o u r s . E v e r y b o d y took a n in te res t in t he b lue s tones ; s o m e of t h e m even fo l lowed us to t he d o l o m i t e q u a r r y a n d also b r o u g h t b a c k ve ry good s a m p l e s just to m a k e us envious . Bu t n o b o d y cou ld u n d e r s t a n d w h a t we col lected those s tones for.

O n e ve ry du l l a u t u m n e v e n i n g some of o u r f e l low-pa t i en t s a t t he s a n a t o r i u m asked m e to tell t h e m a b o u t these b lue stones, w h y they w e r e f o r m e d in t h e ye l low Kis lovodsk d o l o m i t e a n d w h a t good t h e y w e r e . W e g a t h e r e d in a cozy r o o m , I s p r e a d t h e s a m p l e s b e f o r e m y l is teners a n d s o m e w h a t e m b a r r a s s e d by this u n e x p e c t e d a u d i e n c e , in w h i c h m a n y h a d n o k n o w l e d g e of e i t he r c h e m i s t r y o r m i n e r a l o g y , b e g a n m y s tory.

. . . W a y back , m a n y , m a n y mi l l ions of years ago , t h e U p p e r Jurass ic Sea ro l led its w a v e s t o t h e m i g h t y C a u c a s i a n M o u n t a i n s . T h e sea n o w r e c e d e d a n d n o w a g a i n i n u n d a t e d t h e shores , e r o d e d the g r a n i t e cliffs a n d depos i t ed a l o n g the shores t h e f ine red s a n d wh ich n o w covers t h e p a t h s n e a r t h e s a n a t o r i u m .

L a r g e sa l t - lakes w e r e f o r m e d in t h e sha l low bays a n d in t he s t o r m y o v e r f l o w i n g r ivers r u n n i n g d o w n f r o m t h e m o u n t a i n peaks of t he p r i m e v a l C a u c a s u s . T h e J u r a s s i c Sea r e c e d e d to t h e n o r t h whi le a rg i l l aceous s ed imen t s , s ands , t h i n layers of g y p s u m a n d in some p laces rock salt w e r e d e p o s i t e d a l o n g t h e shores a n d on the floors of lakes, f i r ths a n d sha l low seas.

C o n t i n u o u s layers of d o l o m i t e w e r e depos i t ed in d e e p e r places . T h e s e d o l o m i t e s n o w f o r m h e a v y s t r a t a of u n i f o r m yel low, g rey a n d w h i t e co lour .

Bu t h o w i n t r i c a t e a n d va r i ed was t h e fa te of this sea, in w h i c h these s e d i m e n t s w e r e d e p o s i t e d ! N u m e r o u s l iv ing c r e a t u r e s s w a r m e d a l o n g its shores. H e r e w e cou ld h a v e a d m i r e d the v a r i e g a t e d p i c t u r e of life w h i c h a m a z e s us o n t h e cliffs of t h e M e d i t e r r a n e a n coas t a n d even in t h e w a r m bays of t h e K o l a F i o r d .

V a r i o u s b l u e - g r e e n a n d p u r p l e seaweeds , h e r m i t c r a b s wi th the i r b e a u t i f u l shells, snails a n d shel ls of al l possible fo rms a n d co lour

. 6 7

Sanator ium of the Minis t ry of the Coa l Indus t ry in Ki s lovodsk . Bui l t of local d o l o m i t e

D o l o m i t e s taircase in Kis lovodsk . N o r t h Caucasus

i n h a b i t e d these cliffs, cove r ing t h e m w i t h a p a r t i c o l o u r e d c a r p c t . S e a - u r c h i n s w i t h the i r r ed quil ls , l a rge five-pointed stars w i th s inuous po in t s a n d je l ly-f ish of mos t d iverse fo rms g l e a m e d in t he w a t e r .

I n n u m e r a b l e smal l r a d i o l a r i a n s l ived on s tones on the f loor of t he sea n e a r t h e coas t l ine ; s o m e of t h e m w e r e t r a n s p a r e n t as glass a n d consis ted of p u r e opa l , o the r s w e r e smal l w h i t e g lobules n o l a r g e r t h a n o n e m i l i m e t r e wi th a smal l s t em t h r e e t imes t h e size of t he b o d y . T h e y w e r e p e r c h e d on s tones, on b e a u t i f u l o v e r g r o w t h s of sea mosses a n d s o m e t i m e s even covered the qui l ls of s ea -u rch ins t r ave l l ing wi th t h e m a l o n g t h e b o t t o m of t h e sea.

T h e s e w e r e t he f a m o u s r a d i o l a r i a n s - a c a n t h a r i a , whose skeletons w e r e m a d e of f r o m 18 to 32 needles . F o r a l ong t i m e n o b o d y k n e w w h a t they w e r e m a d e of a n d it was on ly acc iden t a l l y d iscovered t h a t t h e y were no t m a d e of silica o r opa l , b u t s t r o n t i u m s u l p h a t e . T h e s e i n n u m e r a b l e r a d i o l a r i a n s a c c u m u l a t e d in the i r i n t r i c a t e life's process s t r o n t i u m s u l p h a t e , w h i c h they e x t r a c t e d f r o m t h e sea -wa te r , a n d g r a d u a l l y bu i l t t he i r c rys ta l l ine needles .

T h e d e a d r a d i o l a r i a n s fell to t h e b o t t o m of t h e sea. Thus b e g a n t h e a c c u m u l a t i o n of o n e of t he r a r e m e t a l s wh ich got i n t o t he l i t tora l w a t e r s of t he C a u c a s i a n seas f r o m t h e e r o d e d g r a n i t e massifs, f r o m the w h i t e fe ldspars t h a t f o r m p a r t of t he C a u c a s i a n g ran i t es .

W e shou ld p r o b a b l y neve r h a v e t h o u g h t of t he exis tence of these a c a n t h a r i a in t he U p p e r J u r a s s i c Seas a n d it w o u l d neve r h a v e occu r r ed to chemis t s to look for s t r o n t i u m in t he p u r e l imes tones a n d do lomi te s of o u r q u a r r i e s if a n o t h e r even t h a d no t d i s t u r b e d the c a l m of t he old s e d i m e n t s in t he J u r a s s i c Seas in those d i s t an t t imes of the geological pas t .

T h e C a u c a s u s b e g a n to expe r i ence n e w p a r o x y s m s of its vo lcan ic ac t iv i ty . M o l t e n masses w e r e e r u p t e d a g a i n , f o r m a t i o n of n e w m o u n t a i n r a n g e s was s t a r t ed , ho t v a p o u r s a n d spr ings b e g a n to p o u r out to the su r face t h r o u g h cracks a n d b reaks , whi le the f a m o u s laccol i ths , the Besh tau , Z h e l e z n a y a , M a s h u k a n d o t h e r m o u n t a i n s , w e r e c o m i n g in to b e i n g ra i s ing layers of C r e t a c e o u s a n d T e r t i a r y rocks in the reg ion of M i n e r a l n i v e Y o d v .

T h e ho t b r e a t h of t he e a r t h ' s i n t e r io r s a t u r a t e d t he l imes tones a n d the s e d i m e n t s of g y p s u m a n d salts, a n d the l a t t e r f o r m e d w h o l e u n d e r -g r o u n d seas a n d r ivers of m i n e r a l w a t e r s ; s o m e t i m e s they w e r e cold a n d s o m e t i m e s they w e r e still kep t w a r m by the b r e a t h of t he e a r t h :

jIK)

these waters pierced the dolomites and limestones in the old sedi-ments along the cracks and by their chemical solutions forced them to recrystallize and change to the beautiful and durable dolomite stone of which houses are built.

Under the influence of complex chemical reactions the minutest dispersed atoms of strontium, the remains of the radiolarians-acantharia entered the solution and were again precipitated in the cavities of the Jurassic dolomites growing into beautiful crystals of blue celestite.

Our celestite geodes were gradually formed over a period of many thousands of years and now, when cold solutions of the earth's surface penetrate to them, the crystals of celestite fade, become opaque, their shiny facets are corroded and the atoms of strontium resume their migrations over the earth's surface in quest of new and stabler chemical compounds.

The picture from the history of Kislovodsk celestites I have just painted recurs in many regions of the country. Wherever large sea basins disappeared and shallow seas and salt-lakes were formed during the history of the earth's crust the little globules of the acantharia died and over a period of scores of millions of years the small needles of the formerly living acantharia gave rise to small crystals of stron-tium.

Skeletons of protozoa-acantharia, whose needles consist of strontium sulphate

170

G e o d e of cclest i te spli t in t w o par t s

T h e m o u n t a i n r a n g e s i n C e n t r a l Asia a r e e n g i r d e d by a n u n b r o k e n r i n g of celest i te r o c k ; w e p i c t u r e t o ourselves s imi la r crystals i n t h e m o s t a n c i e n t S i lu r i an seas in t h e Y a k u t i a n R e p u b l i c , b u t t h e l a rges t deposi ts a r e c o n n e c t e d w i t h t h e seas of t h e P e r m i a n e p o c h w h i c h depos i t ed t r e m e n d o u s a m o u n t s of celest i te i n t h e l imes tones a l o n g t h e V o l g a a n d t h e N o r t h e r n D v i n a .

I shal l n o t tel l you w h a t s u b s e q u e n t l y h a p p e n s to t h e crysta ls of celest i te in t h e e a r t h ' s c rus t . M a n y of t h e m , as w e h a v e seen, beg in to dissolve a g a i n , t h j i r a t o m s ge t i n t o t h e soil, a r e c a r r i e d a w a y b y w a t e r , a r e dissolved in t h e b o u n d l e s s oceans , a r e a c c u m u l a t e d a g a i n i n sa l t - lakes a n d sea f i r ths , f o r m need le s of a c a n t h a r i a a g a i n ancl in mi l l ions of yea r s wil l a g a i n give rise t o n e w crystals of celest i te.

I n this c o n t i n u o u s c h a n g e of c h e m i c a l processes, i n t h e c o m p l e x c h a i n of n a t u r a l p h e n o m e n a t h e m i n e r a l o g i s t a n d g e o c h e m i s t g r a s p o n l y s e p a r a t e l inks. H e m u s t p e n e t r a t e w i t h his e x p e r i e n c e d eye, f ine analys is a n d p r o f o u n d scient i f ic t h o u g h t i n to t h e c o m p l e x course of m i g r a t i o n s of t h e a t o m in t h e un ive r se . F r o m s e p a r a t e passages h e r ec rea t e s w h o l e pages a n d f r o m these p a g e s h e compi l e s t h e g r e a t

1 7 1

book of t he c h e m i s t r y of t he e a r t h w h i c h tells us f r o m b e g i n n i n g to end h o w the a t o m m i g r a t e s in n a t u r e , w h o his fe l low- t rave l le rs a r e , w h e r e it f inds its peace fu l or restless d e a t h in t he f o r m of s t ab le crystals , w h e r e t he d ispersed a t o m s e t e rna l ly c h a n g e the i r fe l low- t rave l le rs n o w e n t e r i n g solut ions a n d n o w endlessly s c a t t e r i n g in t he g r e a t vas t -ness of n a t u r e .

A n d the g e o c h e m i s t m u s t ge t a n ins ight i n to these i n t r i c a t e m i g r a -t ions of t he a t o m .

T h e m i n u t e s t crysta l m u s t l ead h i m like a t h r e a d to t he b e g i n n i n g of t he clew. A r e we in a pos i t ion to speak of t h e b e g i n n i n g of t he h is tory of s t r o n t i u m a t o m s ?

W h e r e a n d h o w d id they c o m e i n t o b e i n g in t h e h is tory of t h e un iverse ?

W h y d o the lines of s t r o n t i u m spa rk le p a r t i c u l a r l y b r igh t ly in some stars :' W h a t a r e these lines d o i n g in t he rays of t he sun a n d h o w h a v e they c o m e to be t h e r e ? H o w has this m e t a l a c c u m u l a t e d on the sur -face of t he e a r t h ' s crus t , h o w has it co l lec ted in t he m o l t e n g r a n i t e m a g m a s a n d h o w has it c o n c e n t r a t e d t o g e t h e r wi th c a l c i u m in t he wh i t e crvstals of f e ldspars?

All these a r e ques t ions t he geochemis t c a n n o t answer . H e c a n n o t tell you as c lear ly a b o u t this as I h a v e j u s t told you a b o u t t he b lue crystals of celest i te in t he env i rons of Kis lovodsk . A n d h e c a n tell you as litt le a b o u t the last pages in t he h is tory of t h e s t r o n t i u m a t o m .

M a n h a d long pa id n o a t t e n t i o n to it. H e s o m e t i m e s used it fo r his red lights, b u t for t h a t he d id not h a v e to e x t r a c t l a rge q u a n t i t i e s of s t r o n t i u m salts f r o m t h e en t ra i l s of the e a r t h . T h e n some c h e m i s t found a h a p p y use for s t r o n t i u m in t h e suga r - r e f i n ing i n d u s t r y ; h e found t h a t s t r o n t i u m a n d s u g a r f o r m e d a special c o m p o u n d , s t ron-t ium s a c c h a r a t e , a n d t h a t this c o m p o u n d could be successful ly used in r e f in ing s u g a r f r o m molasses. Ex tens ive u t i l i za t ion of this m e t a l b e g a n a n d l a rge a m o u n t s of it we re m i n e d in G e r m a n y a n d Br i t a in . But a n o t h e r chemis t f o u n d t h a t s t r o n t i u m could be r e p l a c e d by c a l c i u m wh ich is c h e a p e r . T h e s t r o n t i u m m e t h o d p r o v e d u n n e c -essary a n d the me ta l b e g a n to be neg lec ted , t he mines w e r e closed a n d only he re a n d t h e r e w e r e t he wastes of its salts used lor red l ights .

T h e n c a m e the imper ia l i s t w a r of i q 14-18, a n d e n o r m o u s q u a n t i t i e s of signal Hares were n e e d e d . R e d , log-p ie rc ing l ights p roved ind i spensa -ble in l igh t ing the spaces t h a t were to be p h o t o g r a p h e d f r o m t h e a i r ;

t h e c a r b o n s of t he sea rch l igh t s w e r e i m p r e g n a t e d wi th salts of r a r e e a r t h s a n d s t r o n t i u m .

A n e w a p p l i c a t i o n was f o u n d for s t r o n t i u m . L a t e r me ta l lu rg i s t s l e a r n e d to p r o d u c e me ta l l i c s t r o n t i u m . Chemis t s ,

me ta l lu rg i s t s a n d m a n u f a c t u r e r s took a n e w in te res t in s t r o n t i u m . Like m e t a l l i c c a l c i u m a n d b a r i u m it pur i f ies i ron f r o m h a r m f u l gases a n d a d m i x t u r e s .

I t b e g a n to be used in fe r rous m e t a l l u r g y , a n d n o w geochemis t s a r e s e a r c h i n g for its deposi ts a g a i n , a r e s t u d y i n g the a c c u m u l a t i o n s of s t r o n t i u m in t he caves of C e n t r a l Asia, a r e p r o d u c i n g its salts a t l a r g e p l a n t s a n d a r e e x t r a c t i n g it f r o m m i n e r a l w a t e r s ; in a w o rd , s t r o n t i u m has a g a i n b e c o m e a n e l e m e n t of i n d u s t r y . W e c a n n o t tell its f u t u r e fa te . W e , geochemis t s , d o no t yet k n o w e i the r t he first or t h e last pages in t h e h is tory of this m e t a l . . . .

T h a t was h o w I f in ished m y s tory a b o u t t h e b lue s tone to m v l isteners a t t he s a n a t o r i u m .

I n the i r eyes t he useless b lue crysta ls were t r a n s f o r m e d in to a p a r t of socialist c o n s t r u c t i o n . T h e y n o l onge r looked a s k a n c e a t o u r morning-t r ips to t h e q u a r r y , a n d even the chief s u r g e o n ceased g r u m b l i n g t h a t we filled t h e w h o l e r o o m w i t h s tones a n d w e r e v io la t ing the sac red s a n a t o r i u m r e g i m e n . I n a w o r d , celest i te h e l p e d us to m a k e u p a g a i n .

I t was t h e n t h a t I d e c i d e d to wr i t e m v s tory a b o u t it. I t a p p e a r s in m y book en t i t l ed Recollections about a Stone.

I advise those of you w h o w e r e no t b o r e d by this essay to r e a d also t h a t ' l i t t le s tory in o r d e r t h a t you b e t t e r r e m e m b e r w h a t a fine s tone o u r b lue celest i te is.

TIN Ml "FA I. OF THE F001)-CAI\

Sn 118,70

t i n is a m o d e s t a n d s e e m i n g l y i n 110 w a v d i s t i n g u i s h e d m e t a l . W e

\ c r v s e l d o m h e a t ' o f it i n o u r e v e r v d a v l i l e t h o u g h w e u s e it v e r y o f t e n .

T h e f a t e o f t h i s m e t a l is t o s e r v e m a n u n d e r a d i l f e r e n t n a m e .

B r o n z e , w h i t e m e t a l , s o l d e r , b a b b i t t , p r i n t e r ' s s t o n e , a r t i l l e r v m e t a l ,

t i n - f o i l , b e a u t i f u l p o r c e l a i n e n a m e l s , p a i n t s a n d t h e l i k e a r e s o m e

o f t h e d i i l e r e n t a n d u s e f u l t h i n g s o l w h i c h m a n y p e o p l e w o u l d n e v e r

t h i n k t i n f o r m s t h e m o s t e s s e n t i a l c o n s t i t u e n t .

T h i s m e t a l is n o t a b l e f o r i t s r e m a r k a b l e a n d v e r v s i n g u l a r p r o p -

e r t i e s ; s o m e o f t h e m a r e s t i l l a m v s t e r v a n d a r e n o t v e t h i l l y u n d e r -

s t o o d I n g e o c h e m i s t s .

T h e g r a n i t e m a g m a w h i c h r i s e s I r o m t h e i n t e r i o r o t t h e e a r t h a n d

is r i c h in s i l i c a i . i n d a s it is c u s t o m a r i l y c a l l e d " a c i d " " ! is t h e s o u r c e

o f t i n . H o w e v e r , t m is l a r I r o m b e i n g l o u n d m e v c r v a c i d m a g m a ,

a n d w e d o n o t k n o w v e t w h a t l a w g o v e r n s t h e b o n d s o l t i n w i t h g r a n i t e ,

w h y it is f o u n t ! i n o n e g r a n i t e a n d w h y t h e r e is h a r d l y a n y t r a c e o l

it in a n o t h e r , s e e m i n g l y t h e s a m e , g r a n i t e .

A n o t h e r i n t e r e s t i n g q u e s t i o n i s : w h v d o e s n o t t i n , a h c a v v m e t a l ,

s i n k in t h e m a g m a l i k e o t h e r h c a v v m e t a l s , b e c a u s e o l i t s g r a v i t y ,

b u t t e n d s t o c o m e u p a n d is l o u n d i n t h e u p p e r m o s t l a y e r s o l t h e

g r a n i t e m a s s i t ;'

T h e t h i n g is t h a t a m o n g t h e v i g o r o u s h i g h l y v o l a t i l e v a p o u r s a n d

g a s e s d i s s o l v e d in t h e m a g m a t h e h a l o g e n s , c h l o r i n e a n d ( l u o r i n e ,

p l a \ a n i m p o r t a n t p a r t . W e k n o w I r o m e x p e r i e n c e t h a t t i n c o m b i n e s

w i t h t h e s e g a s e s e v e n a t l o o m t e m p e r a t u r e . I l l t h e m a g m a it l o r m s

v e i \ v o l a t i l e c o m p o u n d s w i t h t h e s e g a s e s t m c h l o r i d e s a n d t i n

l l u o r i d e s . A n d 111 l l u s g a s e o u s s l a t e t m t o g e t h e r w i t h o t h e r v o l a t i l e

P e g m a t i t e veins with t ins tone in grani tes . T u r k e s t a n M o u n t a i n s

c o m p o u n d s , those of s i l icon, s o d i u m , l i t h i u m , b e r y l l i u m , b o r o n a n d o thers , m a k e s its w a y to t h e u p p e r z o n e of t h e g r a n i t e massif a n d even b e y o n d it i n to t h e c racks in t he su r f ace rocks .

H e r e u n d e r d i f f e r e n t p h y s i c o - c h e m i c a l c o n d i t i o n s t he t in ch lo r ide a n d t in f l uo r ide r e a c t w i t h w a t e r v a p o u r s . L e a v i n g ils f o r m e r c a r -r iers tin c o m b i n e s w i t h t h e o x y g e n it t akes u p f r o m t h e w a t e r a n d is n o w n o longer l i b e r a t e d in t he gaseous s t a te , b u t in t h e f o r m of a h a r d , s h i n y m i n e r a l ca l l ed cass i ter i te or t i n s tone , w h i c h is t he p r inc i -pal i ndus t r i a l t in o re . M a n y o t h e r in te res t ing m i n e r a l s a r e sometime") l i b e r a t e d t o g e t h e r w i t h cass i t e r i t e ; these i n c l u d e t o p a z , s m o k y q u a r t z , be ry l , f luor - spar , t o u r m a l i n e , w o l f r a m i t e , m o l y b d e n i t e , e tc .

W e f o u n d o u t q u i t e r ecen t ly t h a t l a r g e depos i t s of cass i ter i te a r e f o r m e d no t on ly f r o m vola t i le ha lo id c o m p o u n d s of t h e g r a n i t e m a g m a .

175

They also arise at later periods in the hardening of the granite residue when the water vapours are transformed into liquid water which trans-ports compounds of various metals far away from the maternal cent re ; these compounds are mostly sulphides—sulphur compounds. The re is a good deal in these processes we do not unders tand as yet, but we do know that tin is carried out of the m a g m a also in this manner . It is remarkable that having used sulphur as a carrier this t ime tin abandons it as it formerly did the halogens and combines with oxygen again forming its favourite mineral—cassiterite.

Greatest accumulation of g p Q

I ++1 Granite

Cli Copper

AU Gold

VI Tungsten

Sn Tin

S n O , Cassiterite

N b Niobium

T a Tantalum

T R Rare-earth elements

2n Pb MO Molt/bdenum

Zn 7inc

P b Lead

Diagram of distr ibution of tin and its fe l low-travel lers in the upper par t of a grani te massif

We know that tin also forms part of many other minerals, but all of these are very rarely encountered (some—exceptionally rarely) and are of no industrial importance. Cassiterite, S n 0 2 , which con-tains about 78.5 per cent pure tin, has always been the only tin ore.

Cassiterite (from the Greek word cassiteros—tin) is mainly a black or brownish mineral . Its black colour is explained by admixtures of iron and manganese. I t is rarely honey-yellow or red and still more

176

Cu Au

rarely colourless. Its crystals are usually very small. Because of its hardness, chemical stability and gravity cassiterite does not disinte-grate and is not dispersed during weathering, but accumulates with other heavy minerals on the sites of granite destruction, i.e., in river-beds or on sea coast, some-times forming vast placer deposits ol" tinstone.

Cassiterite is, thus, obtained from primary and secondary de-posits.

Whatever way the tin ore is obtained, first of all it goes through a process of concentration, i.e., it is purified from various admixtures, after which it is smelted. At this time the tin is reduced by the carbon of the fuel. Combining with carbon oxygen is liberated as carbon dioxide, while pure metallic tin remains.

Pure tin smelted from cassiterite is a soft, silvery-white (a little duller than silver) malleable metal. The capacity of tin to be rolled into thin sheets is remarkable. Tin melts at 2310 C.

Tin has very many peculiar properties. It is known to be able to yell, i.e., to produce a special characteristic sound when bent. Another singular, though far from indifferent, feature of this metal is its sensitiv-ity to cold. Ou t in the cold tin takes sick: from silvery-white it turns grey, increases in volume, begins to crumble and not infrequently breaks up into a powder. This is a serious disease and it is called "tin plague." This disease has ruined many a tin object of great artistic and historical value. Sick tin may infect healthy metal. Fortunately tin plague can be cured. The metal must be resmelted and slowly cooled. If this operation (especially cooling) is performed sufficiently thoroughly tin resumes its former appearance and properties.

In the very distant past it was precisely tin that gave a powerful impetus to the cultural development of man. Man has known tin for

W orking a tin vein 111 L la l l agua , Bo-l ivia, a t an a l t i tude of 4,500 met res a b o v e sea level (1940)

12 1 7 7

Field of tin-bearing sands on Malacca Peninsula. Washed by hydromonitor (water gun). Washed mud flows along ditches. Johore Bahtu Mine (1940)

a very long time and was able to smelt it five or six thousand years B. C., i.e., long before he learned to smelt and process iron.

Pure tin is a soft and weak metal, and is unfit for manufacture. But "bronze" (from the Persian word bronlpsion, meaning alloy), a gold-coloured alloy consisting of copper and 10 per cent tin, is known for its fine properties; it is harder than copper, is easily cast, forged and processed. If we designate the hardness of tin by the conventional number of 5, copper will have a hardness of 30, while bronze, an alloy with a small amount of tin, will have a hardness of 100 to 150. Because of these qualities bronze was so widespread in its time that archae-ologists even distinguish a special epoch -the Bronze Age—when work-tools, arms, housewares and decorations were made mainly of bronze. How man discovered this remarkable alloy we do not know. I t is possible that man repeatedly smelted copper ore with an admixture of tin (we do encounter such "complex" deposits of copper and tin), finally noticed the result of this joint smelting and grasped its signifi-cance.

During excavations of ancient settlements archaeologists very fre-

7 8

quently find well-preserved bronze-wares—household utensils, coins and statuettes. If it is necessary to know whether these bronze-wares are local or imported a chemical analysis of the objects can provide valuable information.

Ancient metal was very imperfectly refined, and by modern exact methods of analysis we can detect in it many different elements in the form of in-significant admixtures—impurities. The composition of these impurities some-times offers a clew to the deposits where the copper and tin used in this bronze were obtained. If the historian or archaeologist definitely prove that the found bronze articles were manufactured where they were found the geologist and the geochemist must immediately start looking for tin in that region, this way to rediscover long forgotten tin deposits.

But bronze did not lose its importance even when the Bronze Age was replaced by the Iron Age. M a n used it for objects of art, for minting coins and for casting church-bells and cannon.

Tin can also form remarkable alloys with other metals, for example, with lead, antimony, etc.

In our time alloys are a sphere of technical wonders, a world of ' 'magic" transformations. Soviet scientists have come to know and interpret these "wonderful" phenomena, these regroupings of atoms which occur when two or more metals are alloyed. Owing to the changes in molecular structure the alloy acquires new properties alien to each of the metals taken separately. For example, an alloy of soft metals often unexpectedly becomes very hard.

Alloys of tin and lead, so-called babbitts, are used in powerful and precision apparatus and in machinery, wherever the action of a steel rod revolving at an enormous speed must be rendered harmless. These so-called "antifr ict ion" alloys are verv durable (they are said to have

Chinese boy w a s h i n g t in-bear ing sands in a di tch. M a l a y a n Archi-pe l ago

I t is possible in

m

12 179

a low friction coefhoent) . They are very important technically because they prolong the life of costly machinery.

Tin possesses the remarkable capacity for being welded to metals; the use of the so-called solders, i.e., alloys of tin with lead and anti-mony, in engineering is based on this property.

Not everybody knows what tin means to printing. It is the principal component of the so-called "type metal" of which cliches, i.e., forms with relief drawings to reproduce illustrations, are cast.

Nothing in the world imparts tliat mirror-like lustre to beautiful white and coloured marbles in polishing as does the white tin-oxide powder.

Various tin compounds are widely used in the chemical and rubber industries, in print works, in dyeing wool and silk, in the manufacture of enamels, glazes, stained glass, gold and silver leaf. It also plays a very important part in warfare.

The oldest tin deposits have been known in Asia and in Europe, in the south of the British Isles which were even called "Cassiteridcs." It is hard to say, though, whether cassiterite got its name from the isles or the isles were named after the Greek word "cassiteros" which we encounter in Homer's Iliad where it is used to signify tin. It is note-worthy that in Cornwall cassiterite is found together with chalcopyrite, a copper mineral, so that when smelted this ore at once produces bronze.

The main source of tin today is Malacca Peninsula, which yields close to half the world's output of this metal, and where more than 200 deposits in granites and a vast number of rich placer deposits are known. The placer deposits are worked hydraulically; they are washed by powerful streams of water discharged from monitors. Liquid mud com-posed of a mixture of different minerals flows into special ditches with riffles where it is vigorously stirred by workers from the local popula-tion. This hard work is done mainly by children. Owing to its high specific gravity cassiterite is retained by the riffles, whence it is removed from time to time. The method of production, as you see, is very primitive and is based on cruel exploitation.

The concentrate containing 60 to 70 per cent cassiterite is transported to plants where it is smelted for tin.

The imperialist countries have been waging a fierce struggle for tin. During the Second World War J a p a n strove to take possession of

1 8 0

the tin deposits oil the continent and on the islands, and the tin-smelting plants in Singapore owned by British firms in order to provide for the needs of her war industry and to help Hitler Germany which was very short of tin. J a p a n and Germany at the same time aimed at depriving the U.S.A. and Britain of the sources of this valuable war metal.

Take a look at the world map and you will see that the zone of tin-bearing granites and, hence, tin deposits, as well as those of tungsten and bismuth, runs along the Pacific Coast, through the Billiton (or Beli-toeng), Banka (Bangka) and Singkep islands, Malacca and Thai peninsulas and South China.

Geochemistry is striving to divine the reasons for the formation of these zones containing rich deposits of tin ores and other chemical compounds found together with tin.

Stacks of canned f o o d s a t a cann ing p l an t

181

In addition to Malacca there are very rich tin concentrations in Bolivia i.South America). They are located in the Cordilleras. Lesser deposits are known in Australia, Tasmania and in the Belgian Congo 'Africa i.

o r the nearlv 200,000 tons of tin constituting the world's annual production 40 to 50 per cent is used in the manufacture of white metal.

Consumption of white metal is sharply increasing with the develop-ment of the canning industry.

Have you ever thought of the importance, of ivhitc meln! and of the part plaved bv the tin can in which millions ol kilograms ol meat, lish, vegetables and fruit are preserved? What is white metal? It is sheet iron covered with a verv thin laser of tin about o.01 mm. ihirk. Tin plating or tinning of the iron sheets or iron cans prevents them from rusting. Pure tin is not dissolved by the liquids of the tanned foods and is practically harmless to man's health. No other plating can compete with tin in stability.

Todav we can sav that tin has outlived its '"bronze age" and has become a metal of the lbod-can.

IODINE THE OMNIPRESEN 1

We all very well know what iodine is; we use it exLernallv when we cut a finger and take its brown-rod drops with milk when we grow old. Iodine is a well-known drug and yet how little we reallv know-about it and about its fate in nature!

It would be hard to find another element as full of eofitradietions and riddles as iodine. Moreover, we know so little about the principal milestones in the historv of its migrations that we cannot sav as vet whv we use it as a medicine and where it has conic from.'

It will be observed that even 1). Mendelevev ran into the unpleasant properties of iodine. He distributed his elements in the order of increas-ing atomic weights but iodine and tellmium upset the order: tellurium stands before iodine though its atomic weight is higher. It is still that way today.

Iodine and tellurium were nearly the onlv elements that disturbed the harmony of Mendelevev's I,aw. 'I'rue, wo have an idea of what is what today, but for manv vears this was an incomprehensible excep-tion; the critics of Mendelevev's brilliant theorv repeatedly indicated that he placed his elements as he saw fit.

Iodine is solid; it forms grev crvstals with a real metallic lustre. It looks like a metal and it is shot with violet, but at the same lime if we put the metallic iodine crvstals into a glass phial we soon see violet vapours in the upper pari of the phial: iodine is easily subli-mated without passing through the liquid state.

Here is the first contradiction that strikes votir eve, but this is im-mediately followed bv another. The colour of the vapours is dark violet, while that of the iodine itself is metallic grey. The salts of iodine

1 8 3

Mounta in r anges of the Cen t ra l Pamirs . P ic ture m a d e d u r i n g ascent to M o u n t Stalin f r o m an a l t i tude of 6,500 met res

are altogether colourless and look like common salt; only some of them have a slightly yellowish tint.

And here are some other iodine riddles. Iodine is an exceptionally rare element; our geochemists have estimated that the earth's crust contains only about 0.00001 or 0.00002 per cent; nevertheless iodine is found everywhere. We can probably say it even more bluntly: there is not a single thing in our surroundings in which the finest methods of analysis do not, finally, detect a few atoms of iodine.

Everything is permeated with iodine; the solid earth and rocks, even the purest crystals of transparent rock crystal or Iceland spar contain quite a number of iodine atoms. Sea-water contains much more of it, the soils and running waters contain very much, and plants, animals and man contain still more. We absorb iodine from the air which is saturated with its vapours; we consume it with food and water. We cannot live without iodine. Now we can understand the questions: why does iodine exist everywhere? Where does so much iodine come from? Which is its primary source? From what depths of the earth's interior is this rare element brought to us?

1 8 4

Meanwhile even the most precise analyses and observations lail to discover its mysterious source because we do not know a single iodine mineral either in deep igneous rocks or in the molten magmas that have come to the surface. Ceochemists picture the origin of iod'tie on earth as follows: at one time, before the geological history of the earth, when our planet was beginning to be covered with a hard crust, continuous clouds of volatile vapours of various substances enveloped the still hot earth. It was at that time that iodine and chlorine were released from the depths of the molten magmas of our planet and iodine was seized by the first streams of the precipitated hot water vapours, and the first oceans, which gave rise to seas, accumulated iodine from the atmosphere of the earth.

We do not exactly know if this was really so, but we do know that its distribution on the earth 's surface is replete with riddles. In the Arctic countries and in high mountains there is comparatively less iodine: in the lowlands and near seashores the content of iodine in the rocks increases; it increases even more in deserts while in the salts of the large deserts in South Africa or in the Atacama Desert ^South America) we find real mineral compounds of iodine.

Iodine is dissolved in the a i r ; accurate analysis has shown that it is distributed in the air according to a verv definite law: its amount varies with the altitude. At the altitudes of the Pamirs and the Altai, more than 4,000 metres above sea level, there is much less iodine than at the level of Moscow or Kazan .

At the same time we know that iodine exists not only on the earth. We find it in meteorites which come to us from unknown spaces of the universe. Scientists have long been looking for it with the aid of new methods in the atmospheres of the sun and stars, but so lar to no avail.

Sea-water contains quite a lot of iodine about two milligrams per litre, which is already an appreciable quant i ty . Sea-water con-denses near the shores, in firths and in littoral lakes where salts accu-mulate and cover the flat shores with a white film. These salt concen-trations have been verv well studied 011 the Cr imean Black-Sea coast and in the lakes of Central Asia, but no iodine has been found in them; it has disappeared somewhere. Some part of the iodine, apparent ly , accu-mulates in silts on the bot tom, but the greater part of it evaporates, goes up into the air, and only a small portion of it is retained in the

i«:>

Inferior -reefs —

'crt/sialline)

Disintegration \of roctrs

fresh water

\ fresh water

Seas and oceans

fresh wafer - animals

y Marine ^ plants

Man

Marine animals

Iodine evele on earth

r e s i d u a l b r i n e s . B u t h a r d l y a n y i o d i n e is f o u n d w h e r e t h e s a l t s o f p o t a s -

s i u m a n d b r o m i n e a r e a c c u m u l a t e d .

V e g e t a t i o n s o m e t i m e s d e v e l o p s n e a r t h e s h o r e s o f s a l t - l a k e s a n d

s e a s , f o r m i n g w h o l e f o r e s t s o f s e a w e e d s w h i c h c o v e r t h e l i t t o r a l s t o n e s .

I t is i n t h e s e s e a w e e d s t h a t i o d i n e a c c u m u l a t e s a s a r e s u l t o f s o m e

i n c o m p r e h e n s i b l e b i o c h e m i c a l p r o c e s s e s , a n d e a c h t o n o f s e a w e e d s

c o n t a i n s s e v e r a l k i l o g r a m s o f p u r e i o d i n e , t h i s r e m a r k a b l e e l e m e n t .

C e r t a i n s e a - s p o n g e s c o n t a i n e v e n m o r e i o d i n e , i . e . , u p t o 8 o r 10 p e r

c e n t .

S o v i e t i n v e s t i g a t o r s h a v e m a d e a p a r t i c u l a r l y g o o d s t u d y o f t h e

P a c i f i c c o a s t . A l o n g t h e e n t i r e v a s t c o a s t t h e w a v e s b r i n g , m a i n l v

i n a u t u m n , a t r e m e n d o u s q u a n t i t y ( o v e r 3 0 0 , 0 0 0 t o n s ) o f s e a - k a l e .

T h e s e b r o w n s e a w e e d s c o n t a i n i n a n v h u n d r e d s o f t h o u s a n d s of k i l o -

g r a m s o f i o d i n e . T h e y a r e c o l l e c t e d , p a r t l y u s e d f o r f o o d a n d p a r t l y

c a r e f u l l y b u r n e d t o e x t r a c t i o d i n e a n d p o t a s h f r o m t h e m .

B u t t h e h i s t o r y o f i o d i n e i n t h e e a r t h ' s c r u s t d o e s n o t e n d w i t h t h a t .

I o d i n e is a l s o b r o u g h t b y o i l w a t e r s . L a k e s o f w a s t e w a t e r s f r o m w h i c h

i o d i n e is n o w e x t r a c t e d a r e f o r m e d n e a r B a k u .

1 8 6

I O D I N E C Y C L E

-Precipitations

ferresfrial plants

Lcrnd animals •

^ marine ' sedimentat/oo

Air Air rain and snow)

Air

Soil

It is also extruded by some volcanoes from their mysterious entrails. The fates of this element in the history of our earth are so diverse

that it is hard to paint a full and coherent picture of the life and wander-ings of this incessantly migrating atom.

The!) iodine gets into the hands of man and a new riddle arises: we treat sick people with iodine, stop haemorrhages with it, kill bac-teria, prevent the infection of wounds, but for all that iodine is ex-ceptionally poisonous: its vapours irritate the mucous membrane. Too many drops or crystals of iodine can prove fatal to num. But the most surprising thing is that man is worse off when there is too little iodine. The organism of man and, probablv, of a number of animals must have a definite amount of iodine. We know that iodine dcficiencv in some regions manifests itself in a special disease t ailed goitre. This disease usually affects people living in Alpine regions. We know some villages in the high mountains of the Central Caucasus and the Pamirs where this disease is widespread. It is also very well known in the Alps.

American investigators have recently found that goitre is also wide-spread in America. It appears that if we chart the incidence of goitre and draw up a map of the percentage of iodine contained in the water the data of the two maps will coincide.

The human organism is exceptionally sensitive to iodine, and a decrease in its content in the air and water immediately affects the health of man. Man has learned to treat goitre with salts of iodine.

Xo less interesting are the ways in which iodine is employed in industrv; the latter makes more extensive, and more diverse use of iodine with each passing vear. On the one hand, man has discovered compounds of iodine with organic substances which create an armour impenetrable by X-rays; at the same time if these compounds arc introduced into the organism they make it possible to photograph the internal tissues with especial clarity.

We have learned that iodine has recently found entirely new fields of application. Particular importance is attached to the use ol iodine in the celluloid industry where special salts of iodine in the form ol small needle-like crystals are employed. These needle-like crystals are so distributed in the celluloid that the waves of a light ray cannot go through them in all directions. The result is what we call a polarized ray. We have long built special, very expensive polarizing microscopes,

i !>7

i j u t n o w t h i s n e w f i l t e r - p o l a r o i d h a s h e l p e d u s t o i n v e n t m a g n i f y i n g g l a s s e s

w h i c h h a v e r e p l a c e d t h e m i c r o s c o p e . T h e y c a n h e u s e d d u r i n g e x -

p e d i t i o n s i n t h e field. B v c o m b i n i n g t w o o r t h r e e p o l a r o i d s it is

p o s s i b l e t o i m p a r t v e r y b r i g h t c o l o u r s t o t h e d r a w i n g : I c a n p i c t u r e

t o m y s e l f a l i g h t e d d e c o r a t i v e p a n e l o r m o t i o n - p i c t u r e s c r e e n w h e r e

t w o r o t a t i n g p o l a r o i d s w i l l p r o d u c e r e m a r k a b l e p i c t u r e s q u e e f f e c t s

r a p i d l y c h a n g i n g a l l c o l o u r s o f t h e s o l a r s p e c t r u m . W h e n a p o l a r o i d

p l a t e is p u t i n t o a n a u t o m o b i l e ' s w i n d s h i e l d y o u c a n d r i v e a l o n g a

l i g h t e d s t r e e t a n d t h e b r i g h t h e a d l i g h t s o f c a r s w i l l n o t b l i n d v o u

b e c a u s e in t h e p o l a r o i d y o u w i l l n o t s e e t h e b r i l l i a n t h a l o e s o f t h e

f i e r y l i g h t s b u t o n l y t h e c a r w i t h a s e p a r a t e l u m i n o u s p o i n t .

W h e n a p l a n e r i s e s a b o v e a b l a c k e d - o u t c i t y a n d d r o p s s p a r k l i n g

c o m p o u n d s o f m a g n e s i u m b y p a r a c h u t e p o l a r o i d s p e c t a c l e s m a k e

it p o s s i b l e t o s e e e v e r y t h i n g u n d e r n e a t h t h e flare.

V i m s e e h o w e x t e n s i v e l y a n d d i v e r s e l y t h i s e l e m e n t is u s e d , h o w

m a n y v a g u e p r o b l e m s a n d h o w m a n y c o n t r a d i c t i o n s in the . l a t e o f

its m i g r a t i o n s t h e r e a r c . I t s t i l l r e q u i r e s a l o t o f p r o f o u n d r e s e a r c h

t o r e v e a l a l l i t s p r o p e r t i e s a n d t o u n d e r s t a n d t h e n a t u r e o f t h i s o m n i -

p r e s e n t e l e m e n t .

T h e h i s t o r y o f t h e d i s c o v e r y o f t h i s e l e m e n t is a l s o i n t e r e s t i n g .

I t w a s d i s c o v e r e d i n t h e a s h e s o f p l a n t s i n l 8 t i b y C o u n o i s , a p h a r m a -

c e u t i s t w h o o w n e d a s m a l l f a c t o r y p r o c e s s i n g t h e a s h e s o f p l a n t s

1 8 8

c o n t a i n s 0 .5 t o 2 h i l l i o n th s : g o i t r e 5 t o 15 e a s e s . B l a c k s p a c e s h o w s a r e a in w h i c h

w a t e r c o n t a i n s o t o c m b i l l i o n t h s of i o d i n e : g o i t r e is -^c c a s e s p e r i . o o o p o p u l a t i o n

D i a g r a m of t h e i n c i d e n c e o f

g o i t r e in t h e U . S . A . a n d t h e

i o d i n e c o n t e n t in w a t e r ; w h e r e -

e v e r t h e r e is l i t t l e i o d i n e there -

a r e m a n y g o i t r e c a s e s . W h i t e

s p a c e s h o w s a r e a in w h i c h d r i n k -

i n g w a t e r c o n t a i n , f r o m 3 t o

2 0 b i l l i o n t h s of i o d i n e w i t h

1 g o i t r e ca.sc p e r 1 , 0 0 0 p o p u l a -

t i o n a n n u a l l v . S t r a i g h t s h a d e d

s p a c e s h o w s a r e a w h e r e w a t e r

c o n t a i n s l e s s t h a n 2 t o 9 b i l -

l i o n t h s o f i o d i n e : g o i t r e w e n t

u p t o 5 c a s e s . D i a g o n a l ! * , s h a d e d

s p a c e s h o w s a r e a in w h i c h w a t e r

into saltpetre. However, the discovery of this element did not particularly impress the world's scientists and it was duly appreciated only 100 years later.

With this I could finish my story about this interesting element, but one more thought still occupies my mind. There is a vacant box below iodine in the same group in Mende-leyev's table. It was pointed out yet by D. Mendeleyev who said that a new element would have to be found for it; he named it ekaiodine. We call this box No. 85. But where is this element No. 85 found or where is it hiding? It must exist somewhere in the world and it must be discovered.

It was long searched for in residual brines of lakes and salt deposits. It was sought in interplanetary spaces among the dispersed atoms, which are observed in the universe amid the stars and sunS, planets and comets; it was also looked for in all natural metals, but was never found.

Many times scientists thought that in their instruments they saw a flash of a line corresponding to the luminescent atoms of No. 85, but subsequent investigations failed to confirm this discovery, and box No. 85 is vacant to-date.*

What is this mysterious undiscovered atom? It probably continues the puzzling history of iodine; it is likely endowed with even more wonderful properties and it is precisely this that renders its discovery difficult. I t may exist in the universe for so short a time that even the most accurate instruments are unable to detect i t ; it may have so strong a charge that it cannot exist in our world. But if No. 85 is discovered on earth it will prove an even more remarkable element than iodine and will have even more fabulous properties.

It is well worth the scientists' while to work on the riddles of iodine and its fellow-element in the table.

* See the word "astatine" in the dictionary of elements.

Pocke t minera log ica l magn i fy ing glass wi th po l a ro id m a d e of iod ine compounds . D e s i g n e d by P ro fes so r V . A r s h i n o v

FLUORINE THE OMNIVOROUS

F9 19,00

When I planned this book I intended to write a chapter on fluorine and its remarkable properties, but as I came to it I had to stop. I had never worked with fluorine and its compounds, had never taken an interest in its fine minerals or in its use in industry and was, therefore, in a quandary.

I had to resort to mv numerous old notes and poring over them I found a number of pages from which I compiled this chapter.

Charles Darwin points out in his autobiography how a scientist must work. He savs that a scientist cannot and does not have to remem-ber even tiling, that he must make a note of everv interesting obser-vation and whatever curious information he finds in books on separate slips of paper, and that he should put everv book that deals with questions he is interested in on a separate shelf together with the n< ites.

Darwin did not think a scientist should have a large and diverse library. He always planned his major problems a few years ahead and fullv devoted himself to their solution. For each problem he picked iiis materials do/ens of times, and one or two shelves in his bookcase were occupied by the materials on individual problems.

In several vcars iand sometimes it took a dozen years), he would, thus, accumulate enormous factual material for each scientific problem. He would look through this material and these books once more and write the corresponding chapter of his famous treatise that has laid the basis for modern biological science.

This idea of compiling big books and monographs is very convenient and I confess that already 20 years ago T began to follow this wonderful

i<)<>

V i e w of s o u t h e r n T r a n s - B a i k a l r e g i o n

example set by Darwin and decidcd to prepare the books and materials for my works in an exactly similar manner . I presented my large l ibrary to the Khib iny Moun ta in Station on Kola Peninsula and retained only the books that were connected with the tasks I faced in the immedia te future .

These tasks included a big problem—to write a history of all chemi-cal elements in the earth, to show geologists, mineralogists and chemists the intricate course travelled by the atoms of any metal in their migra-tions in the universe, and to tell about their properties and behaviour on earth and in the hands of man .

W h e n I came to write the chapter on fluorine I found five small sheets of paper in the paper-case which bore the inscription "F luor ine . " I shall give them to you approximate ly the way they were writ ten.

Charles Darw in

S H E E T 1

I have long since wan ted to visit the famous Trans-Baikal deposits whence I received remarkable crystals of topaz, the beautiful rare

191

mineral containing fluorine, crystals of all colours and druses of multi-coloured fluor-spar produced for the needs of industry.

Finally, we got out of the express train which was on its way to the Manchuria Station.

At the station we were met by a troika and we drove down the wonderful steppes in the south of Trans-Baikal region covered with a continuous white carpet of beautiful edelweiss. The enchanting picture opened up ever more widely before us as we climbed the gently sloping hills. Here in separate granite outcrops crystals of blue and yellowish topaz were extracted; here in the cavities of granite pegmatites we saw beauti-ful octahedrons of fluor-spar compounds of fluorine and the metal calcium. But we were particularly impressed by the picture of a rich deposit of this mineral in a certain small valley.

Here they were no longer separate small crystals precipitated from the hot aqueous solutions of cooled granites, but enormous concen-trations of pink, violet ajid white fluor-spar of the most diverse shades; they shone and sparkled in the bright Manchurian sun.

This valuable stone was quarried in order to be sent all across Siberia to the metallurgical plants in the Urals, Moscow and Leningrad. A grand picture of gaseous emanations of ancient and deep molten granites arose before my eyes. Concentrations of fluor-spar were formed from volatile fluorine compounds. One of the stages in the process of slow cooling of the granite massif, surrounded by the vapours and gases it gave off, in the interior of the earth was reflected in these formations.

I recalled another picture from the historv of the same, fluor-spar. The fluor-spar of enchantingly beautiful colours from which the valuable Murino vases were manufactured and which was described in the oJd mineralogv textbooks came to niv mind.

I also recalled that in Britain there was a whole industry for the processing of this stone and that in museums we could see beautiful articles made from it.

Finally, quite different pictures from the environs of Moscow occurred to me.

As a young teacher at the First People's University in Moscow I charged my students with th>' task of studying the minerals found in the environs of our city. These minerals included a remarkable violet-coloured stone which had been found more than 140 years

1 9 2

ago (181 o) in the small Ra tov ravine, Vereya District, Moscow Region, and had been named ratovkite.

I t occurred in individual con-centrations in the form of beautiful violet strata amid limestones..Zones of its dark-violet cubes were found along the banks of the Osuga and Vazuzya rivers, t r ibutaries of the Volga. W e started actively studying this stone whicli turned out to be a pure calcium fluoride, the fluorite I a m telling you about . Its beaut i ful violet-coloured pebbles were encountered in such large amounts and the strata were so regu-larly deposited amid the limestones tha t it was ha rd to a t t r ibute their formation to the hot emanat ions of molten granites which had given rise to the lovely Trans-Baikal topazes and the Manchur i an fluor-spar deposits.

More than 2,000 metres separated these deposits f rom the ancient granites, which form the basis of Moscow rocks, and we had to look for some other chemical agents tha t accumulated this beautiful stone along the Volga tributaries. Wi th the aid of Academician A. K a r -pinsky our young people were able to divine the origin of this stone.

I t appears ratovkite was connected with the ancient sediments of the Moscow seas and tha t in its concentrat ion a pa r t was played by living creatures, i.e., sea-shells, especially the lime-shells tha t accu-mula ted crystals of calcium fluoride in their cells. T h e pictures I have painted here clearly show the peculiar and intr icate course travelled by fluorine in its migrations in na ture .

S H E E T 2

A brief description of one day spent in Copenhagen, the Danish capital, dur ing my tr ip to a geological congress.

A c a d e m i c i a n A l e x a n d e r K a r p i n s k y (1847-1936)

13 193

After the congress we visited the famous cryolite mill in the environs of this city. The snow-white stone resembling ice is brought here from peaks on the icy coast of Greenland. Due to some strange natural coincidence this stone, in no way differing in appearance from ice, is encountered only in one place on earth—in the polar regions of the west coast of Greenland where it is quarried in vast fields, loaded on ships and sent to Copenhagen. Cryolite goes to special mills where it is separated from the other minerals, especially lead, zinc and iron ores, and only a pure snow-like powder remains and is used as flux for the production of aluminium.

Highly valuable, this powder is shipped in special boxes to chemical plants where a new fate awaits i t : it is smelted together with alu-minium ore in electric furnaces and the stream of molten metal glitter-

Ta j ik s examin ing ore conta in ing crystals o£ f luor i tc f r o m a depos i t in Ta j ik i s t an

194

Profes so r Moissan ob ta in ing the first fluorine in his Par i s l abo ra to ry in 1886

ing like silver runs down into large tanks prepared beforehand. This metal is a luminium and modern a luminium product ion cannot do wi thout cryolite.

So far there are no other methods of producing this metal which is necessary for the industries of both war and peace and the annual world ou tpu t of which now runs into two million tons.

Enormous electric installations use the power of large rivers and waterfalls to dissolve a lumin ium oxide in cryolite and to produce pure metallic a luminium. T r u e na tu ra l cryolite is now replaced by an artificial salt of a luminium and sodium fluoride. But it is the same cryolite only produced by m a n a t chemical plants.

S H E E T 3

Fragments of pure t ransparent fluorite were found on the steep slope of a cliff overhanging a beautiful lake in Tajikistan. I t was so t ransparent tha t lenses for microscopes and precision instruments

13 i95

could be m a d e f rom it. T h e demand for t ransparent fluorite was so great tha t it was neces-sary to send a special expedition to the steep cliffs border ing the lake.* In the reports of the ex-pedition we read with keen inter-est about the unusual difficulties of extracting the t ransparent white fluorite imbedded in dense limestones.

I t took a lot of ha rd work to break small paths to the deposit overhanging the lake. But it was still ha rder to br ing separate valuable pieces of the minerals down to the village located on the shores of this lake. Passing large boulders of this rare stone

A t L a k e I s k a n d e r - K u l , T a j i k S.S.R. L e f t - f rom h a n d to h a n d in a chain "S tone M u s h r o o m s " - r e s u l t of rock w e a t h e r - Ta j ik mountaineers brought t hem l n 8 down, packed them in soft grass, crated them and delivered them to Samarkand on pack animals .** T h e optic instrument industry obtained exceptionally pure fluorite and was able to manufac tu re fine, pure lenses and to build some of the world's best optic instruments f rom this mineral .

S H E E T 4

While taking a course of t reatments a t a Czechoslovak heal th resort we were asked to visit a glass-works located in the environs of the city; the works was equipped according to the last word of engineering.

* Tajiks call fluorite "sang i-safet" ;—"white stone." The deposit, was found by a shepherd-boy, named Nazar-Ali, in 1928.

** Optic fluorite is an extraordinarily delicate mineral: it can be spoiled not only by shocks and blows but even by sharp changes in temperature. If the mineral is immersed in water with a temperature differing by a few degrees from that of the air a network of cracks result, destroying its high optic qualities.

1 9 6

We examined the shops where large-size plateglass was made. The glass was monstrously large. Immense sheets of window glass were smelted in a continuous band. Separate shops produced highest grades of cutglass variously stained by salts of rare earths and uranium. How-ever, the shop of artistic drawings proved the most interesting. A vase of purest crystal was covered by a thin layer of paraffin, an experienced artistic engraver made an intricate pattern on the paraffin, then with a scalpel he took some paraffin off in one place, cut thin lines in another and before us appeared a picture of a forest and a deer hunt. This pat tern was later reproduced. By means of a special apparatus the contours of the pattern were traced and it was reproduced on dozens of other vases covered with paraffin. O n all of them we gradually saw the picture of a forest and a deer hunted down by dogs. Then the vases were placed in special lead-lined furnaces and the latter were filled with vapours of poisonous fluorine compounds. The hydrofluoric acid corroded the glass that was not covered by par-affin penetrating now deeper and now only a little so that the surface just turned frosted. Later the paraffin was melted in hot al-

D r a w i n g glass cyl inders . W h e n the cyl inders reach a length of a b o u t 10 met res they a re s t r a igh tened out and cut in to s epa ra t e p la tes . T h e p ic ture on the r ight shows pro-duc t ion of p l a t e glass a t a glass p l an t

197

cohol, sometimes in water or by mere heating, and we beheld a beautiful and delicate etching made by fluorine vapours. All that had to be done now was to deepen the etching in some places by means of rapidly revolving cutters and the job was completed.

S H E E T 5

At last, among my notes and recollections of fluorine and its min-erals I found the following notes from a university chemistry course.

"Fluorine is a gaseous element with an unpleasant pungent odour; it is exceedingly active chemically. I t combines with nearly all the elements, even with gold, exploding or heating brightly as it enters into combination. It is not without reason that it was so hard to obtain. It was obtained in pure form in 1886, though it had been discovered by Scheele in 1771."

In nature it is known only in the form of salts of hydrofluoric acid, chiefly as calcium fluoride, i. e., the beautifully coloured mineral called fluorite.

However, fluorine also abounds in nature in other compounds; for example, apatite contains up to three per cent of it.

In its geochemical history it is connected with volatile sublimates from molten granite magmas, but is also rather rarely encountered in the form of marine sediments which yield a certain accumulation of fluorides from organic substance.

Pieces of fluorite are used for optic glasses which, unlike ordinary glass, also lets through ultra-violet rays; it is used as a decorative stone in beautifully coloured trinkets.

T e e t h : hea l thy and co r roded by f luor ine

198

K.Scheele

However, the chief use of fluorine is based on its capacity for facilitat-ing the melting of metals. I t is also used in the production of hydro-fluoric acid, which is a very strong solvent and corrodes glass and even rock crystal.

As a binary salt of sodium and aluminium hydrofluoric acid forms the mineral cryolite which is required for the electrolysis of metallic aluminium. Fluorine plays an enormous part in the life of plants and other living organisms, but an excess is harmful and causes a number of diseases.

It also plays an important part in the life of the sea where it accu-mulates partly by biological processes (shells, bones, teeth) and partly in the form of complex carbonates and especially, phosphates (phos-phorites). Sea-water contains one milligram of fluorine per litre, while oyster shells contain twenty times as much.

While analyzing the properties of fluorine on the basis of Mende-leyev's table scientists have recently discovered a new remarkable use for fluorine, namely, they have learned to produce a special sub-

Checking u p on electr ic r e f r i ge r a to r s a t the L ikhachov P l a n t

Smelting of aluminium

Cryolite

Suits. Fighting

agricultural pests

CF„ Hydrofluoric

acid Sefrigeration

Chemistry Efchjng (analysis of silicates) on glass

Main uses of f luor ine in indust ry

stance—carbon tetraflnoride—which is not poisonous, does not explode when mixed with air, is very stable and is capable of changing from the solid to the gaseous state with a great absorption of heat. This prop-erty has made it possible to use carbon fluoride in special refrigera-tors. It has been possible to develop tremendous refrigerators for preserving various foodstuffs only by the use of carbon tetra-fluoride.

C O N C L U S I O N

I told you in my own words the contents of the five sheets I had found in my paper-case. They seem to exhaust the chapter on this remarkable natural element, but its future is much greater. The most complex gaseous products of the future are connected with fluorine. There are no poisons more dangerous than the combinations of this

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F CaF2 (ore) / ,

Impregnation of fabrics

and timber NaF

tvoxwus gases

Gases

Smelting of metals

U S E S OF F L U O R I N E

element and at the same time there is no better way for preserving foods inexpensively in small cabinets by maintaining temperatures as low as minus ioo° C.

Very little is known about fluorine as yet. I t has immense poten-tialities which arise from the peculiar properties of its complex com-pounds, and it is now hard to foresee its future uses in the national economy and its fate in future engineering.

ALUMINIUM—METAL OF THE 20TH CENTURY

Af Aluminium is one of the most interesting chemical elements. It

is interesting not only because in a space of several decades it has rapidly won an important place in our life, our industry and the leading branches of our national economy and together with magnesium has created the winged power of the plane, but also because of its prop-erties and, primarily, its geochemical role. The point is that alu-minium, whose acquaintance civilized humanity has made only re-cently, is one of the most significant and most abundant chemical elements.

You and I know very well that under the cover of clays and sands, which were formed at different times as a result of weathering and destruction of massive rocks, there is a continuous stony shell of the earth or, as it is often referred to, the earth's crust that envelops the whole globe.

This stony shell is at least 100 kilometres thick and maybe, as it is now supposed, even much thicker. In the interior this shell gradually changes to another—an ore shell which contains iron and other metals and, finally, in the centre of the earth there is, apparently, an iron core.

The stony shell forms enormous projections—continents—on the earth's surface. Folds in the shape of long mountain ranges have, in turn, come to be formed on the continents.

The stony shell of the earth which composes the base of the conti-nents and their mountain ranges is made up of alumosilicatcs and silicates. The alumosilicatcs consist, as their name indicates, of silicon, aluminium and oxygen. This is why the stony shell is often

2 0 2

C r y o l i t e m i n e r a l - a l u m i n i u m a n d s o d i u m fluoride. I t is b r o u g h t to E u r o p e f r o m G r e e n -l a n d . C r y o l i t e is u s e d f o r t h e p r o d u c t i o n of m e t a l l i c a l u m i n i u m

called SiAl, which is a combinat ion of the first syllables of the names—Sil icon a n d Aluminium.

This shell, formed mainly of granite, consists of approximately 50 per cent oxygen, 25 per cent silicon and 10 per cent a luminium by weight. Thus , a lumin ium is the third most a b u n d a n t chemical element and the most plentiful metal on earth. The re is more a luminium on the ear th than iron.

Aluminium, silicon and oxygen are, together, the chief elements of which the earth 's crust is m a d e ; in the stony shell of the earth they form various minerals. These minerals a re combinations of atoms whose centre is occupied either by an a tom of silicon or an a luminium atom, while a round them the atoms of oxygen a r range themselves regularly in four corners forming a te t rahedron.

2 0 3

We are the chief elements

in the earth's crust

Thus aluminium-oxygen tetra-hedrons ai ise. in addi t ion to those of silicon-oxygen. I n these cases a lumin ium plays a dual role: it is either ar ranged, like other metals, between the silicon-oxygen tetrahedrons binding them to each other, or it takes the place of silicon in some of the tetrahedrons.

I t is jus t f rom these silicon and a lumin ium tet rahedrons combined in various ways tha t m a n y of the most im-por tan t minerals of the ear th 's

crust are formed under the general n a m e of alumosilicates. At first sight the intricate pa t te rn in the a r rangement of the a luminium,

Various combina t ions of s i l icon-oxide t e t r a h e d r o n s - s i n g l e t e t r ahed rons , doub le (sand-glass), rings, chains, r ibbons and fiat ne tworks of hexagona l rings. T h e bo t tom row shows frai .c s t ructures of f e ld spa r and na t ro l i t e (a minera l f r o m the zeol i te g roup) in two projec t ions

Si I icon-oxide t e t r ahedrons

2 0 4

> Silicon O Oxyqen

silicon and oxygen atoms reminds us of fine lace or rug ornaments. This picture could be ascertained only by means of X-rays, which photographed, as it were, the internal structure of the minerals.

Let us recall how drab and monotonous the stones appeared to us in our childhood and what an intricate and varied picture arises before us now as we penetrate into their structure.

Some alumosilicates are very abundan t . Suffice it to say that more than half the earth 's crust is composed of minerals called feldspars. They form par t of granites, gneisses and other stony rocks which envelop the earth by a sort of continuous stony a rmour and j u t out as powerful mounta in ranges.

Vast accumulations of clays, consisting of 15 to 20 per cent alu-minium, were deposited on the earth 's surface as a result of weathering of the feldspars over a period of thousands of years. T h e a luminium discovered in the composition of these widespread rocks was even called " a l u m ear th , " though this name has not persisted and is now used somewhat altered to designate its oxide—alumina.

Fortunately, we find a luminium in na ture not only in this intricate composition whence it is ra ther hard to extract. We find a considerable amount of a luminium precisely in the form of a lumina, its natural compound with oxygen. This compound is encountered in widely differing forms.

W e find the anhydrous a luminium oxyde (A1303) in the form of the mineral co rundum noted for its re-markable hardness and, sometimes, unusual beauty. T h e t ransparent varieties of a lumina, which in addi-tion to a luminium and oxygen con-tain only diminutive amounts of elements—dyes—of chromium, tita-n ium and iron, belong to the first-class precious stones. W h a t a variety and wealth of colour is imparted to a lumina by a negligible admixture of some substance or other! These are the brilliant red ruby and blue sapphire which have fascinated m a n

N e e d l e s of zeol i te , so-cal led na t ro l i t e , in igneous phonol i t e . T h e sample is in the col lect ion of the Minera log ica l M u -seum of the U.S.S.R. A c a d e m y of Sciences

2 0 5

from time immemorial. So many fairy-tales are told about these stones! M a n has long been using the less pure, opaque, brown, grey, bluish and reddish crystals of corundum which are inferior in hardness only to diamonds.

With their aid we process various hard materials, includ-ing the shiny steel of tools, arms and machinery.

We are all familiar with the fine crystals of the same corundum mixed with magnetite and other

c , , , , , . , , minerals, the so-called emery: you Sample of baux i t e of spher ical f o r m - ' ' ' ' a lumin ium ore f r o m the " K r a s n a y a Sha- have probably cleaned your

Corundum could naturally serve as an easy source for obtaining metallic aluminium, but it is very valuable in itself and there is not much of it in nature.

Since time immemorial, since the very dawn of human culture, since the stone age, man has extensively utilized granites, basalts, porphyries, clays and other alumosilicate rocks, constructing cities, erecting buildings, creating works of art, manufacturing utensils and producing ceramics, faience and porcelain.

But for thousands of years man never even suspected the noble properties of aluminium, the metal which these rocks concealed.

Never and nowhere in nature is aluminium found in the metallic form, but always in various compounds absolutely different in their properties and appearance from the metal aluminium.

It required the genius of man and his persistent labour to bring this wonderful metal to life.

The first time it was possible to isolate a small amount of the shiny silvery metal was about 125 years ago. At that time nobody thought it would ever play any part in the life of man, especially since it was so very hard to produce. But then, in the beginning of last century, several scientists managed by means of electrolysis to isolate aluminium

p o c h k a " deposi t s in the Ura l s pen-knife with emery many a time.

2 of

Ynu never find me as a

metal in nafure

on a cathode under a crust of slags from aluminium compounds smelted at high temperatures. This was a pure silvery metal— "silver from clay," as they said at that time.

This method of aluminium production was employed in plants and the metal soon began to be widely used. I t resembles silver in colour and its prop-erties have really proved won-derful.

Pure aluminium oxide is not extracted from clay. As a con-venient ore nature gives us a hydrous a luminium oxide (hydrate of alumina) in the form of the minerals of diaspore and hydrargillite. Fre-quently mixed with iron oxides and with silica these minerals form deposits of clay-like or stone-like rocks—bauxites—mainly amid littoral sedimentations.

Bauxite contains a very large amount of aluminium oxide (50 to 70 per cent) and is the principal industrial aluminium ore. Soviet chemists have developed and mastered a new process of changing the Khibiny mineral, called nephelite (Na2Al2Si208), into aluminium oxide. Attempts have lately been made to utilize also disthene shales, which contain 50 to 60 per cent aluminium oxide, and other minerals: leucite and alunite. But neither of these minerals, except nepheline, can replace bauxite.

T h e production of metallic aluminium is based on two independent processes. First of all a pure anhydrous aluminium oxide—alumina—is extracted from the bauxite by a rather complex process. The aluminium oxide is then electrolyzed in special baths lined with graphite.

The alumina powder is loaded into these baths in mixture with cryolite powder. A high-intensity electric current develops a high tem-perature (about i,ooo° C.) ; the cryolite melts and dissolves the alumina

2 0 7

which is subsequently decomposed by the current into aluminium and oxygen. The floor of the bath serves as the cathode (negative pole) and the molten aluminium accumulates on it. Through a spccial tap it is let out and poured into moulds where it hardens in the form of shiny silvery bars.

One hundred years ago it was very hard to produce this light white metal and a pound of aluminium cost forty gold rubles. Today the might of rivers, transformed into electric power, makes it possible to produce it in enormous quantities.

Some of the properties of aluminium are well known to everybody. It is a very light metal, nearly one-third the weight of iron. It is very malleable and at the same time sufficiently strong; it can be drawn into wire and rolled into thinnest sheets. No less remarkable are its chemical properties. On the one hand, it does not seem to fear oxida-tion ; we know this from the behaviour of aluminium wares, pots, pans and cans. But it also has a great affinity for oxygen. Mendeleyev was one of the first to notice this apparent contradiction. The point is that after smelting the aluminium, which shines like silver, becomes covered with a dull oxide film which protects it from further oxidation. Not every metal has this capacity for self-defence. Iron oxide, for example, well-known rust, in no way prevents the further destruction of the metal; it is too friable and penetrable to air and water. The thin oxide film which covers aluminium is, on the contrary, very dense and elastic and serves as a reliable protection.

When heated aluminium greedily combines with oxygen, changing to aluminium oxide and liberating an enormous quantity of heat. This property of aluminium to liberate heat during combustion has been used by industry for smelting other metals from their oxides by mixing them with powdered metallic aluminium. In this process of aluminothermy the metallic aluminium abstracts the oxygen from the oxides of the other metals and reduces them.

If you mix, for example, iron oxide powder with pulverized alu-minium and kindle the mixture with a magnesium ribbon a violent reaction will develop before your very eyes, an enormous amount of heat will be liberated, the temperature rising to 3,000° C. The iron displaced by the aluminium melts at this temperature, and the aluminium oxide which forms rises as a slag to the surface. M a n has

2 0 8

made use of this activity of aluminium for producing certain refractory and technically valu-able metals.

Metallic t i tanium, vanadium, chromium, manganese and other metals are smelted this way. Since a high temperature is developed in aluminothermy, the mixture of iron oxide and aluminium, known as ther-mite, is used for welding steel.

We could hardly name many elements that have made so fast and brilliant a career as alu-minium.

Aluminium has very rapidly made its way into the auto-mobile, machine-building and other branches of industry, in many cases replacing steel and iron. In naval ship-building its use has wrought a revolution, making it possible, for example, to build "pocket battleships" (ships the size of light cruisers with the power of dreadnoughts).

M a n has learned to produce this "silver" from natural minerals on an enormous scale, and the "silver from clay" has enabled him fully to conquer the air.

Aluminium and its light alloys offer the best material for the con-struction of rigid airships, fuselages, wings and all-metal planes.

This new industry, which has so extensively utilized aluminium, has grown with wonderful speed before our very eyes.

When we see a plane flying over our heads let us recall that alumi-nium makes up 69 per cent of its weight (without the motor) and that even in an aircraft engine the weight of aluminium and magnesium, the two lightest metals, constitutes close to 25 per cent.

In addition to the vast consumption of aluminium by the heavy

14 2 0 9

Pour ing a lumin ium

»

M o d e r n express t ra in . Bui l t ma in ly of l ight a lumin ium al loys

industry, the construction of all-aluminium railway carriages, and the utilization of this metal in machine-building (especially aircraft-building) hundreds of thousands of tons of it are used in the manu-facture of aluminium wires and parts employed in tfrtr electrical in-dustry.

And still this does not exhaust the uses of the metal. Let us add the reflective mirrors in searchlights, the main parts

of shells and machine-gun cartridge belts, the flares and the aluminium powder mixed with iron oxide in incendiary bombs. Let us recall the tremendous importance of artificial crystalline alumina (electro-corundum, alundum) now produced from the same bauxites and used for abrasives chiefly in machining metals.

By crystallizing pure aluminium oxide with an addition of dyes we produce rubies and sapphires in no way inferior to the natural stones either in hardness or beauty. We use them mainly as durable support stones in the principal parts of precision instruments: watches, scales, electric meters, galvanometers, etc.

We coat iron with fine aluminium powder and produce a sort of rustproof aluminium white metal. The same powder serves for the

2 1 0

m a n u f a c t u r e of l i t h o g r a p h i c ink . O f l a t e it h a s also e a r n e d t h e a p p r e -c i a t i on of ar t i s t s w h o p a i n t o n w o o d .

W h y d o w e call a l u m i n i u m t h e m e t a l of t h e 20 th c e n t u r y ? Because o w i n g to its r e m a r k a b l e p r o p e r t i e s it is i nc reas ing ly m a d e

use of a n d its e n o r m o u s reserves a r e i n e x h a u s t i b l e ; we h a v e every r eason to be l ieve t h a t a l u m i n i u m is n o w b e c o m i n g p a r t of e v e r y d a y life l ike i r on d i d in its t ime .

I n a f ew cen tu r i e s t h e y will p r o b a b l y cal l o u r t i m e t h e a l u m i n i u m age .

14

[ They call me the metal of ^

the 20th century

BERYLLIUM—METAL OF THE FUTURE

Be4 9.02

Historians tell us that Nero, the Roman emperor, liked to watch fighting gladiators in the circus through a large crystal of a green emerald.

When Rome, set on fire by his order, was burning he took delight in the raging lire by watching it through a green emerald glass in which the red colours of the fire blending with the green of the glass appeared black and sinister.

When the artists of ancient Greece and Rome, who did not know-any diamonds, wanted to engrave somebody's face in stone in order to immortalize him and show their admiration for him they used a pure emerald from the Nubian Desert in Africa.

Like the emeralds, golden-yellow chrysoberyls found in the sands of Ccvlon, greenish-yellow snake-coloured beryls and bJuish-green aquamarines the colour of sea-water were also always highly valued in India. The euclase, one of the rarest minerals of delicate "blue water," as the jewellers put it, and the fiery-red phenacite, which fades in the sun in the course of a few minutes, came to be known later.

All these stones have long attracted man's attention by the beauty of their play and the remarkable sparkle and purity of colour, and though many chemists tried to divine their chemical nature they found nothing new in them and erroneously believed them to be com-pounds of ordinary alumina.

Beryls and emeralds were mined two thousand years ago in the intricate bends of Cleopatra's famous underground galleries in the arid Nubian Desert.

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Beryls . T h e b o a r d shows a h e x a g o n a l section of a crystal

The green stones extracted from the interior of the earth were delivered by camel caravans to the Red Sea coast and thence to the palaces of Indian rajahs, the shahs of Persia and the rulers of the Ot toman Empire.

In the 16th century, after the discovery of America, remarkably beautiful and big dark-green emeralds were brought to Europe from South America.

After a hard struggle against the Indians the Spaniards seized the fabulous wealth of emeralds mined in Peru and Colombia and brought to the altar of the goddess whose sacred image was an emerald crystal the size of an ostrich egg.

They looted the temples of the local population, but the precious stone deposits in the inaccessible mountains of Colombia had long remained a secret to the invaders and the Spaniards got to the mines and took possession of them only after a long struggle.

By the end of the 18th century all these mines were exhausted. At the same time aquamarines of enchanting colours began to be

found in the sands of sunny Brazil. I t is not without reason that this stone was named aquamarine, i.e., " the colour of sea-water," since

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its colours are as changeable as those of the southern sea in all the magnificence and diversity of its shades familiar to every one who has ever been on the Black Sea coast or has seen Aivazovsky's remark-able paintings.

While gathering brushwood in a forest in 1831 a Urals peasant, named Maxim Kozhevnikov, found the first Russian emerald under an uprooted tree.

The emerald mines were worked for more than 100 years. Trainloads of light-coloured beryl were extracted from the earth but only the bright-green stones were faceted, while the rest were discarded.

. . . Such is the past history of the green precious stones which were described under the name of "beryllos" several centuries B.C.

Such is the picture of the beginning of the history of the metal of the future, called beryllium, as it comes to our mind.

But until 1798 it never occurred to anybody that these beautiful bright stones contained a yet unknown valuable metal.

At a solemn sitting of the French Academy on the 26th Pluviose of the sixth year of the Revolution (February 15, 1798) the French chemist Vauquelin made the astounding statement that what had for-merly been considered alumina or alum earth in a number of minerals was really an absolutely new substance for which he proposed the name of glucinum (from the Greek word meaning sweetness) because its salts tasted sweet to the chemist.

This statement was soon confirmed by numerous analyses of other hemists, but it turned out that the minerals contained but little of

this new metal, usually only from four to five per cent. When chemists began studying the distribution of beryllium in detail they found that it was generally a very rare metal. The earth's crust contains no more than 0.0004 P e r cent of it, and still there is twice as much beryllium in the earth as lead or cobalt and 20,000 times as little as its brother-metal aluminium with which it had always been confused.

Then our chemists and metallurgists went to work on this metal, and an entirely new picture has presented itself to us in the last fifteen years; it is not without reason that we can now call beryllium the greatest metal of the future.

It really appears that this silvery metal is twice as light as the well-known light aluminium. It is only 1.85 times the weight of \vater,

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G i a n t br ight green o p a q u e beryl f r o m a f e ld spa r quar ry . W e i g h t 18 tons

w h e r e a s i r on is 8 t imes as h e a v y a n d p l a t i n u m is m o r e t h a n 20 t imes as h e a v y .

I t y ie lds fine a n d also v e r y l igh t al loys w i t h c o p p e r a n d m a g n e s i u m . T r u e , t h e ex tens ive u t i l i za t ion of b e r y l l i u m is still k e p t secret (it

is a m i l i t a r y secre t of a n u m b e r of count r i es ) b u t w e a l r e a d y k n o w v e r y wel l t h a t t h e al loys of th is m e t a l find ever w i d e r a p p l i c a t i o n in t h e a v i a t i o n of al l coun t r i e s , t h a t t o p r o d u c e g o o d a u t o m o b i l e s p a rk -p lugs a b e r y l l i u m p o w d e r is a d d e d to t h e p o r c e l a i n mass , t h a t t h i n m e t a l l i c p l a t e s m a d e of b e r y l l i u m easily t r a n s m i t X - r a y s a n d t h a t t h e al loys of b e r y l l i u m a r e a m a z i n g for t he i r l ightness a n d s t r e n g t h . P a r t i c u l a r l y r e m a r k a b l e a r e spr ings m a d e of b e r y l l i u m b r o n z e .

B e r y l l i u m is rea l ly o n e of t h e m o s t r e m a r k a b l e e l e m e n t s of t r e m e n -d o u s t h e o r e t i c a l a n d p r a c t i c a l i m p o r t a n c e .

W e h a v e a l r e a d y l e a r n e d t o p r o s p e c t fo r i t ; w e k n o w i t is f o u n d in reg ions of g r a n i t e massifs, w h e r e i t c o n c e n t r a t e s i n t h e las t b r e a t h s of m o l t e n g r a n i t e s a n d a c c u m u l a t e s t o g e t h e r w i t h o t h e r vo la t i l e gases a n d r a r e m e t a l s i n t h e final ex t rac t s of t h e r e m n a n t s of g r a n i t e s h a r d e n i n g i n t h e i n t e r io r .

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In these lodes, which we call granite pegmatites, we encounter beryllium in the form of fine sparkling precious stones.

We also find it with other ores; we know where to look for it because we know its behaviour, character and properties. It is prospected for on an ever grow-ing scale.

The paths travelled by beryl-lium in the earth's crust suggest to us its uses in industry. Tech-nologists are studying the meth-ods of its extraction from ores, while metallurgists are learning

Crystals of beryl in f e l d s p a r to use it in super-light alloys for the construction of planes.

Mastery of the air and daring flights of planes and balloons into the stratosphere are impossible without light metals, and we can already foresee that beryllium will come to the aid of the modern

Large crystal of beryl

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aircraft metals—aluminium and magnesium. Our planes will then fly at a rate of thousands of kilometres per hour.

The future belongs to beryllium! Geochemists, you must search for new beryllium deposits. Chemists, learn to separate this light metal from its fellow-trav-

eller—aluminium. Technologists, make the lightest possible alloys that do not sink,

are hard as steel, elastic as rubber, strong as plat inum and eternal as' precious stones. . . .

Today these words may sound fantastic. But think of the fantasies that have become reality and daily practice before our very eyes; we seem to forget that only some 20 years ago our radio and talking pictures sounded like the greatest fantasy.

VANADIUM—BASIS OF THE AUTOMOBILE

" H a d there been no vanadium there would be no automobile," said Henry Ford who had begun his career precisely with successfully utilizing vanadium steel for the axles of his car.

" H a d there been no vanadium certain groups of animals could not exist," said Y. Samoilov, well-known Russian mineralogist, when

it was discovered that the blood of some Holothurioidea contained close to 10 per cent of this metal.

Some geochemists believe that had there been no vanadium there would be no oil in the earth; they ascribe to vanadium a special influence on the forma-tion of oil.

This remarkable metal was long unknown to man ; controversies and a struggle for obtaining it continued for many decades.

"Long, long ago, in the extreme North there lived Vanadis, the beautiful and beloved goddess. One day somebody knocked on her door. The goddess was comfortably seated in an armchair. 'Let him knock again,' she thought. But the knocking ceased and somebody walked away from the door. The goddess wondered who the modest and diffident visitor was. She opened a window and looked out. She saw a man named Wohler who was hastily departing from her palace.

"Several days later she heard someone knocking on the door again but this time the knocking continued

O n e o£ H o l o -thur io idea con-ta in ing v a n a -d ium in its b lood

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v23 " 50.95

until she went and opened ~the door. Before her stood a handsome young man by the name of Nils Sefstrom. They soon fell in love with one another and gave birth to a son whom they named Vana-dium. This is the name of the new metal discovered in 1831 by the Swedish physicist and chemist Nils Sefstrom."

Thus begins the story of vana-dium and its discovery in the letter of the Swedish chemist Berzelius. But in his story he forgets to mention that somebody else had knocked on the goddess' door before and that this remarkable person was the famous don Andres Manuel del Rio, one of" the purest souls of old Spain, an ardent champion of Mexico's liberty and fighter for its future, fine chemist and mineralogist, mining engineer and mine-surveyor who was able to imbibe the ideas of the foremost scientists of the time. As early as 1801, while studying the brown lead ores of Mexico Andres del Rio discovered in them what appeared to him a new metal. Since its compounds were of all possible colours he named it panchromium at first, but later substituted erythronium, i.e., red, for it.

However, Andres del Rio was unable to prove his discovery. The chemists to whom he sent samples took the element contained in the brown lead ore for chromium; the same mistake had been made by the German chemist Wohler who so diffidently and unsuccessfully knocked on the goddess Vanadis ' door.

After long doubts and many unsuccessful attempts to prove the independence of this metal the young Swedish chemist Sefstrom found a solution. Blast-furnaces for smelting iron were being built in different parts of Sweden at that time. I t turned out that the iron ores of some mines yielded brittle iron, while high grades of flexible and ductile

A n d r e s M a n u e l de l R i o , p r o f e s s o r of M i n e r a l o g y a n d C h e m i s t r y in M e x i c o (1764-1849)

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metal were obtained from other mines. In checking up on the chemical composition of these ores the young chemist soon isolated a special black powder from the magnetite ores of the Taber Mountain in Sweden.

Continuing his research under the supervision of Berzelius he proved that he was dealing with a new chemical element and that the same element was contained in the Mexican brown lead ore spoken of by Andres del Rio.

Wha t was Wohler to do after this indubitable success of the young Swede? In a letter to his friend he wrote: " I was a real ass to have overlooked the new element in the brown lead ore, and Berzelius was right when he ridiculed me for so timidly and unsuccessfully knocking on the door of the goddess Vanadis ."

The remarkable metal vanadium has now become one of industry's most important metals. But it was very long before man finally laid his hands on it. At the outset a kilogram of vanadium cost 50,000 gold rubles, while now it costs only ten rubles. Only three tons of it were produced in 1907 because nobody wanted it, whereas today a

Passenger cars and lorries just come off the conveycr

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Bat t lesh ips which n e e d v a n a d i u m steel

keen struggle is being waged for vanadium deposits in all countries. Its properties are remarkable and the need for it is great in every country. In 1910 150 tons of the metal were produced and deposits were discovered in South America; in 1926 its production reached 2,000 tons; now it exceeds 5,000 tons.

Vanadium is one of the most important metals for the automobile, for armour and armour-piercing shells which go through plates of the best steel 40 centimetres thick; vanadium is the metal of the steel plane and of fine chemical products; it is used in the production of sulphuric acid and various fine dyes.

Wha t are its main merits? I t influences steel by making it more resilient and less brittle; it prevents the steel from recrystallizing under the action of shocks and jolts, and this is precisely what automobile axles and motor shafts need because they are subject to a lot of shaking.

No less remarkable are the salts of this metal—green, red, black as ink, yellow and golden as bronze. They yield a whole scale of beauti-ful colours for porcelain, photo paper and special inks. They are also used in treating the sick. . . .

There is no need enumerating all the remarkable uses of this metal;

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we must only mention one more. Vanadium helps in the production of sulphuric acid, this central nerve of the chemical industry. In this case it behaves very "cunningly"; it only helps the chemical reaction, it catalyzes it, as the chemists say, itself remaining unchanged and unspent. True, some substances poison and spoil it, but there are medicines for this, too. The presence of metallic vanadium and of some of its salts seem to have a mysterious effect on the production of the most complex organic compounds which cannot be produced without its participation.

But if vanadium is so wonderful a metal why do we know so little about it? Why have some of you readers never even heard of it before? Besides, only about 5,000 tons of it is produced in the world annually; and this is 20,000 times as little as the annual output of iron and only five times as much as that of gold.

Something is, evidently, wrong with its deposits and production, and to find out what it is we must ask our geologists and geochemists. Here is what they tell us about the behaviour of this metal in the earth's crust.

It seems there is quite a bit of vanadium in our earth. In the accessible part of the earth's crust our geochemists estimate an average of 0.02 per cent, and this is not so little at all if we recall that the earth's crust contains 15 times as little lead and 2,000 times as little silver. There is essentially just as much vanadium in the earth as there is zinc and nickel, and the last two metals are produced in hundreds of thousands of tons.

But not only the earth and the accessible earth's crust contain vana-dium. 'I here are probably rather large quantities of vanadium where native iron is concentrated. This is betokened by the meteorites which fall on our earth. Their metallic iron contains from two to three times as much vanadium as the earth's crust. In the spectrum of the sun our astronomers see the sparkling lines of its atoms, but this is just what grieves the geochemists. There is a lot of vanadium everywhere; this odd metal abounds in the universe, but there are few places where it is concentrated and could easily be mined for industry. It is really found in most of the iron ores, and where its content reaches at least tenths of one per cent industry begins to produce it. The possibility of extracting this costly metal from thousands of tons of iron is becoming interesting and even profitable.

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T i t a n o - m a g n e t i t e mine in the U r a l s ; v a n a d i u m is ex t rac ted f r o m this ore

When chemists discover an ore containing one per cent vanadium the newspapers report the discovery of a rich vanadium deposit. Some internal chemical forces, apparently, always strive to disperse the atoms of this metal. Our science must find out what concentrates and accu-mulates these dispersed atoms and what is likely to break their passion for dispersion and migration. Such forces do exist in nature, and studying the deposits of this metal we are now reading remarkable pages con-cerning the processes which concentrate the atoms of vanadium and force them to accumulate.

Vanadium is primarily a metal of deserts; it is afraid of water which easily dissolves it and transports its atoms over the earth's surface; it is also afraid of acid soils. I t finds "peace" only in the southern latitudes where there is a lot of oxygen in the air and where veins of sulphide ores are eroded. In the hot sands of Rhodesia and in its native land (sunny Mexico) amid Agaves and cacti, it creates yellow-

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brown iron hats, brown hills resembling soldiers' helmets which cover the outcrops of the sulphide ores.

We see the same compounds in the old deserts of Colorado and encounter them in the ancient Permian desert in the region of the Urals bordering in the East on the expanding range of the great Uralides. The salts of vanadium are formed everywhere under the hot sun and in sands, and accumulate from dispersed atoms in deposits of industrial importance.

And still its reserves are very small; its atoms strive to escape the hands of man ; but there are some powerful forces that retain vanadium and do not let it disperse; these are cells of living substance, organisms whose blood corpuscles are built of vanadium and copper rather than of iron.

Vanadium accumulates in the bodies of certain marine animals, especially sea-urchins, ascidia and Holothurioidea which cover thou-sands of square metres of bays and sea coasts. I t is hard to say where they catch the atoms of vanadium since it has been impossible to find this metal in the water itself. These animals, apparently, possess some special chemical ability for extracting vanadium from particles of food, silt, remains of seaweeds, etc. Not a single chemical reagent works with the efficiency of a living organism which is able out of millionths of a gram to accumulate in its body and leave after its death such enormous quantities that man can extract metals from it for his industry.

But as great as the forces of life are, there are still few real deposits of this metal, it occurs in negligible quantities and is hard to extract from black asphalts, bitumens and oils. The ways its atoms accumulate on the earth's surface are a mystery, and scientists will have to do a lot more work to solve the riddle of its extraction and to be able coherently to tell its history in order that the separate links in the life of vanadium merge into one continuous chain.

We shall then know not only the past fates of this metal, but also where and how to look for it, and profound theoretical inferences will be transformed into major industrial victories.

The automobiles will get their metal for axles and the battleships and tanks will receive a higher percentage of vanadium in their armour steel. Very fine chemical reactions with the aid of vanadium catalysts will produce hundreds and thousands of new and most

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complex organic compounds we need for nutrition, for the economy and for culture.

This is what geochemists tell us about the deposits of vanadium. We cannot be satisfied with this; we must ask them to work harder and more persistently in order that they master this metal for the needs of the country.

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GOLD—KING OF METALS

Gold came to the attention of man a long time ago, probably in the form of glittering yellow grains in river sands.

We shall learn a lot that is remarkable and instructive if we trace the history of the use of gold in the intricate course of man's develop-ment. From the verv cradle of human culture down to the imperialist wars gold has been connected with military campaigns, conquests of continents, the struggle of several generations of peoples, crime and blood.

Gold plays an enormous part in the ancient Scandina-vian sagas, and the struggle of the Nibelungs is a struggle for freeing the world from the curse of gold and its power. The ring forged from the gold of the Rhein symbolizes the principle of evil. Sigfried must free the world from the power of. gold and overthrow the gods of Valhalla at the cost of his life.

Ancient Greek mythology has a myth about the voyage of the Argonauts to Kolchis in quest of the golden fleece.

T h e Argonau t s in Kolchis (ancient n a m e of Geo rg i a ) examin ing the go lden fleece. O l d engrav ing

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They were supposed 10 find the fleece, i.e., sheepskins covered with gold dust, on the Black Sea coast, in present-day Georgia, and take them away from the dragon who was guarding them.

We can read about the struggle lor gold on the Mediterranean in the ancient Greek legends and in Egyptian papyri. For the con-struction of the famous temple in Jerusalem King Solomon required a great deal of gold; he undertook several campaigns to the ancient country Ophir which historians are vainly trying to find at the source of the Nile and in Ethiopia. Some scientists believe the word " O p h i r " to mean merely "weal th" and "gold."

There is a legend about ants that extract gold. There are many versions of this legend in the interpretation of different investigators.

The basis of this legend is the story about one of the Indian tribes that lived in a sandy desert where the ants were as large as foxes. Together with sand these ants dug out of the interior of the earth a lot of gold which was carried away by the inhabitants on camels. Herodotus confirms this story; something of this sort can also be found in Strabon who wrote in 25 B.C. Pliny cites a somewhat different version, but at any rate the European and Arab writers alike repeatedly turned to this story in the Middle Ages. There is no plausible explanation of this legend as yet; the most plausible is probably the one which tells us that in Sanscrit the words " a n t " and "gra in" (of alluvial gold) are expressed by the same sounds. The origin of the legend is prob-ably based on this similarity between the words "particle of gold" and "an t . "

Wonderful gold articles were found in the ancient treasures of the Scythian epochs in the South of Russia. These remarkable

Golden comb with picture of battle be-tween Scythians and Greeks. Culture of tin. ;th and the end of the 4th ccnturies B.C. Solokha Burial Mound (Ukrainian S.S.R.). Collection of the State Hermitage

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Kidney-shaped gold nuggets. Kachkar , South Urals

articles made by unknown Scythian jewellers are chiefly representations of animals in rapid motion. They are kept at the Hermitage together with similarly fine gold articles found in the famous Siberian treasures.

The ancients always attached great importance to gold. Alchemists used the symbol of the sun for it. While the Slav, German and Finnish peoples had the letters G, Z, O and L in the root of the word (zoloto [Russian] and gold), the Indo-Iranian peoples put the letters A, U

and R in its root, hence, the Latin word " a u r u m " and the modern chemical symbol for gold—Au.

Philologists have conducted special research in their attempts at finding the roots of the term "gold." These investigators have tried to locate the centres of gold in the ancient world. It is interesting to note in this connection that in Egypt the hieroglyph for gold was a kerchief, a bag or a trough, which, apparently, denotes the method of mining it.

Gold was distinguished by its quality and colour. Sands whose location was described in detail in a number of written monuments were the source of gold in Egypt. Gold was found in different parts of North-western Egypt, as well as along the Red Sea coast, in the sands remaining from the ancient granites in the region of the Nile and, especially, in the region of Qoseir. Old texts indicate numerous points where gold was mined. There were also ancient gold-fields in the Arabian and the Nubian deserts. There are indications that gold-mines existed S a m p ( c s of w i r e . s h a p c d c r y s t a l H n e g o id

two to three thousand years B.C. ; n t h c f o rm of hooks and spirals

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In later written monuments gold-mines are shown and very well described by a number of authors. Several texts point out that gold is connected with shiny white rock, apparently, with quartz veins, which some ancient authors incorrectly called by the Greek word marmaros. We know the prices, methods of mining, exploitation, etc.

The discovery of America in the 15th century wrote a new page in the history of gold. The Spaniards W a s h i n g g o l d in an t iqui t,.. old cnprav-

brought tremendous quantities of ing the precious metal from America; they had obtained it by means of war looting and flooded Europe with it.

Rich gold-fields were discovered in the sands of Brazil in the begin-ning of the 18th century (1719). A "gold rush" began everywhere, and other countries also started prospecting for gold. In Russia the first crystals of gold were found in quartz rock near the city of Yeka-terinburg (now Sverdlovsk) in the middle of the same century. A remarkable discovery was made in America one hundred years later, in 1848; deposits of gold were found in the Far West, beyond the Rocky Mountains, almost on the Pacific coast in California, which was then still a mysterious region. The strike was made by John Sutter who later died a pauper.

Gold prospectors rushed there; caravans of ox-drawn waggons moved westward in quest of new luck. Before another 50 years had elapsed gold was discovered in Klondike, Alaska, which had been so recklessly and cheaply sold to the U.S.A. by the tsarist government of Russia. Jack London's stories tell us how the struggle for gold was waged in Klondike. There are photographs showing "black snakes" paving their way across snowy peaks of polar mountain ranges; these were endless streams of people carrying their meagre belongings on their backs or in small sledges and hoping to bring back piles of gold.

The first gold-fields in Transvaal, South Africa, were discovered in 1887, but this wealth did not bring the Boers, who had found it,

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Ini t ia l explo i ta t ion of go ld -bea r ing quar tz i tes in T r a n s v a a l

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any good fortune. After a long and bloody struggle Britain managed to conquer the country and nearly exterminated the freedom-loving Boer people. More than 50 per cent of the world's gold is now mined in Transvaal. Gold is also found in Australia.

The conquest of gold has had its own very peculiar history in the U.S.S.R. In 1745 peasant Yerofei Markov found a gold vein along the Beryozovka River near Yekaterinburg in the Urals. In 1814 Brus-nitsyn, a head-miner, also discovered the first gold-fields in the Urals and organized their industrial exploitation. The Urals is, thus, the cradle of the Russian gold industry. The discovery of gold-fields on the Lena River in Siberia in the second half of the 19th century caused a sensation at the time. The fields were fabulously rich and adventurers of all brands and from all countries rushed there. Some of them drove their stakes and sold the claims, others washed gold under the severe conditions of the taiga and returned rich men while still others mined

gold but spent it all on drink right there and then; there were still others, and they were in the ma-jority, who died from scurvy and exposure.

Even greater resources were dis-covered in the early twenties of this century on the Aldan River.

I chanced to meet one of the prospectors who had worked in the Aldan fields during the first years after their discovery. He told me about the past of the Aldan, about the rush of the adventurers who had deserted the white armies and abandoned everything in order to penetrate to the upper reaches of the Aldan and grow rich on gold. He told me about a priest who had forsaken his parish, reached with enormous hardships the sources of this river, made a raft and penetrated into an almost inaccessible region where he washed almost 900 pounds of this precious metal. He told me, furthermore, how Soviet rule came to the Aldan and the gold-mines, which had been known as the land of gold and tears, became an organized industry. Many other rich gold deposits have been discovered since.

The struggle for gold has, thus, gradually proceeded in the history of mankind. Over 50,000 tons of this metal has been produced; about half of this gold, more than 10,000 million gold rubles' worth, has accumulated in banks. The achievements of engineering have made it possible gradually to mine more and more gold, proceeding from rich to poor ores.

At first these were simple, primitive methods of production; the gold was washed in bowls, pans and later in what was called "Ameri-kankas"* in Russian and was used throughout the world after the discovery of gold in California.

Afterwards placer gold deposits were worked hydraulically, using powerful streams of water, while the gold dust was dissolved in cyanide

* L o n g n a r r o w t r o u g h s w i t h r i f f l e s t o c a t c h t h e g o l d .

Bel l -work gold-raining using whim gin; the usual machinery in prc-rcvo-lutionary Russia

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In the gold-f ie lds . E lec t r i c d r e d g e reach ing to a dep th of 25 me t r e s

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H y d r o m o n i t o r wash ing go ld -bea r ing sands by a s t rong s t ream of wa te r

During the thousands of years of his cultural and economic life man has extracted no more than one-millionth of the gold contained in the earth's crust. But why has man made gold his idol and the basis of his wealth? Gold, no doubt, possesses a number of remarkable properties. I t is representative of the "noble metals," i.e., the metals

solutions; finally, man learned to extract gold from hard native rocks using the most perfect methods at large mills.

M a n uses every possible means to safeguard his gold and keeps it locked up in the strong vaults of state banks, while ships on which gold is transported are escorted by battleships. Gold has been taken out of circulation in the form of coins because it wears too fast.

which do not change 011 the surface, retain their blight lustre and do not dissolve in the usual chemical reagents. As a matter of fact gold can be dissolved only by the free halogens, say, chlorine, or aqua regia which is a mixture of three parts hydrochloric acid and one part nitric acid, as well as by certain rare poisonous cyanic salts.

Gold has a very high specific gravity. Along with the platinum metals it is one of the heaviest elements in the earth's crust; its specific gravity reaches 19.3.. It melts comparatively easily when heated to a little above 1,000' C., but it is transformed into volatile vapours only with great difficulty. To be brought to the boiling point it must be heated to 2,600° C. It is very soft and easy to forge; it is not harder than the softest minerals and in its pure state you can scratch it with a finger-nail.

Chemists determine the presence of gold bv very fine methods. One atom of gold in a thousand million atoms of other metals is enough for chemists to detect it in the laboratory (i.e., they can estimate down to to"10 grams). Even with our modern tcchniqucs this amount ul substance cannot be weighed on any scales.

There is not so little gold in the earth's crust, but it is dispersed; chemists have now estimated that the earth contains an average of about 0.00000005 per cent gold. Just think of it, there is only twice as much silver in the earth's crust though silver is considered a much cheaper metal! The most remarkable thing is that gold is spread all through nature. It has been discovered in the hot vapours of the solar atmosphere, it is found (in lesser quantities than on earth, to be sure; in the falling meteorites, and there is some of it in sea-water. Recent experiments have shown that sea-water contains 0.0000000005 part gold, i.e., there is five tons of gold per cubic kilometre of sea-water.

Gold finds its way into granites, accumulates in the very latest molten granite magmas, penetrates into hot quartz veins and there, together with sulphides of other metals, especially, iron, arsenic, zinc, lead and silver, crystallizes at relatively low temperatures, about 150 to 200' C. Thus, large concentrations of gold are formed. When the granites and quartz veins arc eroded the gold passes into placer deposits where it accumulates in the lower layers of the sands be-cause of its stability and specific gravity. It is hardlv affected by the chemical aqueous solutions which circulate through the Iavers of the earth's crust.

Geologis ts a n d geochemis t s h a v e s p e n t a lot of e f fo r t to l e a r n a b o u t t h e f a t e of go ld o n t h e e a r t h ' s su r face . E x a c t r e s e a r c h h a s s h o w n t h a t it m i g r a t e s h e r e , too.

I t is n o t on ly g r o u n d u p m e c h a n i c a l l y to s u b m i c r o s c o p i c size a n d in this s ta te c a r r i e d a w a y in e n o r m o u s q u a n t i t i e s b y r ivers , b u t is also p a r t l y dissolved, especia l ly i n s o u t h e r n c l imates , w h e r e t h e r ivers c o n t a i n a g o o d d e a l of ch lo r ine , is r ec rys ta l l i zed a n d f inds itself in soils a n d in p l an t s . E x p e r i m e n t s h a v e s h o w n t h a t t h e roo ts of t rees a b s o r b go ld . Severa l yea r s a g o scientists d e m o n s t r a t e d t h a t go ld a c c u -m u l a t e d in t h e g r a in s of m a i z e in r a t h e r l a r g e a m o u n t s . B u t e v e n m o r e gold a c c u m u l a t e s in t h e ashes of s o m e coals w h e r e its c o n t e n t r e a c h e s o n e g r a m p e r t o n of ashes.

T h e fo r ego ing shows t h a t go ld t rave l s m o s t i n t r i c a t e p a t h s in t h e e a r t h ' s c rus t b e f o r e m a n ex t r ac t s it . A n d still, w h a t e v e r m a n h a s d o n e for m o r e t h a n 2 ,000 yea r s in t h e s t rugg le for go ld a n d as g r e a t as i nd i -v i d u a l go ld en te rp r i ses a re , w e d o n o t k n o w t h e c o m p l e t e h i s to ry of this m e t a l . O u r i n f o r m a t i o n o n t h e f a t e of d i spersed gold is so m e a g r e t h a t w e a r e u n a b l e to j o i n t h e s e p a r a t e l inks of its m i g r a t i o n s i n t o

E x c a v a t o r s expose go ld -bea r ing sands

234

a single continuous chain. What has happened to the gold that was carried out into the seas and oceans after the erosion of the great moun-tain ranges and granite cliffs? Wha t has become of the gold of the Permian Sea which has left some of the richest deposits of salts, limestones and bitumens near the Urals?

Geochemists and geologists, you still have a lot of work ahead of you. The millions of square kilometres of our gold-bearing Siberian regions offer ample opportunity for daring scientific thought!

The future of gold is not in the vaults of banks nor in the stock-exchange deals of speculators and capitalists; it will be used for other purposes. This metal is now widely utilized in Soviet science and in the exact branches of industry, for example, in electrical and radio-engineering; it is used wherever an unchangeable metal of high electro-conductivity and resisting all chemical reagents is required. From the vaults and safes gold will come to plants and laboratories as an eternal metal.

E n o r m o u s tanks in which gold is d isso lved by cyan ida t ion

RAKE DISPERSED ELEMENTS

•7TM The earth's crust consists of scores of chemical elements. Only 15 of these arc relatively abundant and usual and we can find them in the composition of most rocks; the others are found more rarely.

At the same time some of the rarer elements accumulate in large quantities as ore minerals in ore deposits; others, as for example gold or platinum, of which the earth's crust contains very little, form minutest, hardly visible granules of native metals and, only very rarely, larger nuggets.

But rare as they are they are found in the form of their own inde-pendent minerals, be they even so small as to be invisible to the eye. There arc other elements, though, of which there is very little in the earth's crust and which do not form their own minerals. The chemical compounds of these elements arc dissolved in other, more usual minerals; as salt or sugar are dissolved in water and you cannot tell by the external appearance whether it is pure water or it has something in solution.

It is similarly difficult and not always possible to judge by the external appearance of minerals what chemically dissolved admixtures they contain. While it suffices to taste water to tell whether it is tasteless, salty or sweet, the chemical analysis of minerals is a much more complex affair and it is especially hard to isolate the chemical elements which have hidden themselves in foreign minerals.

Chemical elements have travelled a long and arduous course through melts and solutions before they have combined into solid minerals, i.e., the most stable chemical compounds, in rocks or mineral veins. In their long travels they have suffered many different transformations.

2 3 6

Mul t ip l e crystal l izat ion of solut ions fo r the division of r a re ea r ths in a m o d e r n l a b o r a t o r y

Those that especially resemble each other have gone through everything together and inseparably.

T h e greater the similarities of the chemical properties of any two elements the harder it is to find a chemical reaction to separate them. Instead of forming their own minerals some rare elements were dissolved and dispersed, sometimes through many minerals or other chemical elements, and we, therefore, call them dispersed elements.

What are these elements, though? You will hardly hear of them in everyday life or even at school chemistry lessons, although with the development of engineering they come more and more into general use.

These elements are gallium, indium, thallium, cadmium, germa-nium, selenium, tellurium, rhenium, rubidium, cesium, radium, scandium and hafnium. We have enumerated only the most characteristic ones, though the list could be continued.

237

Let us see where and how these rare dispersed elements are found in nature, how man has learned to detect them in other minerals and where they are used.

Here we have before us a yellowish-brown mineral which, when broken, forms perfectly smooth shiny surfaces. This mineral is rather heavy and hardly resembles an ore, though it is an ore. I t is known as zinc-blende or sphalerite.

Its composition is very simple: for each atom of zinc there is an atom of sulphur. But this is only the basic background; these are only the main constituents. The com-position of zinc-blende only seems simple. Whereas our sample is yellowish-brown,

other samples of the same mineral may be brown, dark-brown, black-brown and even altogether black; in the last case they have a real metallic lustre.

What is the matter then? I t appears that the dark colour of zinc-blende is due to an admixture

of iron sulphide which is dissolved in i t ; zinc-blendes which do not contain iron are nearly colourless or are yellowish-green or light-yellow. The more iron the darker the zinc-blende. This means that the colour of this mineral is a true index as regards iron. Studies of the internal structure of zinc-blende by X-rays have shown that the separate particles of zinc and sulphur are so arranged in it that each atom of zinc is surrounded by four of sulphur and each atom of sulphur by four of zinc.

What has happened is that iron has taken the place of some of the zinc atoms and has given the zinc-blende its colour; furthermore, the iron atoms have arranged themselves quite uniformly; one atom of iron has taken the place of either every 100th atom of zinc, or every 50th, or every 30th, 20th, 10th. . . . And this is where the good host—zinc—turned to iron and said: "Aren ' t you taking too much room in my house?" Though there is much more iron than zinc in nature the former can replace the latter in zinc-blende only to a certain extent; this peculiarity scientists call limited mixing ability.

G a s bu rne r m a n t l e con-ta in ing tho r ium d iox ide

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This example can be used for another interesting comparison; just as a mouse or a bear would never look for shelter in a foxhole because it is too large for the former and too small for the latter, and can only be used by animals of about the size of a fox, so can zinc in sphalerite be replaced only by the elements whose atoms are close in size to those of zinc.

Cadmium, gallium, indium, thallium and germanium are some of the rare elements we find in zinc-blende. . . . Not only zinc, however, but sulphur, too, is able to play host (though to a much lesser extent) to two other rare dispersed elements—selenium and tellurium.

As you see, the composition of zinc-blende turns out much more complex than it appears- at first sight. Almost the same can be said of the so-called grey copper ores, of copper pyrite (chalcopyrite) and of many other minerals.

But geochemists have discovered additional regularities: it appears that the iron-rich black zinc-blendes hardly ever contain any cad-mium, but they are rich in indium and sometimes in germanium; they have also found that gallium accumulates mainly in light-brown zinc-blendes and cadmium in honey-yellow sphalerite.

The dark-coloured varieties are usually richer in selenium and tellurium. This shows that chemical elements do not equally make

Don't you take up _ too much room in

my house?

Selenic d e p a r t m e n t a t a p lan t

239

friends indifferently, and what "roomers" may be allowed to take the place intended for zinc depends on various conditions and different neighbours.

Detection of rare dispersed elements is no easy matter and requires special methods. Their high value forces man to look for them even when their content is very low. Conventional chemical analysis with its most perfect methods and most sensitive chemical reactions is now supple-mented by spectroscopic and roentgenochemical methods of analysis.

Without requiring complex chemical separations they are capable of showing at once what other chemical elements and in what quanti-ties the mineral contains. Zinc-blende that contains only o.i per cent indium is no longer a zinc, but an indium ore, because even with this meagre content the little indium is of greater value than all of the zinc contained in the mineral.

But why have these rare dispersed elements attracted so much attention? Why this interest in them? What makes them so valuable? The main reason is their specific uses. It is the peculiar, special prop-

Tes t ing tungs ten f i l amen t fo r electr ic bulbs . T o p : S i lhouet te of a 60 w a t t b u l b fila-m e n t magni f i ed 80 t i m e s . C e n t r e : Second spiral coil . B o t t o m : H u m a n hai r f o r compar i son

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erties which either the metals themselves or their compounds possess.

Thus thorium oxide, when heated, sheds a brilliant light, and this property has found its application in Auer's incandescent mantles.

Rubidium and cesium are used in mirrors which easily emit electrons, and this makes them indispensable in photocells.

Let us trace the uses of the rare metals or their compounds produced from the zinc-blende just described.

C a d m i u m . . . . A light-grey, comparatively soft and fusible metal; melts at 321° C. But suffice it to alloy one part of metallic cadmium with one part of tin, two parts of lead and four parts of bismuth (each of which melts at a temperature above 200° C.) to produce an alloy which is known as Wood's metal and which melts at only 70° C.

Jus t think of it! If you make a tea-spoon out of this alloy and begin to stir your hot tea with it the spoon may melt, and you may find a layer of liquid metal on the bottom of your cup. If you combine the same four metals in different proportions you will produce the Lipowitz alloy which melts at only 550 C. With this molten metal you could not even burn your hands.

Fusible metals are used in many branches of industry. There is a metal which can be melted by only being held in the hand, and it is a pure metal and not an alloy. I t is gallium, one of the rare dispersed metals found in zinc-blende (gallium is found, besides, in micas, clays and in some other minerals).

Gallium melts at only 30° C. and after mercury, which melts at — 39° C., it is one of the most fusible metals that successfully replaces mercury; mercury vapours, as is well known, are very poisonous, which cannot be said about gallium. Gallium, like mercury, can there-fore, be used in the manufacture of thermometers ; but while we can measure temperatures over a range of from —40 0 C. to 360° C. by mercury thermometres, because mercury begins to boil at this point, with gallium thermometres we can measure temperatures from 30° C. to the point of glass soften-ing, i.e., between 700 and 900° C., and if we take quartz glass we can

C o w ' s hooves ea ten ou t by se lenium f o u n d in the grass g rown in po l lu ted soil

16 2 4 1

measure temperatures up to 1,500° C., since the boiling-point of gallium is 2,300° C.

If we use special fireproof glass for such thermometers we can measure the temperatures ,of flames and of many metals in the molten state.

Incidentally, gallium has one more interesting peculiarity. Like ice which is lighter than water and therefore floats on the surface of water, solid metallic gallium is also lighter than molten gallium and can therefore float on the surface of liquid gallium.

This rare peculiarity is inherent also in bismuth, paraffin and pig iron. All other substances sink in their own melt.

But let vis come back to cadmium. In addition to yielding valuable fusible alloys this metal is also used for the tramways.

Have you ever seen an old trolley bow? What a deep trough is formed in it as a result of constant friction against the wire! The tram wire against which the bow rubs wears similarly.

And here we find that suffice it to add only one per cent cadmium considerably to reduce the wear of the wire. Cadmium is also used in the production of stained glass for signal lights. The addition of cadmium sulphide to glass colours the latter a beautiful yellow, while cadmium selenide colours it red.

The use of indium is no less interesting than that of cadmium. It is well known that copper-containing alloys corrode rapidly in

salt sea-water. And yet it is not always possible to replace these alloys by chemically stabler substances which are required for submarines and hydroplanes. It appears that an addition of a very small amount of indium to these alloys considerably increases their resistance to the chemical action of salt sea-water.

The addition of metallic indium to silver greatly enchances its lustre, i.e., its reflective ability. This property is utilized in the pro-duction of mirrors for searchlights, since the indium contained in the mirrors appreciably increases their power.

Selenium, a rare and dispersed element and sulphur's closest relative, usually found in small amounts in sulphide ores, possesses most unexpected properties.

The electroconductivity of selenium varies with its illumination. This

property of selenium is used in the techniques of transmitting images

by telegraph and radio. It serves as the basis of many automatic coll-

a r

trollers which register light and dark objects moving on conveyers. Finally, accurate illumination measurements have become possible onlv because of selenium.

Selenium finds another important application in the production of pure colourless glass. Glass is usually made from quartz sand, lime and alkali (soda or sodium sulphate). The sand used must be as pure as possible, and especially free of iron because iron imparts to glass the greenish shade we sec, for example, in bottle glass.

It takes verv little iron to impart this colour to glass. Window-panes require clean colourless glass; even better glass is needed for spectacles, while optical instruments—microscopes, binoculars and telescopes— require absolutely flawless glass. If we add sodium selenite to molten glass the selenium will interact chemically with the iron, will extract the latter from the molten glass resulting in fine colourless glass.

The glass used in the production of special optical instruments, high-magnifving binoculars and powerful cameras must possess a number of other special properties. These properties can be produced by the addition of small amounts of germanium dioxide.

Germanium is one of the rare dispersed elements which, like selenium, is present in small amounts in certain varieties of zinc-blendes. It is also found in some grades of coal.

Now we know how the rare dispersed elements behave in minerals and in ores. We have learned about some of the properties of these unusual metals and about their peculiar uses.

The importance of these uses explains why geochemistry devotes so much attention to the rare dispersed elements.

16

P A R T T H R E E

H I S T O R Y OF THE ATOM IN N A T U R E

METEORITES—HERALDS OF THE UNIVERSE

I t is a dark moonless night. The last gleams of evening twilight have faded. The stars shine brightly in the infinite depths of the firma-ment, sparkling and twinkling iridescently. The noise in the villages has gradually died down. Nothing stirs in the stillness of the night and only a light breeze is barely heard rustling in the trees.

Suddenly everything is illumined by a bright and, as it were, flicker-ing light. A fire-ball rushes across the sky scattering sparks and leaving a barely luminous, misty trace. The fire-ball is extinguished before reaching the horizon as suddenly as it appeared, and everything is envel-oped in the darkness of the night again. But several minutes later sharp sounds like explosions or thunder of heavy artillery pieces are heard. This is followed by a roar, a crackle and a prolonged, gradually fading rumble.

Some of our readers may have witnessed a similar phenomenon. But what is it? What is this fire-ball and where has it come from?

In addition to the nine major planets—Mercury, Venus, the Earth, Mars, Jupi ter , Saturn, Uranus, Nep-tune and Pluto*—a large number

* T h e p l a n e t s a r e n a m e d a c c o r d i n g as t h e i r d i s t a n c e s f r o m t h e S u n i n c r e a s e . Flight of bolide

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of small planets or asteroids move around the sun in interplanetary space. More than 1,500 asteroids are known today; of these Ceres is the largest with a diameter of 770 kilometres while the smallest— Adonis—has a diameter of only one kilometre. There are undoubtedly innumerable other smaller asteroids. Their diameters are measured by metres and even centimetres. These are essentially no longer planets but rather fragments of boulders or stones and small granules which

can be put on the palm of the hand. They are, certainly, not planets. We could not see them from the earth even through the most powerful telescopes. We call them meteoric bodies; none of them have a regular spherical form.

Most of the large asteriods move around the sun, each in its own definite orbit in the space between the orbits of Mars and Jupi ter . Here they form the so-called "asteroid zone." The orbits of an enormous number of small asteroids or meteoric bodies are outside this zone. They cross the orbits of the large planets including that of our earth. While moving around the sun the earth and a meteoric body may find themselves simultaneously at the intersection of their orbits. I t is at this moment that the meteoric body comes flying into the atmosphere of the earth causing the appearance in the sky of a fire-ball called a bolide.

In approaching the atmosphere of the earth the meteoric body may be moving in interplanetary space in a direction opposite to that of the earth. In this case it may develop the extraordinary speed of up to 70 kilometres per second or even more. If the meteoric body is moving in the same direction as the earth, i.e., it is either "catching u p " with the earth or "being caught u p " by it, its initial speed is approximately 11 kilometres per second. But even this slowest rate is very high; it is many times the speed of a shell or a bullet as they leave the gun.

Owing to this high speed (or as it is called cosmic speed) the meteoric body that has come into the atmosphere meets with a strong resistance of the air. FA'en at an altitude of 100 to 120 kilometres where, as we

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Metcoric stream and the earth's orbit

know, the atmosphere is extremely rare the meteoric body encounters such great resistance due to its enormous speed that its surface is heated to several thousand degrees and becomes luminescent. The air surround-ing the meteoric body is also heated. It is at this moment that the speed-ing fire-ball—bolide—appears in the sky. This fire-ball is the hot gaseous shell enveloping the meteoric body. Contrary streams of air precipitately break the continuously melting substance off the surface of the meteoric body and spray it in minutest drops. Hardening in the shape of globules these drops form, as it were, a smoky trace, which the bolide leaves behind.

At an altitude of about 50 to 60 kilometres, where the atmosphere becomes already sufficiently dense for the propagation of sound waves, a so-called ballistic wave is formed around the meteoric body. This is a dense layer of air which precedes the meteoric body. Upon reaching the earth's surface the ballistic wave produces the roar and rumble which are heard several minutes after the disappearance of the bolide.

As the meteoric body precipitately penetrates into the ever denser lower layers of the atmosphere it meets with the rapidly increasing resistance of the air. Its motion is retarded and at an altitude of about 10 or 20 kilometres it loses its cosmic speed. The meteoric body gets "stuck," as it were, in the air. This part of its path is called the "region of delay." Here the heating and disintegration of the meteoric body ceases. If it has not fully disintegrated the molten layer on its surface quickly cools, hardens and forms a crust. The hot gaseous shell around the meteoric body disap-pears. The bolide, which flew across the sky, disappears together with it. The remnant of the meteoric body covered by the formerly molten crust drops nearly vertically aft' r the region of delay, subject to the attraction of the earth. This piece of meteoric body which has fallen on the earth is called a meteorite.

The brightest bolides can be dis-cerned even in the day-time in the full light of the sun. Particularly

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P h o t o g r a p h of a 3-shaped t race of a bo l i de obse rved on Sep tember 24, 1948

well seen are the smoke traces which the bolide leaves behind. These traces can be observed for periods lasting many minutes and even more than an hour.

Under the influence of strong air currents in the upper layers of the atmosphere the trace of the bolide, rectilinear in the beginning, gradually curves. Like a legendary giant serpent it stretches across the sky and disappears by breaking up into small fragments.

It is precisely the bolides and the traces thev leave behind that have given rise to popular legends about flights of fiery serpents and the lairy-talc about the flying dragon.

Bright bolides appear rather rarely. But many of our readers have probably seen meteors or, as they are also called, "shooting stars."

Meteors are formed from very small meteoric bodies weighing fractions of a gram which come Hying into the atmosphere from inter-planetary space. Such minute meteoric bodies completely disintegrate in the atmosphere and do not reach the earth's surface.

We shall now make a closer acquaintance of meteorites, these heralds of the universe, these strangers from interplanetary space.

The Mineralogical Museum of the U.S.S.R. Academy of Sciences in Moscow has the country's largest and the world's best collection of meteorites. The collection includes many rare or singular meteorites. In the numerous show-cases of the large light hall of the museum the visitor can see wonderful samples of stones many of which are described in this book. They surprise the visitor by their diverse and at times very brilliant colours. But in addition to these attractive stones special show-cases display monotonous gra\r, brown and black stones and pieces of partly rusted iron. What are these unattractive exhibits? Why, these are the meteorites. For a long time, for thousands of millions of years they had travelled in space and at last, when they met the earth, their wandering ceased.

The meteorites represent the only unearthly substance which we can study in our laboratories directly by using up-to-date integrated methods of research and complex apparatus. We can hold the meteorites in our hands, determine their chemical and mineralogical composition, and study their intricate structure and physical properties. They open before us remarkable pages from the history of the universe and the evolution of celestial bodies. They can tell us about many most interesting and wonderful phenomena occurring outside our earth. There is a great

2 y i

deal that is as yet unknown about meteorites and some of their interesting features have not yet been fully explained. However, the studies of meteorites be-come more profound with each passing year and our knowledge of them is grow-ing ever more complete.

The main task facing the scientists, who are studying the meteorites, is to ascertain the conditions under which they are formed and their sub-sequent history.

M e t e o r i t e s a r e d i v i d e d i n t o irons, stones a n d stony-irons. I r o n m e t e o r i t e s consist of an iron-nickel alloy. They fall much more rarely than stone meteorites. Thus an average of only one iron meteorite falls for every sixteen stone meteorites. Stony-iron meteorites fall still more rarely.

Here we have a black irregularly shaped fragment. This is the Kuz-netsovo stone meteorite* which fell in western Siberia on May 26, 1932 ; it weighs a little over 2 %kg. and is covered all-around by a black fused crust. A small split on the meteorite shows its internal ash-gray sub-stance.

It hardly differs from terrestrial rocks externally. But if you examine the fracture carefully you can see numerous minute sparklets dispersed in the meteorite's substance. These are inclusions of ferro-nickel (iron and nickel alloy). In these inclusions you can see bronze-yellow spark-lets; these are a mineral, known as troilite, a chemical compound of iron and sulphur. In addition to troilite we encounter inclusions of another, lighter mineral, which is a compound of iron and phos-phorus and is called schreibersite.

The fracture shows that the fused crust which covers the meteorite

T h e K u z n e t s o v o s tone meteor i t e we igh ing more than 2.5 kg. I t fe l l in N o v o s i b i r s k Region 011 M a y 26, 1932

* Each meteori te is n a m e d af ter the popu la ted point closest to the location of its fall.

251

Fall of a me teor i t e in Swi tzer land (a f t e r a 15th-century d rawing)

is very thin; it is only about a tenth of a millimetre thick. The attention of the visitor is attracted by peculiar now round and now somewhat oblong dents on the surface of the meteorite resembling traces of fingers. These dents are called regmaglypts. They are formed on meteorites as a re-sult of the action of separate heated gaseous streams during the movement of the meteoric body through the atmosphere

at cosmic speed. The fused crust and the regmaglypts are the principal signs of meteorites.

And here we have another stone meteorite. It is half-split; the point of fracture shows its internal substance which is as black as its fused crust. This is the so-called Staroye Boriskino carbonaceous chondrite which fell in Orenburg Region on April 20, 1930. This meteorite also has other features of which we shall learn later.

Next to this meteorite we see a stone meteorite nearly all white both inside (at the point of fracture) and outside (colour of the fused crust). This meteorite known as the Staroye Pesyanove fell in Kurgan Region on October 2. 1933.

More than a dozen separate stones weighing a total of about 3.5 kg, were found after the fall of this meteorite. This meteorite is very brittle. It crumbles easily even when lightly touched. I t is surprising that so brittle a meteorite could have overcome the enormous resistance of the terrestrial atmosphere without crumbling into sand as it rushed through the atmosphere at cosmic speed. The point is, however, that its region of delay was high above the earth in a layer of very rare atmosphere.

We have made the acquaintance of samples of meteorites which show their typical signs and the differences in the colour of their internal substance.

Let us continue examining the meteorite collection. In the adjacent show-case we seefgroups of stones of different sizes and irregular shapes.

The show-case bears the inscription: "Meteori te Rains."

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H u m b o l d t and B o n p l a n d obse rve a meteor ic ra in in South Amer ica in 1799

Metcor i t i c crater in the Sta te of Ar i zona (U.S .A.) . D i a m e t e r of c r a t c r - i , 2 c o metres , d c p t h - a b o u t 180 met res

It appears that in moving through the terrestrial atmosphere at cosmic speed meteoric bodies nearly always break up into separate parts which are dispersed over the earth's surface covering an area of dozens of square kilometres. The meteoric bodies usually break up before reaching the region of delay where the resistance of the air increases especially sharply. Owing to the irregular shape of the meteor-ic. bodies the pressure of the air which reaches enormous values is distributed unequally along their front surface and the latter breaks up.

There had been cases of real stone rains after which many thousands of separate small meteorites were collected. The most abundant mete-orite rain fell near Holbrook, the U.S.A., on July 19, 1912. Fourteen thousand stones weighing a total of 218 kg. were collected here 011 an area of about 4 sq. km.

In the show-case we sec the stones from the Pervomaisky Posyolok meteorite rain. This was one of the most abundant meteorite rains in the U.S.S.R. It fell in Ivanovo Region 011 December 26, 1933; 97 stones weighing a total of about 50 kg. were found on an area of nearly 20 sq. km.

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School children took an active par t in collecting this meteori te rain which fell in winter . Separate meteorites went through the snow and were retained on the surface of the congealed ground. This m a d e it possible to collect the meteorites in the fields without any difficulty the following spring, as soon as the snow had melted.

Next to the stones of the Pervo-maisky Posyolok meteori te rain we see the stones of another , so-called Zhov-tnevy Khu to r , meteori te rain which fell in Stalino Region on October 9, 1938. These stones are noted for their large size, the largest of them weighing 32, 21 and 19 kg., the total weight of the 13 collected stones being 107 kg.

T h e stones of another meteorite rain, known as the Pultusk mete-orite rain, which fell in Poland on J a n u a r y 30, 1868, are also interesting. 3,000 stones were collected after this rain.

In the next show-case we see side by side two interesting meteorites: a giant and a dwarf. O n e of them weighs 102.5 kg-, the other, the size of a nut , weighs only 7 grams. These meteorites fell simultaneously in the T a t a r A.S.S.R. on September 13, 1937, about 27 km. apar t . Fifteen more stones weighing a total of about 200 kg. were collected here in addit ion to these two meteorites.

Let us proceed to the next show-case. Here we see samples of mete-orites which have typical form. T h e most usual form is the f ragmentary . But here is a meteori te tha t looks like a war-head. I t is the Karakol stone meteorite which fell in Semipalatinsk Region on M a y 9, 1840. I t weighs about 3 kg. This meteorite acquired its conical shape as a result of the gr inding action of the terrestrial a tmosphere dur ing its movement through the latter a t cosmic speed. I t fell on the earth without breaking u p in the atmosphere.

Next to this meteori te we see another one ; it is also a conically-shaped iron meteorite called Repeyev Khuto r . It fell in Astrakhan Region on August 8, 1932, and weighs more t han 12 kg.

O u r at tent ion is a t t racted by the next meteorite. Its shape resembles

2.r>5

T h e K a r a k o l s tone meteor i t e weigh-ing a b o u t 2.8 kg. I t fel l in Semi-pa la t insk Reg ion in M a y 9, 1840. T h e me teo r i t e is conical ly-shaped and looks l ike a w a r - h e a d

T h e meteor i t e which fel l on S e p t e m b e r 29, 1938. I t w e n t th rough the roof of a ga rage and the top of an a u t o m o b i l e and d r o p p e d on a seat . We ighs 1,814 g rams

an enormous crystal. This is the Timokhina stone meteorite which weighs about 49 kg.; it fell on the territory of Smolensk Region on March 25, 1807. The meteorite has acquired its form as a result of the initial break-up of one meteoric body into several parts during its movement through the atmosphere at cosmic speed.

Studies have shown that stone meteorites can split along their smooth surfaces like lumps of sugar. This is explained by the properties of their internal structure and mineralogical composition. We see that in many other meteorites of the stone class, including some of the stones of meteorite rains, separate surfaces are also flat and smooth.

The largest meteorites are displayed on special stands. T h e largest of these, a sample of the Sikhota-alin iron meteorite rain weighs nearly two tons (1,745 kg.). The meteorite attracts our attention by the very

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T h e T i m o k h i n a s tone me teo r i t e weigh-ing close to 49 kg. I t fe l l in Smo-lensk Reg ion on March 2;, 1807. T h e m e t e o r i t e has a mul t i - s ided f o r m which resembles a crystal

interesting structure of its surface. I t has sharply pronounced oblong regmaglypts directed radially to-wards the central pa r t of its wide surface. T h e regmaglypts show how separate heated gaseous streams flowed past the meteori te dur ing its movement th rough the a tmosphere at cosmic speed.

Three more large samples of the same Sikhota-alin ra in weighing 500, 450 and 350 kg. respectively lie next to this meteorite.

T h e Boguslavka iron meteorite, which fell in the Fa r East on October 18, 1916, is also remarkable . I t con-sists of two pieces weighing 199 and 57 kg. respectively. This meteori te broke u p in its motion through the air.

And here is another very large stone meteori te named Kashin ; it fell on the territory of former Tver Region on February 27, 1918, and weighs 127 kg.

T h e next show-case brings us to the end of our meteorite excursion. I n this case we see a large meteori te cut in halves; originally it weighed more t han 600 kg. Both cut surfaces have been polished and now show its remarkable internal structure. I t looks like an iron sponge the cavi-ties in which are filled with a t ransparent glassy greenish-yellowish substance—a mineral known as olivine. I t is the first of the preserved meteorites in our country given the n a m e of pallas iron. This meteorite belongs to the class of stony-irons (parasites). T h e meteorite was found in Siberia in 1749 by a blacksmith named Medvedev. I n 1772 the meteori te was brought to the Academy ofSciences in Petersburg by Academician P. Pallas. The re it was studied by E. Khladny , well-known scientist and corresponding member of the Academy. T h e re-sults of his studies were published in a special book in Riga in 1794. I n this book he was the first to prove the unear th ly origin of this l u m p of iron, i.e., its appur tenance to meteorites, and the possibility of mete-

.orites' falling on the ear th .

E. K h l a d n y

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T h e la rges t me teo r i t e f r o m the Sikhota-a l in i ron me teo r i t e ra in which fe l l in the F a r E a s t on F e b r u a r y 12, 1947. T h e me teo r i t e weighs 1,745 kg.

T h e Bogus l avka iron me te -or i t e ; fe l l in the F a r E a s t on O c t o b e r 18, 1916. I t consists of t w o par t s we igh ing 199 a n d 57 kg.

At that time Khladny's inferen'ces were criticized and ridiculed by West-European scientists. They did not be-lieve the fall of meteorites possible and thought the reports of eyewitnesses to have been inventions. But about ten years after the publication of Khladny's book an abundant meteorite rain fell near the town of L'Aigle, France, on April 26, 1803; close to 3,000 stones were gathered in after that rain. Numerous inhabitants saw this meteorite rain. Following this the scientists of Paris, as well as other scien-tists of Western Europe, could not help acknowledging the existence of meteorites.

The foregoing shows that Russia was the birth-place of thq science of meteorites— meteoritics.

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The aforesaid large meteorites in the collection of the U.S.S.R. Academy of Sciences are not the very largest. The largest meteorite in the world is the Goba iron meteorite found in West Africa in 1920. I t weighs close to 60 tons and has the shape of a rectangular slab 3 X 3 X 1 metres in size. T h e meteorite is still located where it was found and is exposed to the disinte-grating action of the atmosphere.

There are also other iron meteorites weighing 33.5, 27 and 15 tons. T h e largest stony meteorite weighs about one ton. I t fell in the U.S.A. in 1948.

Now let us examine the internal structure of meteorites.

In a separate show-case we see specially arranged samples. Here is an iron piece with a polished surface and a mirror-like lustre. Next to it lies another sample whose polished surface has been treated with a weak acid solution. O n this surface we see a wonderful pattern of interweaving lines and fine shiny borders. This pattern is a result of the unequal pickling action of the acid.

The point is that the iron meteorites are not uniform in their mass. They are composed of separate plates from a fraction of a millimetre to two and more millimetres wide. These plates consist of iron with a small admixture of no more than seven per cent nickel. Because of this the polished surfaces of the plates are acted upon by the acid and after pickling become rough and lustreless. Contrariwise, the shiny narrow lines bordering these plates consist of iron with a large admixture of about 24 to 25 per cent nickel.

T h e P a l l a s o v o Zhe l ezo meteor i t e f o u n d south of K r a s n o y a r s k in 1749. T h e pic ture shows grains of o l iv ine in meta l l ic i ron

W i d m a n s t a t t e n figures on the e tched sur facc of a p l a t e cut ou t of t he C h e b a n k o l iron me teo r i t e

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Owing to this they resist the action of the acid solution and after pickling remain as shiny as ever. The pat tern obtained on the pickled plates of iron meteorites is known as Widmanstatten

figures, named after the scientist who .had first discovered them.

The iron meteorites which show Widmanstat ten figures are called octa-hedrites because the plates which form the figures are arranged along the sides of a geometric figure that has eight sides and is called an octahedron.

Not all iron meteorites show Wid-manstatten figures after pickling. Some pickled surfaces of iron mete-orites show fine parallel lines called Neumann lines after the scientist who discovered them.

The meteorites showing Neumann lines contain the least nickel (about five to six per cent). They are monocrvstals in their entire mass, i.e., single crystals of the cubic system with six sides, and are called hexahe-drons. The iron meteorites which show Neumann lines are, therefore, called hexahedrites.

We encounter one more type of iron meteorites, known as ataxites, which means "devoid of order." These meteorites contain the most nickel (more than 13 per cent) and when pickled their polished surfaces show no definite pattern.

Stony meteorites also have a very interesting structure.

Here is a fragment of a meteorite in a fracture of which we can see perfectly regular globules, resembling shot, even with a naked eye. Under a microscope the entire surface of the

Neumann lines on the etched sur-face of a plate cut out of the Bogu-slavka iron meteorite (see picture on page 258)

Chondrules in the fracture of a stone meteorite (chondrite). Saratov

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fracture in some meteorites seems covered with these globules whose size is a fraction of a millimetre and even smaller. T h e globules are called chondrules, while the meteorites containing them are known as chondrites.

T h e chondrites are the most widespread meteorites and constitute approximately 90 per cent of all stony meteorites. T h e chondrules are structures typical only of meteorites. They are never found in terrestrial rock and their presence in an unknown sample may, therefore, serve-as a reliable indication that this sample is a stony meteorite. Scientists have come to the conclusion tha t the chondrules are rapidly cooled drops of molten substance of the meteorite and tha t they were formed at the same moment as the meteorites.

In addit ion to the chondrites there are also stony meteorites which do not contain any chondrules and which are called achondrites; true, these achondrites are much fewer. T h e fractures of these meteorites show-angular fragments of separate minerals cemented by the fine-grained principal mass of the meteorite. T h e structure of these meteorites very much resembles that of terrestrial rock. The re are still other, rarer types of stony meteorites with their own peculiarities, but we shall not dwell on these.

Now let us examine the composition of the meteorites. T h e following table shows the chemical composition of meteorites of different classes.

Average Chemical Composition of Meteorites of Different Classes

Chemical elemenis

Average chemical composi t ion

Chemical elemenis I rons Stony-

irons Stones

I r o n 90 .85 49-50 15.6 Nickel 8-5 5 .00 I . I O C o b a l t 0.60 O.25 0.08 C o p p e r 0.02

O.25 0 . 0 1

P h o s p h o r u s O . I 7 — O . I O S u l p h u r O.O4 — 1.82 C a r b o n O.I3 — 0 .16 O x y g e n 2 ! .30 41.0 M a g n e s i u m 14.20 14.30 C a l c i u m — 1.80 Sil icon 9-75 2 1 . 0 0 S o d i u m

9-75 0.80

P o t a s s i u m — 0.07 A l u m i n i u m — — ..56 M a n g a n e s e — — O. 16 C h r o m i u m — — O.4O

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I n t h e t ab l e w e see all f ami l i a r c h e m i c a l e l ements a n d n o t a single n e w one. Is it possible t h a t t h e meteor i tes , these s t rangers t h a t h a v e c o m e to us f r o m d i s t an t spaces of t h e universe , d o n o t real ly h a v e a n y n e w chemica l e lements , a n y m o r e w o n d e r f u l c h e m i c a l e l ements t h a n t h e ones w e k n o w on e a r t h ? Is it possible t h a t in t h e d i s t an t pa r t s of in t e r -p l a n e t a r y space t h e r e is n o t h i n g new, n o t h i n g unl ike t h e th ings we h a v e on our e a r t h ?

As a m a t t e r of f ac t t h e mos t a c c u r a t e a n d mos t p a i n s t a k i n g analyses of t h e most diverse me teor i t e s c o n d u c t e d over a pe r iod of m o r e t h a n 100 years by a l a rge n u m b e r of scientists h a v e s h o w n t h a t t hey do not con-tain a single chemical element unknown on the earth. A t t h e s a m e t i m e w e find i n the meteor i tes p rac t i ca l ly all of t h e chemica l e lements we k n o w o n the e a r t h t h o u g h mos t of t h e m cons t i tu te a very negl igible p a r t de t ec t ed only by fine spec t ra l analysis .

I n r ecen t years scientists h a v e o b t a i n e d one m o r e i m p o r t a n t con-firmation of the c o m m o n or ig in of these celestial bodies .

Scientists h a v e s tud ied t h e isotopic compos i t ion of a n u m b e r of c h e m -ical e lements of b o t h ter res t r ia l a n d me teor i t i c or ig in . T h e y h a v e f o u n d also in this case a complete identity of the isotopic composition of the elements.

T h e foregoing t ab l e shows t h a t t h e s tone meteor i tes c o n t a i n mos t ly the fol lowing chemica l e l emen t s : oxygen (41.0 p e r cen t ) , i ron (15.6 p e r cen t ) , silicon (21.0 p e r cen t ) , m a g n e s i u m (14.3 pe r cen t ) , s u l p h u r (1.82 p e r cen t ) , c a l c ium (1.8 pe r cen t ) , nickel (1.1 p e r cent ) a n d a l u m i n i u m (1.56 p e r cen t ) .

O x y g e n is p resen t in t h e meteor i t es in c o m b i n a t i o n w i t h o t h e r ele-m e n t s f o r m i n g var ious mine ra l s (silicates a n d oxides) . I r o n is also con-t a ined pa r t l y in c o m b i n a t i o n w i t h o the r e lements a n d pa r t l y in t h e

meta l l i c p h a s e in t h e f o r m of these m i n u t e s t sparkle ts w h i c h w e see in t h e f r ac tu r e s of meteor i tes a n d w h i c h a r e s p r e a d t h r o u g h o u t the i r mass .

H o w e v e r , t h e c o n t e n t of c h e m i c a l e lements in s e p a r a t e meteor i t es m a y cons ide rab ly d i f fe r f r o m the i r a v e r a g e c o m -posi t ion.

Marshy terrain in the region of the fall of the Tunguska meteorite

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Ue are actually all veryctose

relatives

Precious metals are found in meteorites in negligible quantities. For example, an average of five grams of silver and gold and 20 grams of plat inum are found per ton of meteoritic substance.

Meteorites fall on the earth incessantly. Scientists have estimated that at least 1,000 meteorites fall on our earth annually. However, only an insignificant part of them, about four to five meteorites, are discovered during the year.

The rest of the meteorites which fall into seas and oceans, in polar countries and deserts, in mountainous or wooded regions, away from inhabited areas in general, are never found. They disintegrate under the action of the atmosphere and become part of the soil.

Meteoritic atoms mix with those of the earth. From the soil they get into plants and through the plants, which are used for food, as well as through the animals, which eat the plants and serve as food for man, the meteoritic atoms find their way into man's organism.

We see that not only our earth, but also the organic life on it is closely interlinked with the part of the universe surrounding it.

Scientists have tried to estimate the annual increase in the mass of the earth due to the fall of meteorites. I t appears that from five to six tons of meteoritic substance fall on the earth every day.

Thus, the mass of the earth annually increases by about 2,000 tons. This is, of course, a negligible amount even if it is somewhat increased by the settling of atmospheric meteoric dust formed on the earth by the movement and destruction of the meteoric bodies. Academician V. Vernadsky did not believe that the mass of the earth increased. He wrote that while the earth received substance in the form of meteorites and meteoric dust it gave off into the solar system other material particles, atoms, mainly gaseous, and very fine dust. This resulted in a mobile material equilibrium. Academi-cian Vernadsky thus came to the conclusion that we were dealing "not with accidental falling of separate meteorites, bolides and cosmic dust on the earth, but with a great plane- Fe l l ed t rees in the region of the fa l l of

the T u n g u s k a m e t e o r i t e

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The largest crater, 28 metres in diameter and 6 metres deep at the site of the fall of the Sikhota-alin iron meteorite rain

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tary process, with a material exchange between our planet and cosmic space." I t is in this process tha t the inevitable interact ion between our planet and the environment , i.e., with in terplanetary space, consists.

While the chemical analysis of meteorites has not yielded anything new, though very impor tant inferences about the material unity of the celestial bodies and the earth have been m a d e as a result of this analysis, the study of the mineralogical composition of meteorites has shown their peculiarities.

Meteorites are essentially composed of the minerals which are also abundan t in terrestrial rocks. These are olivine and anhydrous silicates: enstatite, bronzite, hypersthene, diopside and augi te ; minerals of the feldspar group are also encountered.

But many minerals, which are products of weathering, have not been found in the meteorites. Nor have any organic substances been discovered in them.

Characteristic of meteorites is also the absence of minerals of the hydrous silicate group, i.e., minerals containing chemically-combined water. Scientists have m a d e many persistent a t tempts to find such min-

Fragmen t ot a large meteori te f r o m the Sikhota-alin iron meteori te rain

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erals in meteorites but they h a v e all been of no avail. Only very recently did Soviet scientists discover a mineral of the chlorite group, i.e., a hydrous silicate. I t is contained, however, only in the meteorites which belong to the rare type of stony meteorites, the so-called carbon chondrites.

Investigations have shown that the chemically-combined water which forms part of the chlorites constitutes 8.7 per cent of the total weight of the meteorite.

This discovery is of great importance to the solution of our main problem, i.e., the finding out of the conditions under which meteorites arise.

The discovery of minerals unknown on the earth in meteorites is also of great importance. True, the meteorites contain

meteorites are formed under conditions very small amounts of these minerals. Nevertheless, they show that the

which differ from those under which the earth's crust was formed. The ascertainment of these conditions represents one of the most important prob-lems of meteoritics. The discov-ery of phenomena of meta-morphism in meteorites under which not only the structure of meteorites but also the miner-als themselves have changed is of particularly great interest. This metamorphism was due to the heating of the mete-orites by the rays of the sun during their numerous ap-proaches to it as they moved in interplanetary space through-

Ind iv idua l meteor i te ot the Sikhota-alin iron meteor i te rain covered by a fused crust and showing sharply pronounced regmaglypts

out their existence. T h e de-tailed studies of the meta-morphism of meteorites, especially extensive in recent years, reveal the history of the meteorites, the history of their wanderings in space.

Meteorites also contain radioactive chemical elements. One of these elements is potassium present in stony

Struc ture of the f u s e d crust of an i nd iv idua l meteorites in appreciable meteor i t e f r o m the Sikhota-a l in iron meteor i te- quantities. Radioactive dis-r a in ; magni f ied 7 t imes integration of potassium

produces argon. We can therefore judge the age of the meteorites by the proportions of argon and potassium contained in them, i.e., we can estimate the time that has elapsed since the formation (hardening) of the meteorites.

Soviet scientists have recently estimated the age of meteorites by argon and potassium. These estimates have shown that the mete-orites are from 600 million to 4,000 million years old.

Today we know whence the meteorites come to earth. But when and how the meteorites were formed is still one of the most important problems on which scientists studying the meteorites are now working.

Most Soviet scientists believe that the meteorites and the asteroids are fragments of one or several large celestial bodies (planets) which broke up in the distant past. But this is only a conjecture, a working hypothesis, which requires further thorough studies of meteorites to be confirmed and fully demonstrated. There can be no doubt that the problem of the origin of meteorites, of their role in the formation of the planetary system and of the subsequent development of the latter will find its final solution.

ATOMS IN THE EARTH S INTERIOR

Several entertaining novels by Jules Verne, George Sand and Acad-emician V. Obruchev describe trips to the centre of the earth, to the inaccessible interior of the world. In other books the fantasy of the writer flies to unknown heights. These books from the fantastic novels of the 17th century all the way to K. Tsiolkovsky's carefully calculated "flights to the moon" lead us to distant, seemingly inaccessible worlds.

These fascinating novels show the inquisitive mind of man who cannot reconcile himself to the fact that he lives on a thin film of earth and that his eye can only see into some 20 or 25 km. of the earth's interior.

In the struggle for expanding and mastering the world man has undoubt-edly made great headway in the last 50 years. T h e ascents to the highest snow peaks frequently made by man out of pure sport were replaced by-scientific expeditions of the U.S.S.R. Academy of Sciences aimed at mastering the Pamirs.

T h e ideas that the higher layers of the atmosphere, which are not reached by the hustle and bustle of the earth or the chemical struggle of the terrestrial molecules, are inaccessible have also

M o u n t Stalin in the Pami r s , 7,495 met res a b o v e sea level

267

receded into the past: Fedoseyenko, Vasenko and Usyskin, Soviet stratonauts, have made the first successful attempts at mastering the altitudes at the peril of their lives.

The flights on stratostats and those of rockets have greatly advanced the knowledge of the spheres where the amount of substance sharply decreases, where one cubic metre of air contains millions of times as few particles as that on the earth's surface.

Man is primarily attracted by altitudes and here his achievements are very real; engineering has made enormous progress, and the scien-tists know this distant and still inaccessible world much better than that which spreads under our feet, i.e., the world of the earth's interior.

We do not know very much about the interior of the earth. Man is attracted to the interior mainly by his struggle for oil and gold. He drills pits and sinks mines which penetrate into the entrails of the earth, but the deepest oil-wells are no deeper than 5 km., while the deepest gold-mine is less than 3,000 metres deep. And this is considered a great accomplishment.

In his pursuit of gold and oil man will, naturally, be able to penetrate still deeper. It is quite probable that the accomplishments of modern engineering will make it possible to break these records by a few more kilometres. But what are these kilometres compared with the earth's radius of 6,^77 km.? It is only some 0.001 of it.

It is quite natural therefore that man cannot reconcile himself to this and that all men of science, from the philosophers of early antiquity to the astronomers of our time, have always been interested in the problem of the internal structure of the earth and in the ways and means of mastering the interior of our planet. Let us at least form a cursory picture of what we know of the earth's interior by taking an imaginary trip from the earth's surface into the interior and let us see what we can find.

* * *

We find the first a t tempt to describe a trip into the earth's interior in Lomonosov's writings. True, his ideas are scattered through a number of his works, but A. Radishchev in his Word about Lomonosov (1790) collected them into a single volume. Ending his famous Journey from Petersburg to Moscow Radishchev curiously enough devotes just the last pages of his story about the hard journey over the filthy and bumpy

272

post road to the peculiar trip made by Lomonosov to the centre of the earth and tells us what the scientist might have seen had he descended successively from the earth's surface to ever deeper layers of the earth. We quote this remarkable description:

" . . . he (Lomonosov) steps with trepidation into the opening and soon loses the sight of the life-giving sun. I should very much like to follow him in his underground trip, to collect his thoughts and state them in the order and in the connection in which they come to his mind. The picture of his thoughts would certainly be amusing and instructive to us.

" I n going through the first layer of the earth, the source of all life, the underground traveller finds it unlike the next layers since it differs from the others in its great fertile power. He may conclude from this fact that the earth's surface consists of nothing but animal decomposition and germination, that its fertility, a nutritive and restorative force, takes its source in the indestructible and primary parts of al! existence which without changing its essence only changes its appearance, the latter being a matter of accident. In going further the underground traveller sees that the earth is always arranged in layers.

" I n these layers he sometimes finds remains of marine animals and of plants and may conclude that the stratification of the earth is a result of the fluidity of waters and that by moving from one part of the earth to another these waters impart to the earth the appearance which it has in its interior.

"Losing sight of this uniform stratification he sometimes imagines it as a mixture of many various layers. He concludes this from the fact that the fierce element of fire by penetrating into the earth's entrails met the resistance of moisture and in its rage stirred, shook, overturned and scattered all that offered it any resistance.

"By stirring up and mixing the heterogeneous, the hot breath of fire gave rise to the attractive force of metals and joined them. There Lomonosov beholds these dead treasures in their natural state, remem-bers the cupidity and suffering of man and with a heavy heart leaves this dark abode of human greed."

Examining this text we can now say that it fully corresponds to our modern ideas; not a single word of it can be refuted.

But if we try to compare this fantastic picture drawn by a scientist of the 18th century with the picture of our own ideas (which are much

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closer to reality) about the earth's entrails studied by means of boring tools we shall see the following.

A small derrick invisible from the street was built near Krestvanskaya Zastava in Moscow a few years ago. There was a boring machine in the derrick; this machine was supposed to bore deep into the earth to find out the structure of the ground underneath Moscow.

Working hard and persistently the borers tried to reach a depth of several kilometres. At first they bored through the clays and sands which had been deposited on the Moscow plain by the southern streams of the great glacier that had come from Scandinavia. These were the last paroxysms of the glacial epoch when all of the north European part of the Soviet Union was covered by a continuous coat of snow and ice.

Under these clays came different limestones, then layers of marls and clays again; in some places there were lime skeletons and shells among the limestones, the limestones were replaced by sands with separate coal layers which indicate the coal-field that supplies the central industrial region with its fuel and gas.

The geologists examined in detail the ancient Carboniferous seas and found that they had been shallow in the beginning, that their shores had been covered by luxuriant vegetation which had grown stormily under the conditions of a humid and hot climate. Later these seas became deeper, waters rushed in from the east and north and broke up the forests and destroyed the vegetation; the luxuriant world of living submarine creatures laid the basis for the coral reefs and banks of shells. It was at that time that the limestones, used in the construction of Moscow houses owing to which Moscow was given the name of "White-stoned," were deposited. The same limestones are also widely used today.

The bore-hole went through the entire complex series of layers depos-ited during the long Carboniferous epoch, which had lasted many scores of millions of years, and ran into new layers of enormous amounts of gypsum. It went through hundreds of metres of gypsum sediments, through argillaceous layers and through large quantities of water.

These waters were at first saturated with sulphates and later, as the bore-hole reached deeper, they contained ever more salts of chlorine. The bore-hole penetrated into brines containing ten times as much salt as sea-water. These were mainly sodium and calcium chlorides, but there were also many salts of bromine and iodine.

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Mul t i - s to r i ed b u i l d i n g near K r a s n i y e V o r o t a in M o s c o w . F a c e d wi th w h i t e M o s c o w l imes tone

I t was n o longer a p i c t u r e of t h e C a r b o n i f e r o u s e p o c h , b u t of a n o lder , so-cal led D e v o n i a n e p o c h . T h e s e w e r e d i s a p p e a r i n g seas w i t h sal t- lakes, firths a n d deser ts w h i c h h a d s u r r o u n d e d the seas ; t h e salts depos i t ed o n t he i r floors in h e a v y layers w e r e in te r spe r sed w i t h t h i n layers of silts a n d dus t b r o u g h t b y h u r r i c a n e s a n d t o r n a d o s of t h e D e v o n i a n deser t .

T h e bo re -ho l e was n o w 1.5 k m . d e e p . W h a t cou ld we expec t n o w ? W h a t cou ld we f ind u n d e r t h e s e d i m e n t s of t h e old D e v o n i a n seas a n d w h a t n e w p ic tu res w o u l d t h e geologis t see as h e b o r e d a n o t h e r few-h u n d r e d m e t r e s ? I n t r i c a t e c o n j e c t u r e s a g i t a t e d t h e m i n d s of scientists a n d d a r i n g t h o u g h t s e a r c h e d for va r i ous hypo theses . A n d t h e n , a t a d e p t h of 1,645 me t r e s , t h e y s u d d e n l y r a n i n t o sands . T h e s e were , a p p a r e n t l y , t h e shores of t h e D e v o n i a n sea ; t h e sands s ignif ied t h a t l a n d was n e a r . T h e y i n c l u d e d s e p a r a t e p e b b l e s of i gneous rocks a n d po l i shed f r a g m e n t s of t h e seashore . T h e s e w e r e a l r e a d y shores , r ea l shores , a n d a f t e r a n o t h e r t en m e t r e s t h e bo re -ho l e r e a c h e d h a r d g r a n i t e .

T h u s t he b o r i n g tool in M o s c o w for t h e first t i m e c u t i n to t h e g r a n i t e base , t h e f o u n d a t i o n of all R u s s i a n l a n d f r o m L e n i n g r a d in t h e n o r t h to t he U k r a i n e in t h e sou th . S o o n n e w bore -ho les in S y z r a n a n d f u r t h e r east r e a c h e d t h e g r a n i t e b e d a t a p p r o x i m a t e l y t h e s a m e d e p t h a n d c o n f i r m e d t h e forecasts m a d e by A c a d e m i c i a n A . K a r p i n s k y t h a t a n c i e n t g r a n i t e masses u n d e r l i e t h e e n t i r e su r f ace of o u r E u r o p e a n p l a in , i. e., t he old p l a t f o r m o r shield as w e k n o w it f r o m t h e b e a u t i f u l g r a n i t e a n d gneiss cliffs of K a r e l i a in t h e n o r t h a n d a l o n g t h e b a n k s of t h e D n i e p e r a n d t h e B u g in t h e sou th . T h e b o r e - h o l e w e n t t h r o u g h a n o t h e r t w e n t y m e t r e s in h a r d g r a n i t e . A c c o r d i n g to t h e e s t ima tes of geologists these w e r e rea l g r a n i t e rocks, t h e a n c i e n t depos i t s w h i c h m a y b e a t least 1,000 mi l l ion yea r s o ld .

T h e bo re -ho l e h a d t h u s r e a c h e d t h e d e e p g r a n i t e b e d u n d e r n e a t h M o s c o w . B u t w h a t was f u r t h e r d o w n ? W h a t co u l d b e e x p e c t e d u n d e r these g r a n i t e s ? C o u l d a n o t h e r 2 ,000 m e t r e s b e b o r e d in o r d e r t h a t t h e d e p t h s w h e r e t h e g r a n i t e masses f loat m a y b e r e a c h e d ? T h i s q u e s t i o n g a v e rise to s t o r m y cont rovers ies .

S o m e be l ieved t h a t f u r t h e r b o r i n g was useless, t h a t m a n y h u n d r e d s a n d even t h o u s a n d s of m e t r e s w o u l d h a v e to b e b o r e d b e f o r e t h e h a r d layers of t h e g r a n i t e gneiss p l a t f o r m e n d e d .

O t h e r s insis ted t h a t t h e b o r i n g b e c o n t i n u e d in o r d e r t h a t t h e r i d d l e of still g r e a t e r d e p t h s m i g h t b e solved. T h e bo re r s e n c o u n t e r e d e n o r m o u s

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Smoking cra ter on a s lope of a vo lcano

difficulties, their work growing ever more complicated with each metre; from a depth of nearly two kilometres they brought to the surface beautiful pink hard rocks of granite and gneisses.

It is as yet impossible to reach the deepest layers of the earth because human engineering is still too weak. In order to master deeper zones of the earth other ways and means must be used. This was first suggested by Eduard Suess, young Austrian geologist, in 1875.

He proposed to take a bird's-eye view of the earth from the positions of geology and the already existing geochemistry. Suess tried to outline the essential and more uniform layers of which the earth consists. For this purpose he followed, primarily, in the footsteps of the old philos-ophers and divided the earth into three simple shells: the air or at-mosphere which completely surrounds the earth; the hydrosphere, i.e., the waters and the ocean which cover solid earth and saturate it and, finally, the lithosphere, i.e., the sphere of stone the interiors of which contain the eternally raging fire exhaled by the volcanoes.

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He continued this division on the basis of the analysis of the chemical composition of hard rocks.

In 1910 the English naturalist Murray subdivided the layers of the earth into separate shells and named them geospheres.

I t was at that time that chemists and physicists, geochemists and geophysicists began their hard and persistent work in order to get a further and deeper insight into the structure of these separate shells or geospheres. The Russian scientist V. Vernad^ky and his school posed this problem in its entirety.

Instead of drawing an external picture of the "face of the ear th" the geologists and geochemists were confronted with the problem of re-creating all the processes occurring in each geosphere and of painting a complete picture of the internal structure of our planet.

We shall now endeavour briefly to characterize the shells of which our planet consists as they are pictured by geophysics on the basis of studying the behaviour of the resilient oscillations of waves which reach enormous depths and mark the borders of separate geospheres by their reflection.

Scientists now count 13 shells from the inaccessible interstellar space filled with meteors and molecules of hydrogen and helium and separate atoms of sodium, calcium and nitrogen.

The lower border of this layer is at an altitude of about 200 km. Below this begins the stratosphere, and the amounts of nitrogen and oxygen increase. A layer of ozone separates individual parts of the stratosphere. The northern lights go on at altitudes of several hundred kilometres and luminous clouds rise to an altitude of 100 kilometres.

The second layer, which we call the troposphere, begins at an altitude of 10 to 15 kilometres.

This is our atmosphere, the air we are accustomed to with its nitrogen, oxygen, helium and other noble gases, saturated with water vapours and carbon dioxide.

This is followed by a zone of about five kilometres which is called the biosphere, i.e., the sphere of living substance. It also includes the upper portions of the earth's crust and its aqueous shell.

Then comes the aqueous zone known as the hydrosphere. This sphere is composed of hydrogen, oxygen, chlorine, sodium, magnesium, calcium and sulphur.

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Mud bed several kilometres long formed by mud streaming out of cracks during the earthquake in Yangi-Kurgan District of Namangan Region (Uzbekistan) on the night of November 3, 1946

The hard shell comes after this; in the beginning it is the well-studied crust of weathering with its acid salts and soil layer; this is followed by the layer of sedimentary rocks—sediments of the old seas, i.e., clays, sandstones, limestones and coal layers. Already at a depth of 20 to 40 km. we encounter a new layer called metamorphic.

Still deeper down are the granites rich in oxygen, silicon, aluminium, potassium, sodium, magnesium and calcium. Somewhere in the interior, at a depth of about 50 to 70 km., they are replaced by basalts with mag-nesium, iron, t i tanium and phosphorus which substitute for aluminium and potassium.

A sharp change occurs at a depth of 1,200 km. Here the hard layers are replaced by peculiar melts and the new peridotitic or olivine shell consists of oxygen, silicon, iron and magnesium with heavy metals— chromium, nickel and vanadium.

The studies of earthquake waves registered by sensitive instruments, called seismographs, clearly show that there are shells of different composition in the interior of the earth. The very sensitive instruments invented by B. Golitsyn, Soviet academician, has made it possible

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to detect not only the waves that travel the shortest route but also those which run around the entire globe and those that are reflected from the borders of layers of the earth of different densities, for example, from the core of the earth. These data serve as weighty arguments in favour of the existence of lithospheric layers. Some scientists believe that an ore shell with accumulations of titanium, manganese and iron runs to a depth of 2,450 km.

A still greater leap in densities is observed at a depth of 2,900 km. where, as it is believed, the central core begins; this core whose proper-ties we do not know as yet in all probability consists of iron and nickel with an admixture of cobalt, phosphorus, carbon, chromium and sulphur.

Tha t is the way geophysicists and geochemists picture the structure of our earth, and each of these layers is characterized by the elements which prevail in its composition. Each of them also has its typical

temperatures and pressures. In this complex and in many

respects, perhaps, inexact picture there is still one sphere which in-variably attracts our attention. I t is the sphere in which we live and which differs from all the other geospheres by its special properties.

I t is a zone of 100 km., a zone of chemical life, a sphere of terrestrial chemical processes, a sphere of stormy paroxysms, variations in temperatures and pressures, a sphere of earthquakes and volcanic erup-tions, a sphere of disintegration in some places and restoration in others, a sphere of cooling of Plutonic melts, hot springs and lodes and, finally, the sphere of life of man with his stormy aspirations, constant struggle against nature and for nature, the sphere inhabited by millions of species of living crea-tures, the sphere of new peculiar

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K a m c h a t k a . A v a c h a Bay nea r the city of Pe t ropav lovsk . A v a c h a V o l c a n o in the d is tance

L a k e in the crater of the Santor in V o l c a n o ( f o r m e d abou t 3,500 years ago) , G r e e k Arch ipe l ago

and intricate combinations of chemical molecules, the sphere of life and struggle and quests, the sphere of new processes and new trans-formations.

This sphere of life is, not without reason, called by geologists the troposphere, i.e., the zone of movement. This zone lives its own complex chemical life, and the processes of construction and combinations of chemical elem'ents in it determine all the fates of our earth in its various geological epochs. It is a zone of purely terrestrial reactions and it is remarkable that though thousands and thousands of celestial stones, meteorites fall on earth and thousands of fragments of cosmic bodies find themselves in the hands of scientists not a single one of them has ever given us at least a piece that might remind us of this stormy zone of life and death on our planet.

It is thus the chemical processes in the interior of our earth appear to man, whose physical existence is limited to a film only several kilo-metres thick.

But in the slow and stubborn struggle of his genius man constantly expands his knowledge of the world.

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We are firmly convinced that both the interior of the earth and the spheres above the clouds will be conquered not only by the scientist's abstract thinking but also by engineering.

We see how the waves of large geophysical instruments penetrate into the interior of the earth by the will of man and reflected there bring us the answer as to the structure of the earth's shells. The enor-mous explosions made in the Urals and in the south of the country bring us entirely new ideas about this structure. A series of precision machines, fireproof pipes and rods with cutters of super-hard alloys and diamond crowns will easily and with the fabulous speed of hundreds of metres per shift cut into the hard granite, and we are sure it will not be many years before the Moscow bore-holes, which seemed the height of technical accomplishment, will recede into the distant past.

Man will conquer the interior of the earth scores of kilometres deep not only in novels, but in actual life by winning another technical victory over the earth.

There are no limits to cognition of the world! There are no limits to conquests by the human mind!

HISTORY OF THE ATOMS IN THE HISTORY OF THE EARTH

More than 100 years ago upon his return from a trip to the then unknown American countries Alexander Humboldt (1769-1859) deliv-ered a series of lectures at Berlin University; in this lecture he attempted to paint before his listeners unusual pictures of the universe.

Subsequently he set these ideas forth in his book entitled Cosmos. The word cosmos comes from the Greek and expresses the idea not only of world but also of order and beauty, because in the Greek language this word equally signifies the universe and the beauty of man.*

In Humboldt 's exposition the cosmos represented a totality of various facts.

Basing himself on the accomplishments of 19th century science, he endeavoured to explain order by the unity of natural laws and in the picture of the present he wanted to see something more than merely one of the moments in the complex process of the development of the world. He failed, however, because the world in his ideas was still broken up into separate natural kingdoms. Each of these kingdoms had its own representatives with no common bonds between them.

The old classification divided the world into individual cells and separated the minerals, plants and animals from each other by im-passable barriers.

The old ideas of the 17th and 18th centuries were still adhered to, the world still appeared immutable and made by the will of God from an enormous number of independent "kingdoms" and, though

V* A. H u m b o l d t

* W e k n o w th is ve ry we l l f r o m life b e c a u s e w e s p e a k of cosmic w o r l d s a n d c o s m e t i c s .

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Alexander Humboldt wanted to show that all natural phenomena were interlinked, he was unable to do so because he had no facts, no proofs, no units which he could take as a basis for the relationships existing in the nature that sur-rounds us.

I t is atoms that have proved to be these units, and in our time the picture of the cosmos is painted against an entirely different back-ground. Inexhorable laws of physics and chemistry govern the compli-cated and long history of the mi-grations of individual atoms. We have already seen that separate atoms are deprived of their electrons in the centre of cosmic bodies; we have seen a gradual creation of

a complex particle of element with the electron-planets rotating around the centre.

We have seen molecules, i.e., chemical combinations, born in a desert world of cooling stars, by interlacing with and being engirded by the rings of these planets. Then ever more complicated structures come into being; ions, atoms and molecules form crystals, these new remarkable elements of the world, elements of a higher order, mathe-matically perfect and physically beautiful. We can take as an example of this the transparent pure crystal of quartz which even the ancient Greeks had named crystallos, i.e., "petrified ice."

We have seen the growth and destruction of beautiful structures of the crystal on the very surface of the earth; we have seen a new mechanical system arise from these fragments—a world of colloids, minutest groups of atoms and molecules. And in this environment it is a new type of complex and large carbon-containing molecules, the type we call a living cell, that proves to be stable.

New laws of development of living substance increasingly com-plicate the fates of atoms in the course of their history, creating complex

Por t ion of solar sur face p h o t o g r a p h e d in hydrogen rays

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clots of myceliums, minutest semi-animals, semi-plants, semi-colloids which we call viruses, hardly visible in ultra microscopes and, finally, the first unicellular organisms which we now well distinguish in our microscope, i. e., bacteria and infusoria.

It is through these historical stages that the atoms of different elements of our world travel, and a history of life can be constructed for each one of them from the moment the first terrestrial particle had cooled all the way up to their migrations in the living cell.

Once upon a time, almost the way wc read about it in fairy-tales, a cluster of atoms arose in world chaos and began to emanate electro-magnetic waves; the heat movement gradually decreased, as the astronomers say, and the system cooled.

It does not make any difference to us who was the first of the numer-ous astronomers and philosophers to try and divine the mechanics of this proccss, nor when it was done. The only thing that matters is that the cluster is formed where the atoms of individual elements come in contact with each other.

We know the composition of this cluster: modern geochemists tell us that it is cotnposcd of about 40 per cent iron, 30 per cent oxygen, 15 per cent silicon atoms, 10 per cent magnesium, and 2 to 3 per cent, nickel, calcium, sulphur and aluminium. Then come the elements which constitute lesser amounts—sodium, cobalt, chromium, potas-sium, phosphorus, manganese, carbon, etc. This list shows that the chief chemical elements of which the universe is composed are all stable atoms built according to the laws the evenness of which wc have already mentioned.

This intricate cluster consists of nearly 100 types of atoms, with some of them encountered in enormous quantities and others only in billionths of one per cent.

In subsequent cooling the free atom-gases little by little form liquids and coming together as separate molten fiery-liquid drops, go through all the processes to which molten ores are subjected in the blast-furnace.

The structure of our planet was unexpectedly divined not by theoreti-cians, not by geophysicists, but by metallurgists, the people who have learned to smelt metal, to get rid of the slags and to guide the fate of the individual atoms in the heat of the blast-furnace. According to the laws of physics and chemistry the atoms repel each other and the initial melt divides into separate parts. At this time all the chemical

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H o t lava e rup ted on Sep tember 6, 1934, f o r m i n g a l ava lake. Sandwich I s l ands

elements arrange themselves in a definite order. The light, mobile parts rise to the top, and the heavy ones go to the centre.

A metallic nucleus is thus accumulated. A layer of metal sulphides is not infrequently formed above the nucleus with a crust of silicious compounds deposited still higher as a scale or slag. Geophysicists say that all the separate shells or geospheres, of which our earth is composed, correspond precisely to the separate zones, the separate products of smelting in a large blast-furnace.

In the very interior of the earth at a depth of about 2,900 kilometres there is the iron core. Here we have an accumulation of the metals which go along with iron in the blast-furnace; these are, primarily, iron itself and its closest friends and analogues—nickel and cobalt.

Here, too, are the elements which chemists call siderophiles or "iron-loving," thereby repeating almost exactly the words of the alchemists who were ridiculed by the scholastics of the 18th century. The siderophiles include platinum, molybdenum, tantalum, phospho-rus and sulphur which are undoubtedly akin to iron. Thus do we picture the composition of the deepest part of our earth.

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Metallic core

. Ore shell

. Oxide zone

Above the core, at a depth of probably 1,200 to 1,300 kilometres, there is another zone; controversies as to its chemical composition raged for a long time, but there is no doubt that it is the zone which we know very well f rom smelting copper or nickel. These are metal sulphides. And it is not without reason that enormous zone of the earth's crust 1,500 kilometres thick is frequently called the ore shell.

This is the place where sulphides of copper, zinc, lead, tin, antimony, arsenic and bismuth must accumulate. The majority of them, however, are constituents of the sulphide minerals, which we also find in the more superficial zones of the earth's crust.

Then comes the very "scale," or oxide zone. I t is also divided into separate zones. In the interior we have vast accumulations of rocks rich in silicon, magnesium and iron. This is a zone of which we began to get a notion only after we had studied the enormous diamond pipes in South Africa filled with the densest and heaviest materials—prod-ucts of crystallization of the interior melts brought out from the deeper layers.

Above this, beginning ap-proximately with a depth of 1,000 kilometres, is the silicate envelope 011 which we live. We picture it as a rather complicated system of various rocks and minerals though we actually know it to a depth of only 20 kilometres.

Its composition sharply differs from the average composition of the earth and may be expressed in the following figures: one half of it is oxygen; silicon con-stitutes about 25 per cent, a luminium—7 per cent, iron—4 per cent, calcium—3 per cent, sodium, potassium

. Silicate envelope

C o l o n n a d e b u i l t of M o s c o w s a n d s t o n e in L e f o r t o v o ( M o s c o w )

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and magnesium—2 per cent each; then come hydrogen, t i tanium, chlorine, fluorine, manganese, sulphur and all the other elements.

We have seen that these figures are the result of thousands of indi-vidual calculations and analyses. We get the firm conviction at every step that our earth's hard crust is not uniform, that the distribution of atoms is unusually complicated, and that it is very difficult to form a picture of the structure of the earth's crust composed now of pink, sparkling granite, now of heavy dark basalts, now of altogether white limestones and sandstones or of coloured slates. We know that sul-phurous metals, salts, and minerals are dispersed on this variegated and intricate basis in a similarly chaotic disorder. Is it at all possible to find any laws governing the distribution of atoms in this complex picture ?

Recent studies of geochemists have shown that this apparent world of accidents has its own unusually clear-cut and inexhorable laws. Geochemists have not only isolated the earth's crust, the silicious scale, from this fiery, live cluster, but have also divided it into separate atoms and are now studying the behaviour of each of them in strict order.

The molten mass and scale resemble the slag which has been drained from the blast-furnace and which has gradually begun to cool. One after another various minerals started crystallizing from it. T h e first to separate were the heavy substances which began settling to the bot tom; the lighter constituents, i.e., gases and volatile substances,

rose to the top. Minerals rich in iron and magnesium thus dropped from the molten basalts to the bot tom; in them we en-counter compounds of chromium and nickel and find the sources of precious diamonds and costly platinum ores; on the other hand, other substances rose to the sur-face, to the upper field and gave rise to the rocks which we call granites. These proved suc-cessive extracts, as it were, of the cooling massif; it is precisely A hot spring. T h e w a t e r is too h o t to

touch

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these granites that formed the basis of our continents which float, as it were, on the heavy basalt layer that lines the greater part of the ocean floor.

Strict laws of physical chemistry governed this new distribution of atoms in space, and new ideas were born in science at the time geochemists began making use of the laws of physical chemistry.

The process of granite cooling is complex; the granite centres give off superheated steam and volatile gases which permeate through the nearby rocks and form hot water solutions that we know well by our mineral springs. This hot breath surrounds the granite centre with a sort of halo; the gases and vapours with various contents of volatile substances break through the cracks and fractures of the cool-ing granite rocks; hot underground rivers flow, gradually getting cool and forming on their walls crystalline crusts of minerals; later they change to cold springs on the surface.

In this halo of cooling granite we see primarily the residual melts; these are the famous pegmatite lodes which are, as it were, bearers of the heavy atoms of radioactive ores. They carry with them precious stones, sparkling crystals of beryl and topaz; in them we find traces of tin, tungsten, zirconium and rare metal compounds.

Lodes of quartz with tin and wolframite run in the complex process of gradual stratification; still further are branching quartz lodes with gold and then deposits of zinc, lead and silver which form the polvmetallic veins, while far from the hot centre, several kilometres away from the boiling layers of the molten granites, we find com-pounds of antimony, red crystals of mercury sulphide and fiery yellow or red arsenic compounds.

These ore masses are distributed according to the laws of the same physical chemistry. When they harden in the long fractures of the earth the accumulations of atoms stretch out in long rings or bands regularly following each other around the heated massifs. Grand pictures of these ore zones open up before us on the surface of the earth; some of them run through both American continents beginning in the north somewhere in the region of California. They carry lead, zinc and silver. Others cut across Africa along the meridian. Still others engird in the form of garlands the stable petrified shields of Asia, creating a zone rich in ores and semi-precious stones, traced for many hundreds of kilometres.

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T h e i n c o m p r e h e n s i b l e p i c t u r e of o r e depos i t s seeming ly sca t t e r ed in d i so rde r is thus t r a n s f o r m e d for t h e geochemis t i n to a c l ea r - cu t r e g u l a r p i c t u r e of d i s t r i b u t i o n of a t o m s . T h e g rea tes t p r a c t i c a l p r o b l e m s a n d a c c o m p l i s h m e n t s a r e d e c i d e d on t h e basis of this n e w idea of t he n a t u r a l laws of d i s t r i b u t i o n of a t o m s in t h e e a r t h ' s c rus t a c c o r d i n g to the i r p rope r t i e s a n d b e h a v i o u r .

T h e old obse rva t ions of m e d i e v a l m i n e r s a n d the old e x p e r i e n c e of m i n i n g a r e n o w r e p l a c e d by rea l laws of w h i c h A g r i c o l a d r e a m t so m u c h as ear ly as t he 16th c e n t u r y w h e n h e spoke of t h e mys t e r ious love of va r ious e l e m e n t s for e a c h o t h e r .

M . L o m o n o s o v , t h e R u s s i a n scient is t , h a d t h e s a m e t h i n g in his m i n d w h e n h e ca l led on t h e chemis t s to u n i t e w i t h me ta l lu rg i s t s t w o h u n d r e d years a g o in o r d e r to find t h e e q u i l i b r i u m a n d the reasons for t he j o i n t d iscovery of ores a n d to a n s w e r t h e q u e s t i o n s : w h y z inc a n d lead were a lways e n c o u n t e r e d toge the r , w h y c o b a l t so f r e q u e n t l y fo l lowed silver, w h y the m e t a l s of nickel a n d coba l t , these t w o g n o m e s so host i le to m i n i n g , w e r e a lways f o u n d w i t h t h e s t r a n g e e l e m e n t u r a n i u m .

W h a t is it t h e n t h a t forces t h e va r ious a t o m s to b e d i s t r i b u t e d so r egu la r ly in g r a n i t e rocks? H e r e w e h a v e n e w forces of n a t u r a l p r o c -esses; a n d w h e r e a s in t h e i n t e r io r of t he e a r t h , w h e n t h e m o l t e n c lus ter was d iv ided in to a nuc leus , scale a n d slag, t he m a i n laws of divis ion w e r e d e t e r m i n e d by t h e n a t u r e of t h e a t o m s themse lves , h e r e n e w laws h a v e c o m e to t ake t he i r p lace .

T h e a t o m s a n d t he i r p a r t s b e g a n to c o m b i n e f o r m i n g no t c n l y a system of p i l e d - u p f ree a t o m s a n d molecules , w h i c h w e call l i qu id or glass, b u t also s t r u c t u r e s w h i c h a r e n o t f o u n d in t h e i n t e r io r of t h e e a r t h a n d w h i c h d r i f t in space on ly w h e r e t h e cold of in te rp lane ta ry-space cools t h e s to rmi ly m o v i n g a t o m s to b e l o w 2,000° C .

T h i s r e m a r k a b l y h a r m o n i o u s s t r u c t u r e , w h i c h d e t e r m i n e s t h e h a r -m o n y of o u r w o r l d , has b e e n g iven the n a m e of crys ta l . W e h a v e a l r e a d y m e n t i o n e d t h a t 1 c u b i c c e n t i m e t r e of crys ta l is bu i l t u p of 40 ,000 tr i l l ion a t o m s w h i c h a r e l oca t ed a t de f in i t e po in t s in space a n d a t de f in i t e d i s tances f r o m e a c h o t h e r f o r m i n g sorts of la t t ices a n d ne t -works . T h e e n t i r e u p p e r l aye r of t h e e a r t h ' s c rus t , as wel l as t h e over -w h e l m i n g p a r t of t h e w o r l d t h a t s u r r o u n d s us, is bu i l t of crystals .

T h e crysta l a n d its laws d e t e r m i n e t h e d i s t r i b u t i o n of e l e m e n t s w h i c h m a y f r e q u e n t l y r e p l a c e e a c h o t h e r in these s t r u c t u r e s ; th is

2 8 6

gives rise to the possibility for some elements to migrate within the crystal, others to form bonds by electric forces of fabulous power, thus creating the strength of the crystal, its mechanical endurance, and its ability to resist all the hostile forces in the universe.

There, in the interior of the cosmic bodies, we find a disorderly chaos of atoms; here, on earth, there is no more chaos, there is an endless series of points and meshes distributed as regularly as the boards of parquet on a floor, or as lamps in a large hall.

We have now come to the earth's surface. The earth's entrails cease to affect the life of the atoms and cede their influence to the sun and the emanations of the cosmos; and under the influence of new types of energy the atom resumes its migrations on the surface of the earth in accordance with the laws of physical chemistry and crystallo-chemistry.

Half a century ago V. Dokuchayev, Russian naturalist, developed his ideas on the laws of soil formation on the earth's surface in his lectures at Petersburg University. He said that the climate, plants and animals led to the formation of separate soil zones and at the same time the different distribution of atoms of substance in the soil. The soil was revived in his generalizations as a new peculiar world of atoms.

Dokuchayev was fond of saying: " T h e soils are the fourth kingdom of nature ."

He subordinated to the laws of this world not only the fertility of the soil but the life of man as well. But it is precisely here on this thin film of the earth's surface that the atoms have grown unusually com-plex. The simple and clear schemes of the quiet growth of crystals in the interior have proved insufficient here.

The complex geographical landscape has subordinated the atoms themselves, while the frequent changes of climate, seasons, day and night and the life's processes began to leave their imprints and to demand new forms of equilibrium and new conditions of stability.

In the interior of the earth it is quiet; there is a quiet process of spatial distribution of crystals, while on the surface there is a stormy kingdom of variable, contradictory influences, a struggle of forces, a change of temperatures and a domination of processes of destruc-tion. Here, instead of our precise crystalline structures, their fragments,

2 8 7

Gcochemica l d i a g r a m of the d is t r ibut ion of e lements and some minera l s in connect ion with the d is t r ibut ion of rocks f rom the p r imary m a g m a

Ext inc t t w o - p e a k e d vo lcano in Ca l i fo rn ia . H c i g h t - 4 , 3 0 0 met res

as a new dynamic system, acquire the greatest importance. These fragments we call colloids.

There arises a contradiction between the world of order in the interior of the earth and the chaotic world of jelly-like colloids on the surface. Under the rapidly changing conditions of surrounding nature the chemical reactions cannot proceed so quietly and regularly as in the interior. The construction of the crystal just begun breaks up and is replaced by a new one. The fragments of crystals sometimes merge, and these large particles, sometimes built of hundreds and thousands of atoms, give rise to a new form of substance, to an unstable system of colloid, i.e., the jelly and glue which we know so well in the organic world.

But it is not only this force of destruction which characterizes the system of minerals of the earth's surface; it conceals tremendous active forces; it contains more energy than the dead, stable system of crystals.

In the clays, and in various types of brown-iron and manganese films that surround us, in the multiformity of the different atomic combinations of iron, aluminium and manganese, in the balls and

19 a8<)

concretions of phosphoric compounds new forces come into play caused by the contact of various media with each o ther ; these new forces of chaos manifest themselves wherever there is construction side by side with destruction, where new regularities arise and determine the na ture of the soils, facilitating migrations of individual metals and causing their mutua l exchange in the soil.

We thus gradually approach the last stage in the history of the a tom—the processes of life. T h e colloid has already paved the way for the. creation of the new system; this complex concatenat ion of purposive molecules, which conceal t remendous surface forces, gives rise to embryos of a new substance which is the living cell.

I t is here, in this peculiar and flexible structure, where the a toms are now bound and now free, tha t life was born as a na tura l develop-ment , as a logical consummation of the system of atoms that was be-coming ever more complicated. Following the complex paths of evolution this life only reproduced the pictures we have painted above. Subject to a new form of grouping it began to complicate the a tomic structure and has become the dominat ing phenomenon on the ear th 's

surface f rom the minutest unicel-lular organism all the way u p to man .

We cannot erase anything f rom our surroundings. Life together with inorganic na ture , air and water has merged into a single whole and has created the numerous geographic landscapes tha t surround us. This is the highest form of the system of atoms which has come about as a result of the laws of evolution and development of the organism. T h e H o m o sapiens has come into being with an intellect capable of cognizing the mighty laws of energy which govern this new, still more unstable and at the same, t ime still more powerful active system.

2 9 0

Clitf of volcanic tuff. Karadag, the Crimea

T h e Cr imea . G u r z u f . G e n e r a l v i e w aga ins t the background of the M e d v c d M o u n t a i n of laccoli th or " w o u l d - b e volcano" '

T h e history of migrations of the atom shows us how its fate has gradually grown more complicated.

I t began as an electrically charged free proton; subsequently nuclei were formed. It grew more and more complicated, and with the transition to the colder system of the c o s m o s the electron shell came back to the atom. These atoms have gradually merged in a regular and rigid geometric form, in what we have named a chemical compound.

The crystal was the form of expression of these laws, the form of the greatest order, the greatest harmony, the least reserves of energy and, therefore, the most inert form of substance devoid of any free force. But right there and then complication began and a new colloidal system of atoms and molecules came into being.

T h e living cell was created; complex molecules began to be built of hundreds and thousands of separate atoms; and as the highest form of the still undeciphercd chemical system protein bodies came into being and created the multiformity, complexity and mysteriousness of the organic world that surrounds us.

But in the history of nature the atom has always rushed about in quest of new forms. We cannot say as yet whether there are any new

295 291

Studying the e rupt ion of a K a m c h a t k a vo l cano

forms of equilibrium more stable than crystals and more actively charged with energy than living substance. All our ideas about nature run up against the insufficiency of our knowledge of the new paths travelled by the atom, and nobody would dare say that we have already learned about the entire course of its migrations and that man has already mastered the powerful forces which he could unleash in the atomic cluster.

ATOMS IN THE AIR

W h a t is a i r ? H o w l i t t l e w e k n o w a b o u t it a n d w h a t l i t t l e i n t e r e s t

w e e v e n s h o w i n t h i s q u e s t i o n . W e h a v e g r o w n u s e d t o t h e f a r t t h a t

w e a r e s u r r o u n d e d b v a i r a n d . l i k e h e a l t h , w e b e g i n t o a p p r e c i a t e

it o n l y w h e n w e l o s e i t , w h e n w e g e t i n t o c i r c u m s t a n c e s w h e r e t h e r e

is n o t e n o u g h a i r .

W e k n o w h o w d i f f i c u l t it is t o b r e a t h e a t h i g h a l t i t u d e s , h o w s o m e

p e o p l e g r o w w e a k b e c a u s e o f t h e m o u n t a i n s i c k n e s s a l r e a d y a t a n

a l t i t u d e o f t h r e e k i l o m e t r e s ; w e k n o w h o w l l i e r s s u f f e r w h e n t h e y

r i s e i n t h e i r p l a n e s t o a n a l t i t u d e o f m o r e t h a n f i v e k i l o m e t r e s ; a t a n

a l t i t u d e o f f r o m e i g h t t o t e n k i l o m e t r e s t h e r e is d e f i n i t e l y n o t e n o u g h

a i r a n d t h e s u p p l y o f o x y g e n o n t h e p l a n e m u s t b e m a d e u s e of .

W e k n o w h o w h a r d i t is t o d e s c e n d i n t o m i n e s , h o w l o n g it r i n g s

i n y o u r e a r s b e f o r e y o u g e t u s e d t o t h e n e w a i r p r e s s u r e a t a d e p t h

of 1 . 5 0 0 m e t r e s .

T h e a i r n o w c o n s t i t u t e s o n e o f t h e m o s t i n t e r e s t i n g p r o b l e m s n o t

o n l y f o r s c i e n c e , b u t a l s o f o r t h e c h e m i c a l i n d u s t r y .

I t w a s a v e r y , v e r v l o n g t i m e b e f o r e m a n c o u l d u n d e r s t a n d w h a t

a i r a c t u a l l y w a s . F o r a n u m b e r o f c e n t u r i e s t h e c o n v i c t i o n r e i g n e d

in p r i m i t i v e c h e m i s t r y t h a t a i r w a s c o m p o s e d o f a s p e c i a l g a s phlo_,, .^-

t o n - a n d t h a t w h e n a n y t h i n g b u r n e d it l i b e r a t e d p h l o g i s t o n w h i c h

f i l l e d t h e w o r l d a s a s p e c i a l f i n e s u b s t a n c e .

T h e n , t h e b r i l l i a n t d i s c o v e r y o f L a v o i s i e r m a d e i t c l e a r t h a t t h e a i r

w a s e s s e n t i a l l y c o m p o s e d o f t w o s u b s t a n c e s : o n e l i f e - g i v i n g s u b s t a n c e ,

w h i c h w a s n a m e d o x y g e n , a n d a n o t h e r , i n d i f f e r e n t t o l i f e , w h i c h w a s .

t h e r e f o r e , g i v e n t h e n a m e o f " a z o t e " ( t h e G r e e k f o r " l i f e l e s s " ' . T h e

l a t t e r is n o w m o r e c o m m o n l y k n o w n a s " n i t r o g e n " i n E n g l i s h .

LAVOisier

In 1894 it was quite unexpectedly discovered that the composition of the air was much more complex and that in addit ion to nitrogen, the air contained a number of other, heavier chemical elements, which play an impor tan t par t in it.

Modern physicists set the composition of the air as follows:

By w e i g h t

N i t r o g e n 75-7°/o O x y g e n 23 .01 °/0 A r g o n 1 . 2 8 % C a r b o n d i o x i d e 0 . 0 3 % H y d r o g e n 0 . 0 3 %

By w e i g h t

Neon 0.00125 °/0 Helium 0.00007 % Kryp ton 0.0003 °/o Xenon 0.00004 °/o W a t e r v a p o u r s — v a r i a b l e a m o u n t s

Today we know the composition of the air ocean so well tha t not a single d rop dispersed anywhere in it escapes the at tent ion of our chemists.

Now it turns out that the gaseous ocean tha t surrounds us is not only the basis of all of our life, but also tha t of a new great industry.

T h e British have recently estimated tha t the entire populat ion of England and Scotland daily consumes u p to 20 million cubic

metres of oxygen f rom the air, while special installations extract u p to one million cubic metres of this gas for the needs of industry dur ing the same period of time.

At the same t ime industry burns coal and oil, thus consuming oxygen and giving off large amounts of carbon dioxide to the atmosphere. T h e same process goes on in living systems. For example, m a n gives off about three litres of carbon dioxide per day.

T o give the reader a good idea of wha t this figure means suffice it to point out that it takes a euca-lyptus, a large tree, one day to de-compose approximately one-third of the carbon dioxide exhaled by

Eucalyptus alley- on a state farm in the central part of the Kolchis Lowland (Georgian S.S.R.)

o n e p r i s o n a n d i r i n n i f r e e u x v g r n u > I l i e a t m o s p h e r e . l l i o i l o w - .

t h a i t h r e e l a r g e e u c a l y p t u s d e c s w i l l d e c o m p o s e a s m u c h c a r b o n

d i o x i d e a s i s g i v e n o i l b v o n e p e r s o n a n d w i l l t h u s r e s t o r e t h e b a l a n c e

i n t h e c o m p o s i t i o n o l t h e a t m o s p h e r e .

T h i s s h o w s t h e g r e a t i m p o r t a n c e o l t h e v e g e t a t i o n t h a i s u r r o u n d s

u s a n d t h a t w e s o r a r e t u i l v s a l e g u a r d a n d p l a n t m o u r c i t i e s , T h e

l i f e o l p l a n t s i s t h e o n l v s o u r c e o f r e s t o r i n g t h e o x v g c n c o n s u m e d b \

m a n . M e a n w h i l e , o x y g e n i s b e i n g u s e d i n e v e r l a r g e r a m o u n t s .

I n i f ' H " ) s m a l l f a c t o r i e s p r o d u c i n g b a r i u m p e r o x i d e l a i d t h e b a s i s

l o r t h e i n d u s t r i a l u t i l i z a t i o n o f t h e o x v g c n c o n t a i n e d i n t h e a i r . T o d a \

t h e o x y g e n o l t h e a i r s e r v e s a s t h e b a s i s o ! s e v e r a l b r a n c h e s o f t h e c h e m -

i c a l i n d u s t r y . P u r r o x y g e n i n s t e a d o f a i r i s n o w b l o w n I n t o b l a s t -

l u r n a e e s . ( ) x v g e n i s a n i n d i s p e n s a b l e o x i d i z i n g a g e n t 111 a n u m b e r o l

b r a n c h e s o f t h e < h e m i e a l i n d u s t r y .

T h e n u m b e r o l i n s t a l l a t i o n s w h i c h e x t r a c t o x v g e n f r o m o u r a t m o s -

p h e r e t h r o u g h l i ( ] i i i d a i r g r o w s w i t h e a c h p a s s i n g y e a r .

I n a d d i t i o n t o o w g e n . m a n h a s b e e n m a k i n g i n c r e a s i n g l y w i d e r

u s e o l o t h e r g a s e s .

l . ' n t i l \ ' e r \ ' r e c e n i h i n d u s t r y m a d e n o u s e o f a r g o n w h i c h ( o t i s t i t u i e s

o n e p e r c e n t o l t h e a i r . N o w c o m p l e x i n s t a l l a t i o n s a n n u a l h e x -

t r a c t a l m o s t o n e m i l l i o n c u b i c m e t r e s o l t h i s r a r e s t o l g a s e s h o m

t h e a i r .

N o t m a n y o l u s k n o w t h a t m o r e t h a n i . 0 0 0 m i l l i o n e l e c t r i c b u l b s

a r c a n n u a l l y t i l l e d w i t h t h i s g a s .

f i l e h u n n i o u s a d v e r t i s e m e n t s o f l a r g e c i t i e s a n n u a l h - m a k e e \ e i

g r e a t e r u s e o l n e o n , a n o t h e r n o b i e g a s c o n t a i n e d i n t h e a i r . T h e r e

i s v e r y l i t t l e o l i t 111 t h e a i r o c e a n o n e p a r i o f n e o n p e r " , " , . 0 0 0 p a r t s

o l a i r . A n d s t i l l t h e n e o n i n d u s t r v h a s b e e n g r o w i n g f r o m \ e a r t o

y e a r .

H e l i u m i s a l s o b e g i n n i n g t o b e e x t r a c t e d f r o m t h e a i r . T h e r e i s

s t i l l l e s s h e l i u m t h a n n e o n , t h o u g h t h e a t m o s p h e r e a b o v e e a c h s q u a i e

k i l o m e t r e o l l a n d c o n t a i n s a b o u t J O t o n s o f t h i s m o s t \ a l u a b l e G A S

o l t h e s u n . H e l i u m i s e x t r a c t e d I r o n ; t h e a i r a n d m a i n l v I r o i n u n d e i -

g r o u n d g a s e o u s s t r e a m s : i t i s u s e d l o r f i l l i n g d i r i g i b l e s : i n r c l r i g c r a t i o n

e n g i n e e r i n g 11 i s e m p l o y e d l o r p r o d u c i n g t h e w o r l d ' s l o w e s t t e m p e r a -

t u r e s .

l ' A ' e n t h e r a r e s t g a s e s . k r \ p t o n a n d x e n o n , a r e b e g i n n i n g t o b e u s e d

m o u r m d u s t i \ .

The air contains less than o.ooi per cent krypton. And yet how helpful it would be if we could get it in greater amounts because we could then increase the brightness of electric bulbs by 10 per ceht, and with the use of xenon by 20 per cent. This means our lighting installa-tions would consume 20 per cent electric power.

But the most important raw material- for industry extracted from the air is of course nitro-gen.

T h e first attempts to utilize nitrogen compounds for fertilizer were made in 1830.

No one thought of the nitrogen contained in the air at that time and even the saltpetre brought by ships from Chile did not always find application in the poor fields of Western Europe. However, the gradual introduction of chemistry into agriculture required ever greater amounts of the life-giving substances on which the chemical life of plants is built, i.e., nitrogen, phosphorus and potassium. The need for nitrogen began to increase to such an extent that in i8q8 Crookes, physicist and chemist, predicted a nitrogen famine and suggested that new methods for the extraction of nitrogen from the air be found.

Time wore on. Chemists have learnt to transform the nitrogen of the air into ammonia, nitric acid and cyanamide by means of elec-tric discharges.

During the First World War nitrogen, which was necessarv for the production of explosives, became the object of numerous investigations. More than 150 nitrogen works are now operating throughout the world; they extract four million tons of nitrogen from the air annually. But even this figure is negligible compared with the vast reserves of this gas which constitutes approximately 81 per cent of the total volume of the air.

Beacon of neon tubes at an airf ie ld

296

Suffice it to say that all of the nitrogen installations in the world annually extract as much nitrogen as is contained in a column of the atmosphere over 0.5 square kilometre of the earth's surface. We picture to ourselves the new industrial ways of uti-lizing the air as follows. Industry is making increasing use of the constituents of the aerial ocean.

7 1

The atmosphere is transformed into an immense source of I n s t r u m e n t s w i t h w h i c h P r i c s t i c y studicd the mineral raw materials, the composition of the air in 1774-90

reserves of which are practi-cally inexhaustible. However, man has not yet found the means of mastering these reserves.

The processes by means of which man divides the air into its con-stituents are quite imperfect. T h e extraction of nitrogen requires high pressures and tremendous quantities of energy. To separate the noble gases and obtain oxygen requires complex and expensive machinery; the air must first be transformed into the liquid state in order that the various gases may then be extracted. Great head-way has been made in this direction in the Soviet Union in recent years.

New remarkable machines, which make it possible very thoroughly to divide enormous quantities of air into its constituents, have been built at the Institute of Physical Problems of the U.S.S.R. Academy of Sciences.

But we can already imagine little machines installed in every room. We open a tap marked "oxygen," and instead of air a bluish liquid cooled to minus 200°'C. comes flowing out of it.

We open another tap and a liquid noble gas, krypton or xenon, flows out of it drop by drop, and somewhere on the bottom, like ash in a stove, solid carbon dioxide accumulates; this compound is fed to a special press and gives us hard dry ice which you have all seen when buying ice-cream; this dry ice cools our apartments on hot davs

2 9 7

In the picture 1 have just painted I may have run a bit too far ahead. There arc no such portable little machines which can be plugged in in our rooms as yet, but I am sure it will not be long before we are able to utilize the riches contained in the air for our needs and the chemical industry is built on the immeasurable reserves of nitrogen and oxygen, the two elements of outstanding importance to the life of the earth.

I could finish my story right here, but I do not believe it would be corrilpete.

I have not said anything about utilizing the carbon dioxide of the air or about the possibilities of making use of all the gases formed during the combustion of coal and wood and the kilning of limestones.

Industry is already calculating the enormous amounts of carbon dioxide which are thrown out into the air as waste-products. It pro-poses that the carbon dioxide be used for manufacturing dry ice and it wants to extract from our atmosphere the o.< >j per cent carbon dioxide it contains.

The physicists go even farther; they say that our air consists not only of the ten gases mentioned above, but that it contains tremen-

dous quantities of even rarer gases which are dispersed in millionths of one per cent, i.e., radioactive gases.

They mean the emanations of ra-dium and of different volatile gases, the products of disintegration of light metals. These gases do not live long in our atmosphere: some of them live for days, others for seconds, and still others for millionths of a second. The air is saturated \vith these products of disintegration of world atomic nuclei. The cosmic rays destroy atoms and give rise to unstable gases at each step; these gases must disappear again and change to stabler forms of solid substance.

P h o t o g r a p h of a l ightning

2 9 8

C h e m i c a l r e a c t i o n s a r e c o n t i n u o u s l v t a k i n g p l a c e in t h e a e r i a l

o e e a n . M o s t i n t r i c a t e p r o c e s s e s o c c u r b e t w e e n t h e d i s p e r s e d a t o m s ol

s u b s t a n c e a n d w e s t i l l k n o w v c r v l i t t l e a b o u t t h e c o n s t a n t a n d c o m p l i -

c a t e d s h i f t s a n d a b o u t t h e e l e c t r i c d i s c h a r g e s w h i c h o c c u r in t i n s

a e r i a l o c e a n a r o u n d u s .

T o s o l v e t h i s p r o b l e m is t o m a k e o n e m o r e s t e p t o w a r d s s u b o r d i n a t -

i n g n a t u r e t o o u r n e e d s .

ATOMS IN WATER

T h e spr ings , rivers,1" seas, oceans a n d u n d e r g r o u n d wa te r s t o g e t h e r f o rm t h e c o n t i n u o u s w a t e r shell of t h e e a r t h , t h e so-cal led h y d r o s p h e r e . The sun c o n s t a n t l y e v a p o r a t e s w a t e r f r o m t h e vas t su r faces of t h e

oceans . In t h e a t m o s p h e r e t h e w a t e r condenses a n d falls on t h e e a r t h in the

fo rm of r a in , snow a n d ha i l . I t e rodes t h e soils, l ixiviates t h e m , b r e a k s u]) rocks, dissolves a mass of va r i ous subs t ances a n d ca r r i e s t h e m all b a c k in to t h e seas a n d oceans .

W a t e r , thus , r u n s its cycle m a n y mil l ions of t i m e s : o c e a n ^ a t m o s -p h e r e >ear th >ocean . A n d e a c h t i m e it ex t r ac t s n e w a m o u n t s of wa t e r - so lub l e subs tances f r o m t h e solid rocks of t h e e a r t h .

I t has been e s t i m a t e d t h a t all t h e r ivers of t he wor ld a n n u a l l y c a r r y f rom the su r face of t h e e a r t h a b o u t 3 , 0 0 0 mi l l ion tons of subs t ances dissolved by t h e m in to t he o c e a n . I n o t h e r words , every 25 t h o u s a n d years t he wa te r s des t roy a n d c a r r y a w a y f r o m t h e e a r t h a l ayer of rock n e a r l y o n e m e t r e th ick .

T h e w a t e r rea l ly does a lot of w o r k o n t h e e a r t h . W a t e r , whose f o r m u l a is H 2 0 , is o n e of t h e most a b u n d a n t sub -

s tances 011 e a r t h . T h e v o l u m e of w a t e r c o n t a i n e d in t he w o r l d o c e a n cons t i tu t e s

1,370 mi l l ion c u b i c k i l ome t r e s ! W a t e r has p l a y e d a n e n o r m o u s l y i m p o r t a n t p a r t in t h e h i s to ry

of t h e e a r t h a n d , c o n s e q u e n t l y , in g e o c h e m i s t r y . T h i s is w h y t h e geological sciences o n c e h a d a hypo thes i s t h a t al l

rocks o n e a r t h h a d o r i g i n a t e d i n a n a q u e o u s m e d i u m .

3 0 0

T h e a d h e r e n t s o f t h i s h y p o t h e s i s , t h e X e p u i n i s t s , n a m e d a l t e r N e p t u n e ,

t i i e m y t h o l o g i c a l g o d o f w a t e r , c o n t e s t e d t h e P l u t o n i s t s , w h o i n t h e i r

t u r n m a i n t a i n e d t h a t a l l r o c k s 011 t h e e a r t h a r o s e I r o m m o l t e n m a s s e s

w h i c h h a d p o u r e d t o t h e s u r l a c e I r o m t h e i n t e r i o r o l t h e u n d e r g r o u n d

k i n g d o m o f t h e g o d P l u t o .

T o d a y w e k n o w t h a t b o t h t h e s e f o r c e s , w a t e r a n d v o l c a n o e s , w e n -

i n v o l v e d i n t h e f o r m a t i o n o l t h e e a r t h ' s r o c k s .

T h e r e is h a r d l y a n y w a t e r i n n a t u r e t h a t d o e s n o t c o n t a i n c e r t a i n

a d m i x t u r e s o r s u b s t a n c e s d i s s o l v e d i n i t . I n o t h e r w o r d s , n a t u r e h a s

n o d i s t i l l e d w a t e r . E v e n r a i n w a t e r c o n t a i n s c a r b o n d i o x i d e , t r a c e s

o f n i t r i c a c i d , i o d i n e , c h l o r i n e a n d o t h e r c o m p o u n d s .

I t is v e r y h a r d , n o t t o s a v i m p o s s i b l e , t o o b t a i n c h e m i c a l l y p u n -

w a t e r . T h e g a s e s o f t h e a i r a n d t h e w a l l s o f t h e v e s s e l c o n t a i n i n g t h e

w a t e r d i s s o l v e i n i t , e v e n t h o u g h i n v e r y s m a l l q u a n t i t i e s . F o r e x a m p l e

S h a p o of MI<t\v flakes

Fantas t ic shapes of e r o d e d sed imen ta ry rocks. N e w Z e a l a n d

thousand millionths of a fraction of silver are dissolved in the water con-tained in the silver vessel. The silver of a tea-spoon dissolves in water in negligible amounts. A chemist can hardly notice these traces. But certain lower organisms, for example seaweeds, are so sensitive to traces of silver and to some other atoms in the water that they arc killed by them.

Natural water, while running through extraordinary diverse terres-trial rocks—sands, clays, limestones, granites, etc., certainly, extracts various compounds from them. Some scientists say that if we knew the bed of the river we could tell the composition of its water.

But despite the fact that alumosilicates, as we already know, arc abundant in nature, the waters do not, as a rule, contain large amounts of aluminium or silicon. If these metals arc present, they are there mainjy in the form of lees or in mechanical suspension. On the other hand, all the waters of rivers and seas always contain alkalis sodium, potassium, as well as magnesium, calcium and other elements. But what does all this mean?

3 0 2

I t a p p e a r s t h a t t h e c h e m i c a l c o m p o s i t i o n of t h e sa l t s d i s so lved i n w a t e r s d e p e n d s t o a g r e a t e x t e n t o n t h e d e g r e e of t h e i r s o l u b i l i t y i n w a t e r . T h e m o s t s o l u b l e c o m p o u n d s a r e t h e m o s t u s u a l c o n s t i t u e n t s of n a t u r a l w a t e r s . A s b e f o r e s t a t e d , t h e m a i n m a s s of t h e sa l t r e s i d u e of n a t u r a l w a t e r a l w a y s cons is t s of a t o m s of s o d i u m , p o t a s s i u m , c a l -c i u m , m a g n e s i u m , c h l o r i n e , b r o m i n e a n d s o m e o t h e r e l e m e n t s .

T h e s a l t - s a t u r a t e d w a t e r s , i .e . , b r i n e s , a l so c o n t a i n p r e c i s e l y t h e s e s o l u b l e c o m p o u n d s of a t o m s e r o d e d f r o m rocks .

T h e o c e a n is t h u s a s t o r e h o u s e o f s o l u b l e sa l t s w h i c h h a v e a c c u m u -l a t e d i n i t s i nce t h e e x i s t e n c e of t h e e a r t h as a r e s u l t o f t h e c o n t i n u o u s c i r c u l a t i o n of w a t e r b e t w e e n t h e c o n t i n e n t a n d t h e o c e a n .

Sc ien t i s t s a t t e m p t e d t o e s t i m a t e t h e a m o u n t of sa l t s a n n u a l l y c a r r i e d b y r ive r s i n t o t h e o c e a n s b y t h e a m o u n t s of t h e sal ts d i s so lved in t h e

o c e a n . O n th i s bas i s t h e y e s t i m a t e d t h e a g e of t h e o c e a n o r t h e n u m b e r of y e a r s r e q u i r e d f o r t h e w a t e r of t h e o c e a n t o a c q u i r e t h e c o n c e n -t r a t i o n of sal ts n o w o b s e r v e d . H o w -e v e r , t h e figures o b t a i n e d a r e n o t e x a c t .

T h u s t h e s o l u b l e c o m p o u n d s of a t o m s f o r m t h e bas i s of t h e sa l t c o n s t i t u e n t of n a t u r a l w a t e r s . T h e w a t e r of t h e o c e a n c o n t a i n s 3 .5 p e r c e n t sa l ts , o f w h i c h m o r e t h a n 8 0 p e r c e n t is s o d i u m c h l o r i d e , t h e wel l -k n o w n c o m m o n sa l t . E v e r y b o d y k n o w s t h a t i t d issolves v e r y eas i ly .

3<>3

N i a g a r a Fal ls in Amer ica

O n the coast of t he A z o v Sea

3°4

T h e other soluble compounds a rc found in the water in only very small quant i -ties. All chemical elements can be found in any natural water , i.e., seas and underground springs. It depends on how good our methods of research are.

If we remember there arc altogether about 100 chemical elements, we shall easily unders tand how the waters encountered in na ture differ in their composition. As a mat te r of fact, scientists have established the existence of numerous classes of water .

T h e waters of the ocean anywhere— on the surface and in the deep (but away from the coast)—arc very constant in composition and

Geyser in Yellowstone Park (U.S.A.)

contain the same quanti t ies of all chemical elements. River-waters are very similar in composition but less constant. T h e fact that the rivers flow in different rocks and under different climatic conditions leaves an imprint on their composition. Thus the rivers of the nor thern latitudes contain more iron and humus and are often even coloured by them. T h e rivers of the middle lati tudes contain mainly sodium, potassium, sulphates and chlorine. In the warmer latitudes, especially in regions where the water does not dra in into seas or oceans, river-water, and more frequently, lake-water, is salty.

A similar variation in the composition of water according to zones is observed also vertically for the ground waters. T h e deeper these waters run, the more they resemble brines. T h e waters whose com-position differs most arc precisely the mineral underground waters which not infrequently form mineral springs, often medicinal, as they come to the surface.

Here we can find waters containing calcium, iodine, bromine, radium, l i thium, iron, sulphur, magnesium, boron, etc.

T h e origin of these mineral waters is connected with the solution of the mineral deposits by underground waters, with the process of lixiviating rocks of different composition.

To divine the entire process by which these waters are formed by their chemical composition is an entertaining and, at the same time, a very impor tant scientific problem.

T h e following table shows the composition of sea-water (in per-centages) :

O x y g e n 86 .82 H y d r o g e n 10.72 C h l o r i n e 1.89 S o d i u m 1.056 M a g n e s i u m 0 . 1 4 S u l p h u r 0 . 0 8 8 C a l c i u m 0 . 0 4 P o t a s s i u m 0 . 0 4 B r o m i n e 0 . 0 0 6 C a r b o n 0 .002 S t r o n t i u m 0 .001 B o r o n .">.0004 F l u o r i n e n . o o o i S i l icon 0 . 0 0 0 0 5 R u b i d i u m 0 . 0 0 0 0 2 L i t h i u m 0 . 0 0 0 0 1 5 N i t r o g e n 0 . 0 0 0 0 1 I o d i n e 0 . 0 0 0 0 0 5 P h o s p h o r u s 0 . 0 0 0 0 0 5 Z i n c 0 . 0 0 0 0 0 5 B a r i u m 0 . 0 0 0 0 0 5 I r o n 0 . 0 0 0 0 0 5 C o p p e r 0 . 0 0 0 0 0 2 A r s e n i c 0 . 0 0 0 0 0 1 5

A l u m i n i u m . . . 0 . 0 0 0 0 0 1 1 L e a d 0 . 0 0 0 0 0 0 5 M a n g a n e s e . . . . 0 . 0 0 0 0 0 0 4 S e l e n i u m 0 . 0 0 0 0 0 0 4 Nicke l 0 . 0 0 0 0 0 0 3 T i n 0 . 0 0 0 0 0 0 3 C e s i u m 0 . 0 0 0 0 0 0 2 U r a n i u m . . . . . . 0 . 0 0 0 0 0 0 2 C o b a l t 0 . 0000001 M o l y b d e n u m . 0 . 0000001 T i t a n i u m 0 .0000001 C e r m a n i u m . . . 0 . 0000001 V a n a d i u m . . . . 0 . 0 0 0 0 0 0 0 5 G a l l i u m 0 . 0 0 0 0 0 0 0 5 T h o r i u m o.0000000*4 C e r i u m 0 . 0 0 0 0 0 0 0 3 Y t t r i u m . 0 . 0 0 0 0 0 0 0 3 L a n t h a n u m . . . 0 . 0 0 0 0 0 0 0 3 B i s m u t h 0 . 0 0 0 0 0 0 0 2 S c a n d i u m . . . . 0 . 0 0 0 0 0 0 0 0 4 M e r c u r y 0 . 0 0 0 0 0 0 0 0 3 Si lver 0 . 0 0 0 0 0 0 0 0 4 G o l d 0 . 0 0 0 0 0 0 0 0 0 4 R a d i u m 0 . 0 0 0 0 0 0 0 0 0 0 0 0 0 1

It will be seen from the table tha t sea-water contains 99.99 per cent by weight of the first fifteen chemical elements while the remaining 74 elements constitute about 0.01 per cent.

In absolute figures, however, this is not so little, because there are, for instance, millions of tons of gold in sea-water.

Scientists have made manv at tempts to build a physico-chemical factory which would make the extraction of gold from sea-water prof-itable. So far all their a t tempts have failed.

A concentration of bromine, iodine and, of course, chlorine, i.e., the chemical elements which are very impor tant to man, is charac-teristic of sea-water. T h e iodine contained in sea-water is consumed by the seaweeds and the mar ine animals. It is from seaweeds that m a n extracts the main mass of industrial iodine.

309 :s°r>

O n thc beach in Sukhumi (Abkhaz ian A .b .b .K . ;

When the seaweeds die, the iodine they contain goes over to the silt on the bottom of the sea. Rocks are gradually formed from the sea-silt. The waters are squeezed out of them and ground waters are formed. These ground waters take the iodine with them. Ground waters are often discovered in drilling for oil. They are rich in iodine and bromine. Man has now learned to extract these elements from them. Sea-water is an unlimited reservoir of bromine which is now extracted in a number ,of places directly from sea-water (like magne-sium).

The history of calcium atoms in natural waters is of particular interest because they are frequently supersaturated with ions of calcium and in these cases the latter precipitates as calcium carbonate and forms limestones or chalk.

Carbon dioxide plays a big part in the history of calcium. A surplus of carbon dioxide makes calcium dissolve while its insufficiency makes calcium carbonate precipitate from solutions. And if we recall that green plants consume carbon dioxide, we shall get a clear, picture of their role in the precipitation of calcium from water. As a matter of fact, enormous islands in the warm sea—atolls—are fully formed

3 0 6

Uhe Sprude l M i n e r a l Spring in K a r l o v y Vary (Ca r l sbad ) Czechos lovakia . The t e m p e r a t u r e of the wa te r is close to 75° C . ; t he spr ing spurts to a he igh t of 9 met res

of calcium carbonate deposited as a result of the vital activity of marine plants as well as from the lime skeletons of marine animals.

We wanted to show by this example that the composition of natural waters is considerably influenced by the living population of the reservoir.

Without the knowledge of how "living substance" influences the composition of water, it is impossible fully to understand how the waters of the rivers, lakes, seas and oceans have come to have their present-day composition.

311

ATOMS ON THE SURFACE OF THE EARTH. FROM THE ARCTIC TO THE SUBTROPICS

I r e m e m b e r t a k i n g a t r i p f r o m M o s c o w t o t h e S o u t h o f ( J r e e c e w h e n

I w a s s t i l l a b o v : m y c h i l d i s h m i n d h a s l o r e v e r r e t a i n e d t h e p i c t u r e

o f c h a n g i n g c o l o u r s w h i c h u n f o l d e d i t s e l f b e f o r e m e a s I m o v e d s o u t h -

w a r d .

It w a s a c l e a r d a v in M o s c o w b u t I s a w t h e g r e y m o n o t o n o u s e a r t h ,

g r e v - r e d , b r o w n c l a v s o f t h e R u s s i a n s c r o z c i n . T h i s w a s f o l l o w e d b v a

m o r e m o t l e v p i c t u r e ol c h e r n o z e m c o l o u r s i n t h e e n v i r o n s ol O d e s s a ,

i l l u m i n e d b v t h e b r i g h t rav.s o f t h e s p r i n g s o u t h e r n s u n . I r e m e m b e r

h o w t h e s e c o l o u r s c h a n g e d a s w e e n t e r e d t h e B o s p h o r u s : t h e b l u e ol

t h e w a t e r a n d t h e c h e s t n u t - b r o w n so i l s o f t h e v i n e y a r d s . 1 c a n s t i l l s e e

t h e l a n d s c a p e o f s o u t h e r n G r e e c e b e f o r e m e t h e d a r k - g r e e n c y p r e s s

t r e e s , t h e r e d so i l s a n d t h e r e d f i l m s of i r o n o x i d e s a m i d t h e s n o w - w h i t e

l i m e s t o n e s .

I r e m e m b e r t h e d e e p i m p r e s s i o n t h i s p i c t u r e o f c h a n g i n g c o l o u r s

h a d m a d e o n m e a n d h o w I i n s i s t e d t h a t m v f a t h e r e x p l a i n w h y t h e

c o l o u r s c h a n g e d a s t h e v d i d . I t w a s o n l y m a n y y e a r s l a t e r t h a t 1 u n d e r -

s t o o d 1 h a d w i t n e s s e d o n e o f t h e g r e a t e s t l a w s o f t h e e a r t h ' s s n r l a c e .

t h e l aw o f t h e o x i d a t i v e c h e m i c a l p r o c e s s e s w h i c h v a r y so m u c h a t t h e

d i f f e r e n t l a t i t u d e s o f t h e e a r t h .

S i n c e t h e n 1 h a v e c h a n c e d t o t r a v e l a g r e a t d e a l t h r o u g h t h e S o v i e t

U n i o n , f r o m t h e c o n t i n u o u s f o r e s t s o f t h e t a i g a , t h r o u g h t h e p l a i n s ,

t u n d r a s a n d p o l a r o c e a n s a l l t h c w a y t o t h e s n o w - c a p p e d s u m m i t s of

t h e " r o o f o f t h e w o r l d " t h e P a m i r s . A n d t h i s p i c t u r e of t h e v a r i o u s

c h e m i c a l r e a c t i o n s a n d t h e d i f f e r e n t f a t e s / o f t h e a t o m s o n t h e s u r f a c e

o f t h e e a r t h f r o m t h e d e e p e s t A r c t i c t o t h e h o t s u b t r o p i c s r o s e b e f o r e

m e e a c h t i m e b u t o n a n e v e r l a r g e r s c a l e .

31 >8

i . d g e of glacier in A la ska

Let us take a look at this small map and then travel along the arrow drawn on it from Spitsbergen in the North to Ceylon in the Indian Ocean.

Around old Svaldbard we find continuous ice; it is a dead ice desert. There are no chemical reactions; rocks do not break up into clays or sands; the action of frosts spreads inward and tremendous boulder-stones are formed. Only now and then, at the seashore colonies of birds, do remains of organic life accumulate and films of phosphates are nearly the only minerals amid the continuous ice.

The chemical reactions occur just as slowly on Kola Peninsula or in the Urals transpolar region. How fresh all the rocks on Kola Peninsula are! O n a cold morning you can observe the rocks through binoculars dozens of kilometres away as if you were viewing them in a museum. Thin films of brown iron oxides can be seen over vast spaces. Only in lowlands do peat bogs accumulate, the organic substance of plants burns slowly and is transformed into brown humic acids; the spring waters carry them away together with other soluble salts colouring the layers of jelly-like masses of the peat bogs and sapropels in lakes and marshes.

3°9

We can observe other chemical reactions farther south, in the vicinity of Moscow. Here, too, the combustion of organic matter is slow, the same stormy spring waters dissolve iron and aluminium, white and grey sands surround the environs of Moscow and bright spots of blue layers of phosphates gleam here and there in the vast peat bogs.

Further south the colours gradually change, the course of chemical reactions alters, and the atoms find themselves in new conditions. The

chernozems of the Middle Volga regions replace the grey argillaceous soils of Moscow. We see how the bright sun gradually modifies the surface of the earth, provoking ever stormier, ever more vigorous chemical processes.

As soon as we cross the Volga we encounter new natural reactions: we find ourselves in a vast salt zone which stretches from the borders of Rumania through Moldavia, along the slopes of the Northern Caucasus, runs through all of Central Asia, and ends on the Pacific Coast. Various salts of chlorine, bromine and iodine accumulate. Calcium, sodium and potassium are the metals of these salts in the firths and dying lakes, scores of thousands of which are scattered over the territory of this zone. Here we observe a complex process of sediment formation.

3 1 0

Still further south we find our-selves in the region of deserts. A new picture rises before ous eyes: enormous salines with their white fields gleam amid the green spots of the steppe vege-tation across which the Amu-Darya carries its chocolate-red waters. Bright colours denote new-chemical reactions, the atoms shift, and in the sands acquire a new chemical equilibrium. Some of them accumulate as sands which form deserts, others are dissolved, are transported by winds and stormy tropical rains, and precipitate in the salines and sors amid the deserts.

In the foothills of Tien Shan we see still brighter colours. Here stormy chemical reactions are encountered at every step, and the migration paths of the atom on the surface of the earth are very complex. I am

still impressed by those bright and variegated colours which struck my eye when I visited one of the remarkable deposits for the first time. In my book on the colours of stones I described this picture as follows:

"Bright blue and green films of copper compounds covered frag-ments of rocks now deepening into olive-green, velvety crusts of vana-dium minerals and now interlacing in azure and blue tones of hydrous silicates of copper.

"Numerous compounds of i ron -its oxide hydrates—lay before us in a motley scale of shades. There were yellow, golden ochres, bright-red hydrates with low water con-

G l a c i e r in Arct ic regions tent, brown-black combinations o(

An Arct ic l andscape . A geologis t with a dog t eam on Seve rnaya Zcn i lya

311

D e s e r t l andscape . Sand dunes in the K a r a K u m s ( T u r k m e n S.S.R.)

iron and manganese; even rock crystal acquires bright-red colours, transparent barite becomes yellow, brown and red 'ore bari te ' ; red needles of alaite-^free vanadic acid—are crystallized on the pink clayey sediments of caves, while bright green-red sheets of the newly-formed mineral grow on the white bones of the human skeleton."

The picture of the variegated bright colours is unforgettable, and the geochemist scrutinizes it in order to guess its cause. He sees, first of all, that all the compounds are highly oxidized and that these minerals are characterized by the highest degree of oxidation of manganese, iron, vanadium and copper. He knows that they owe this to the southern sun, the ionized air with its oxygen and ozone, the discharges of electric-ity during tropical thunderstorms, when nitrogen is transformed into nitric acid.

But the arrow leads us farther beyond the border of the sands. Climb-ing to an altitude of 4,000 metres we find ourselves in a desert again,

1 but this time, in a desert of ice; here we see neither the bright colours nor the migration of atoms we have just observed in the lowlands of Central Asia. Before us is nearly the same picture we saw on Novaya Zemlya and Spitsbergen. All around there are immense boulderstones of mechanical sediments; the fresh rocks hardly know any chemical

312

reactions, and only here and there amid the snows and ice we see afflorescences of solitary salts and accumulations of saltpetre.

This picture resembles the arctic wastes, and only rare thunder-storms remind us of life; they form electrical discharges in the air and create particles of nitric acid which precipitates in the form of saltpetre in the alpine deserts of the Pamirs and, in still greater cjuantitics, in Atacama Desert in Chile.

But let our arrow lead us further across the heights of the Himalayas, and we shall again sec the bright colours of the southern subtropics. Continuous warm rains are fol-lowed by a dry tropical summer, and most complex chemical reactions occur on the surface of the earth, transporting soluble salts and accumulating enormous layers of red sediments, ores of aluminium, manganese arid iron.

Further on, we run into the blood-red laterite soils of Bengal. Wild wind-spouts sometimes drive these soils skyward.

We now come to the chocolate-red colours of the soils of tropical India ; we see gleaming fragments of rocks heated by the sun and covered by a sort of semi-metallic lacquer; only here and there do we observe deposits of "ba ths" of white and pink salt interspersing this picture of the red soils of the Indian subtropics.

In the south of India, where the emerald-green waters of the Indian Ocean wash the red shores and the depths of the sea bring the breath of the volcanic eruptions of basalt, we observe an even livelier and wider picture of migrations of the atoms.

Complex chemical formations vary the picture of the sea-bottom at each step, beginning with the shallow waters near the coast with their shells, sea-mosses and corals, and ending with the deep waters with their coral reefs and immense accumulations of coral limestones.

3 i 3

In Cen t ra l T i e n Shan (Ki rgh iz S.iS.R.)

Subtropical landscape . Pa lm alley in the city of G a g r a on the Caucas ian coast

In the deep waters, in silt, where the remains of skeletons of organisms accumulate, phosphoric salts are formed in the shape of phosphorite nodules.

Radiolarians with their armour of silica brought by rivers construct their open-work shells, while Foraminifera consume barium and calcium in building their skeletons. Su.ch is the speed with which the atoms replace each other from the Arctic to the subtropics, and so great are the processes of migrations of the individual elements on the surface of the earth.

What causes this difference in the landscapes between the extreme north and the tropical south? Today we know it is the action of the solar rays, fading, an abundance of moisture, and the high temperatures of the earth. I t is also caused by stormily developing organic life, which

3 ' 4

W e a t h e r i n g of clay layers

requires tremendous amounts of various atoms. Large accumulations of the remains of living cells decompose in the hot southern sun into carbon dioxide, and the carbon dioxide saturates the water with its acid solutions.

The chemical reactions are many times as fast in the south; we geochemists very well know one of the principal rules of chemistry that in most cases the rate of the usual chemical reactions increases two-fold for every ten degrees rise in temperature.

And we begin to understand the immobility and rest of the atoms in the arctic wastes and the intricate paths of their migrations in the subtropics and the deserts of the south. We see that we can now talk about chemical geography, that nature with its diversity of'continents and countries is linked by strong ties to the chemical processes which take place all around.

Among the factors determining the course of geochemical processes, man himself acquires ever greater importance. In the last hundred years his vigorous activity has been connected with the middle latitudes and he is only gradually beginning to master the wastes of the Arctic and the sand deserts of the south. He brings along his own complex

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Myster ious s ta tues hewn f r o m volcanic rock; E a s t e r I s l and in the Pacific

chemical reactions and disturbs the natural processes, provoking new movements and migrations of the atoms he needs. T h e new chemical geography was outlined a long time ago when the principles of the soil science were laid down; this science was born in Russia and its fu ture is bound up w i th the fate of the fer-tility of the fields.

And we recall how in the eighties of last century in a small lecture hall at Petersburg University V. Dokuchayev, the famous "father of soil studies," painted in his lec-tures fascinating pictures of a new science by pointing out the soil zones which cover the earth from the polar tundras to the southern desert.

At that time his wonderful construction could not yet be translated into the language of chemistry. But now, when chemistry has powerfully invaded the field of geological science, when agrochemists have begun to control the life of plants and the reactions which occur in the soil, when the investigations of geochemists embrace all spheres of atomic migrations, we begin to understand the intricate path travelled by each atom in the different latitudes of our earth.

At the same time, the past teaches us that these latitudes changed. The life of our earth's crust has varied over a period of nearly 2,000 million years, the location of the poles altered, mountain ranges at first raised their snow-capped summits only in the polar countries, but folding gradually shifted southward, forming such ranges as the Alps and the Himalayas. Large seas engirding the earth also shifted from north to south ; zones changed and with them changed the landscapes. In each place the seas were repeatedly replaced by mountains, the moun-tains by deserts and by seas again.

The course of the chemical reactions and migrations of individual atoms, thus, changed in the long geological history of the earth, and the

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soils and superficial layers at each given point of the earth are only a reflection of the chemical fates suffered by the atoms in the long periods of the diverse history of the earth.

Today we know that every-thing lives, that everything is fluid, that everything changes in time and space, and that the most mobile thing in na-ture in constant quest of new paths is the atom, the pri-mordial brick of which the re-markable structures of the world are made, the atom which eternally seeks rest and equilibrium and obeys the principal laws of the natural processes.

I t seeks rest, but does not and never will find it, because in nature there is no rest, there is only eternal matter in eternal motion. . . .

Figu re of B u d d h a J2 me t r e s high hewn f r o m sands tone . A f g h a n i s t a n

ATOMS IN THE LIVING CELL

We can see with the naked eye that coal is formed from remains of plants. The shells of the fossils of marine molluscs not infrequently form layers of limestones.

But if we examine limestones, chalk, diatomite and many other so-called sedimentary rocks under the microscope, we shall see that they consist completely of the remains of skeletons of microscopic organ-isms.

In a word, geology has long since recognized the enormous part played by the organisms inhabiting the earth in all the processes which occur in the earth's surface.

Living substance takes a more or less active part in such geochemical processes as the formation of rocks, concentration and dispersion of separate chemical elements, precipitation of substances from water, and formation of limestones from lime skeletons of organisms.

But by far not all marine organisms have lime skeletons. Some of them, for example sponges, have silicious skeletons.

Even more essential, however, is the fact that in the process of life all organisms of the earth, plants and animals, extract, consume or devour and again liberate enormous masses of various substances and pass these substances, as it were, through themselves.

This process is especially rapid in the minutest organisms: bacteria, simplest seaweeds, and other lower organisms. It is connected with the enormous rate of their reproduction. They divide every five to ten minutes but do not live long.

Estimates show that this process of cell division involves many thou-sands of times the amounts of substance that is contained at each given

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moment in all the organisms of the earth, plants and animals, or, as we say, in all the living substance of the planet.

I t will be remembered that in the light, green plants liberate oxygen from their leaves and absorb carbon dioxide. The oxygen of the air, thus formed, oxidizes the plant remains and some rocks, and is consumed by animals during respiration.

In plants, carbon dioxide is transformed into carbohydrates, proteins, and other compounds. Imagine for a moment what would happen if all organisms disappeared from the surface of the earth, from the seas and oceans, from the plains and mountains.

The oxygen would be combined with organic substance and would vanish from the atmosphere. The composition of the latter would change. There would be no more microscopic marine organisms with lime skeletons and, consequently, no more layers of limestone and chalk would be formed, and chalk mountains would no longer rise. The face of the earth would change completely.

The geochemical activity of organisms varies extraordinary. Different organisms may take part in the most diverse processes.

In order to ascertain what geochemical part organisms play, we must first of all know their chemical composition. Organisms build their bodies entirely from the substances they, in some way or other, extract from their environ-ment—from water, soil and air.

It has long since been estab-lished that water —HzO—is the chief constituent of all organisms, that the latter contain an average of about 80 per cent of it and that the plants have a little more water than the animals.

Consequently, oxygen consti-tutes the greater part of the organisms by mass.

Carbon plays an uncommonly important part in the structure of the bodies of organisms. I t forms many thousands of various G e n e r a l view ot ooli t ic m a n g a n e s e ore

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The organisms hkemefrom

carbon dioxide

compounds with hydrogen, oxygen, nitrogen, sulphur and phosphorus which in their turn build the proteins, fats, carbohydrates and the bodies of organisms.

Carbon dioxide is the main source of these carbon compounds in living substance. The organisms, furthermore, contain considerable amounts of nitrogen, phosphorus and sulphur in the form of complex organic compounds.

Finally, the organisms always* contain calcium, especially in their skeletons, potassium, iron and other chemical elements.

At first it was believed that the ten or twelve elements found in the organisms in greater quantities were of exceptional importance to all organisms.

It turned out later that there were organisms which in addition to the most frequently encountered ten or twelve chemical elements concentrated now iron, now manganese, now barium, now strontium and now vanadium, as well as many other rare chemical elements. It has thus been found, for example, that silicon plays an important part in the life of flint sponges, microscopic radiolarians and diatomite seaweeds whose skeletons are loaned from silicon oxide.

Iron bacteria concentrate iron in their bodies. Bacteria, which simi-larly concentrate manganese and sulphur, have also been discov-ered.

Barium and strontium have been found instead of calcium in the skeletons of some marine organisms.

Certain organisms, for example marine invertebrate tunicates, extract and accumulate atoms of vanadium from sea-water and sea-silt which contain only negligible traces of this element.

After the death of these organisms, vanadium concentrates in marine sediments.

Microscopic pic ture of the s t ructure of oolitic m a n g a n e s e ores. P h o t o g r a p h e d in ref lected l ight

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Other organisms as, for ex-ample, seaweeds, extract from sea-water the iodine which the latter contains in only mil-lionths of one percent . The io-dine is then deposited with the remains of the seaweeds on the sea bottom. Iodine-containing mineral waters are later formed in the rock composed of these deposits. We extract iodine from ground waters by drilling-deep into the rock where there was once the sea.

The geochemical role of these concentrator-orga nisms is enormous.

The more perfect the techniques of investigating the composition of organisms, the greater the number of chemical elements we find in them, even if in very small quantities, to be sure.

At first it was even assumed that the silver, rubidium, cadmium and other chemical elements found in organisms were only accidental im-purities, but it has now been firmly established that the organisms contain practically all the chemical elements. The only question is, how much of these elements the different organisms contain. I t is precisely this question that occupies the scientists' minds today.

We can say beforehand that the composition of the organisms does not in any way reiterate the composition of their environment—the rocks, waters and gases put together.

For example, the soils and rocks contain considerable amounts of titanium, thorium, barium and other chemical elements, but we find many thousands of times as little t i tanium in the organisms as we do in the soils, etc.

On the other hand, the soils and waters contain little carbon, phospho-rus, potassium and other chemical elements which accumulate in or-ganisms in much greater quantities.

From the geochemical point of view it has now become clear that the main mass of the body of organisms is built of the chemical elements,

A m m o n i t e shell tha t has changcd into mar-casi tc (FeS 2) minera l . E n v i r o n s of the city of U lyanovsk on the Vo lga

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which under the conditions of the earth's surlace, i.e., the biosphere (the region where the organisms live on our planet) form mobile com-pounds or gases. In point of fact, C 0 2 , N2, O., and H , 0 are all mobile gases or liquids accessible to the organisms in the process of their life.

Iodine, potassium, calcium, phosphorus, sulphur, silicon and many others easily form water-soluble compounds.

But then titanium, barium, zirconium and thorium do not form water-soluble and, consequently, easily shifting compounds in the bio-sphere though they are found in the soils and rocks in sufficient quanti-ties. They are less accessible or entirely inaccessible to organisms which do not accumulate them but contain them in unproportionallv small amounts.

The organisms also contain very little of the chemical elements of which there is not enough in the biosphere, for example, radium and lithium.

The chemical elements found in organisms in very small quantities, about hundredths of one per cent and less, are often called microelements.

It has now been recognized that the microelements play a very important physiological role. Many microelements form part of physiolog-ically important substances of organisms: for instance, iron is a con-stituent of the haemoglobin of the blood, iodine forms part of the hormone of the thyroid gland of animals, and copper and zinc are components of animal and plant ferments.

We could draw up a map of the anatomical structure of organisms indicating the organs and tissues in which the chemical elements are concentrated. But we arc now concerned only with the geochemical role of the organisms.

We must agree that various organisms discharge different geochemi-cal functions depending on their ability to concentrate particular chemi-cal elements or, in other words, depending on their chemical-element composition.

"Calc ium" organisms from whose skeletons limestones are formed also participate in the geochemical history of calcium in the bio-sphere; the organisms that concentrate silicon, vanadium and iodine play an important part in the history of these atoms.

We are facing the problem of studying the influence of organisms on the geochemical history ol various atoms in the biosphere, of estimating this influence and of utilizing it.

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M I C R O E L E M E N T S

It is already possible to find deposits of metals by observing the nature of the vegetation in a given place and by finding the plants known as the concentrators of these metals. An ore lying under a soil cannot help pollut-ing the soil. The content of nickel, cobalt, copper and zinc increases in such soil and, consequently, also increases in plants.

We now, therefore, analyze the content of these elements in plants. If the content is high, we dig ditches and bore holes. It is in this manner that some zinc, nickel, molybdenum and other deposits were discovered.

Organisms-—plants and ani-mals - have grown "accustomed" to certain concentrations of par-ticular chemical elements in the environment, i.e., in the waters, soils and rocks. Wherever there hap-pens to be lessor, on the contrary, more of them, the organisms respond by a change in form and growth. Iodine deficiency in the soils, waters and foods in some mountainous regions is responsible for endemic goitre in man and animals, while calcium deficiency causes the bones to be brittle, etc.

All this shows the close interdependence between the so-called dead nature and living substance.

They are connected by the common history of the atoms of the'chemi-cal elements.

The better and more extensively we know the history of the migration of chemical elements atoms—on earth, the clearer and more precisely will we know the geochemical activity of living organisms and for this we must know, first of all, their quantitative chemical-element compo-sition.

M a n is m a d e of the same chemical ele ments as inorganic na tu r e

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ATOMS IN THE HISTORY OF MANKIND

I n t r a c i n g the h is tory of t h e d i scovery of t h e c h e m i c a l e l emen t s , w e r u n in to s t r a n g e a n d su rp r i s ing th ings . M a n l e a r n e d a b o u t t h e first e l e m e n t s in pass ing, w i t h o u t t h i n k i n g of t h e m , w i t h o u t e v e n suspec t ing t h a t h e h a d m a s t e r e d s o m e t h i n g w h i c h to a keen m i n d w o u l d r evea l t h e m o s t i m p o r t a n t secrets of n a t u r e . T h e i dea a c q u i r e d in p r a c t i c e t h a t s imp le subs tances lie a t t h e basis of t h e s t r u c t u r e of al l m a t t e r p e n e t r a t e d i n t o m a n ' s consciousness slowly a n d w i t h g r e a t d i f f icu l ty .

A lchemis t s d id n o t k n o w a n y m e t h o d s for d i s t i ngu i sh ing a s i m p l e b o d y f r o m a c o m p l e x b o d y , b u t they k n e w me ta l s a n d c e r t a i n subs tances , for e x a m p l e , a r sen ic a n d a n t i m o n y . T h e he igh t s of a l c h e m i c a l w i s d o m a r e set fo r th in t he fo l lowing n o t e of a n a l c h e m i s t :

L i k e t h e p l a n e t s u p in h e a v e n , M e t a l s a lso n u m b e r ' s e v e n ; C o p p e r , i r on , s i lver , g o l d , T i n a n d l e a d , t o s m e l t a n d m o u l d C o s m o s g a v e u s ; l i s ten f u r t h e r : F i e r y s u l p h u r w a s the i r f a t h e r . A n d t h e i r m o t h e r — m c r c u r y ; T h a t , m y son , is k n o w n to m e !

For some t i m e the a lchemis t s , a n d l a t e r also chemis ts , cal led t h e m e t a l s by t he n a m e s of p l a n e t s : g o l d — S u n , s i l v e r — M o o n , q u i c k s i l v e r — M e r -cury , c o p p e r — V e n u s , i r o n - M a r s , t i n — J u p i t e r , l e a d — S a t u r n . Arsen ic a n d a n t i m o n y w e r e no t cons ide red meta l s , t h o u g h t he i r p r o p e r t i e s to o x i d a t e a n d s u b l i m a t e w h e n h e a t e d w e r e v e r y wel l k n o w n .

R e g r e t t a b l y t h e a lchemis t s o f t en c a m o u f l a g e d the i r r ec ipes b y in-c o n g r u o u s a n d some t imes h a r d l y u n d e r s t a n d a b l e al legories .

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Chemica l l a b o r a t o r y in the 18th century. T h e tab le b e l o w shows the convent iona l symbols used by scientists of t ha t t ime to des igna te va r ious chemical e lements . T h e top symbol in the first column s tands fo r a c i d ; the symbol a t t he bo t tom ef the s e tond column signifies gold , ctc.

Here, for example, we have the "philosophical hancl of alchemists." In the palm of the hand you see a fish—symbol of mercury, and fire— symbol of sulphur. A fish in fire — mercury in sulphur—was, according to the alchemists, the primary source of all types of substance.

The five main salts sprang from the combination of these elements like the fingers grew out of the hand ; the symbols of these elements are at the fingertips: the crown and moon were the symbols of saltpetre; the six-pointed star represented iron vitriol ; the sun signified ammonium chloride; the lantern indicated a lum; the key stood for common salt.

I t is now clear that when the alchemist wrote: "When you take the king you must boil h i m . . . " he meant saltpetre, and when he put a "pound of the long finger" into his retort, he was thinking of ammonium chloride.

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The alchemists also knew each metal had its respective "ea r th" or " l ime" and were able to extract these "limes" (or as we now say "ox-ides") from all metals by means of acids. But they thought these "limes" were the simpler bodies, while the metals were compounds of "limes" with "phlogiston," a special volatile fire-princ.iple.

It required the genius and industry of Lomonosov and Lavoisier to prove that it was, contrariwise, "mercurial l ime" that was a complex body consisting of mercury and oxygen, the gas just discovered by Priestley, and that the weight of this gas exactly equalled the addition in weight of the "mercurial ear th ." The time of this discovery (1763-75) is rightfully considered the beginning of modern chemistry and of the collapse of the alchemical fantasies which had long impeded the scientific study of nature.

Several dozen elements were already known by this time: Brandt discovered phosphorus as early as 1669, while cobalt and nickel were discovered in the middle of the 18th century, and man learned to pro-duce zinc from the "zinc ear th." Finally, in America in 1748, Antonio Ulloa described a new metal, which looked like .silver and which turned out to be platinum.

But a real revision of all "simple" bodies began only in the last quarter of the 18th century and in the beginning of the 19th century. Oxygen and chlorine were discovered in 1774, while in hydrolyzing water by the current of galvanic cells ten years later Cavendish discovered hydrogen and ascertained the composition of water.

The subsequent discoveries of elements proceeded regularly: new natural bodies were broken up into their constituents. New elements were found in a number of cases. Manganese, molybdenum, tungsten, uranium, zirconium and other elements were discovered in this manner .

In 1808, Davy perfected electrolysis which showed its potentialities in the hands of the Russian scicruist Yakoby who boosted the current

Chemical utensils n u d e of t an t a lum. I t is as d u r a b l e as p la t inum and cheaper

and learnt to protect the electrolysis products from oxidation by means of kerosene and mineral oils. It was thus that the alkali metals were obtained in the pure state; potas-sium, sodium, calcium, magnesium, barium and strontium were thus discovered. Fourteen elements were

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1775

discovered in the fourteen years, between 1804 and 1818 (iodine, cadmium, selenium and lithium were discovered in addition to those we have already men-tioned). These were followed by bromine, aluminium, thorium. vanadium and ruthenium. Then came a break; the old methods had already exhausted their potentialities and new methods were required.

Only when spectral analysis was discovered in 1859, did the scientists find new elements; these were elements closely related in properties to those formerly studied and could not be distinguished from them by the old scientific methods. The elements discovered were: rubidium, cesium, thallium, indium, erbium, terbium and some others. When D. Mendeleyev discovered his famous law in 1868 he already knew 60 elements.

From then on science knew of the existence of particular elements. It turned out that each element had its own place in the Periodic

Table and that the total number of all elements was limited, while the vacant boxes represented the as yet undiscovered elements.

Mendeleyev predicted the principal chemical and physical properties of three of them—eka-aluminium (box No. 31), ekasilic.on iboxNo. 32) and ekaboron (boxNo. 21). His prediction was brilliantly confirmed when these elements were discovered. Ekaboron was named scandium, eka-aluminium was given the name of gallium and ekasilicon was called germanium.

You must not think, however, that man learned about the elements frequently encountered in the earth's crust first and about the rare ones later. Nothing of the sort. For example, there is very little gold, copper and tin in the earth's crust, but at the same time these were the first metals man had learned about and used for various purposes. Moreover, the earth's crust contains an average of several millionths of one per cent tin, a few ten-thousandths of one per cent copper and only one or two ten-millionths of one per cent gold.

/he first metals man has ever

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Furnacc fo r smel t ing tungsten ores

T h e mos t a b u n d a n t e l emen t s in t h e e a r t h ' s c rus t as, for e x a m p l e , a l u m i n i u m w h i c h cons t i tu tes 7.5 p e r c e n t of it w e r e d i scovered v e r y la te . A l u m i n i u m was still cons ide r ed a r a r e m e t a l as r ecen t ly as t h e b e g i n n i n g of t he 2 0 t h c e n t u r y .

T h e r eason is t h a t it all d e p e n d s u p o n h o w easily t h e m e t a l is f o r m e d in its n a t i v e s ta te a n d h o w f r e q u e n t l y a c c u m u l a t i o n s in w h i c h this m e t a l d o m i n a t e s , i .e., so-cal led " d e p o s i t s , " a r e e n c o u n t e r e d .

I t was t h e t e n d e n c y of t h e m e t a l s to a c c u m u l a t e in o n e p lace , t h a t fac i l i ta ted t he i r d i scovery a n d u t i l i za t ion for t he needs of m a n .

As e a c h n e w e l e m e n t is d i scovered chemis t s a r e t h e first t o b e g i n s t u d y i n g its p r o p e r t i e s in t h e l a b o r a t o r y . T h i s is, so t o s p e a k , t h e first a c q u a i n t a n c e . A t this t i m e chemis t s look for t h e pecul ia r i t i es of t h e e lements , for its d i s t inguish ing , o r ig ina l f ea tu res .

I s n ' t it cur ious , for e x a m p l e , t h a t t h e specific g r av i ty of l i t h i u m is 0.53, so t h a t this m e t a l floats even in b e n z i n e ? O s m i u m , on t h e o t h e r h a n d , has a specif ic g r av i ty of 22.5, so t h a t it is 40 t imes as h e a v y as l i t h i u m . Is it n o t s t r a n g e t h a t g a l l i u m mel t s a t on ly 30° C. , b u t t h a t i t c a n h a r d l y b e b r o u g h t t o boi l ing , b e c a u s e it boils a t 2 ,300° C . a n d this is well b e y o n d t h e h i g h t e m p e r a t u r e s o r d i n a r i l y used in e n g i n e e r i n g ? " W h a t is so cu r ious o r s t r a n g e a b o u t i t ? " y o u will ask. L e t m e t ry a n d tell you .

I shal l tell y o u a b o u t g a l l i u m first. W h e n eng inee r s a n d chemis t s use h igh t e m p e r a t u r e s in l a b o r a t o r i e s a n d a t fac tor ies , t h e y a lways w a n t to k n o w t h e t e m p e r a t u r e to w h i c h t h e m a t e r i a l or t h e a r t i c le a r e h e a t e d . O f course , t h e y m u s t m e a s u r e t h e t e m p e r a t u r e , first of all . But t he t r o u b l e is t h a t t e m p e r a t u r e is easily m e a s u r e d on ly u p to 360° C . ; it is m u c h h a r d e r t o m e a s u r e h i g h e r t e m p e r a t u r e s b e c a u s e m e r c u r y boils a t 360° C. a n d m e r c u r y t h e r m o m e t e r s j u s t w o n ' t do . B u t h e r e w e h a v e g a l l i u m , w h i c h will do . I f w e t a k e r e f r a c t o r y qua r t z -g l a s s a n d fill t he t h e r m o m e t e r w i t h m o l t e n g a l l i u m , we c a n m e a s u r e a t e m p e r a t u r e of nea r ly 1,700° C. , a n d g a l l i u m d o e s n ' t even feel like bo i l ing . If w e find m o r e r e f r a c t o r y glass, w e shal l b e a b l e to m e a s u r e t e m p e r a t u r e s of u p to 2,000° C .

N o w a b o u t we igh t . W e i g h t is t h e force wi th w h i c h a b o d y is a t t r a c t e d to t he e a r t h . W e i g h t resists m o t i o n , speed a n d ascen t to u n k n o w n he ights . But m a n w a n t s to m o v e fast a l o n g the e a r t h a n d to fly in t h e a i r like a b i rd . F o r this w e m u s t c o n q u e r g rav i ty , a n d m a n searches for l ight a n d s t rong s t ruc tu res , for l ight a n d s t rong m a t e r i a l s . T w o m e t a l s h a v e

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1500°

proved especially suitable: aluminium with a specific gravity of 2.7 and magnesium, whose specific gravity is only 1.74.

Most of the parts of a modern plane are made of aluminium or, to be exact, from its alloys with copper, zinc, magnesium and other metals. However, aluminium has not won its dominating position all at once, but in a stubborn struggle for the improvement of its qualities: strength, hardness, resilience, and resistance to fire and oxidizers. When the difficulties of obtaining metallic aluminium were overcome, it conquered the kitchen first. Light and clean unoxidizable pots and pans, spoons and cups used up its first reserves. In the beginning engineering had made no use of i t ; it seemed this soft, not particularly strong, non-soldering and fusible metal could not be good for anything else. Alumin-ium conquered the world only when duraluminium, a hard alloy was produced by "kitchen methods." Various metals were added to aluminium in the crucible one after another, and each new alloy was tested for strength and other qualities.

Moscow. K r y m s k y Br idge bui l t of du ra lumin

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Nobody could understand at that time why four per cent copper, 0.5 per cent magnesium and insignificant admixtures of other metals changed the soft and pliable aluminium into duraluminium, a strone metal capable of being tempered like steel. The remarkable properties of duraluminium do not manifest themselves at once, and this consider-ably facilitates and simplifies its machining. After tempering duralumin-ium remains soft for a few more days. During this time it "gathers strength" while the copper particles, which form the skeleton of dur-aluminium, shift within the alloy. But there are other alloys which are in some respects even better than duraluminium. Such, for example, is the Russian kolchugaluminium which is stronger than duraluminium.

The production of duraluminium and other light alloys is of tremen-dous importance to all types of transport. Cars of the underground railway or tramcars built of aluminium weigh one-third less than those made of steel. In the steel trarncar there are 400 kilograms of dead weight per passenger place, but with the metal parts of the t ram manu-factured from aluminium the weight per passenger place is reduced to 280 kilograms.

A few words must here be said about magnesium. The history of this metal is very curious; 'we can say it was discovered twice. It was dis-covered for the first time by Davy and since then it had been considered one of the most useless metals for over 100 years. It was used only for Christmas tree pyrotechnics in the form of ribbons and powder. But in the 20th century it was found that this " toy" metal possessed such remarkable properties that its utilization might cause a veritable revo-lution in various branches of engineering.

Aluminium has given man real wings. But it is not enough for man just to fly; he must fly as far as possible. And if the weight of the metal of which the plane is built is reduced by, say, 20 per cent it means an extra ton of fuel and, consequently, additional thousands of kilometres in the air. But where can we find a lighter metal than aluminium?

This is when man remembered magnesium because of its specific gravity of 1.74, i.e., 35 per cent lower than that of aluminium. Magne-sium, however, does not have the qualities required for a structural metal, i.e., it is not strong enough and does not resist oxidation; it reacts even with boiling water, it deprives the latter of its oxygen and is transformed into a white powder magnesium oxide. In the air it burns better than wood. Designers and chemists did not lose heart, however,

3 3

for they knew that alloys were the thing that would help them find the metal with the requisite properties. As a matter of fact, it has turned out that the slightest additions of copper, a luminium and zinc rob magnesium of its combustibility and impart to it the strength of duraluminium. All the alloys con-taining over 40 per cent magnesium are called "electrons." In addition to magnesium, the electrons include aluminium, zinc, manganese and copper.

And now in the 2 0 t h century magnesium was discovered for the second time and it immediately won a permanent place as an aircraft-building metal. It is especially widely used in aircraft engines. Their parts made of magnesium alloys are very strong and tireless.

Do metals ever tire? Unfortunately, they do. By contracting and expanding hundreds of thousands of times a steel spring loses its re-siliency, becomes brittle and breaks - it "tires." In "aging" the shaft of a motor cracks. Engineering has discovered that some alloys are "tire-less"; in these alloys the atoms of the different metals fit each other so well that despite all the shocks they get they never come apart. Such are the magnesium alloys. Naturally, it is not only aircraft-building where magnesium can be utilized. It is also widely used in automobile-building. Machine-tools arid machine parts made of magnesium alloys are notably strong and light; they are from five to six times as light as the same things made of steel and arc as strong, and sometimes even stronger.

Magnesium is a very abundant metal in the earth's crust and is found everywhere. Like iron it easily accumulates in large quantities and is not hard to mine. Considerable amounts of it are contained in sea-water and in salt-lakes, for instance, in the Sivash waters off the Crimean coast.

The principal magnesium ore is carnallite ( K C l ' M g C l 2 ' 6 H 2 0 ) , and the Soviet Union has plenty of it. In the Solikamsk deposits large reserves of it lie in layers 100 to 200 metres deep. In mines carnallite is blasted by ammonal , cut and then brought to the surface.

l"urnacc for p roduc t ion of metal l ic m o l y b d e n u m

33'

On the surface it takes a lot of work to separate the magnesium from the chlorine with which it is very closely bound. For this purpose carnallite must be melted and direct current passed through it. The electricity breaks the bonds between the magnesium and chlorine, and the white metal runs in lively streamlets into the moulds.

The time has now come for magnesium to be extracted from seawater which contains 3.5 per cent salts <vml of which magnesium constitutes one-tenth. One cubic metre of sea-water, thus, contains 3.5 kg.' of metallic magnesium.

The extraction of magnesium is very simple: filtered sea-water is poured into reservoirs and slacked lime is added with the result that magnesium hydroxide precipitates in the form of lees; the water is then poured off. The precipitate is dried on filters, neutral-ized by hydrochloric acid and completely dehydrated. The magnesium chloride pbtained is electrolyzed in a molten state at approximately 700° C., like carnallite. This is all there is to the process.

But magnesium is not only a structural metal. Engineering has not forgotten its ability to burn and develop an enormous temperature of up to 3,500° C. Magnesium is an important constituent of special bronzes, while magnesium and aluminium dust forms the most powerful mixture for incendiary bombs. Industry needs a lot of magnesium and the latter has a brilliant future.

But let us come back to aircraft. There is one more "flying" metal, and aircraft-builders are only just beginning to make use of it. This metal is beryllium. It has a specific gravity of 1.84, but it is stabler and "stronger" than magnesium.

Beryllium alloys excel all the alloys used in aircraft-building until now. Tools made of these alloys work noiselessly and produce no sparks.

Beryllium enhances the qualities of magnesium alloys and makes them particularly strong and unoxidizable. A very slight addition of beryllium to magnesium does away with the necessity of protecting metallic magnesium against oxidation during teeming.

332

Tes t ing tungsten contacts in a special l abo ra to ry

But the question arises: aren ' t there any still lighter alloys? Let us recall the metal known as lithium. Its specific gravity is 0.53,

i.e., like that of cork, but added to aluminium and magnesium alloys in small amounts it makes them especially hard.

It is a matter of regret that no stable alloys with a large amount of lithium have been found as yet. But they are worth looking for be-cause lithium is an abundant metal; there is as much of it in the earth's crust as there is zinc, and it occurs in large quantities in certain deposits in the form of spoduinene minerals and in lithium micas.

Hence, if the alloys of lithium and beryllium, for instance, were found suitable lithium could be procured in sufficient quantities. The studies of lithium alloys have not brought any constructive results as yet, and these alloys still constitute an important problem of the day.

Lithium is found in mineral waters and physicians ascribe especially curative properties to lithium-rich waters (as, for example, the Vichy waters in France). But the prospects for obtaining a light, durable and non-oxidizable metal for aircraft are still the most tempting.

However, the light metals and alloys arc still far from having replaced the ferrous metals iron, steel and their alloys—in the .transport and in many other branches of industry. We shall now say a few words about these "old-timers" who are still hale and hearty, however, and who produce ever new alloys of excellent quality.

O c e a n l iner with hull bu i l t of m o l y b d e n u m steel

i I am also a "flying" \

' metal! J

If we take into account all the complex, so-called alloyed steels, we shall see that they consist of a series of closely related metals-—iron, titanium, nickel, cobalt, chromium, vanadium, manganese, molybde-num and tungsten. All these alloys are basically "steels," i.e., they consist of carbonaceous iron whose qualities have been essentially improved by "alloying" or by the addition of a rare metal.

By successively replacing larger and larger parts of the iron with rare metals technologists have produced alloys which no longer contain any iron. Such, for instance, is stellite which consists of tungsten, chromium and cobalt. This alloy is the father of the now well-known superhard alloys which have given engineering the unprecedented metal-cutting speeds, first, of 70 to 80 and now of hundreds of metres per minute.

Tungsten has given rise to superhard alloys and the powerful technique of metal-cutting. Tungsten and molybdenum have produced hundreds of new grades of uncommonly strong, fireproof, armour, spring, shell, armour-piercing and other steels.

There is scarcely a branch of engineering that has not undergone any-radical changes connected with the discovery of the properties of such rare metals as tungsten, molybdenum, etc.

Climax, m o l y b d e n u m deposi t s in the Rocky Moun ta in s . H e r e layers of molyb-denum a re depos i t ed in grani tes . R i g h t - c o n c e n t r a t i o n fac tory

334

I also have aff real future in aviation/

Incidentally, they have already outlived the term "rare . " If we consider their content in the earth's crust we shall find there is twice as much molybdenum and seven times as much tungsten as there is lead in it. Then why call them rare? In industry they are also becoming common, while their output is increasingly growing and is catching up with that of the usual "non-rare" metals.

Steel alloys containing molybdenum are used for the manufacture of gun barrels and gun-carriages. Manganese-molybdenum steel is used in armour and in armour-piercing shells.

Automobile and aircraft designers make three basic demands on metal: maximum resilience, great viscosity and high resistance to pro-tracted shaking and frequent shocks. Increased molybdenum con-sumption in recent years, especially in combination with chromium and nickel, is due precisely to its extensive use in shafts, connecting rods, support machinery, aircraft engines and pipes.

High-quality grey cast iron is another form of molybdenum consumption. A negligible addition of 0.25 per cent molybdenum enhances the physical properties of the cast iron, particularly, its resistance to bending and tension, as well as its hardness.

Considerable amounts of tungsten and molybdenum are used by electrical engineering in the form of thin wires in vacuum valves. Electric bulb filaments are made of tungsten. Tungsten melts at 3,350° C. which is the highest melting point among the metals. Carbon is the only element that melts at a still higher temperature, i.e., 3,500° C. Two elements have melting points very close to that of tungsten: tantalum—3,030° C. and rhenium- 3,160° C, The little anchors that hold the incandescent tungsten filaments in electric bulbs are made of molybdenum whose melting temperature is 2,600° C.

Thus we can see that it is not enough to discover an element; we must study it and find the quality in it that is particularly valuable for manufacture; the element is then discovered for the second time, as it were, and it becomes useful and necessary. Take, for example, the tung-sten contacts in automobile motors where a tungsten plate o. 1 milli-metre thick ensures the electric contact in the interrupter and works faultlessly for hundreds of hours.

Isn't the example of niobium instructive? Niobium was considered a useless element that "polluted" tantalum together with which it is ustlally found. When it was discovered, however, that steel with an

3 3 5

N i o b i u m in watch case

admixture of niobium was an excellent material to be used in electric welding of steel, because it produced an unusually strong seam, niobium became as necessary as tantalum.

There is no end to the intro-duction of ever new elements into industry, nor will there ever be, because technical progress is

unlimited. Both chemists and geochemists play an honourable part in it.

But how does technical progress affect the earth which provides all the substances required by engineering? M a n strives to reshape the earth's crust in his own way taking all he wants from it and paying no heed to the fact that whatever he takes is irreplaceable. Isn't man exhausting the earth?

These are the questions that occur to us when we watch the general development of mankind. There is one more circumstance that impels us to pose this question and that is the ever increasing amounts of useful products annually extracted from the interior of the earth.

Mining ore by excava tor

A mining engineer told me he had once stopped at a little house near a mountain of magnesite. Within two or three weeks the mountain vanished: it had been hauled away to a cement plant.

Suffice it to look at the mountains of slags thrown out by our iron and steel mills to understand that man's activity is a geological factor that is reshaping the earth's . crust.

336

One of the most important problems of the world chemical economy is the fate of carbon in which man has especially vigorously interfered. Carbon is distributed in nature in three forms: in organic substance, in accumulations of coal and oil and in an oxidized state, i.e., in the form of carbon dioxide in the atmosphere and in the waters of the rivers and oceans. But the greatest amount of carbon dioxide is found in combi-nation with calcium in hard limestones.

The atmosphere contains more than 2 X io12 tons of carbon dioxide and, consequently, over 600,000 million tons of carbon. Man annually extracts more than 1,000 million tons of coal and hundreds of millions of tons of oil. He burns both, transforming them into carbon and carbon dioxide. More than 3,000 million tons of carbon dioxide is, thus, an-nually liberated into the atmosphere and in 200 to 300 years its quantity should have doubled if it were not for the contrary processes, i.e., its dissolution in the ocean and its consumption by plants.

R o t a t i n g f u r n a c c for calc inat ing carbon ma te r i a l s ; ins ta l led in the e l ec t rode shop of an a lumin ium p l an t

22 337

By utilizing the carbon of the coal layers man aids in dispersing this element on so large a scale that his activity assumes the scope of real geological transformations.

N o less imperiously does man interfere in the fate of metals; he has about 1,000 million tons of iron and iron wares in circulation; the metal is in an unstable native form and it is being oxidized.

During a certain period of time oxidation depreciates nearly as much iron as is produced during the same period so that the accumulation of iron cannot outstrip its dispersion.

With gold the situation is somewhat better: about one ton of it is used up annually for reagents and for gold-plating and is dispersed by wear, which is a lot less than is produced (about 600 tons).

And such metals as lead, tin and zinc are extracted by man from ac-cidental natural accumulations in the earth's crust, the so-called deposits, in order to become irretrievably dispersed in the process of their utili-zation.

Man's agricultural and engineering activities are quite comparable in their scope to the influence of the elemental processes.

The tilling of the superficial layer of the earth (soil) for agricultural needs is of tremendous geochemical importance since more than 3,000 cubic kilometres of it are annually exposed to the vigorous action of the atmospheric waters and the air.

The cultivated plants take an enormous amount of mineral substances out of the soil, namely, 10 million tons of phosphoric anhydride and 30 million tons of nitrogen and potassium. This is many times the amount introduced into the soil during fertilization. The extracted elements enter the cycle of substances in the animal world and are finally dis-persed.

By his agricultural and technical activities man disperses substances. More than one cubic kilometre of rocks is annually extracted from all mines. This figure will have to be doubled or even trebled if we add the construction of dams, irrigation canals, etc.

The amount of slags annually produced by all of the world's metallur-gical furnaces probably also comes close to one cubic kilometre. And just think of the waste-products of the chemical industry brought out by man on to the surface of the earth!

If we compare these figures with the 15 cubic kilometres of sediments annually carried away by all the rivers from the earth's surface we shall

3 3 8

L a b o r a t o r y for tes t ing the physical p roper t i es of minera l s

have to acknowledge that human activity is as serious a factor as that of the rivers.

And what about the art of building and the quantities of stones and cement consumed by it annually! The intensive construction of cities in the U.S.S.R. uses up more than 1,000 million tons of various building materials every year.

M a n is reshaping nature at an ever increasing rate. If we consider the total reserves of metal in the earth we shall find them large enough to make any talk about exhausting them premature. But not all of these reserves can be made use of because industry can actually avail itself only of the rich accumulations of any particular metal, and there are not so many of them.

The real reserves of many metals scarcely meet the requirements of industry. Legions of geological prospectors and geochemists must therefore search hard for metals in order to satisfy the ever growing industrial needs.

22

P A R T F O U R

P A S T A N D F U T U R E OF G E O C H E M I S T R Y

FROM THE HISTORY OF GEOCHEMICAL IDEAS

I d o n o t w a n t t h e r e a d e r s t o ge t t h e impress ion t h a t e v e r y t h i n g is c lea r , e v e r y t h i n g is k n o w n , a n d t h a t al l e l emen t s h a v e b e e n dis-c o v e r e d . I s h o u l d n ' t w a n t t h e m to feel t h a t w e h a v e a c q u i r e d o u r k n o w l e d g e w i t h o u t a n y diff icul t ies , t h a t t h e sc ience of t h e c h e m i s t r y of s u b s t a n c e has g r o w n u p of itself w i t h o u t a s t rugg le o r searches , w i t h o u t h a r d a n d pers i s ten t w o r k .

N o , m y f r i ends , t h e p a s t of sc ience t e aches us t h a t t h o u s a n d s of p e o p l e h a v e s t rugg led for its t r u t h s for m a n y h u n d r e d s of years , t h a t t h e y h a v e m a d e mis takes , s e a r c h e d fo r n e w ways , w o r k e d d a y a n d n i g h t in old b a s e m e n t l abo ra to r i e s , f o u g h t i g n o r a n c e a n d t h e oppress ion of t h e c h u r c h a n d m o n a s t e r i e s a n d b a t t l e d for a n u n d e r s t a n d i n g of n a t u r e .

A n d this u n d e r s t a n d i n g h a s n o t c o m e all a t once . I r e m e m b e r s t a n d i n g o n t h e shore of L a k e V u d j a r v o n K o l a P e n i n -

sula . Before us lay a ci ty, a n d a u t o m o b i l e s k e p t r u n n i n g d o w n t h e h i g h w a y t o w a r d s t h e ci ty. I t was on ly w i t h d i f f i cu l ty t h a t I was a b l e to i m a g i n e t h e wi ld a n d f o r b i d d i n g t u n d r a , a l m o s t lifeless a n d cold as I h a d seen i t fo r t h e first t i m e j u s t t en yea r s be fo re .

L o o k i n g a t t h e ci ty w i t h its l a r g e p o p u l a t i o n , t h e s t r a igh t w i d e h i g h w a y s a n d t h e s p e e d i n g lorries, t h e n e w c o m e r c a n h a r d l y be l ieve t h a t on ly r ecen t ly th is was t h e r e m o t e t u n d r a . B u t has it o c c u r r e d t o h i m t h a t exp lo re r s w a n d e r e d a r o u n d h e r e s e a r c h i n g for ores a n d m i n e r a l s o n l y a f e w yea r s a g o ? H a s h e t h o u g h t of t h e h a r d w o r k a n d d e p r i v a t i o n s t h a t t h e p r o s p e c t i n g for t h e resources , c o n c e a l e d in t h e severe t u n d r a , r e q u i r e d in o r d e r to call this r eg ion to l ife?

3 4 3

I t is t h e s a m e i n s c i e n c e ; w h e n w e s t u d y t h e a c h i e v e m e n t s o f m o d e r n s c i e n t i f i c t h o u g h t a n d v i e w t h e t e m p t i n g p r o s p e c t s o f t h e n e a r f u t u r e f r o m t h e c o n q u e r e d h e i g h t s , w e f o r g e t t h e h a r d s h i p s , t h e t i m e a n d t h e s a c r i f i c e i t t o o k t o c l e a r u p t h e d e n s e fores t s o f i g n o r a n c e .

T h e s c i e n c e w h i c h w e c a l l g e o c h e m i s t r y is t h e h i s t o r y o f t h e c h e m i c a l e l e m e n t s o f o u r p l a n e t . I t c o u l d t a k e final s h a p e o n l y o f l a t e w h e n n o t o n l y t h e i d e a o f t h e a t o m i c s t r u c t u r e o f m a t t e r h a s b e c o m e a r e a l i t y , b u t w h e n s c i e n c e h a s a l s o p e n e t r a t e d d e e p l y i n t o t h e s t r u c t u r e o f t h e a t o m a n d h a s l e a r n e d its e s s e n t i a l f e a t u r e s .

M o d e r n g e o c h e m i s t r y d a t e s f r o m t h e b e g i n n i n g o f t h e 2 0 t h c e n t u r y . I n a b r o a d s e n s e , h o w e v e r , g e o c h e m i c a l i d e a s , c o n c e r n e d w i t h c h e m i c a l e l e m e n t s , c h e m i c a l c o m p o s i t i o n o f m i n e r a l s a n d t h e s i g n s for f i n d i n g ores a n d m i n e r a l s , h a v e e x i s t e d a n d d e v e l o p e d i n t h e c o u r s e o f t h e las t t h r e e o r f o u r c e n t u r i e s .

M i n e r a l o g y a n d c h e m i s t r y , w h i c h h a v e g o n e t h r o u g h m a n y s t a g e s i n t h e i r d e v e l o p m e n t b e f o r e r e a c h i n g t h e i r p r e s e n t s t a t e , h a v e f o r m e d t h e bas i s o f g e o c h e m i s t r y .

I n t h e s t r u g g l e for e x i s t e n c e m a n l e a r n e d as e a r l y a s p r e - h i s t o r i c t i m e t o find t h e s t o n e s h e c o u l d u s e for w e a p o n s a n d t o o l s ; a l r e a d y t h e n h e w a s v e r y m u c h i m p r e s s e d b y t h e b e a u t y o f t h e p r e c i o u s s t o n e s .

A t a h i g h e r s t a g e o f d e v e l o p m e n t m a n b e g a n t o w o n d e r a b o u t t h e e a r t h a n d h o w it h a d c o m e t o b e . L e g e n d s a b o u t t h e o r i g i n o f t h e w o r l d , or s o - c a l l e d c o s m o g o n i e s , b e g a n t o c o m e i n t o b e i n g a n d w e r e s l o w l y a n d g r a d u a l l y r e p l a c e d b y m o r e p o s i t i v e i d e a s . T h e m o s t c i v i l i z e d a n c i e n t p e o p l e s o n t h e M e d i t e r r a n e a n c o a s t a l r e a d y h a d r a t h e r w e l l d e v e l o p e d c o n c e p t i o n s e x p r e s s e d b y s u c h t h i n k e r s a s D e m o c r i t u s , A r i s t o t l e a n d L u c r e t i u s .

T h e i d e a s o f A r i s t o t l e , t h e g r e a t e s t n a t u r a l i s t o f a n t i q u i t y ( 3 8 4 - 3 2 2 B. C . ) , a r e o f p a r t i c u l a r i n t e r e s t t o us , s i n c e h e b e l i e v e d t h e e a r t h t o b e a s p h e r e . A c c o r d i n g t o th i s t h i n k e r , t h e u n i v e r s e h a d t h e s h a p e o f a s p h e r e a n d t h e e a r t h a s t h e h e a v i e s t b o d y w a s i n t h e c e n t r e ; it w a s s u r r o u n d e d b y w a t e r a n d b y t h e a i r m a n t l e . T h e l i g h t e s t e l e m e n t w a s fire, a n d t h e n c a m e e t h e r . T h e e a r t h , a ir , w a t e r , fire a n d e t h e r c o n s t i t u t e d t h e five e l e m e n t s . D e s p i t e t h e e r r o n e o u s n e s s o f m a n y o f A r i s t o t l e ' s i d e a s , h e e x e r t e d a n e x c e p t i o n a l l y g r e a t i n f l u e n c e o n t h e d e v e l o p m e n t o f t h e n a t u r a l s c i e n c e s . M a r x c o n s i d e r e d h i m t h e g r e a t e s t t h i n k e r o f a n t i q u i t y w h o w a s a b l e t o g e n e r a l i z e a l l o f n a t u r a l s c i e n c e o f t h a t t i m e i n h i s w o r k s .

344

Aristotle

345

T h e o p h r a s t u s ( 3 7 1 - 2 8 6 B . C . ) , A r i s t o t l e ' s p u p i l , w a s t h e first t o l ist t h e m i n e r a l s k n o w n a t t h a t t i m e a n d t o m a k e a n a t t e m p t a t c lass i -f y i n g t h e m . H e c a n b e r i g h t f u l l y c o n s i d e r e d t h e f o u n d e r n o t o n l y o f m i n e r a l o g y , b u t a l s o o f t h e s c i e n c e o f so i l s a n d p l a n t s .

A r e m a r k a b l e w o r k f o r its t i m e , t h a t o f P l i n y t h e E l d e r , t h e R o m a n i n v e s t i g a t o r w h o d i e d d u r i n g t h e e r u p t i o n o f V e s u v i u s i n 7 9 A . D . , c o m e s t o t h e f o r e i n t h e first c e n t u r y A . D . I n a d d i t i o n t o f a n t a s t i c l e g e n d s , t h i s w o r k c o n v e y s a l o t o f t r u e i n f o r m a t i o n a b o u t m i n e r a l s , w h o s e n a m e s h a v e p a r t l y b e e n p r e s e r v e d t o - d a t e .

D u r i n g t h e M i d d l e A g e s , t h e e x a c t s c i e n c e s d i d n o t d e v e l o p i n E u r o p e . A t t h a t t i m e t h e n a t u r a l s c i e n c e s a n d c h e m i s t r y d e v e l o p e d m a i n l y i n t h e E a s t .

I n t h e s i n g u l a r t rea t i s e s o f t h e A r a b t h i n k e r s o f t h e 9 t h a n d 1 0 t h c e n t u r i e s , w e find i n d i c a t i o n s o f t h e c o e x i s t e n c e o f s e p a r a t e m e t a l s i n n a t u r e . T h u s , L u k e B e n - S e r a p i o n i n t h e f o r e w o r d t o h i s Book about Stones w r i t e s t h a t " t h e r e a r e s t o n e s t h a t a r e e n c o u n t e r e d t o g e t h e r a n d s t o n e s t h a t a v o i d e a c h o t h e r ; t h e r e a r e s t o n e s w h i c h a r e u n t r u e t o o t h e r s t o n e s , a s t h e r e a r e s t o n e s w h i c h c o l o u r o t h e r s t o n e s . "

T h e s e a r c h for ores , t h e i r p r o c e s s i n g a n d t h e p r o d u c t i o n o f m e t a l s a n d a l l o y s u n d o u b t e d l y m a d e m a n c o n t i n u o u s l y w o n d e r a b o u t t h e c o n d i t i o n s u n d e r w h i c h c h e m i c a l e l e m e n t s w e r e f o u n d t o g e t h e r . T h e g e n e r a l i z a t i o n s a b o u t l o v e a n d h a t r e d b e t w e e n v a r i o u s s u b s t a n c e s w h i c h t h e n c a m e i n t o m a n ' s m i n d w e r e t h e f irst g e o c h e m i c a l l a w s t h a t h a v e r e t a i n e d t h e i r s i g n i f i c a n c e .

T h e w o r k o f A v i c e n n a , t h e p h i l o s o p h e r f r o m B u k h a r a ( 9 8 5 - 1 0 3 7 ) , is p a r t i c u l a r l y i n t e r e s t i n g . T h e p h i l o s o p h e r w r o t e a t r e a t i s e o n m i n e r a l i n w h i c h h e c l a s s i f i e d t h e m a s : 1) S t o n e s a n d e a r t h s , 2) C o m b u s t i b l e a n d s u l p h u r o u s c o m p o u n d s , 3) S a l t s a n d 4 ) M e t a l s .

A n o t h e r o u t s t a n d i n g s c i e n t i s t , A1 B i r u n i ( 9 7 3 - 1 0 4 8 ) o f K h o r e z m , w r o t e a r e m a r k a b l e b o o k i n A r a b i c e n t i t l e d Complete Knowledge of Precious Minerals i n w h i c h h e g e n e r a l i z e d al l t h e m i n e r a l o g i c a l d a t a o f t h a t t i m e .

T h e w o r k s o f a l c h e m i s t r y i n A r a b i c , w h i c h m a d e t h e i r a p p e a r a n c e i n t h e 9 t h c e n t u r y , a r e o f g r e a t i m p o r t a n c e t o t h e h i s t o r y o f c h e m i s t r y , s i n c e t h e y w e r e t h e first t o se t f o r t h t h e p r o b l e m s o f t r u l y c h e m i c a l m e t h o d s o f r e s e a r c h .

T h e a l c h e m i s t s w o r k e d m a i n l y o n s y n t h e s i s , i . e . , t h e y t r i e d t o o b t a i n n e w s u b s t a n c e s f r o m t h e o n e s t h e y a l r e a d y k n e w . A l e x a n d r i a w a s t h e

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c r a d l e o f a l c h e m i s t r y , w h e n c e c h e m i c a l k n o w l e d g e a n d ski l l s p e n e t r a t e d i n t o S y r i a . T h e A r a b s b o r r o w e d a l c h e m i s t r y f r o m t h e S y r i a n s a n d b r o u g h t it t o E u r o p e t h r o u g h S p a i n .

A l c h e m i s t r y u s u a l l y i m p l i e s t h e d e c e p t i v e ar t o f m a k i n g g o l d f r o m v a r i o u s o t h e r m e t a l s . A s a m a t t e r o f f a c t m e d i e v a l a l c h e m i s t s a t t e m p t e d m a i n l y t o e n n o b l e t h e u s u a l m e t a l s b y t r y i n g t o t r a n s f o r m t h e m i n t o s i lver or g o l d . B u t t h e s e w e r e n o t t h e o n l y p r o b l e m s t h e y w e r e w o r k i n g o n . T h e y w e r e a l s o s e a r c h i n g for r e m e d i e s a n d t h e " p h i l o s o p h e r ' s s t o n e . "

T h e u n s u c c e s s f u l e n d e a v o u r s t o c h a n g e t h e m e t a l s g r a d u a l l y f o r c e d t h e a l c h e m i s t s t o f i n d a n e w a p p l i c a t i o n for t h e i r art . T h e i r a t t e n t i o n w a s f o c u s e d o n t h e h e a l t h o f m a n a n d a l c h e m i s t r y b e c a m e t h e h a n d -m a i d e n o f m e d i c i n e .

T h o u g h t h e a l c h e m i s t s w e r e a c c u s e d o f q u a c k e r y , t h e y e n o r m o u s l y b e n e f i t e d t h e d e v e l o p m e n t o f c h e m i s t r y , b e c a u s e t h e y c o n d u c t e d e n d l e s s c h e m i c a l e x p e r i m e n t s , a n d d e s p i t e t h e f a c t t h a t t h e i r i n i t i a l i d e a s w e r e w r o n g , t h e y s o m e t i m e s a c h i e v e d i m p o r t a n t resul ts .

T h e f a m o u s p h i l o s o p h e r L e i b n i t z w r o t e v e r y w e l l a b o u t t h e a l c h e m i s t s , s a y i n g : " T h e s e o r d i n a r y p e o p l e h a v e g r e a t i m a g i n a t i o n a n d e x p e r i e n c e , b u t t h e i r i m a g i n a t i o n is a t v a r i a n c e w i t h t h e i r e x p e r i e n c e . T h e y c h e r i s h p u r e h o p e s , a n d th i s l e a d s t h e m t o f a i l u r e o r m a k e s t h e m a l a u g h i n g s t o c k . A n d st i l l s u c h p e o p l e n o t i n f r e q u e n t l y k n o w m o r e f a c t s f r o m t h e i r e x p e r i e n c e a n d o b s e r v a t i o n o f n a t u r e t h a n m a n y a r e s p e c t e d s c i e n t i s t . "

C a m e R e n a i s s a n c e . I t s i g n i f i e d a c h a n g e for a n e w a n d h i g h e r s t a g e o f c u l t u r e .

T h e first i m p e t u s t o t h e d e v e l o p m e n t o f m i n e r a l o g y w a s t h e p r o s p e r i t y o f t h e m i n i n g i n d u s t r y i n H u n g a r y , S a x o n y a n d B o h e m i a .

T h e r e m a r k a b l e w o r k s o f A g r i c o l a ( 1 4 9 0 - 1 5 5 5 ) , p h y s i c i a n a n d m i n e r a l o g i s t i n t h e S a x o n i a n m i n i n g c e n t r e , l a i d t h e bas i s f or t h e e x a c t a n d d e e p u n d e r s t a n d i n g o f t h e o b j e c t i v e s o f m i n e r a l o g y a n d g e o c h e m i s t r y . H i s r e a l n a m e w a s G e o r g B a u e r . H e l e f t m a n y b o o k s w h i c h r e p r e s e n t a s u m m a r y o f t h e k n o w l e d g e o f o r e d e p o s i t s o f t h a t t i m e . H i s m o s t r e m a r k a b l e b o o k s a r e De natura fossilium ( 1 5 4 6 ) a n d De re metallica ( 1 5 4 6 ) . H i s c l a s s i f i c a t i o n o f m i n e r a l s is o f a s c i e n t i f i c c h a r a c t e r . I t i n c l u d e s for t h e first t i m e t h e i d e a o f c o m p l e x i t y o f c o m p o u n d s , i . e . , c h e m i c a l p r i n c i p l e s . T h i s s y s t e m f o r m s t h e bas i s o f a l l s u b s e q u e n t m i n e r a l o g i c a l w o r k s u p t o a n d i n c l u d i n g t h e 1 8 t h c e n t u r y .

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J o n s J a k o b B e r z e l i u s ( 1 7 7 9 -1 8 4 8 ) , S w e d i s h c h e m i s t a n d m i n e r a l o g i s t , w o r k e d o n t h e c h e m i c a l a n a l y s e s o f m i n e r a l s a n d w a s t h e first t o g i v e t h e i r rea l c h e m i c a l c l a s s i f i c a t i o n ; h e w a s a l s o t h e first t o i n t r o d u c e t h e t e r m " s i l i c a t e s . "

S c i e n t i f i c s o c i e t i e s a n d a c a d -e m i e s , e s p e c i a l l y t h e o l d e s t a c a d -e m y — A c a d e m i a d e l C i m e n t o — w h i c h w a s f o u n d e d i n 1 6 5 7 , p l a y e d a n i m p o r t a n t p a r t i n t h e h i s t o r y o f g e o l o g y a n d m i n e r a l o g y . T h e R o y a l S o c i e t y w a s o r g a n i z e d i n L o n d o n i n 1 6 6 2 a n d is t h e B r i t i s h A c a d e m y o f t o d a y .

S c i e n t i f i c s o c i e t i e s a n d l a r g e K u n s r k a m m e r s b e c a m e v e r y p o p u l a r a t t h e e n d o f t h e 1 7 t h a n d , e s p e c i a l l y , t h e b e g i n n i n g o f t h e 1 8 t h c e n -tur ie s . T h e S w e d i s h A c a d e m y o f S c i e n c e s , a n d t h e n t h e R u s s i a n , f o u n d e d i n 1 7 2 5 i n P e t e r s b u r g , h a v e p l a y e d a t r e m e n d o u s p a r t i n t h e d e v e l o p m e n t o f s c i e n c e .

I n R u s s i a , g e o c h e m i c a l i d e a s w e r e g i v e n t h e i r first v i v i d e x p r e s s i o n i n t h e w o r k s o f M . L o m o n o s o v ( 1 7 1 1 - 6 5 ) — O n the Structure of Terrestrial Layers a n d On the Birth of Metals. L o m o n o s o v w a s t h e first t o s u g g e s t t h a t m e t a l s a n d m i n e r a l s m i g r a t e d . " M e t a l s m o v e f r o m p l a c e t o p l a c e , " w a s h i s b r i l l i a n t c o n c l u s i o n . H e g a v e r ise t o n e w i d e a s a b o u t m i n e r a l s a s p r o d u c t s r e s u l t i n g f r o m t h e l i f e o f t h e e a r t h ' s crus t , i d e a s w h i c h i n t h e 2 0 t h c e n t u r y f o r m e d t h e bas i s o f t h e n e w s c i e n c e o f g e o c h e m i s t r y .

D o z e n s o f b o o k s a n d h u n d r e d s o f a r t i c l e s w e r e w r i t t e n a b o u t L o m o -n o s o v ; t h e m o s t p r o m i n e n t i n v e s t i g a t o r s , s c i en t i s t s , w r i t e r s a n d p o e t s d e v o t e d t h e i r b e s t p a g e s t o t h e a n a l y s i s o f th i s g i a n t o f R u s s i a n t h o u g h t a n d it is st i l l i m p o s s i b l e t o e x h a u s t t h i s s u b j e c t , b e c a u s e t h e g e n i u s o f M i k h a i l L o m o n o s o v , t h i s A r k h a n g e l s k pornor w a s s o g r e a t a n d p r o f o u n d .

W e c a n i m a g i n e t h e p o w e r f u l figure o f t h i s T i t a n h a r d e n e d i n t h e s t r u g g l e a g a i n s t p o l a r n a t u r e , " w i t h h i s n o b l e s t u b b o r n n e s s " b e c a u s e o f w h i c h h e w o u l d n e v e r y i e l d t o a n y b o d y or a n y t h i n g .

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Prospecting for ore deposits. Picture taken from Agricola's book. 1556

C o u r a g e , r e s o l v e a n d d a r i n g b o r d e r i n g o n s t o r m y f a n t a s y , a t h i r s t t o k n o w e v e r y t h i n g , d o w n t o t h e r o o t o f t h i n g s a n d t o t h e s o u r c e o f a l l s o u r c e s , a n d a c a p a c i t y f o r p r o f o u n d p h i l o s o p h i c a l a n a l y s i s i n c o m -b i n a t i o n w i t h a b r i l l i a n t a b i l i t y t o c o n d u c t e x p e r i m e n t s , w i t h o u t w h i c h h e c o u l d n o t t h i n k o f s c i e n c e , w e r e s o m e o f L o m o n o s o v ' s tra i t s . A n d w h e r e a s s e v e n c i t i e s o f a n t i q u i t y d e b a t e d t h e h o n o u r o f k e e p i n g H o m e r ' s g r a v e , m o r e t h a n a d o z e n d i f f e r e n t s c i e n c e s a n d a r t s a r e f i g h t i n g f o r t h e m a i n h e r i t a g e o f L o m o n o s o v : p h y s i c s a n d c h e m i s t r y , m i n e r a l o g y a n d c r y s t a l l o g r a p h y , g e o c h e m i s t r y a n d p h y s i c a l c h e m i s t r y , g e o l o g y a n d m i n i n g , g e o g r a p h y a n d m e t e o r o l o g y , a s t r o n o m y a n d a s t r o p h y s i c s , r e g i o n a l s c i e n c e a n d e c o n o m i c s , h i s t o r y , l i t e r a t u r e , p h i l o l o g y a n d e n g i n e e r i n g . T o b e s u r e , L o m o -n o s o v w a s , a s P u s h k i n w a s w o n t t o s a y : a " w h o l e u n i v e r s i t y " i n h i m s e l f .

L o m o n o s o v m a y n o t h a v e b e e n u n d e r s t o o d b y h i s c o n t e m p o r a r i e s , b u t n e w g e n e r a t i o n s w h i c h h e w a s s o f e r v e n t l y t e a c h i n g a n d t o w h i c h h e w a s m a k i n g h i s a p p e a l , w e r e a l r e a d y c o m i n g i n t o b e i n g .

Come, Russian youths of piercing ken, From fertile fields and forests broad, To take the place of learned men Today invited from abroad. Blessed be your days for evermore; Strive on with neither doubt nor awe, And with your great achievements show That Newtons, Platos of our own And other men of world renown On Russian soil can also grow!

T w o h u n d r e d y e a r s h a v e p a s s e d s i n c e t h e n , b u t o n l y n o w a r e h i s b r i l l i a n t f o r e s i g h t a n d d a r i n g t h e o r i e s b e i n g e m b o d i e d i n t o t h e g r e a t e s t s c i e n t i f i c t r u t h s b e f o r e o u r v e r y e y e s , a n d h i s c h e r i s h e d d r e a m s a b o u t t h e g r e a t n e s s a n d g l o r y o f o u r c o u n t r y b e c o m i n g r e a l i t y .

L o m o n o s o v u n d e r s t o o d s c i e n c e n o t o n l y a s a m e r e d e s c r i p t i o n o f p h e n o m e n a , b u t a s t h e i r e x p l a n a t i o n . H e b e l i e v e d i t w a s n e c e s s a r y t o s t u d y n o t t h e b o d i e s i n t h e m s e l v e s , b u t t h e i r i n t e r n a l s t r u c t u r e a n d t h e c a u s e s o f t h i s s t r u c t u r e , a s w e l l a s t h e f o r c e s w h i c h a c t e d i n s i d e s u b s t a n c e . H e k n e w t h a t a l l o f s c i e n c e i n a l l i t s m a n i f e s t a t i o n s d e p e n d e d o n t h e s o l u t i o n o f t h e o n e g r e a t p r o b l e m : t h a t o f s u b s t a n c e , i ts s t r u c t u r e a n d c o m p o s i t i o n .

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Mikha i l L o m o n o s o v , Russian scientist (1711-65)- T h e first inves t iga tor in the field of geology to l ink u p the p r o b l e m s of s tudying minera l s and rocks wi th those of chemistry and physics. F o u n d e r of geochemical a n d physico-chemical ideas in Russ ia

L o m o n o s o v c a m e t o t h e c o n c l u s i o n t h a t s u b s t a n c e c o n s i s t e d o f s e p a -r a t e p a r t i c l e s w h i c h p o s s e s s e d s p e c i a l a t t r a c t i o n , i n e r t i a a n d m o t i o n ; s o m e o f t h e m w e r e s m a l l e r — t h e s e w e r e t h e s i m p l e a t o m s ; o t h e r s w e r e l a r g e r — t h e s e w e r e t h e m o l e c u l e s . N o n e o f t h e m w a s v i s i b l e t o t h e e y e , a n d t h e y w e r e a l l i n c o n s t a n t m o t i o n a n d r o t a t i o n . E s s e n t i a l l y , th is r e m a r k a b l e i n f e r e n c e f u l l y c o r r e s p o n d s t o t h e m o d e r n a t o m i s t i c w o r l d o u t l o o k .

N e a r l y h a l f a c e n t u r y b e f o r e t h e g r e a t F r e n c h c h e m i s t L a v o i s i e r , L o m o n o s o v m a i n t a i n e d t h a t n o t h i n g c o u l d b e los t i n n a t u r e , t h u s , e s s e n t i a l l y , e s t a b l i s h i n g t h e g r e a t l a w o f n a t u r e , t h e l a w o f c o n s e r v a t i o n o f m a t t e r a n d e n e r g y .

B y g r a d u a l l y i n v e s t i g a t i n g t h e n a t u r e o f t h e o r i g i n a l p a r t i c l e s t h r o u g h p h y s i c s , L o m o n o s o v b e g a n s t u d y i n g c h e m i s t r y . C h e m i s t r y is a s c i e n c e a b o u t t h e c h a n g e s o c c u r r i n g i n t h e c o m p o s i t i o n o f a b o d y , i . e . , a s c i e n c e w h i c h d e p e n d s o n t h e p h e n o m e n a o f p h y s i c s a n d m e c h a n i c s .

I n h i s b r i l l i a n t Word about the Benefit of Chemistry, a p a p e r r e a d t o a g e n e r a l m e e t i n g o f t h e A c a d e m y o f S c i e n c e s i n 1 7 5 1 , h e d i s c l o s e d t h e g r a n d p r o s p e c t s o f t h e n e w c h e m i s t r y ; h e r e j e c t e d t h e o l d i d e a s o f t h e a l c h e m i s t s b o r n i n t h e i r m y s t e r i o u s l a b o r a t o r i e s , a n d l a i d t h e f o u n d a t i o n for t h e n e w e d i f i c e o f c h e m i s t r y , i n w h i c h n u m b e r a n d w e i g h t a n d t h e l a w s o f m a t h e m a t i c s p r e v a i l e d . H e c a r r i e d h i s i d e a s i n t o p r a c t i c e .

I n 1 7 4 8 , a f t e r a s t r u g g l e o f m a n y y e a r s , h e , finally, o r g a n i z e d o n A p t e k a r s k y P e n i n s u l a i n P e t e r s b u r g t h e first R u s s i a n s c i e n t i f i c c h e m i c a l l a b o r a t o r y w h e r e h e k e p t e x a c t r e c o r d s o f m e a s u r e , w e i g h t a n d p r o -p o r t i o n s o f s u b s t a n c e .

I n 1 7 5 2 - 5 3 L o m o n o s o v t a u g h t t h e first c o u r s e i n " p h y s i c a l c h e m i s t r y " i n t h e w o r l d . H e s a i d t h a t " c h e m i s t r y p l a y e d a n i m p o r t a n t p a r t i n a l l h u m a n a f f a i r s " a n d h e w o r k e d p e r s i s t e n t l y i n o r d e r t o s a t i s f y t h e p r a c t i c a l n e e d s o f h i s c o u n t r y . H e p r o d u c e d a n e w c o m p o s i t i o n o f o p t i c a l g l a s s ; a f t e r 3 , 0 0 0 e x p e r i m e n t s , h e b e g a n t o m a n u f a c t u r e a c o l o u r e d s m a l t f or m o s a i c s , b u i l t a s p e c i a l m o s a i c f a c t o r y , s t u d i e d t h e c o m p o s i t i o n o f t h e U r a l s m i n e r a l s a n d w o r k e d o n p r o b l e m s o f s a l t p e t r e a n d p h o s p h o r u s .

T h e first p r o b l e m s p o s e d b y L o m o n o s o v b e f o r e t h e n e w e x p e r i -m e n t a l l a b o r a t o r y i n c l u d e d t h e p r e p a r a t i o n o f p u r e s u b s t a n c e s . T h i s l e d L o m o n o s o v t o t h e s t u d y o f p u r e m e t a l s , sa l t s a n d s a l t p e t r e , a n d t h e o l d l e s s o n s o f t e c h n o l o g y a n d m i n e r a l o g y w e r e r e v i v e d i n a n e w

3 5 0

1 7 5 2 - 1 7 5 3

f o r m . F o r h i m a m i n e r a l w a s a m i x t u r e o f p r i m a r y p a r t i c l e s a n d i ts p r o p e r t i e s d e p e n d e d o n " t h e m u t u a l u n i o n o f t h e p a r t i c l e s . "

L i k e a n y o t h e r s u b s t a n c e s , s t o n e h a d i ts o w n h i s t o r y o f l i f e a n d d e a t h a n d L o m o n o s o v u r g e d t h a t n a t u r a l m i n e r a l s b e s t u d i e d b y n e w m e t h o d s .

H e l i n k e d t h e c o n d i t i o n s o f m i n e r a l f o r m a t i o n t o g e o l o g i c a l p r o c -es ses ; h e e n d e a v o u r e d t o d i v i n e t h e s e p r o c e s s e s i n t h e i n t e r i o r o f t h e e a r t h i n t h e fissures o f v o l c a n o e s filled w i t h i n c a n d e s c e n t v a p o u r s o f s u l p h u r ; o n t h e s u r f a c e h e s a w t h e g e n e s i s o f s t o n e s i n t h e r e m a i n s o f a n i m a l s a n d p l a n t s . T h u s , i n t h e m i n d o f L o m o n o s o v , w h o c o m b i n e d i n h i s p e r s o n a n a t u r a l i s t , p h i l o s o p h e r a n d c h e m i s t , s t o n e c a m e t o l i f e i n t h e l i g h t o f n e w i d e a s .

H e r e is w h a t M . L o m o n o s o v w r o t e i n h i s r e m a r k a b l e b o o k On Terrestrial Layers p u b l i s h e d i n 1 7 6 3 :

" T h i s is w h a t t h e e n t r a i l s o f t h e e a r t h a r e l i k e ; h e r e w e h a v e l a y e r s a n d h e r e v e i n s o f o t h e r s u b s t a n c e s w h i c h n a t u r e h a s p r o d u c e d i n t h e i n t e r i o r . W e m u s t o b s e r v e t h e i r d i f f e r e n t p o s i t i o n , c o l o u r a n d w e i g h t a n d i n o u r t h i n k i n g u s e t h e i d e a s a n d a d v i c e o f m a t h e m a t i c s , c h e m -i s try a n d p h y s i c s i n g e n e r a l . "

T h i s w a s n o l o n g e r t h e o l d a n d t e d i o u s d e s c r i p t i v e m i n e r a l o g y , b u t a n e w s c i e n c e — g e o c h e m i s t r y , i . e . , c h e m i s t r y o f t h e e a r t h . A n d as h e h a d f o r m e r l y b u i l t t h e f o u n d a t i o n for t h e g r e a t e d i f i c e o f p h y s i c a l c h e m i s t r y o n t h e b o r d e r s b e t w e e n p h y s i c s a n d c h e m i s t r y for t h e first t i m e i n t h e h i s t o r y o f s c i e n t i f i c t h o u g h t , h e n o w l a i d t h e c o r n e r - s t o n e o f t h e n e w s c i e n c e o n t h e b o r d e r s b e t w e e n c h e m i s t r y a n d g e o l o g y , t h e s c i e n c e w h i c h a t t h a t t i m e h a d n o n a m e as y e t . S e v e n t y m o r e y e a r s w e r e r e q u i r e d b e f o r e t h e w o r d " g e o c h e m i s t r y " first c a m e o f f t h e l i p s o f o n e o f t h e m o s t p r o m i n e n t n a t u r a l i s t s i n 1 8 3 8 ; i t w a s t h e S w i s s c h e m i s t C h r i s t i a n F r i e d r i c h S c h o n b e i n ( 1 7 9 9 - 1 8 6 8 ) w h o f o u r y e a r s l a t e r w r o t e :

" S e v e r a l y e a r s a g o I m a d e a p u b l i c s t a t e m e n t o f m y c o n v i c t i o n t h a t w e m u s t h a v e a g e o c h e m i s t r y b e f o r e w e c a n s p e a k a b o u t a r e a l g e o l o g i c a l s c i e n c e w h i c h , o b v i o u s l y , m u s t d e v o t e i ts a t t e n t i o n t o t h e c h e m i c a l n a t u r e o f t h e m a s s e s t h a t c o n s t i t u t e o u r e a r t h , t o t h e o r i g i n a t l e a s t a s m u c h as t o the1 r e l a t i v e a n t i q u i t y o f t h e s e f o r m a t i o n s a n d t o t h e r e m a i n s o f t h e a n t e d i l u v i a n p l a n t s a n d a n i m a l s b u r i e d i n t h e m . W e a r e w a r r a n t e d i n s a y i n g t h a t g e o l o g i s t s w i l l n o t f or e v e r p u r s u e t h e d i r e c t i o n t h e y a r e f o l l o w i n g n o w . I n o r d e r t o e x p a n d t h e i r s c i e n c e a s s o o n as t h e foss i ls fa i l s u f f i c i e n t l y t o s e r v e t h e m , t h e y w i l l h a v e t o

35 >

1838

l o o k for n e w a u x i l i a r y m e a n s a n d w i l l t h e n , n o d o u b t , i n t r o d u c e m i n e r a l o - c h e m i c a l m e t h o d s o f r e s e a r c h i n t o g e o l o g y . T h e t i m e w h e n th is w i l l h a p p e n d o e s n o t s e e m v e r y d i s t a n t t o m e . "

A n d h e r e t h e h i s t o r y o f s c i e n c e te l l s u s h o w a n e w i d e a a n d a n e w s u c c e s s r e s u l t e d f r o m t h e p r e c e d i n g d e v e l o p m e n t o f t h o u g h t .

L o n g a n d p a i n s t a k i n g w o r k w i t h f a c t s w a s r e q u i r e d for e x t e n s i v e c h e m i c a l r e g u l a r i t i e s t o b e r e l i a b l y g e n e r a l i z e d i n t o g e o c h e m i c a l l a w s , i n o r d e r t h a t f r o m b r i l l i a n t c o n j e c t u r e s t h e y m i g h t b e t r a n s f o r m e d i n t o firmly e s t a b l i s h e d a n d v e r i f i e d s c i e n t i f i c g e n e r a l i z a t i o n s .

T h e R u s s i a n s c i e n t i s t D m i t r y M e n d e l e y e v ( 1 8 3 4 - 1 9 0 7 ) h a d m a d e a n e n o r m o u s c o n t r i b u t i o n i n t h i s d i r e c t i o n ; b y d i s c o v e r i n g t h e l a w o f p e r i o d i c i t y o f t h e p r o p e r t i e s o f c h e m i c a l e l e m e n t s h e l a i d a r e a l f o u n d a t i o n for t h e t h e r e t o f o r e b a r r e n c o n c e p t o f t h e u n i t y o f t h e s t r u c t u r e o f t h e u n i v e r s e .

D . M e n d e l e y e v b e g a n w o r k i n g as a c h e m i s t i n t h e fifties o f t h e 1 9 t h c e n t u r y w h e n R u s s i a n i n d u s t r y s t a r t e d i ts v i g o r o u s d e v e l o p m e n t . S i n c e M e n d e l e y e v a r d e n t l y l o v e d h i s c o u n t r y h e d i d n o t s h u t h i m -se l f o f f f r o m p r a c t i c e b u t e n g a g e d i n i t w i t h t h e e n e r g y s o t y p i c a l o f h i m .

H e w r o t e a b o u t u t i l i z a t i o n o f o i l a n d c o a l a s w e l l a s a b o u t t h e i r o r i g i n a n d re serves , i n v e n t e d s m o k e l e s s p o w d e r , a n d s t u d i e d t h e p o s -s ib i l i t i e s f or t h e d e v e l o p m e n t o f t h e i r o n i n d u s t r y .

H e b e l i e v e d t h e u l t i m a t e a i m o f s c i e n t i f i c s t u d i e s t o b e " f o r e s i g h t a n d b e n e f i t . "

M e n d e l e y e v ' s c h i e f w o r k , t h e Fundamentals of Chemistry, w a s p u b l i s h e d i n 1 8 6 9 , r e p u b l i s h e d i n e i g h t e d i t i o n s d u r i n g h i s l i f e t i m e , a n d r e p e a t -e d l y a f t e r h i s d e a t h .

M e n d e l e y e v c o n s i d e r e d t h i s b o o k h i s f a v o u r i t e b r a i n - c h i l d . " T h i s b o o k c o n t a i n s m y i m a g e , m y e x p e r i e n c e o f a t e a c h e r a n d m y m o s t c h e r i s h e d s c i e n t i f i c t h o u g h t s .

" T h e Fundamentals of Chemistry c o n t a i n e d m y s p i r i t u a l p o w e r s a n d m y l e g a c y t o t h e c h i l d r e n , " h e w r o t e i n 1 9 0 5 .

T h e d i s c o v e r y o f t h e p e r i o d i c s y s t e m o f c h e m i c a l e l e m e n t s u n d o u b t -e d l y c h a r t e d a n e w c o u r s e f o r t h e d e v e l o p m e n t o f c h e m i s t r y a n d b r o u g h t D m i t r y M e n d e l e y e v w o r l d f a m e .

T h i s l a w w a s g i v e n a r e m a r k a b l e a p p r a i s a l b y F . E n g e l s . H e s a i d :

" M e n d e l e y e v p r o v e d t h a t v a r i o u s g a p s o c c u r i n t h e ser ie s o f r e l a t e d e l e m e n t s a r r a n g e d a c c o r d i n g t o a t o m i c w e i g h t s i n d i c a t i n g t h a t h e r e

3 5 2

D m i t r y M e n d e l e y e v , Russian chemis t (1834-1907). Crea to r of the per iod ic system of e l emen t s

2 3

n e w e l e m e n t s r e m a i n t o b e d i s c o v e r e d . H e d e s c r i b e d i n a d v a n c e t h e g e n e r a l c h e m i c a l p r o p e r t i e s o f o n e o f t h e s e u n k n o w n e l e -m e n t s . . . .

" A f e w y e a r s l a t e r , L e c o q d e B o i s b a u d r a n a c t u a l l y d i s c o v e r e d t h i s e l e m e n t . . . . B y ( u n c o n s c i o u s l y ) a p p l y i n g H e g e l ' s l a w o f t r a n s f o r m a t i o n o f q u a n t i t y i n t o q u a l i t y , M e n d e l e y e v a c h i e v e d a s c i e n t i f i c f e a t . . . . " *

M e n d e l e y e v p r e d i c t e d n e w c h e m i c a l e l e m e n t s , c o r r e c t e d a t o m i c w e i g h t s a n d g a v e t h e r i g h t f o r m u l a e for m a n y c h e m i c a l c o m p o u n d s .

H e w a s t h e first t o l i k e n t h e a t o m s t o c e l e s t i a l b o d i e s — t h e s tars , t h e s u n a n d t h e p l a n e t s ; h e a s s u m e d t h a t t h e s t r u c t u r e o f t h e a t o m w a s s i m i l a r t o t h a t o f t h e c e l e s t i a l s y s t e m s , i . e . , l i k e t h e s o l a r s y s t e m o r t h e s y s t e m o f b i n a r i e s .

F o r g e o c h e m i s t r y t h e P e r i o d i c L a w h a s b e e n t h e bas i s f o r t h e s y s t e m -a t i c s t u d y o f t h e l a w s g o v e r n i n g t h e c o m b i n a t i o n o f c h e m i c a l e l e -m e n t s u n d e r n a t u r a l c o n d i t i o n s .

T h e l a w w a s d i s c o v e r e d . B u t i t r e q u i r e d a n o t h e r 7 5 y e a r s , a l o n g p e r i o d o f v a s t r e s e a r c h , a p e r i o d o f s t r u g g l e o f . d i f f e r e n t t r e n d s t o e x p l a i n i t a n d d e m o n s t r a t e its p u r p o r t a n d s i g n i f i c a n c e f o r o u r e n t i r e w o r l d u n d e r s t a n d i n g ; i t r e q u i r e d n u m e r o u s n e w e x p e r i m e n t s .

I n e s t a b l i s h i n g t h e c l o s e s t r e l a t i o n s h i p b e t w e e n c h e m i c a l a n d p h y s i c a l p h e n o m e n a , M e n d e l e y e v p u t i n p r a c t i c e t h e f a m o u s words , o f L o m o n o -s o v : " A c h e m i s t w i t h o u t a k n o w l e d g e o f p h y s i c s is l i k e a m a n w h o m u s t g r o p e i n t h e d a r k . T h e s e t w o s c i e n c e s a r e s o c l o s e l y r e l a t e d t h a t n e i t h e r c a n b e p e r f e c t w i t h o u t t h e o t h e r . "

W h y h a s t h e P e r i o d i c L a w o f c h e m i c a l e l e m e n t s p l a y e d a n d w i l l c o n t i n u e t o p l a y so i m p o r t a n t a p a r t i n t h e h i s t o r y o f s c i e n c e ? B e c a u s e M e n d e l e y e v ' s P e r i o d i c T a b l e is v e r y s i m p l e a n d r e p r e s e n t s a s i m p l e ser ies o f n a t u r a l f a c t s c o r r e c t l y c o m b i n e d w i t h e a c h o t h e r i n a d e f i n i t e s p a t i a l , c h r o n o l o g i c a l , p o w e r a n d g e n e t i c r e l a t i o n s h i p . T h e r e is n o t h i n g f a b r i c a t e d i n i t . I t i s n a t u r e h e r s e l f . T h e r e a l w o r l d o f s u b s t a n c e s t h a t s u r r o u n d s u s a n d is a c c e s s i b l e t o o u r p e r c e p t i o n is e s s e n t i a l l y a g r a n d t a b l e u n f o l d e d a c c o r d i n g t o l o n g p e r i o d s a n d d i v i d e d i n t o s e p a r a t e par t s .

O f c o u r s e , n e w t h e o r i e s w i l l c o m e i n t o b e i n g a n d d i e , b r i l l i a n t g e n e r a l i z a t i o n s a n d n e w c o n c e p t i o n s w i l l r e p l a c e t h e o u t d a t e d i d e a s ; t h e g r e a t e s t d i s c o v e r i e s a n d e x p e r i m e n t s w i l l e x c e e d b y f a r a l l t h e

* F . Engels , Dialectics of Nature, M o s c o w , 1954, p . 90 .

354

p a s t a n d w i l i o p e n u p i n c r e d i b l y n o v e l a n d e x t e n s i v e h o r i z o n s . A l i t h i s w i l l c o m e a n d g o , b u t M e n d e l e y e v ' s P e r i o d i c L a w w i l l a l w a y s l i v e a n d d e v e l o p ; i t w i l l c o n s t a n t l y b e r e n d e r e d m o r e p r e c i s e a n d w i l l s e r v e as a g u i d e i n a l l q u e s t s .

Irf h i s w o r k s , M e n d e l e y e v a p p e a l e d t o u s t o c o n t i n u e d e v e l o p i n g t h e l a w .

I n o n e o f t h e i n t r o d u c t i o n s t o t h e Fundamentals of Chemistry h e w r o t e :

" W i t h t h e k n o w l e d g e o f h o w f r e e l y a n d h a p p i l y o n e l i v e s i n t h e s p h e r e o f s c i e n c e , I c a n n o t b u t w i s h t h a t m a n y p e o p l e e n t e r e d th i s s p h e r e a n d th i s is r e a l l y w h y I a m w r i t i n g m y b o o k . I t is f or th i s r e a s o n t h a t I c a n n o t h e l p r e i t e r a t i n g t h e d e s i r e t h a t t h e c h e m i c a l w o r l d o u t -l o o k w h i c h I t r i e d m y b e s t t o d e v e l o p i n t h e r e a d e r s i m p e l t h e m t o c o n t i n u e s t u d y i n g t h e s c i e n c e . T h e c o n s c r i p t i o n o f t h e y o u n g g e n e r a t i o n i n t h e s e r v i c e o f s c i e n c e s h o u l d n o t f r i g h t e n t h o s e w h o a r e a w a r e o f t h e u r g e n t n e c e s s i t y for o u r c o u n t r y ' s p r a c t i c a l a c t i v i t i e s i n a g r i c u l t u r e , i n d u s t r y a n d m a n u f a c t u r e . O n l y w h e n t h e t r u t h s a r e l e a r n e d i n t h e i r a b s o l u t e p u r i t y , c a n t h e y b e a p p l i e d i n l i f e . "

A l l o f M e n d e l e y e v ' s w o r k s a r e i m b u e d w i t h th i s a p p e a l t o t h e y o u n g g e n e r a t i o n . H i s l e c t u r e s w e r e a t t e n d e d b y s t u d e n t s f r o m al l f a c u l t i e s . H i s w o r d c a p t i v a t e d h i s l i s t e n e r s a n d t h e a u d i t o r i u m w a s a l w a y s c r o w d e d . T h e s t u d e n t s c a m e n o t t o h e a r r e a d y - m a d e s c h e m e s , b u t t o h e a r t h e i r t e a c h e r t h i n k a n d c r e a t e .

I n t h e 1 9 t h c e n t u r y s t u d i e s o f t h e c h e m i c a l p r o c e s s r e l a t e d m i n e r a l o g y t o p h y s i c a l c h e m i s t r y a n d g a v e s c i e n t i s t s n e w a n d m o r e p r e c i s e k n o w l e d g e o f t h e r e g r o u p i n g o f c h e m i c a l a t o m s i n t h e e a r t h ' s crus t .

T h i s t r e n d , p r e v a i l i n g i n t h e las t y e a r s o f t h e 1 9 t h c e n t u r y , p a v e d t h e w a y for g e o c h e m i c a l i d e a s b y r e q u i r i n g t h a t t h e e l e m e n t s o f w h i c h t h e m i n e r a l s a r e c o m p o s e d b e t a k e n i n t o c o n s i d e r a t i o n i n a n a l y z i n g t h e p r o c e s s o f t h e i r f o r m a t i o n . B u t g e o c h e m i s t r y c o u l d n o t c o m e i n t o b e i n g a s l o n g as t h e r e w a s a n y v a g u e n e s s i n t h e i d e a a b o u t t h e a t o m i tse l f , t h e e l e m e n t o r c r y s t a l .

O n l y M e n d e l e y e v ' s P e r i o d i c L a w a n d t h e a c h i e v e m e n t s o f p h y s i c s , e s p e c i a l l y o f c r y s t a l l o g r a p h y , m a d e t h e a t o m a r e a l i t y a n d t h e c r y s t a l l o -g r a p h i c g r i d a c t u a l l y a n a t u r a l p h e n o m e n o n , a n d l i n k e d t h e e l e m e n t a n d i ts p r o p e r t i e s t o t h e s t r u c t u r e o f t h e a t o m .

T h e g r o u n d for t h e c r e a t i o n o f g e o c h e m i s t r y h a d b e e n c l e a r e d b u t i t st i l l r e q u i r e d a t r e m e n d o u s n u m b e r o f f a c t s a n d o b s e r v a t i o n s , e x t e n -s i v e e x p e r i m e n t a l w o r k h a d t o b e c o n d u c t e d i n a n u m b e r o f i n s t i t u t e s

23* 355

where not hundreds but thousands of complex and difficult de-finitions outlined correct working methods. Only these new factual gains together with the theoretical advances of physicists and crystallographers have opened up new prospects before modern geochemistry.

This independent science, developed mainly by the efforts of Russian, Norwegian and American investigators, now aims at studying the atom and its fates under natural conditions.

Unlike the other geological sciences, geochemistry does not study the fates and properties of molecules, chemical compounds, rocks or their geological complexes; it studies the fates of the atom under the conditions of the earth's crust accessible to exact experiment; it studies its behaviour, the processes of its shifts, migrations, com-binations, dispersion and concentrations. In doing this geochemistry

Academicians Vladimir Vernadsky (1863-1945) and Alexander Fersman (1833-1945). founders of the Russian school of geochemists

3 5 6

m u s t n o t o n l y d i s c o v e r a n d o u t l i n e t h e l o n g a n d i n t r i c a t e h i s t o r y o f e a c h e l e m e n t i n M e n d e l e y e v ' s P e r i o d i c T a b l e , b u t m u s t a l s o l i n k t h i s h i s t o r y t o t h e p r o p e r t i e s o f t h e a t o m s o n w h i c h t h e v i t a l f a t e o f t h e e l e m e n t s d e p e n d s .

G e o c h e m i s t r y w a s g i v e n a n e x a c t d e f i n i t i o n a n d d e v e l o p m e n t i n o u r c o u n t r y , a n d R u s s i a n s c i e n t i s t s h a v e p l a y e d a v e r y i m p o r t a n t p a r t i n i t . S o v i e t g e o c h e m i s t r y h a s m a d e s u c h h e a d w a y t h a t i t h a s q u i t e d e s e r v e d l y w o n t h e m o s t h o n o u r a b l e p l a c e i n w o r l d g e o c h e m i c a l s c i e n c e .

T h e b a s i s f or t h e R u s s i a n s c h o o l o f g e o c h e m i s t r y w a s l a i d a t M o s c o w U n i v e r s i t y b y a c a d e m i c i a n s V . V e m a d s k y a n d A . F e r s m a n , t h e a u t h o r o f t h i s b o o k .

The chemists and geologists in the U . S . A . , Germany and Norway developed their own school, but its work has been of a SQmewhat different and much narrower nature.

F r a n k C l a r k e ( 1 8 4 7 - 1 9 3 1 ) , a W a s h i n g t o n g e o l o g i s t , d e s e r v e s s p e c i a l m e n t i o n . H e p u b l i s h e d h i s Data of Geochemistry i n 1 9 0 8 . F o r 3 6 y e a r s C l a r k e c o l l e c t e d c h e m i c a l a n a l y s e s o f r o c k s a n d m i n e r a l s a n d a f t e r a c r i t i c a l t r e a t m e n t o f c o n s i d e r a b l e f a c t u a l m a t e r i a l m a d e g e n e r a l c o n c l u s i o n s o n t h e a v e r a g e c h e m i c a l c o m p o s i t i o n o f v a r i o u s t erres tr ia l r o c k s a n d o f t h e e a r t h ' s c r u s t a s a w h o l e .

B u t C l a r k e d i d n o t r e g a r d h i s d a t a a s a bas i s f o r s t u d y i n g terres tr ia l p r o c e s s e s .

T h e d e v e l o p m e n t o f g e o c h e m i s t r y w a s g r e a t l y i n f l u e n c e d b y t h e N o r w e g i a n s c i e n t i s t s J o h a n n e s V o g t ( 1 8 5 8 - 1 9 3 2 ) a n d V i c t o r M o r i t z G o l d s c h m i d t ( 1 8 8 8 - 1 9 4 7 ) .

J . V o g t f o u n d e d p h y s i c o - c h e m i c a l p e t r o g r a p h y w h i c h s e r v e s a s t h e b a s i s f o r s t u d y i n g m a g m a t i c p r o c e s s e s a n d o f f e r s e x a m p l a r y o p p o r t u n i t i e s f o r e s t i m a t i n g t h e c h e m i c a l c o m p o s i t i o n o f t h e e a r t h ' s c r u s t . B y c l o s e l y l i n k i n g c r y s t a l l o g r a p h y w i t h t h e p h y s i c s o f s o l i d b o d i e s V . G o l d s c h m i d t d e v e l o p e d t h e p r i n c i p l e s o f m o d e r n c r y s t a l l o c h e m -i s try a n d c o n t r i b u t e d a g r e a t d e a l t o t h e g e o c h e m i s t r y o f t h e d e e p s h e l l s o f t h e e a r t h ' s c r u s t . T h e s er i e s o f h i s p a p e r s o n t h e Laws of Distribution of Chemical Elements in the Earth's Crust h a v e w o n w i d e r e n o w n .

U n l i k e C l a r k e a n d G o l d s c h m i d t t h e R u s s i a n s c h o o l o f g e o c h e m i s t s m a k e e x t e n s i v e u s e o f t h e i d e a s o f g e o c h e m i s t r y f o r s o l v i n g p r a c t i c a l p r o b l e m s .

357

O u r g e o c h e m i s t s a r e t r y i n g t o f o l l o w M . L o m o n o s o v a n d t o e m p l o y t h e " m e t h o d s o f m a t h e m a t i c s , p h y s i c s a n d c h e m i s t r y " i n a n a l y z i n g s u r r o u n d i n g n a t u r e ; a t t h e s a m e t i m e t h e y m a k e a d e e p e r g e o c h e m i c a l a n a l y s i s o f M e n d e l e y e v ' s p e r i o d i c s y s t e m .

A c a d e m i c i a n V l a d i m i r V e r n a d s k y w a s o n e o f t h e m o s t o u t s t a n d -i n g s t u d e n t s o f o r g a n i c a n d i n o r g a n i c n a t u r e , t h e c r e a t o r o f n e w s c i e n t i f i c t r e n d s a n d t h e f a t h e r o f R u s s i a n m i n e r a l o g y a n d w o r l d g e o c h e m i s t r y .

H e s t u d i e d a t t h e p h v s i c o - m a t h e m a t i c a l f a c u l t y o f S t . P e t e r s b u r g U n i v e r s i t y a n d w a s g r a d u a t e d f r o m it i n 1 8 8 5 . I t w a s t h e t i m e w h e n D . M e n d e l e y e v w a s a t h i s h e y d a y a n d p l a y e d a p r o m i n e n t p a r t i n t h e l i fe o f t h e U n i v e r s i t y .

Y o u n g V e r n a d s k y w a s f a s c i n a t e d b y M e n d e l e y e v ' s n e w i d e a s a n d w a s o n e o f h i s m o s t e n t h u s i a s t i c c h e m i s t r y s t u d e n t s . H e a p p r e c i a t e d t h e v a l u e o f e x p e r i m e n t i n e x a c t k n o w l e d g e .

A n o t h e r p e r s o n w h o e x e r t e d a n e n o r m o u s i n f l u e n c e o n V . V e r n a d s k y i n t h o s e r e m a r k a b l e y e a r s o f s t r u g g l e f o r s c i e n c e w a s V . D o k u c h a v e v , a m a n o f r a r e i n i t i a t i v e a n d e f f i c i e n c y . A t h i s l e c t u r e s V . V e r n a d s k y l e a r n e d t o u n d e r s t a n d t h e i m p o r t a n c e o f e x a c t k n o w l e d g e a n d p r e c i s e m e t h o d s o f r e s e a r c h .

F r o m D o k u c h a y e v ' s c l a s s i c a l w o r k Russian Chernozem V e r n a d s k y b o r r o w e d t h e p r o f o u n d i d e a o f t h e soi l a s a s p e c i a l n a t u r a l - h i s t o r i c a l b o d y , a n d m a n y o f h i s t h o u g h t s i n b i o g e o c h e m i s t r v s p r i n g f r o m V . D o k u c h a y e v ' s s c i e n t i f i c i d e a s .

V e r n a d s k y ' s l o n g l i fe ( 1 8 6 3 - 1 9 4 5 ) w a s o n e o f p e r s i s t e n t w o r k a n d b r i l l i a n t c r e a t i v e t h o u g h t , a l i fe w h i c h o p e n e d n e w fields i n s c i e n c e a n d c h a r t e d a n e w c o u r s e i n n a t u r a l s c i e n c e i n o u r c o u n t r y .

V e r n a d s k y a l s o p l a y e d a v e r y i m p o r t a n t p a r t a s a h i s t o r i a n o f s c i e n c e b e c a u s e h e a l w a y s l a i d t h e h i s t o r i c a l p r i n c i p l e a n d t h e h i s t o r i c a l m e t h o d a t t h e bas i s o f n a t u r a l s c i e n c e .

H e i n v a r i a b l y w a n t e d h i s p u p i l s t o e l u c i d a t e t h e h i s t o r y o f a p r o b l e m . H e u s e d t o s a y : " W e n a t u r a l i s t s m u s t l e a r n t h e p r o f o u n d h i s t o r i c a l m e t h o d s o f u n d e r s t a n d i n g t h e p a s t f a t e s o f m a n k i n d f r o m h i s t o r i a n s . O n l y b y u s i n g t h e s e m e t h o d s w i l l w e b e c o m e h i s t o r i a n s o f n a t u r e . "

T w e n t y - o n e y e a r s o f V e r n a d s k y ' s l i fe ( 1 8 9 0 - 1 9 1 1 ) w e r e c o n n e c t e d w i t h M o s c o w U n i v e r s i t y w h e r e h e w o r k e d as p r o f e s s o r o f m i n e r a l o g y a n d c r y s t a l l o g r a p h y .

I t w i l l b e o b s e r v e d t h a t b e f o r e V e r n a d s k y t h e t e a c h i n g o f m i n e r a l o g y

3 5 8

A c a d e m i c i a n V. V e r n a d s k y a m o n g his young s tuden t s a t M o s c o w Univers i ty . Pho to-graph taken in 1911. V. V e r n a d s k y is s i t t ing in the cen t re ; A . F e r s m a n is s t and ing on the r ight

at Moscow University was confined to a tedious description of the minerals. The collections were in disorder. Vernadsky not only put them in order, but also enriched them with his own exhibits collected during his numerous excursions and travels. He very frequently travelled in Russia and abroad and considered these excursions very important in the matter of training future scientists. V. Vernadsky radically reorganized the teaching of mineralogy replacing the dry descriptive science by a chemical mineralogy based on history and by teaching a separate course of crystallography. He organized the first scientific mineralogical circle which included all the mineralogists of Moscow. At the same time he obligated his co-workers and pupils to do experimental work in physico-chemical description of chemical compounds and minerals, which played a very big part in developing the school of mineralogy.

359

T h e s e w e r e t h e s o u r c e s o f R u s s i a n c h e m i c a l m i n e r a l o g y a n d l a t e r

o f g e o c h e m i s t r y , a n d t h e s c h o o l o f V . V e r n a d s k y ' s p u p i l s , t h e m i n e r a l -

o g i s t s - g e o c h e m i s t s , t h u s c a m e i n t o b e i n g a t M o s c o w U n i v e r s i t y .

T h e first e d i t i o n o f h i s v o l u m i n o u s f u n d a m e n t a l c l a s s i c a l w o r k

Experiment in Descriptive Mineralogy m a d e i t s a p p e a r a n c e i n 1 9 0 6 a s

a r e s u l t o f b r o a d l y c o n c e i v e d a n d r e g u l a r i n v e s t i g a t i o n s o f n u m e r o u s

d e p o s i t s o f v a r i o u s m i n e r a l s ( t h e w o r k w a s c o m p l e t e d i n 1 9 1 8 ) .

I n 1 9 0 9 V l a d i m i r V e r n a d s k y w a s e l e c t e d M e m b e r o f t h e A c a d e m y

o f S c i e n c e s . I n 1 9 1 i ~ . i c m o v e d t o P e t e r s b u r g a n d b e g a n a n e w s t a g e

i n h i s l i f e ; w h e r e a s t h e f i r s t 2 0 y e a r s h a d b e e n s p e n t o n d e v e l o p i n g

a n e w s c i e n t i f i c s c h o o l , t h e s u b s e q u e n t y e a r s ( t h e P e t e r s b u r g p e r i o d )

w e r e d e v o t e d t o o r g a n i z i n g n e w s c i e n t i f i c w o r k .

T h i s c h a n g e w a s n o e a s y m a t t e r . V e r n a d s k y m i s s e d M o s c o w a g r e a t

d e a l . H e g a v e u p t e a c h i n g a n d t r i e d t o d e v o t e h i m s e l f f u l l y t o r e s e a r c h

w o r k c o n c e n t r a t i n g i t i n t h e w a l l s o f t h e A c a d e m y o f S c i e n c e s . H e

e n t e r e d t h e A c a d e m y a t t h e t i m e i t w a s h e a d e d b y A . K a r p i n s k y ,

t h e R u s s i a n s c i e n t i s t w h o h a d l a i d t h e b a s i s f o r s t u d y i n g t h e g e o l o g i c a l

s t r u c t u r e o f t h e R u s s i a n P l a i n .

V e r n a d s k y c o n d u c t e d e x t e n s i v e s p e c t r o s c o p i c i n v e s t i g a t i o n s o f t h e

d i s t r i b u t i o n o f r a r e a n d d i s p e r s e d c h e m i c a l e l e m e n t s i n t h e R u s s i a n

r o c k s a n d m i n e r a l s a n d w a s t h e first t o r a i s e t h e q u e s t i o n o f t h e n e c e s s i t y

o f a w i d e a n d r e g u l a r s t u d y o f r a d i o a c t i v e p h e n o m e n a o n t h e t e r r i t o r y

o f R u s s i a .

I n 1 9 2 2 h e f o u n d e d a r a d i u m i n s t i t u t e i n a s s o c i a t i o n w i t h A c a d e -

m i c i a n V . K h l o p i n ; a n a c c u r a t e m e t h o d o l o g y f o r e s t i m a t i n g t h e a g e

o f r o c k s b y l e a d a n d h e l i u m w a s d e v e l o p e d a t t h e i n s t i t u t e .

T h e f o l l o w i n g w o r d s u t t e r e d b y V e r n a d s k y s o u n d a s i f t h e y w e r e

s a i d t o d a y : " W e a r e a p p r o a c h i n g a g r e a t r e v o l u t i o n i n t h e l i f e o f

m a n n o t t o b e c o m p a r e d w i t h a n y t h i n g e v e r e x p e r i e n c e d b e f o r e . I t

w i l l n o t b e l o n g b e f o r e m a n l a y s h i s h a n d s o n a t o m i c e n e r g y , a s o u r c e

o f p o w e r t h a t w i l l e n a b l e h i m t o o r g a n i z e h i s l i f e a t h i s w i l l . T h i s m a y

c o m e a b o u t i n t h e n e a r e s t f u t u r e o r i t m a y t a k e a n o t h e r 1 0 0 y e a r s .

I t i s c l e a r , h o w e v e r , t h a t i t w i l l . B u t w i l l m a n b e a b l e t o u t i l i z e t h i s

p o w e r f o r h i s o w n g o o d r a t h e r t h a n f o r s e l f - d e s t r u c t i o n ? H a s m a n

s u f f i c i e n t l y m a t u r e d t o m a k e u s e o f t h e f o r c e t h a t s c i e n c e m u s t i n e v i -

t a b l y p r o v i d e h i m w i t h ? T h e s c i e n t i s t s m u s t n o t s h u t t h e i r e y e s t o t h e

p o s s i b l e c o n s e q u e n c e s o f t h e i r s c i e n t i f i c w o r k a n d o f t h e s c i e n t i f i c

p r o c e s s . T h e y m u s t f e e l r e s p o n s i b l e f o r t h e e f f e c t s o f t h e i r d i s c o v e r i e s .

3 6 0

T h e y m u s t t i e t h e i r w o r k i n w i t h a b e t t e r o r g a n i z a t i o n o f a l l o f

h u m a n i t y " (Essays and Speeches, 1 9 2 2 ) .

A s a r e s u l t h e d e v e l o p e d a n e w , r a d i o g e o l o g i c a l t r e n d i n s c i e n c e ,

w h i l e t h e w o r k o n r a d i u m w a s p u t o n a b r o a d s c i e n t i f i c b a s i s . S o m e -

w h a t l a t e r h e b e g a n p u b l i s h i n g h i s v o l u m i n o u s History of the Minerals in the Earth's Crust ( 1 9 2 3 - 3 6 ) . T h i s v e r y v a l u a b l e s c i e n t i f i c w o r k

SCIENCES A B O U T M A T T E R CRYSTALLOGRAPHY

Geochemistry among kindred sciences

w a s , u n f o r t u n a t e l y , u n f i n i s h e d . A t t h e s a m e t i m e h e i n t e g r a t e d h i s

r e m a r k a b l e g e o c h e m i c a l i d e a s a n d p u b l i s h e d h i s b o o k e n t i t l e d Essays on Geochemistry ( 1 9 2 7 - 3 4 ) .

I n h i s w o r k V e r n a d s k y s h o w e d o n a n u m b e r o f s e p a r a t e e l e m e n t s

h o w i m p o r t a n t i t w a s t o a b a n d o n t h e o l d p o i n t o f v i e w i n s t u d y i n g

m i n e r a l s a s c o m p l e x m o l e c u l e s a n d t o b e g i n i n v e s t i g a t i n g t h e a t o m

a n d i t s p a t h s o f m i g r a t i o n s i n t h e e a r t h a n d i n t h e c o s m o s .

3 6 1

a s t r o p h y s i c s , a s t r o c h e m i s t r y

physicsi c h e m i s t r y , p h y s i c a l i c h e m i s t r y

g e o c h e m i s t r y )

geophysics ' ' b i o l o g y s o i l s t u d y

m i n e r a l o g y \ p e t r o g r a p h y

m e t a l l u r g y

/ g e o l o g y geog raphy

t e c h n o l o g y

sc ience o f m i n e r a l s

I n 1928 h e f o u n d e d a b i o g e o c h e m i c a l i n s t i t u t e a t t h e A c a d e m y of Sciences a n d b e c a m e t h e f a t h e r of a n e w b r a n c h of g e o c h e m i s t r y — b i o g e o c h e m i s t r y . T h i s sc ience s tudies t h e c h e m i c a l c o m p o s i t i o n of l iv ing o r g a n i s m s a n d t h e p a r t i c i p a t i o n of l iv ing s u b s t a n c e a n d t h e p r o d u c t s of its d e c o m p o s i t i o n i n t h e processes of m i g r a t i o n , d i s t r i b u t i o n , d i spers ion a n d a c c u m u l a t i o n of c h e m i c a l e l e m e n t s i n t h e e a r t h ' s c rus t .

I n 1935 t h e A c a d e m y of Sciences w a s t r a n s f e r r e d t o M o s c o w . D u r i n g t h e second p e r i o d of his M o s c o w act iv i t ies (1935-45) V e r n a d s k y d e v o t e d m o s t of his a t t e n t i o n t o his w o r k i n t h e b i o g e o c h e m i c a l l a b o r a t o r y ; h e pe r sona l ly i nves t i ga t ed t h e b i o c h e m i c a l ro le of c a r b o n , a l u m i n i u m a n d t i t a n i u m a n d p o i n t e d o u t t h e necess i ty fo r d r a w i n g u p a g e o c h e m -ical m a p of t h e b i o s p h e r e .

T h e w o r d " g e o c h e m i s t r y " w a s u t t e r e d m o r e t h a n 100 yea r s ago , b u t r ea l g e o c h e m i c a l sc ience w a s b o r n on ly i n t h e last 30 years , i n t h e years of t h e n e w s t o r m y q u e s t s ; Sovie t sc ience h a s p l a y e d a n especial ly i m p o r t a n t p a r t i n th i s ; i t b o l d l y forges a h e a d , deve lops n e w b r a n c h e s of k n o w l e d g e a n d i n its a sp i r a t i ons a n d a c h i e v e m e n t s c o m b i n e s t h e o r y w i t h p r a c t i c e .

HOW THE CHEMICAL ELEMENTS AND MINERALS WERE NAMED

T h i s q u e s t i o n s h o u l d b e of i n t e r e s t t o a l l o f us . I t is n o t so easy t o r e m e m b e r t h e h u n d r e d s a n d t h o u s a n d s of t h e d i f f e r e n t n a m e s of e le-m e n t s , m i n e r a l s a n d rocks . B u t if w e g r a s p t h e m e a n i n g of e a c h n a m e t h e y m a y b e eas i e r t o r e m e m b e r .

S o m e of t h e r e a d e r s m a y h a v e c o m e ac ros s m y l i t t l e b o o k Recollec-tions about a Stone a n d m a y r e m e m b e r t h e f a c e t i o u s s t o r y i n i t a b o u t t h e w a y n e w m i n e r a l s a n d n e w s t a t i o n s of t h e K i r o v R a i l w a y w e r e n a m e d . I t r i d i c u l e d e spec i a l l y t h e o ld r a i l w a y m e n w h o h a d g i v e n t h e n a m e of A f r i c a n d a t o a s t a t i o n o n l y b e c a u s e t h e y h a d a r r i v e d t h e r e o n a d a y w h e n i t w a s as h o t as i t is i n A f r i c a .

A n o t h e r s t a t i o n w a s n a m e d T i t a n t h o u g h n o t a t r a c e of t i t a n i u m o re s h a d b e e n f o u n d a n y w h e r e a r o u n d .

W e m u s t confess , h o w e v e r , t h a t n o t o n l y o u r o ld r a i l w a y m e n a c t e d th i s w a y ; c h e m i s t s a n d m i n e r a l o g i s t s d i d t h e s a m e w h e n t h e y d i s c o v e r e d a n y t h i n g n e w ; e a c h of t h e m n a m e d t h i n g s a t wi l l a n d al l w e c a n d o n o w is r e m e m b e r t h e s e n a m e s as t h e y a r e . I n c h e m i s t r y i t is s i m p l e e n o u g h ; t h e r e a r e o n l y a b o u t 100 c h e m i c a l e l e m e n t s fo r w h i c h n a m e s h a d t o b e t h o u g h t of . I t is m u c h h a r d e r i n m i n e r a l o g y w h e r e close t o 2 , 0 0 0 m i n e r a l s a r e a l r e a d y k n o w n a n d w h e r e f r o m 2 0 t o 30 n e w o n e s a r e d i s c o v e r e d e v e r y y e a r .

L e t us first t r y a n d m a k e o u t t h e n a m e s of t h e c h e m i c a l e l e m e n t s o n w h i c h t h e s c i e n c e of c h e m i s t r y r e s t s ; t h e c h e m i c a l s y m b o l s w e r e m a d e u p of t h e first l e t t e r s of t h e s e n a m e s in L a t i n : F e ( f e r rum -—iron) , As (arsenicum—arsenic) , e t c .

C h e m i s t s a n d g e o c h e m i s t s m o s t f r e q u e n t l y a n d m o s t w i l l i n g l y n a m e d t h e n e w l y d i s c o v e r e d e l e m e n t s a f t e r t h e c o u n t r y o r c i ty w h e r e t h e

jfyaam/s [Ruthenium | audi uas

borrr in Russia

d i s c o v e r y w a s m a d e o r w h e r e a c o m p o u n d o f t h e g i v e n s u b s t a n c e

w a s first f o u n d .

W e c a n , t h e r e f o r e , e a s i l y u n d e r s t a n d s u c h n a m e s a s e u r o p i u m ,

g e r m a n i u m , g a l l i u m ( f r o m t h e i n d e n t n a m e o f F r a n c e — G a l l i a ) ,

a n d s c a n d i u m ( S c a n d i n a v i a ) ; t h e s e n a m e s c a n b e e a s i l y r e m e m b e r e d ;

i t i s m u c h h a r d e r t o r e m e m b e r t h e n a m e s i n w h i c h a n c i e n t d e s i g n a t i o n s

o f c i t i e s o r c o u n t r i e s w e r e u s e d . I t i s s o m e t i m e s v e r y d i f f i c u l t t o g u e s s

t h e o r i g i n s o f t h e s e n a m e s .

T h u s , w h e n a n e w e l e m e n t w a s d i s c o v e r e d i n C o p e n h a g e n i n

1 9 2 4 i t w a s g i v e n t h e n a m e o f h a f n i u m , t h e o l d a n d u n k n o w n

n a m e o f t h e D a n i s h c a p i t a l . L u t e c i u m w a s s i m i l a r l y g i v e n t h e o l d

n a m e o f P a r i s . T h u l i u m i s t h e o l d S c a n d i n a v i a n n a m e o f S w e d e n

a n d N o r w a y .

T h e m e t a l r u t h e n i u m , w h i c h w a s f o u n d i n K a z a n b y c h e m i s t

R . K l a u s s , w a s n a m e d i n h o n o u r o f R u s s i a , b u t , u n f o r t u n a t e l y , i t

s c a r c e l y o c c u r s e v e n t o m a n y c o m p e t e n t c h e m i s t s t h a t " r u t h e n i u m "

s t a n d s f o r " R u s s i a n . "

A c u r i o u s t h i n g h a p p e n e d t o o n e o f t h e f e l d s p a r q u a r r i e s n e a r

S t o c k h o l m i n S w e d e n ; t h e Y t t e r b i p e g m a t i t e v e i n y i e l d e d a l a r g e

n u m b e r o f n e w e l e m e n t s , a n d t h e n a m e s " y t t e r b i u m , " " y t t r i u m , "

" e r b i u m " a n d " t e r b i u m " r e s u l t e d f r o m t h e d i f f e r e n t v e r s i o n s o f

t h i s n a m e .

M a n y c h e m i c a l e l e m e n t s w e r e g i v e n t h e i r n a m e s o n t h e b a s i s o f

t h e i r p h y s i c a l a n d c h e m i c a l p r o p e r t i e s . T h i s w o u l d s e e m m o r e r a t i o n a l ,

b u t t h e s e n a m e s a r e i n t e l l i g i b l e t o , a n d e a s i l y r e m e m b e r e d b y , t h o s e

w h o h a v e a g o o d k n o w l e d g e o f o l d G r e e k a n d L a t i n .

S i n c e a s e r i e s o f c h e m i c a l e l e m e n t s w e r e d i s c o v e r e d o n t h e b a s i s

o f t h e i r c o l o u r l i n e s i n t h e s p e c t r o s c o p e t h e s e e l e m e n t s w e r e g i v e n

t h e i r n a m e s a c c o r d i n g t o t h e c o l o u r o f t h e s e l i n e s : i n d i u m b y i t s

b l u e l i n e , c e s i u m b y i t s a z u r e - b l u e , r u b i d i u m b y i t s r e d a n d

t h a l l i u m b y i t s g r e e n l i n e .

O t h e r e l e m e n t s w e r e n a m e d a f t e r t h e c o l o u r s o f t h e i r s a l t s ; f o r

e x a m p l e , c h r o m i u m — f r o m t h e G r e e k w o r d m e a n i n g " c o l o u r " — w a s

s o n a m e d b e c a u s e o f t h e b r i g h t c o l o u r i n g o f c h r o m i u m s a l t s , w h i l e

i r i d i u m w a s g i v e n i t s n a m e b e c a u s e o f t h e i r i d e s c e n t c o l o u r s o f t h e

s a l t s o f t h i s m e t a l .

V e r y m a n y c h e m i s t s , w h o w e r e k e e n o n a s t r o n o m y , n a m e d c e r t a i n

e l e m e n t s a f t e r p l a n e t s o r s t a r s . S u c h a r e t h e n a m e s o f u r a n i u m ,

3 6 4

p a l a d i u m , c e r i u m , t e l l u r i u m , s e l e n i u m a n d h e l i u m . O n l y t h e las t n a m e h a s a d e e p e r m e a n i n g b e c a u s e h e l i u m (hel ios—sun) w a s first d i s c o v e r e d i n t h e s u n .

A still g r e a t e r n u m b e r of n a m e s w e r e g i v e n i n h o n o u r of t h e g o d s a n d g o d d e s s e s of a n t i q u i t y . V a n a -d i u m w a s , t h u s , n a m e d in h o n o u r of a g o d d e s s , w h i l e c o b a l t a n d n i cke l , t h e h a r m f u l f e l l o w - t r a v e l l e r s of s i lver o res , w e r e n a m e d a f t e r t h e w i c k e d . g n o m e s w h o w e r e s u p p o s e d t o l ive i n t h e S a x o n m i n e s . Stibnite

T h e n a m e s of t a n t a l u m , n i o b i u m , t i t a n i u m a n d t h o r i u m w e r e t a k e n w i t h o u t a n y p a r t i c u l a r r e a s o n s f r o m a n c i e n t m y t h o l o g y . A n t i m o n y w a s k n o w n i n t h e M i d d l e A g e s b y t h e n a m e of a n t i m u a n , w h i c h m o s t p r o b a b l y s t e m s f r o m t h e G r e e k w o r d m e a n i n g " f l o w e r s , " s i nce t h e c r y s t a l s of s t i b n i t e a r r a n g e t h e m s e l v e s i n b u n c h e s r e s e m b l i n g t h e flowers of t h e c o m p o s i t a e . A c c o r d i n g t o a n o t h e r v e r s i o n a n t i m u a n is d e r i v e d f r o m antimonk a l l e g e d l y b e c a u s e a n t i m o n y l e a d s r e c l u s e m o n k s i n t o t e m p t a t i o n .

M u c h less a t t e n t i o n w a s d e v o t e d t o t h e n a m e s of w o r l d - f a m o u s sc ient i s t s . T h e m i n e r a l g a d o l i n i t e w a s n a m e d i n h o n o u r of t h e R u s s i a n p r o f e s s o r A . G a d o l i n , a n d t h e e l e m e n t w a s n a m e d g a d o l i n i u m a f t e r t h e m i n e r a l .

T h e n a m e " s a m a r i u m " c o m e s f r o m t h e m i n e r a l i n w h i c h i t w a s d i s c o v e r e d ; s a m a r s k i t e w a s first f o u n d i n t h e I l m e n M o u n t a i n s i n t h e U r a l s a n d w a s n a m e d i n h o n o u r of C o l o n e l S a m a r s k y .

R u t h e n i u m , g a d o l i n i u m a n d s a m a r i u m a r e t h r e e e l e m e n t s w h o s e n a m e s a r e of a p u r e l y R u s s i a n o r i g i n . i amatsk i te (black)

365

In addition to all these complicated and at times unreasonable names, however, there are about 30 chemical elements which in the roots of their names have various ancient Arabic, Indian or Latin words.

The origin of the words aurum (gold), plumbum (lead), arsenicum (arsenic), etc., is responsible for many arguments. Finally, there are several new transuranium elements; neptunium (Np) 93, and plutonium (Pn) 94 were named after planets; americium (Am) 95 stems from the word America, and curium (Cm) 96 was named in honour of Marie Curie, etc.

See what chaos and disorder! Greek, Arabic, Indian, Persian, Latin and Slavonic roots, gods, goddesses, stars, planets, cities, countries and surnames frequently without any rhyme or reason.

True, there were attempts to put some order into the system of names of elements, but there are so few of them that it really does not pay. It is quite a different question with the names of minerals.

Here the geochemist and mineralogist must radically alter their practice because more than 25 new minerals must be named every year and it is, certain!)', unreasonable to name such compounds as laurite after the chemist's bride Laura and to give to a series of minerals names of princes and counts out of loyalty to these people who never had anything to do with minerals, as was the case, for instance, with uvarovite.

Finally, some names are so incongruous that we can hardly pronounce them, for example, ampangabeite, named after the place where it was found in Madagascar. The names of the minerals form a most interesting page in the history of mineralogy and chemistry. The origin of the names of a number of minerals is still unknown, and many of them have their roots in an-cient India, Egypt or Persia. Persia has given us turquoise and emerald .smaragd), ancient Greece—topaz

' and garnet, and India—rubies, sapphire and tourmaline. T o p a z f r o m M u r z i n k a deposi t s ( E a s t

Ura ls )

3 6 6

Many minerals were named after their locations. Thus, such names as ilmenite (Ilmen Moun-tains in the South Urals), bai-kalite (Lake Baikal) and mur-manite (Murmansk Region) are very well known and intelligible to us Soviet people. But the most interesting name to us is connected with Moscow; it is moscovite or muscovite, the famous potash mica which plays so important a par t in the elec-trical industry. Very many names were given in honour of well-known scientists, prominent chemists and mineralogists. We shall mention scheelite, so called

in honour of the well-known c , , . c , , Crystals of l imespa t Swedish chemist Scheele, goe-thite—in honour of the poet and mineralogist W. Goethe, and the familiar mendelevite and vernadskite.

I t must be admitted that the names given to minerals on the basis of their colour are very suitable, but one must know Latin or Greek to understand these names. These include, for example, aquamarine (colour of sea-water), auripigment (colouring of gold), leucite (from the Greek word leucos—white), cryolite (from the Greek word meaning "ice") and celestite (from the Latin word meaning "sky").

Very many names stem from the physical and chemical properties of the mineral. Thus, silver-like minerals are called glances, copper-or bronze-like minerals are known as pyrites, minerals which have a capacity for splitting in several directions are called spars, while minerals that contain metal which it is hard to guess by the deceptive exterior are known as blendes.

T h e diamond received its name from the Greek word adamas, i.e., invulnerable, invincible, adamant ine. I t must, finally, be admitted, that many minerals were rightly named after the chemical elements

367

Oriental precious stone merchant. 17th-century engraving

w h i c h f o r m e d t h e i r m a i n

c o n s t i t u e n t . T h e s e i n c l u d e , f o r

i n s t a n c e , p h o s p h o r i t e , c a l c i t e ,

w o l f r a m i t e , m o l y b d e n i t e , e t c .

T h e r e a r e s o m e n a m e s ,

h o w e v e r , t h a t e v o k e a s p e c i a l

i n t e r e s t . S o m e o f t h e m a r e

c o n n e c t e d w i t h l e g e n d s ; t h e

m e a n i n g o f o t h e r s i s c o n c e a l e d

i n t h e e n t r a i l s o f t h e a l c h e -

m i s t s ' l a b o r a t o r i e s . T h u s , a s -

b e s t o s r e c e i v e d i t s n a m e f r o m

t h e G r e e k w o r d m e a n i n g

" u n b u r n a b l e . " N e p h r i t e o w e s

i t s n a m e t o t h e m e d i e v a l

e r r o r t h a t i t a l l e g e d l y c u r e d k i d n e y d i s e a s e . P h e n a c i t e — " d e c e p t i v e "

w a s s o n a m e d b e c a u s e i t s b e a u t i f u l w i n e - r e d c o l o u r f a d e s w h e n

e x p o s e d f o r a f e w h o u r s t o t h e s u n .

A p a t i t e , o r " d e c e i v e r , " w a s g i v e n t h i s n a m e b e c a u s e i t i s h a r d t o

d i s t i n g u i s h f r o m o t h e r m i n e r a l s ; f i n a l l y , a m e t h y s t h a s b o r n e i t s n a m e

s i n c e t h e M i d d l e A g e s w h e n t h e m y s t e r i o u s p r o p e r t y o f s e r v i n g a s a

p r o t e c t i o n a g a i n s t d r u n k e n n e s s w a s a s c r i b e d t o i t .

T h i s b r i e f d e s c r i p t i o n s h o w s w h a t a c o m p l i c a t e d b u s i n e s s t h e n a m i n g

o f m i n e r a l s i s .

I s n ' t i t a t a l l p o s s i b l e t o b r i n g o r d e r i n t o t h i s m a t t e r ? I s n ' t i t p o s s i b l e

t o o r g a n i z e a n i n t e r n a t i o n a l c o m m i s s i o n w h i c h m i g h t s a n c t i o n t h e

n a m e s o f n e w m i n e r a l s a n d w h i c h m i g h t s e e t o i t t h a t t h e y c o r r e s p o n d

t o t h e p r o p e r t i e s o f t h e m i n e r a l s , t h a t t h e y b e e a s y t o r e m e m b e r , t h a t

t h e v e r y n a m e s f o r m s o m e s o r t o f a s y s t e m a n d t h a t t h e y c l a s s i f y t h e

h u n d r e d s a n d t h o u s a n d s o f m i n e r a l s p e c i e s ?

W e h o p e t h a t , a s t h e c h e m i c a l a n d g e o c h e m i c a l s c i e n c e s c o n t i n u e

t o d e v e l o p a n d p r o s p e r , o u r l i t t l e p r o p o s a l w i l l b e g i v e n c o n s i d e r a t i o n

s o t h a t t h e s c h o o l c h i l d a n d t h e s t u d e n t m a y n o l o n g e r b e t o r m e n t e d

w i t h l o n g a n d h a r d - t o - r e m e m b e r n a m e s , a n d t h a t t h e n a m e s g i v e n

t o t h e m i n e r a l s b e c l o s e l y r e l a t e d t o t h e c h a r a c t e r i s t i c p r o p e r t i e s o f

t h e s t o n e , t h e p l a n t a n d t h e a n i m a l i n o r d e r t h a t t h e y m a y b e e a s i l y

c o m m i t t e d t o m e m o r y .

CHEMISTRY AND GEOCHEMISTRY IN OUR TIME

W e a r e l i v i n g a t a t i m e o f g r a n d a c h i e v e m e n t s i n p h y s i c s a n d c h e m -i s t ry .

T h e o l d m e t a l — i r o n — i s b e g i n n i n g t o b e r e p l a c e d b y o t h e r s o r b e c o m b i n e d w i t h a n u m b e r o f r a r e m e t a l l i c s u b s t a n c e s .

C o m p l e x c o m p o u n d s o f s i l i c o n i n g l a s s , p o r c e l a i n , b r i c k , c o n c r e t e a n d s l a g s a r e b e g i n n i n g t o s u b s t i t u t e f o r t h e o l d i r o n s t r u c t u r e s .

O r g a n i c c h e m i s t r y — c h e m i s t r y o f c a r b o n — h a s m a d e t r e m e n d o u s h e a d w a y o f l a t e , a n d l a r g e f a c t o r i e s h a v e a l r e a d y t a k e n t h e p l a c e o f t h e e n o r m o u s fields o f i n d i g o a n d r u b b e r p l a n t a t i o n s .

T h e s e f a c t o r i e s p r o d u c e s y n t h e t i c r u b b e r a n d p a i n t s f r o m p r o d u c t s o f c o a l d i s t i l l a t i o n , w h i c h a l r e a d y n o w n o t o n l y r e p l a c e t h e n a t u r a l v e g e t a b l e d y e s , b u t a l s o y i e l d a m u c h w i d e r s c a l e o f c o l o u r s .

A s a m a t t e r o f f a c t , t h e w o r l d is n o w u s i n g e v e r m o r e c h e m i s t r y i n s c i e n c e , e c o n o m y a n d l i f e . C h e m i s t r y is p e n e t r a t i n g i n t o e v e r y l i t t l e d e t a i l o f o u r d a y - t o - d a y l i f e , i n t o e v e r y p a r t i c u l a r o f t h e m o s t c o m p l e x a p p a r a t u s o f i n d u s t r i a l p r o d u c t i o n .

A n d i t s t a n d s t o r e a s o n t h a t i n a d d i t i o n t o t h e m o r e e x t e n s i v e u s e s o f c h e m i s t r y w e a r e e x t e n d i n g o u r s t u d i e s o f t h e n a t u r a l r e s o u r c e s a n d t h e m i n e r a l r a w m a t e r i a l s b e c a u s e o u r e c o n o m y a n d i n d u s t r y n e e d e n o r m o u s q u a n t i t i e s o f t h e m .

G e o c h e m i s t r y is s o c l o s e l y r e l a t e d t o c h e m i s t r y t h a t i t is f r e q u e n t l y h a r d t o d r a w a l i n e b e t w e e n t h e s e t w o s c i e n c e s .

O r g a n i z a t i o n o f s p e c i a l r e s e a r c h i n s t i t u t e s a n d l a b o r a t o r i e s n o w f o r m s t h e b a s i s o f t h e d e v e l o p m e n t o f t h e c h e m i c a l i n d u s t r y , a n d w e g r a t e f u l l y r e c a l l t h e w o r d s o f t h e f a m o u s F r e n c h b i o l o g i s t P a s t e u r , w h o a s e a r l y a s i 8 6 0 s a i d :

24 3<>9

" I b e s e e c h y o u t o d e v o t e m o r e a t t e n t i o n t o t h e s a c r e d a s y l u m s k n o w n as l a b o r a t o r i e s . I n s i s t t h a t t h e r e b e m o r e o f t h e m a n d t h a t t h e y b e b e t t e r e q u i p p e d . T h e s e a r e t h e t e m p l e s o f o u r f u t u r e , o f o u r w e a l t h a n d o f o u r w e l f a r e . "

S i n c e t h e G r e a t O c t o b e r S o c i a l i s t R e v o l u t i o n a n e x t e n s i v e n e t w o r k o f r e s e a r c h i n s t i t u t e s w o r k i n g i n t h e f i e l d o f c h e m i s t r y h a s b e e n o r g a n i z e d i n t h e S o v i e t U n i o n .

S p e c i a l c h e m i c a l i n s t i t u t e s h a v e b e e n se t u p . M a n y o f t h e s e h a v e a l s o d e a l t w i t h g e o c h e m i c a l p r o b l e m s . S o m e o f t h e m h a v e s u c c e s s f u l l y d e v e l o p e d t e c h n o l o g i c a l s c h e m e s f o r u t i l i z i n g a l u m i n i u m o r e s , o t h e r s h a v e b r i l l i a n t l y s o l v e d t h e p r o b l e m s o f u s i n g b o r o n a n d i ts c a r b i d e s , st i l l o t h e r s h a v e e x t e n s i v e l y s t u d i e d t h e sa l t s f o u n d i n t h e S o v i e t L a n d ' s d e p o s i t s a n d a n u m b e r o f e l e m e n t s — r a r e e a r t h s , p l a t i n u m , g o l d , n i o b i u m , t a n t a l u m , n i c k e l , e t c .

T h e G e o c h e m i c a l I n s t i t u t e o f t h e U . S . S . R . A c a d e m y o f S c i e n c e s , f o u n d e d f o r t h e e l a b o r a t i o n o f m o r e s p e c i a l p r o b l e m s , h a s c o n d u c t e d a n u m b e r o f i n v e s t i g a t i o n s ; t h e w o r k o f t h i s i n s t i t u t e h a s l a i d t h e b a s i s f o r t h e c o l l e c t i v e g e o c h e m i c a l t h o u g h t i n t h e c o u n t r y .

T h e M e n d e l e y e v S o c i e t y , w h i c h c o n t i n u e s t h e g l o r i o u s t r a d i t i o n s o f t h e R u s s i a n P h y s i c o - C h e m i c a l S o c i e t y , is e x t e n s i v e l y p r o p a g a t i n g c h e m i c a l i d e a s ; t h e M e n d e l e y e v S o c i e t y u n i t e s i n i t s i n s t i t u t i o n s a n d b r a n c h e s s e v e r a l t h o u s a n d p e o p l e .

M e n t i o n m u s t a l s o b e m a d e h e r e o f t h e A l l - U n i o n M i n e r a l o g i c a l S o c i e t y f o u n d e d i n P e t e r s b u r g i n 1 8 1 7 a n d s t i l l v i g o r o u s l y e l a b o r a t i n g p r o b l e m s o f m i n e r a l o g y a n d p e t r o g r a p h y .

G e o c h e m i s t r y h a s w o n w i d e p u b l i c r e c o g n i t i o n , a n d g e o c h e m i c a l t h o u g h t h a s b e g u n t o p e n e t r a t e i n t o a l l s c i e n t i f i c s t u d i e s o f m i n -e r a l s .

A S o v i e t c h e m i s t h a s c a l c u l a t e d t h a t m o r e t h a n a m i l l i o n s c i e n t i f i c p a p e r s d e a l i n g w i t h c h e m i s t r y h a v e b e e n p u b l i s h e d i n p e r i o d i c a l s i n t h e l a s t 3 0 y e a r s ; c l o s e t o 8 0 , 0 0 0 o f t h e s e h a v e b e e n p u b l i s h e d i n t h e l a s t f e w y e a r s a l o n e . I n o r d e r t o f o l l o w u p t h i s e n o r m o u s l i t e r a t u r e , t h e r e a r e s p e c i a l j o u r n a l s w h i c h r e v i e w a l l a r t i c l e s p u b l i s h e d t h r o u g h o u t t h e w o r l d i n m o r e t h a n 3 0 l a n g u a g e s , a n d i n n e a r l y 3 , 0 0 0 c h e m i c a l j o u r n a l s .

H o w e v e r , w h e n w e s p e a k o f t h e n u m e r o u s i n v e s t i g a t i o n s c o n d u c t e d i n r e c e n t y e a r s , w e m u s t n o t f o r g e t t h a t a n o v e r w h e l m i n g p a r t o f t h e s e d e a l s w i t h c a r b o n c o m p o u n d s , t h a t a v e r y l a r g e n u m b e r o f t h e m is

37

Chcmica l utensi ls m a d e of quar tz

related to purely technical problems and that only about two per cent of them are closer to the problems of geochemistry, to the prob-lems of studying the substance in the earth's crust, its abundance, migrations, structure, combination and formation into ores of the grades employed in industry.

T h e expansion of scientific work in the research institutes and so-cieties, and the development of publishing has enabled the chemical sciences to pose ever deeper and broader problems. Though 200 years have already passed since Lomonosov's death, we tart still use the first paragraph of his foreword to the lecture on physical chemistry delivered by him in 1751 as the basic motto in our chemical work: " T h e study of chemistry may pursue a double a im; one of these is the perfection of the natural sciences, the other—multiplication of the good things of life."

24' 37'

As a ma t t e r of fact , chemist ry a n d physics have not only per-fected the na tura l sciences, but have also opened before us the mysteries of na tu r e h idden f rom our ryes; science and engineer ing have been able to reveal to us the mul t i formi ty of atoms, of which the world is composed.

O w i n g to the achievements of the chemical sciences, m o d e r n industry now produces a b o u t 50,000 compounds of di f ferent elements, while the n u m b e r of organic compounds developed a n d studied in laboratories runs into one million. T h e r e is no end to the compounds labora-tories can still p roduce .

I low g rand , these figures are compared with the 2,500 compounds we know in na tu r e ! And yet precisely na tu re was our first teacher of the chemical s< iences. O u r industry is based on minera l r aw materials , f l ic direction of the work in chemical laboratories depends on t h e m ;

both the. s t ructure of substance arid the course of chemical reactions have been studied 011 na tura l materials.

T h a i is why it took geochemistry to build a bridge, between the chemical and the geological sciences. By s tudying the. propert ies and reserves of the world's mineral r aw materials, geochemistry has not only revealed the s t ructure of crystals in association with crystallo-graphy, but also charted the course for the deve lopment of industry.

Thus, the. sciences formed a cont inuous cha in f rom geology to geochemistry, f rom geochemistry to the chemical sciences and to physics. And the final a im of all these sciences has been not only the perfection of the natural sciences, but , as l .omonosov said, also the multiplication of tin- good things of life which man lias always striven to produce.

T h e creation ol new valuable, substances and the conquest of raw materials lor the nat ional economy have been the greatest and basic

> r i

Rocn tgenomct r i c l abo ra to ry

s t imul i in o u r days . T e c h n o l o g y has closely jo ined geochemis t ry , s t u d y i n g t h e p rope r t i e s of ores a n d salts, f i n d i n g ou t t he d i s t r ibu t ion of r a r e e l emen t s in t h e m a n d seeking for ways of t h e best a n d fullest possible u t i l i za t ion of t he en t ra i l s of o u r e a r t h .

T h e c o m b i n a t i o n of chemis t ry , g e o c h e m i s t r y a n d t echno logy h a d m a d e m o d e r n d e v e l o p m e n t of t h e c h e m i c a l i n d u s t r y possible.

W e shall no t dwel l a n y l onge r on w h a t benef i t s t h e d e v e l o p m e n t of c h e m i s t r y a n d the c h e m i c a l sciences has b r o u g h t a n d will yet b r ing m a n k i n d ; we spoke a b o u t it in t h e c h a p t e r on t h e h is tory of the a t o m in t h e h is tory of m a n k i n d ; w e shall c o m e b a c k to this in t he fo l lowing c h a p t e r , w h e n we t ry to p a i n t a p i c t u r e of t h e f u t u r e of o u r sciences a n d of t he i r a c c o m p l i s h m e n t s .

W e a r e n o w in te res ted in s o m e t h i n g else, n a m e l y , w h a t t he m o d e r n inves t iga to r in c h e m i s t r y , t h e o n e w h o a d v a n c e s science, c rea tes scient i f ic l a b o r a t o r i e s a n d t hus c o n q u e r s t h e s u r r o u n d i n g wor ld , shou ld b e like.

I n t h e pas t chemis t s took i n d i v i d u a l subs tances (e lements) f r o m rock a n d s tud i ed t h e m in t he i r l a b o r a t o r i e s a n d offices ou t s ide t i m e a n d space , ou t s ide the i r r e la t ions to n a t u r e .

T o d a y m a n p i c t u r e s t h e w o r l d as a c o m p l e x system in w h i c h all t h e i n d i v i d u a l p a r t s a r e closely i n t e r r e l a t e d , w h e r e va r ious forces col l ide, c o m b i n e a n d s t rugg le wi th e a c h o t h e r as in a n e n o r m o u s l a b o r a t o r y , w h e r e on ly as a resu l t of this s t rugg le of i n d i v i d u a l a t o m s a n d of e lec t r ic a n d m a g n e t i c fields subs t ances a r e c r ea t ed in one p l ace a n d des t royed in a n o t h e r .

T h e wor ld is a vas t l a b o r a t o r y , w h e r e all t h ings a r e c o n n e c t e d wi th each o t h e r l ike i n d i v i d u a l gears in a m a c h i n e . A n d t h e m o d e r n c h e m i s t w h o h a s c o m e to r e p l a c e t h e old l a b o r a t o r y rec luse sees e a c h a t o m in a n e w l igh t b y closely l ink ing its f a t e w i t h t he fates of t he un iverse . T h i s is w h y c h e m i s t r y is n o w c o m i n g so close to g e o c h e m i s t r y .

T o d a y a scientist h a s n e w ob jec t ives : it is no t e n o u g h for h i m to desc r ibe i n d i v i d u a l p h e n o m e n a , s e p a r a t e fac ts of s u r r o u n d i n g n a t u r e o r obse rve t h e resul ts of s o m e e x p e r i m e n t s in his l a b o r a t o r y . H e is s t u d y i n g s u b s t a n c e , i .e., h e m u s t u n d e r s t a n d h o w a n d w h y it c a m e to b e a n d w h a t will b e c o m e of i t .

Ex tens ive r e a s o n i n g of a p h i l o s o p h e r a b o u t t h e l aws of n a t u r e will n o l onge r d o for h i m ; h e m u s t s t u d y the i r e t e r n a l course in t h e

3 7 3

p h e n o m e n a a r o u n d u s ; h e m u s t d i scover t h e c o m p l e x re l a t ions b e t w e e n the i n d i v i d u a l p h e n o m e n a .

A n inves t iga to r m u s t n o t d i spass iona te ly ske tch o r p h o t o g r a p h i n d i v i d u a l n a t u r a l p h e n o m e n a , h e m u s t s t r ive t o c o n q u e r a n d s u b -o r d i n a t e t h e m to his will . T h e n e w inves t iga to r m u s t n o t b e a n a r t i s a n in his l a b o r a t o r y , b u t a c r e a t o r of n e w ideas b o r n in t h e s t rugg le a g a i n s t n a t u r e for t h e c o n q u e s t of t h e w o r l d .

N o w the chemis t , like t h e a s t r o n o m e r , m u s t foresee t h i n g s : his expe r i ence is n o t a series of s e p a r a t e a c c i d e n t a l r e a c t i o n s in t h e test-t u b e s of his l a b o r a t o r y ; his e x p e r i e n c e is b o r n as t h e f r u i t of c r e a t i v e t h o u g h t , scient if ic f an t a sy , a n d p r o f o u n d ques ts . T h e m o d e r n c h e m i s t m u s t u n d e r s t a n d t h a t scient i f ic v i c to ry is n o t w o n all a t once , t h a t it g rows g r a d u a l l y by l ong ve r i f i ca t ion a n d n o u r i s h i n g of s e p a r a t e ideas, t h a t it is a c h i e v e d o n l y as a resul t of c o n t i n u o u s ques t s ove r a pe r iod s o m e t i m e s of g e n e r a t i o n s of scientists, t h a t it is n o t i n f r e q u e n t l y t he last d r o p t h a t overfi l ls t h e c u p .

T h a t is w h y discover ies in m o d e r n sc ience a r e f r e q u e n t l y m a d e a t t he s a m e t i m e in d i f f e r e n t coun t r i e s , a n d t h e g rea t e s t ideas for c o n -q u e r i n g the w o r l d t h a t s u r r o u n d s us o c c u r a l m o s t s i m u l t a n e o u s l y to m a n y scientists.

Success in w o r k d e p e n d s on t h e ab i l i ty t o obse rve a n d col lect fac ts . I n t he field of g e o c h e m i s t r y this is o n e of t h e mos t i m p o r t a n t p r o b -lems. W e m u s t confess t h a t in t he i r f a sc ina t i on w i t h a t h e o r y a n d some t imes w i t h logical ly h a r m o n i o u s gene ra l i z a t i ons inves t iga to r s cease to obse rve a n d d o n o t sec t h a t w h i c h is u n c l e a r , w h i c h does no t ag r ee w i t h t he i r f o r m e r c o n c e p t i o n s a n d w h i c h is t h e key to n e w dis-coveries. T h e ab i l i ty to sense w h a t is n e w a n d to r e j ec t in g o o d t i m e the old , c u s t o m a r y hypo theses , is a q u a l i t y i n d i s p e n s a b l e t o a r e a l scientis t .

W h a t if m a n y p e o p l e t h i n k t h a t it is a n a c c i d e n t t h a t is r e spons ib le for a d i scovery , t h a t R o e n t g e n a c c i d e n t a l l y no t i ced t h e a c t i o n of X - r a y s on a l u m i n e s c e n t sc reen , a n d t h a t t h e i nves t iga to r has a c c i d e n t a l l y d iscovered vas t a c c u m u l a t i o n s of m a n g a n e s e c a r b o n a t e in f a r -o f f S i b e r i a ! T h i s a c c i d e n t , h o w e v e r , is a l w a y s n o t h i n g b u t t h e sub t l e s t ab i l i ty to sense t h e n e w .

T o t h i n k of t he n u m b e r of inves t iga tors w h o for a p e r i o d of many-years passed n e a r w h i t e rocks c o n s i d e r i n g t h e m s imple l imes tones , tes ted t h e m w i t h h y d r o c h l o r i c ac id , c o n v i n c e d themse lves t h a t t h e y

3 7 4

Chemica l utensils m a d e of glass

hissed a n d went a w a y ! But they should have noticed tha t in some places in fissures and on the surface, these whi te rocks were covered by a black crust, t ha t this crust was not something alien and tha t it seemed to be bo rn of the whi te stone. I t is thus the largest manganese deposits were discovered in Siberia. A n d it was no accident tha t dis-covered t h e m ; it was p rofound a n d consistent observat ion and the knowledge of facts tha t led to this discovery.

T h e r e is one more aspect in this ability to observe which was so r emarkab ly noticed by Lomonosov. H e said tha t observat ion should give rise to a theory and tha t the theory should correct the observat ion; he was perfectly r ight , because every subtle a n d skilful observat ion is

375

b o r n of a t h e o r y , a n d e a c h t h e o r y m a k e s sense on ly w h e n it is b a s e d o n a n e n o r m o u s n u m b e r of a c c u r a t e l y obse rved a n d precise ly d e s c r i b e d facts .

W h a t m u s t a r ea l geochemis t be like, t h e n ? H e m u s t b e p u r p o s e f u l ; h e m u s t p u r s u e a de f in i t e a i m u n w a v e r -

ing ly ; h e m u s t be a t h o u g h t f u l o b s e r v e r ; h e m u s t h a v e a l ively y o u n g i m a g i n a t i o n ; h e m u s t h a v e t h e y o u t h of m i n d a n d soul w h i c h a r e n o t d e t e r m i n e d by age , b u t by t h e sensi t ivi ty of his very n a t u r e . H e m u s t possess e n o r m o u s p a t i e n c e , m e t t l e a n d i n d u s t r y a n d , a b o v e all , the ab i l i t y to see a t h i n g t h r o u g h to t h e e n d .

I t is no t w i t h o u t r ea son t h a t B e n j a m i n F r a n k l i n , o n e of t h e mos t p r o m i n e n t scientists, said t h a t gen ius was t h e c a p a c i t y for endless work .

B u t a scientist m u s t a t t h e s a m e t i m e h a v e c o m m o n sense a n d scient if ic f an ta sy . H e m u s t h a v e f a i t h in his w o r k a n d in his t h o u g h t ; h e mus t be c o n v i n c e d of t h e cor rec tness of his t h o u g h t , b e bo ld in d e f e n d i n g i t ; h e m u s t b e en thus i a s t i c a b o u t his w o r k a n d love i t . E n t h u s i a s m in w o r k is o n e of t h e * mos t i m p o r t a n t requis i tes for v ic tory . T h e a r t i s ans in sc ience h a v e n e v e r m a d e a s ingle i m p o r t a n t d iscovery .

W i t h o u t e n t h u s i a s m it is imposs ib le to c o n q u e r t h e w o r l d , a n d th is e n t h u s i a s m is b o r n no t so m u c h of t h e f a sc ina t i on of c rea t ivcness itself, as of t h e u n d e r s t a n d i n g of t h e role a n d of t h e respons ib le task w h i c h m a n d i scharges in his c r ea t ive e n d e a v o u r s .

F a s c i n a t i o n w i t h t he i dea of ra i s ing t h e l iv ing s t a n d a r d s , f e r v e n t des i re to s u b d u e life's sinister forces, t h e s t r iv ing to bu i ld a n e w a n d b e t t e r w o r l d a n d to give it n e w resources a n d o p p o r t u n i t i e s for m a s t e r i n g all t h e a c c u m u l a t e d k n o w l e d g e is t h e a i m of life of t h e n e w m a n in t h e n e w , f ree c o u n t r y .

A n d it is on ly t hus t h a t t h e wor ld c a n b e c o n q u e r e d . I n his a u t o b i o g r a p h y C h a r l e s D a r w i n s a i d : " . . . m y success as a

m a n of science, w h a t e v e r this m a y h a v e a m o u n t e d to, h a s b e e n d e t e r -m i n e d , as f a r as I c a n j u d g e , by c o m p l e x a n d divers i f ied m e n t a l q u a l i -ties a n d cond i t ions . O f these, t h e m o s t i m p o r t a n t h a v e b e e n — t h e love of s c i e n c e — u n b o u n d e d p a t i e n c e in l ong re f lec t ing ove r a n y s u b -j e c t — i n d u s t r y in obse rv ing a n d col lec t ing f ac t s - a n d a fa i r s h a r e of i n v e n t i o n as well as of c o m m o n - s e n s e . "

T h e s e a r e t h e t ra i t s w e n o w w a n t to see in t h e gcochemis t . T h e y a r e n o t b o r n in m a n all a t o n c e ; t h e y a r e t r a i n e d b y pers i s ten t w o r k ; t h e y d o n o t c o m e i n t o t h e w o r l d w i t h t h e i n d i v i d u a l , b u t a r e e d u c a t e d a n d d e v e l o p e d in c r ea t ive life.

T h e g rea t e s t c o n q u e s t s of c h e m i c a l t h o u g h t pass b e f o r e o u r eyes a n d t h o u s a n d s of e x a m p l e s s h o w us h o w n a t u r e is v a n q u i s h e d by t h e en thus i a s t s of science.

FANTASTIC TRIP THROUGH MENDELEYEV'S PERIODIC TABLE

" W h a t d o y o u p r o p o s e to exh ib i t as t h e m o s t r e m a r k a b l e ach ieve -m e n t of R u s s i a n s c i e n c e ? " I was a sked b y o n e of t h e o r g a n i z e r s of t he A i l - U n i o n E x h i b i t i o n of Sc i ence a n d E n g i n e e r i n g , t o b e h e l d i n M o s c o w a few yea r s l a te r .

" W e m u s t exh ib i t s o m e t h i n g t h e l ike of w h i c h c a n n o t b e f o u n d a n y w h e r e else in t h e w o r l d a n d w h i c h w o u l d s h o w t h e g lo ry a n d p o w e r of Sovie t sc ience i n its g r a d u a l d e v e l o p m e n t s ince L o m o n o s o v to o u r t i m e . "

W e w e r e c a r r i e d a w a y by this i d e a ; w e t a lked to chemis t s a n d geolo-gists a n d s u b m i t t e d o u r p roposa l . A t first it a p p e a r e d too g r a n d a n d fan tas t ic , b u t l a t e r o u r cr i t ics a g r e e d w i t h u s ; t h e i d e a f a s c i n a t e d t h e m a n d t h e y b e g a n to d e v e l o p it t o g e t h e r w i t h us.

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I m a g i n e a b u i l d i n g in t h e f o r m of a n e n o r m o u s c o n e o r p y r a m i d of c h r o m i u m - p l a t e d steel 20 t o 25 m e t r e s h igh , a p p r o x i m a t e l y l ike o u r five- o r s ix-storey houses . A g r a n d sp i ra l s q u a r e d i n t o boxes r u n s a r o u n d t h e c o n e ; t h e boxes a r e a r r a n g e d as in M e n d e l e y e v ' s sys tem to f o r m ' l o n g series a n d ve r t i ca l g r o u p s . E a c h b o x is a smal l r o o m a n d is o c c u p i e d b y a n i n d i v i d u a l e l e m e n t . T h o u s a n d s of spec ta to r s d e s c e n d t h e sp i ra l e x a m i n i n g in e a c h b o x t h e f a t e of a n i n d i v i d u a l e l e m e n t in t h e m a n n e r t h e y w o u l d e x a m i n e a b e a s t in a c a g e of t h e Z o o .

T o rise to t h e t o p of t h e e n o r m o u s c o n e of M e n d e l e y e v ' s P e r i o d i c T a b l e y o u e n t e r t h e " e l e m e n t a r i u m " o n t h e g r o u n d . A t first a l m o s t c o m p l e t e d a r k n e s s enve lops y o u a n d on ly s e p a r a t e r e d t o n g u e s b e g i n ,

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as i t w e r e , t o l ick y o u r f ee t a n d y o u a r e g r a d u a l l y s u r r o u n d e d b y a s e e t h i n g m a s s of a b o i l i n g fiery m e l t . Y o u find y o u r s e l f i n t h e g l a z e d c a b i n of a l a r g e l i f t . T h e m o l t e n o c e a n of t h e e a r t h ' s i n t e r i o r is a l l a r o u n d y o u . T h e c a b i n s lowly rises a m i d t h e t o n g u e s of fire a n d t h e s t r e a m s o f m o l t e n masses .

T h e first p o i n t s of h a r d e n e d c r y s t a l l i z e d s u b s t a n c e s of t h e m a g m a m a k e t h e i r a p p e a r a n c e s . T h e y a r e still floating i n t h e m e l t , a r e r u s h i n g a b o u t i n m a s s e s a n d a r e g r a d u a l l y a c c u m u l a t e d i n s e p a r a t e sec t ions in t h e f o r m of g l i t t e r i n g s p a r k l e t s , o f h a r d e n i n g rocks .

N o w t h e c a b i n h a s a l r e a d y t o u c h e d th is c o o l e d m a g m a of t h e i n t e r i o r o n t h e r i g h t . Y o u see t h e d a r k still r e d - h o t b a s i c r o c k r i c h i n m a g n e s i u m a n d i r o n . T h e b l a c k s p o t s of c h r o m i t e m e r g e i n t o b a n d s of c h r o m i u m o re s a n d a m i d t h e m y o u see t h e c rys t a l s of p l a t i n u m a n d o s m i r i d i u m , t h e s e f i r s t m e t a l s o f t h e e a r t h ' s i n t e r i o r , s p a r k l i n g l ike s t a r s .

T h e c a b i n is g r a d u a l l y m o v i n g p a s t s u c h a d a r k - g r e e n b o u l d e r . I n i ts l o n g h i s t o r y th i s b o u l d e r b r o k e u p m a n y t i m e s a n d w a s a g a i n s o l d e r e d b y s o m e fiery l i q u i d m e l t . S h i n y l i t t l e c rys ta l s of t r a n s p a r e n t s t o n e g l i t t e r a m i d t h e d a r k g r e e n c rys ta l s . T h e s e a r e c rys ta l s of d i a m o n d s w h i c h w e r e b r o u g h t o u t i n t o s i m i l a r d i a m o n d - b e a r i n g p i p e s i n S o u t h A f r i c a .

Y o u g e t t h e i m p r e s s i o n t h e c a b i n is r i s i ng f a s t e r a n d f a s t e r . Y o u l e a v e t h e d a r k g r e e n r o c k s of i r o n a n d m a g n e s i u m b e l o w . H e r e c o n -t i n u o u s masses of g r e y a n d b r o w n r o c k s — d i o r i t e s , syen i t e s a n d g a b b r o s — m a k e t h e i r a p p e a r a n c e ; w h i t e v e i n s g l e a m h e r e a n d t h e r e a m o n g t h e m . T h e c a b i n s u d d e n l y t a k e s a s h a r p t u r n t o t h e r i g h t , a n d r u n s i n t o m o l t e n g r a n i t e s a t u r a t e d w i t h gases , v a p o u r s a n d r a r e m e t a l s ; i t is a l l i m p r e g n a t e d w i t h a h o t fog . Y o u c a n h a r d l y m a k e o u t t h e i n d i v i d u a l sol id c rys t a l s i n t h e c h a o s o f t h e m o l t e n g r a n i t e . O h , t h e t e m p e r a t u r e h e r e h a s a l r e a d y r e a c h e d ,8oo° C . !

H o t v a p o u r s b r e a k o u t t o t h e s u r f a c e i n s t o r m y s t r e a m s a n d w i t h exp los ions . H e r e y o u see a h a r d e n i n g m a s s of g r a n i t e still p i e r c e d b y m o l t e n r e m a i n s of t h e s a m e g r a n i t e . T h e s e a r e t h e f a m o u s p e g -m a t i t e s i n w h i c h t h e b e a u t i f u l c r y s t a l s o f p r e c i o u s s t o n e s a r e b o r n ; t h e s e i n c l u d e s m o k y m o r i o n s , g r e e n b e r y l s , b l u e t o p a z e s , r o c k c rys t a l s a n d a m e t h y s t s .

A n d t h r o u g h t h e fog of t h e c o o l i n g v a p o u r s t h e c a b i n goes p a s t r e m a r k a b l e p i c t u r e s of p e g m a t i t e cav i t i e s . H e r e y o u see l a r g e s m o k y q u a r t z e s m o r e t h a n a m e t r e i n d i a m e t r e a n d n e x t t o t h e m a l r e a d y

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f o r m e d crysta ls of f e ldspar . P la tes of m i c a g r o w slowly o n the i r su r f ace a n d a b o v e t h e m g l e a m s m o k y q u a r t z e s . M a r v e l l o u s rock crysta ls seem to p ie rce t he cav i ty wi th a t r a n s p a r e n t forest of lances .

T h e c a b i n rises h i g h e r . L i l ac b r u s h e s of a m e t h y s t s e n v e l o p it on all sides. I t b r e a k s o u t of t h e p e g m a t i t e ve in a n d n o w n e w p i c tu re s a t t r a c t y o u r a t t e n t i o n — v e i n s of va r i ous th ickness b r a n c h of f n o w to t he left a n d n o w to t h e r i g h t ; n o w you see c o n t i n u o u s t r u n k s of w h i t e m i n e r a l s a n d g l i t t e r ing su lph ides a n d n o w t h i n ve ins h a r d l y visible to the eye a n d closely r e s e m b l i n g b r a n c h e s of a t ree . E n t i r e sect ions of t he g r a n i t e rock a r e i m p r e g n a t e d w i t h b r o w n crysta ls of t i n s tone a n d ye l low-p ink masses of scheel i te . T h e e lec t r ic l ight in t he c a b i n is t u r n e d off . Y o u find yourse l f in da rkness . T h e levers of a p o w e r f u l m a c h i n e a r e t u r n e d a n d it beg ins to emi t invis ib le u l t r a -violet r ays ; t h e d a r k wal ls a r e n o w i l l u m i n e d by n e w l igh t s ; n o w w i t h t h e de l i ca t e g r e e n of t h e scheel i te crysta ls a n d n o w w i t h t h e ye l low of t h e ca lc i te g ra ins . T h e m i n e r a l s spa rk le , p l a y a n d g l i t t e r w i t h t h e p h o s p h o r i c l ight a n d a m i d t h e m you see d a r k spots of t h e c o m p o u n d s of heavy meta l s .

T h e n t h e l ight goes o n a g a i n . T h e c a b i n leaves t h e c o n t a c t zones of g r an i t e s a n d m o v e s a l o n g o n e of t h e p o w e r f u l t r u n k s r is ing f r o m t h e g r a n i t e massif . T h e c a b i n slows d o w n a n d y o u rise a l o n g a rea l lode . T h e c a b i n n o w r u n s i n t o a c o n t i n u o u s q u a r t z b o d y . Black s h a r p crystals of t u n g s t e n ores p ie rce t h e q u a r t z e s a n d several h u n d r e d m e t r e s f u r t h e r u p t h e first g l i t t e r ing spark le t s of su lph ides , these s i lvery-yel low crystals of c o m p o u n d s of i ron a n d s u l p h u r m a k e t he i r a p p e a r a n c e . T h e s e a r e fo l lowed b y b l i n d i n g b r i g h t - y e l l o w sparkles .

" L o o k , t h e r e is g o l d ! " o n e of y o u exc la ims . T h i n ve ins p ie rce snow-w h i t e q u a r t z e s . T h e c a b i n rises several h u n d r e d m e t r e s m o r e . I n s t e a d of t he gold y o u n o w see t h e g l i t t e r ing s tee l -grey crysta ls of g a l e n a , t h e n t h e z i n c - b l e n d e w h i c h spark les l ike d i a m o n d , va r i ous s u l p h i d e ores, shot w i t h t h e co lours of all me ta l s , t h e ores of l ead , silver, c o b a l t a n d nickel . H i g h e r u p t h e ve ins g r o w l igh te r . T h e c a b i n n o w m o v e s t h r o u g h soft l i m e s p a r p i e r ced b y need les of si lvery s t ibn i t e a n d s o me-t imes by b l o o d - r e d crysta ls of c i n n a b a r . F a r t h e r o n y o u see t h e c o n -t i n u o u s yel low a n d r ed masses of a r sen ic c o m p o u n d s . T h e c a b i n m a k e s its w a y w i t h inc reas ing ease ; ho t v a p o u r s a n d t h e n h o t so lu t ions h a v e l ong s ince r e p l a c e d t h e h o t mel ts .

3 8 0

T h e c a b i n is n o w s h o w e r e d by h o t m i n e r a l spr ings . T h e y see the a n d boil w i th t he b u b b l e s of c a r b o n d iox ide a n d m a k e the i r w a y t h r o u g h t h e s e d i m e n t a r y rocks w h i c h shack le t he e a r t h ' s c rus t . Y o u see t h e m c o r r o d i n g t h e wal ls of l imes tones , d e p o s i t i n g z inc a n d lead ores in t h e m . T h e ho t m i n e r a l spr ings c a r r y t h e c a b i n h i g h e r a n d h i g h e r a n d b e a u t i f u l l ime s ta lac t i tes h a n g f r o m t h e wal ls a r o u n d y o u ; these a r e n o w s ta lac t i t es of b r o w n a r a g o n i t e ( C a r l s b a d s tone) a n d n o w b e a u t i f u l s e d i m e n t s of p a r t i c o l o u r e d m a r b l e onyx .

Bu t the p a t h s of t he ho t spr ings b r a n c h o u t a n d th in s t r e a m s b r eak t h r o u g h to t h e e a r t h ' s su r face , t hus c r e a t i n g geysers a n d m i n e r a l wate rs . O u r c a b i n is n o w m o v i n g t h r o u g h s e d i m e n t a r y rocks ; it is c u t t i n g t h r o u g h layers of coal a n d r u n n i n g in to s t r a t a ol P e r m i a n sal ts ; pic-tu res of t h e d i s t a n t pas t of t h e e a r t h ' s su r f ace o p e n themse lves before y o u r eyes. N o w h e a v y l iqu id d r o p s fall a n d o b s c u r e t he glass walls of t h e c a b i n . T h i s is oil a n d va r ious b i t u m e n s in t he s a n d s of t he sedi-m e n t a r y rocks. T h e c a b i n cu t s t h r o u g h s e p a r a t e hor izons .

U n d e r g r o u n d w a t e r s s h o w e r t h e wal ls of t he c a b i n a g a i n ; it is n o w pass ing t h r o u g h a c o n t i n u o u s wal l of h a r d s a n d s t o n e s ; soft l imestones a n d a rg i l l aceous slates s u r r o u n d t h e c a b i n t h u s s h o w i n g you t h e var ie -g a t e d p a t t e r n of t he past fa tes of t h e e a r t h . T h e c a b i n comes ever closer to t he su r face of t he e a r t h . O n e m o r e r u s h in its r a p i d mo t ion a n d t h e c a b i n stops.

A b r i g h t ( lame rises to m e e t you a n d s n o w - w h i t e c louds of w a t e r v a p o u r s of m a g i c f o r m cover t he sky.

Y o u h a v e c o m e to t he t o p of M e n d e l e y e v ' s Pe r iod ic T a b l e . Before y o u r ve ry eyes h y d r o g e n is b u r n i n g i n t o c louds of w a t e r v a p o u r s .

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Y o u a r e on t h e t o p p l a t f o r m of M e n d e l e y e v ' s t ab le . A s teep spiral l eads you g r a d u a l l y d o w n w a r d s . Y o u hold on to t h e ban i s t e r ol ch ro -m i u m - p l a t e d steel a n d beg in y o u r descen t .

H e r e is t h e first box. I n s c r i b e d o n it in l a rge le t ters is t h e w o r d " H e l i u m . " I t is a r a n - n o b l e gas, first d i scovered in t h e sun , a gas t h a t i m p r e g n a t e s t he en t i r e e a r t h , t h e s tones, t h e w a t e r s a n d the a i r . H e l i u m is a n o m n i p r e s e n t gas a n d we sea rch for it in o r d e r to fill o u r d i r ig ibles . H e r e in this smal l r o o m d e v o t e d to h e l i u m you see its en t i r e his tory f rom the b r i g h t g reen lines of i he solar c o r o n a , to t he black

u n a s s u m i n g clevei te , t h e s t one from t h e S c a n d i n a v i a n ve ins f r o m w h i c h h e l i u m , t h e gas of t h e sun , c a n b e e x t r a c t e d w i t h a p u m p .

Y o u l e a n ca re fu l ly over t h e b a n i s t e r a n d see five m o r e boxes u n d e r t h a t of h e l i u m . T h e n a m e s of o t h e r n o b l e g a s e s — n e o n , a r g o n , k r y p t o n , x e n o n a n d r a d o n , t h e r a d i u m e m a n a t i o n — a r e insc r ibed i n t h e m in fiery le t ters .

T h e spec t r a l l ines of t h e n o b l e gases a r e s u d d e n l y t u r n e d o n a n d e v e r y t h i n g is i l l u m i n e d b y b r i g h t co lours . T h e o r a n g e a n d r e d s h a d e s of n e o n a r e fo l lowed b y t h e b lu i sh t in t s of a r g o n . L o n g t r e m b l i n g b a n d s of b lu i sh h e a v y gases c o m p l e t e t h e p i c t u r e , wh ich , is v e r y f a m i l i a r to us by t h e l u m i n e s c e n t s h o p a d v e r t i s e m e n t s in t h e c i ty .

A l ight goes o n a g a i n a n d y o u see t h e b o x of l i t h i u m . I t is t h e l ightes t a lkal i m e t a l . Y o u see its e n t i r e . h i s to ry all t h e w a y to t h e a i r c r a f t of t h e f u t u r e . Y o u l e an ove r a g a i n a n d a g a i n y o u see t h e l u m i n o u s le t ters of its a n a l o g u e s : t h e ye l low co lou r of s o d i u m , t he violet of po t a s s ium, t h e r ed s h a d e s of t h e signs i n d i c a t i n g r u b i d i u m a n d the b l u e co lou r of ces ium.

T h u s , g r a d u a l l y , s t ep by s tep , e l e m e n t a f t e r e l e m e n t y o u m a k e t h e r o u n d s of t h e g r e a t M e n d e l e y e v P e r i o d i c T a b l e d o w n t h e sp i ra l , a n d all we h a v e to ld y o u a b o u t in t h e p a g e s of th is book , t h e e n t i r e h is tory of t h e i n d i v i d u a l c h e m i c a l e l e m e n t s is s h o w n h e r e in v iv id , real spec imens , in t h e ve ry h i s to ry of e a c h e l e m e n t r a t h e r t h a n in s e p a r a t e w o r d s o r p i c tu res .

C a n you t h i n k of a n y t h i n g m o r e f a b u l o u s t h a n t h e b o x of c a r b o n , t h e basis of life a n d of t h e e n t i r e w o r l d ? T h e e n t i r e h i s to ry of t h e d e v e l o p -m e n t of l iv ing s u b s t a n c e passes h e r e b e f o r e y o u r ve ry eyes as well as t h e en t i r e h i s to ry of t h e d e a t h of this s u b s t a n c e w h e n life b u r i e d in t h e in t e r io r of t h e e a r t h is t r a n s f o r m e d i n t o coal a n d l iv ing p r o -t o p l a s m i n t o l i qu id oil. A n d in t h e r e m a r k a b l e p i c t u r e of t h e c o m p l e x w o r l d of t h e h u n d r e d s of t h o u s a n d s of c h e m i c a l c o m p o u n d s of c a r b o n y o u r a t t e n t i o n is a t t r a c t e d b y its b e g i n n i n g a n d its e n d .

H e r e is a n e n o r m o u s d i a m o n d crys ta l . N o , this is n o t t h e f a m o u s " C u l l i n a n " c u t i n t o p ieces for t h e Eng l i sh k i n g : it is t h e " O r l o v . " I t is set in a g o l d e n c a n e , t h e scep t re of t h e R u s s i a n tsars .

At t h e e n d of t h e s a m e r o o m y o u c o m e u p o n a l ayer of coal . A m i n e r ' s pick cuts i n t o t h e coa l a n d pieces of th is p l a in - l ook ing s tone a r e t r a n s p o r t e d by a l o n g c o n v e y e r t o t h e su r face . T h i s is t h e i n d u s t r y ' s s taf f of life.

3 8 2

T h e n y o u g o t w o m o r e t u r n s d o w n t h e sp i ra l a n d be fo re you is a r o o m w i t h b r i g h t c o l o u r s : ye l low, g r e e n a n d r ed s tones spa rk le ir ides-cen t ly . H e r e y o u h a v e t h e m i n e s of C e n t r a l A f r i c a a n d t h e r e t h e d a r k caves of Asia . T h e film t u r n s s lowly, p re sen t s p i c t u r e s of i n d i v i d u a l m i n e s a n d shows t h e or ig in of me ta l s . T h i s is v a n a d i u m , n a m e d a f t e r t h e l e g e n d a r y o ld S lav ic goddess , b e c a u s e of t he f a b u l o u s s t r e n g t h it i m p a r t s t o i r on a n d steel by m a k i n g t h e m h a r d a n d d u r a b l e , viscous, res i l ient a n d i n d e s t r u c t i b l e — t h e qua l i t i e s so essent ia l to t h e a u t o -m o b i l e ax le . I n t h e s a m e r o o m y o u see axles m a d e of v a n a d i u m steel a f t e r mi l l ions of k i lome t re s of se rv ice ; n e a r - b y y o u obse rve b r o k e n axles m a d e of o r d i n a r y steel w h i c h h a d n o t las ted even 10,000 kilo-me t r e s .

Y o u m a k e a f ew m o r e t u r n s d o w n t h e sp i ra l . P i c tu res fol low e a c h o t h e r . N o w y o u see i r o n — t h e basis of t h e w o r l d a n d of t h e i r on i n d u s t r y , n o w o m n i p r e s e n t i od ine fills t h e s p a c e w i t h its a t o m , n o w s t r o n t i u m g l i t t e r ing i n t h e r e d flares, a n d n o w t h e sh iny m e t a l g a l l i u m w h i c h me l t s in t h e h a n d s of m a n .

O h , h o w b e a u t i f u l t h e r o o m of go ld is. I t g l i t ters w i t h t h o u s a n d s of l ights . H e r e is go ld in w h i t e q u a r t z ve ins a n d h e r e is t h e silvery, a l m o s t g r e e n go ld of t h e T r a n s b a i k a l m i n e s ; t h e r e y o u obse rve a g o l d e n s t r e a m l e t in a smal l m o d e l of t h e L e n i n o g o r s k c o n c e n t r a t i o n mil l in t h e A l t a i ; h e r e y o u see a n i r idescen t go ld so lu t ion , a n d h e r e is finally t h e go ld in t h e h i s to ry of m a n a n d his c u l t u r e . I t is t h e m e t a l of w e a l t h a n d c r i m e , t h e m e t a l of w a r , p l u n d e r a n d v io lence . T h e v a u l t s of t he s t a t e b a n k s w i t h gold bu l l ion pass b e f o r e y o u r eyes in v iv id co lour s ; y o u see dep res s ing p i c tu re s of s lave l a b o u r in t h e f a m o u s W i t w a t e r s r a n d m i n e s a n d of t h e b a n k e r s w h o s h a p e t h e fa tes of stock c o m p a n i e s a n d t h e v a l u e of c u r r e n c y .

O n l y o n e m o r e s t ep a n d y o u a r e in a r o o m of a n o t h e r m e t a l — l i q u i d m e r c u r y . As a t t h e f a m o u s Par i s e x h i b i t i o n of 1937 t h e r e is a f o u n t a i n in t h e m i d d l e of t h e r o o m , b u t it is o n e of l i qu id silver m e r c u r y r a t h e r t h a n of w a t e r . I n t h e r i g h t c o r n e r y o u see a smal l s t e a m e n g i n e b e a t i n g t i m e w i t h its p i s tons a n d w o r k i n g o n m e r c u r y gas, wh i l e o n t h e left you obse rve t h e e n t i r e h i s tory of th is vo la t i l e m e t a l , its d ispers ion in t he e a r t h ' s c rus t , t h e b l o o d - r e d d r o p s of c i n n a b a r in t h e s ands tones of D o n e t s Basin a n d t h e l i qu id d r o p s of m e r c u r y in t h e S p a n i s h mines .

B u t y o u go o n . B e y o n d t h e boxes of l ead a n d b i s m u t h you r u n i n t o s o m e i n c o m p r e h e n s i b l e p i c t u r e . T h e e l e m e n t s a n d t h e boxes

a r c all m ixed u p . Y o u 110 longer f ind a n y c la r i ty o r d is t inc tness in t he s e p a r a t e squa res . Y o u h a v e e n t e r e d a s p h e r e of specia l a t o m s of t he M c n d e l e y e v sys tem. Y o u f ind n o m o r e d u r a b i l i t y o r s tab i l i ty in t h e f a m i l i a r meta l s . S o m e t h i n g v a g u e a n d n e w a p p e a r s be fore y o u ; bu t t h e n t h e fog lifts a n d you see a f a b u l o u s p i c tu re .

The a t o m s of u r a n i u m a n d t h o r i u m d o no t s tay in the i r p laces . T h e y emi t r ays of s o m e k ind a n d g ive rise to t h e g l o b u l a r a t o m s of h e l i u m . O u r a t o m s leave the i r h a b i t u a l boxes . H e r e they j u m p i n t o t h e s q u a r e o c c u p i e d by r a d i u m , shed a mys t e r ious l ight , a r e t r a n s f o r m e d , as in a fa i ry- ta le , i n t o a n invis ible gas ca l led r a d o n , t h e n r u n b a c k a g a i n t h r o u g h M e n d e l e y e v ' s Pe r iod i c T a b l e a n d d ie be fo re y o u r very-eyes in t he box b e l o n g i n g to l ead .

But he r e is a n o t h e r a n d m o r e f r igh t fu l p i c t u r e t h a t r ep laces t h e first o n e ; s o m e very r a p i d l y Hying a t o m s s t r ike u r a n i u m , b r e a k it i n to pieces wi th a g r e a t noise a n d the a t o m of u r a n i u m b r e a k s u p e m i t t i n g b r i l l i an t r ays ; s o m e w h e r e h igh in o u r sp i ra l you see it f lash in t h e box of t h e r a r e e a r t h s a n d t h e n it r u n s d o w n t h e spira l a g a i n , s tops in s e p a r a t e boxes of a l ien m e t a l s a n d g r a d u a l l y dies s o m e w h e r e n e a r p l a t i n u m .

W h a t has h a p p e n e d to o u r a t o m s ? H a v e n ' t t hey v io la t ed o u r l aws? H a v e n ' t t hey s h a k e n o u r conv ic t ion t h a t e a c h a t o m is a n i n v a r i a b l e a n d c o n s t a n t n a t u r a l br ick , t h a t n o t h i n g c a n c h a n g e o r t r a n s f o r m it, t h a t s t r o n t i u m will a l w a y s r e m a i n s t r o n t i u m a n d a n a t o m of z inc will a lways be ail a t o m of z i n c ?

Y o u a r e t e r r ib ly d i s a p p o i n t e d . Desp i te all we h a v e sa id , t h e a t o m p r o v e d uns t ab le . Y o u h a v e e n t e r e d s o m e n e w wor ld w h e r e t h e a t o m t u r n s ou t to b e i n c o n s t a n t , w h e r e it c a n b e b r o k e n u p , no t de s t royed b u t c h a n g e d in to a n o t h e r one .

A n d t h r o u g h the fog of t he e n d of M e n d e l e y e v ' s t ab le , a m i d t h e g l i t t e r ing sparks of t h e f lying a t o m s of h e l i u m a n d t h e X - r a y s you descend to (he last s teps of t h e sp i ra l in to u n k n o w n d e p t h s .

N o w you a r e no t d e s c e n d i n g in to t h e in t e r io r of t he e a r t h , but i n to t h a t of t he b u r n i n g s ta rs s h i n i n g in t he sky. Y o u a r e g o i n g to w h e r e t he t e m p e r a t u r e s a r e m e a s u r e d by h u n d r e d s of mi l l ions of degrees , w h e r e t he pressure c a n n o t be expressed in a n y va lues of o u r a t m o s -pheres , w h e r e t he a t o m s of M e n d e l e y e v ' s Pe r iod ic Table s p a r k l e a n d b r eak u p in fu r ious chaos .

Does this m e a n , t h e n , t h a t all we h a v e sa id is w r o n g ? Is it at all

:»«4

possible t h a t t h e a l chemis t s w e r e r i g h t w h e n t h e y w a n t e d to c h a n g e m e r c u r y to g o l d ? W e r e t h e y r i g h t i n t r y i n g to c r e a t e silver f r o m arsen ic a n d t h e " p h i l o s o p h e r ' s s t o n e " ? Docs it m e a n t h a t t h e d r e a m e r s in sc ience w e r e r i g h t w h e n t h e y said as f a r b a c k as 100 yea r s a g o t h a t t he a t o m s w e r e c h a n g i n g i n t o o n e a n o t h e r , t h a t in t h e c o m p l e x wor lds inaccess ible t o us t h e y w e r e b o r n f r o m e a c h o t h e r ?

M e n d e l e y e v ' s Pe r iod i c T a b l e is n o t a t all a d e a d t ab l e , m e r e l y m a d e u p of boxes . I t is n o t on ly a p i c t u r e of t h e p resen t , b u t a lso o n e of t he pas t a n d of t h e f u t u r e ; it is a p i c t u r e of t h e mys te r ious processes of t h e un ive r se in w h i c h a t o m s a r e t r a n s f o r m e d i n t o o n e a n o t h e r . I t is t he p i c t u r e of t h e s t rugg le fo r ex is tence t h a t p reva i l s in t h e wor ld of a t o m s .

M e n d e l e y e v ' s Pe r iod i c T a b l e is a t a b l e of t h e h is tory a n d the life of t h e un ive r se . T h e a t o m itself is a p iece of t h e un iverse , cons t an t l y c h a n g i n g its p l a c e in t h e c o m p l e x series, g r o u p s a n d boxes of t h e t ab l e .

Y o u h a v e c o m e to t h e mos t r e m a r k a b l e p i c t u r e of t h e s u r r o u n d i n g w o r l d .

25

FUTURE CONQUESTS

T h e s t o r m y d e v e l o p m e n t of physics a n d c h e m i s t r y in o u r d a y s is on ly t h e t h r e s h o l d t o t h e u p s u r g e ever m o r e c lea r ly o u t l i n e d in sc ience, i n d u s t r y a n d e c o n o m y . I be l ieve t h e a g e of c h e m i s t r y is c o m i n g ; t h e a g e i n w h i c h t h e gen ius of m a n will n o t o n l y s u b j u g a t e al l t h e c h e m i c a l e l ements , b u t will also a w a k e n al l t h e forces of t h e a t o m a n d ut i l ize t h e i m m e n s e reserves of e n e r g y c o n c e a l e d i n e a c h mo lecu l e , a t o m a n d e lec t r ic pa r t i c l e . W h a t if t h e fo l lowing p a g e s a p p e a r s o m e w h a t f an t a s t i c? T h e f a n t a s y of t o d a y is v e r y o f t e n t r a n s f o r m e d i n t o t h e e n g i n e e r i n g of t o m o r r o w .

H a v e n ' t J u l e s V e r n e ' s fantas ies , w h i c h still f a sc ina t e us, b e e n t r a n s -f o r m e d in to rea l i ty of t o d a y ! W e find a n even g r e a t e r scope of f a n t a s t i c t h o u g h t in o u r r e m a r k a b l e R u s s i a n scientis t K . Ts io lkovsky a n d t h o u g h on ly s o m e t h i r t y years h a v e e l apsed s ince his d a r i n g p red ic t ions , m u c h of w h a t h e w r o t e t h e n h a s a l r e a d y c o m e t r u e . W e m u s t , t he r e fo re , n e v e r f ea r scient if ic f a n t a s y n o r t a k e i t as s o m e t h i n g a l r e a d y ex i s t ing ; w e m u s t fight fo r it b e c a u s e f a n t a s y is o n e of t h e m e t h o d s of scient i f ic work .

I t was n o t w i t h o u t r e a s o n t h a t L e n i n said t h a t f a n t a s y w a s a q u a l i t y of t h e h ighes t v a l u e , t h a t it was w r o n g to t h i n k t h a t o n l y poe ts n e e d e d it , t h a t it was also necessary in m a t h e m a t i c s b e c a u s e e v e n t h e d i scovery of d i f f e r en t i a l a n d i n t e g r a l ca lcu lus w o u l d h a v e b e e n imposs ib le w i t h o u t f an t a sy .

L e t us d a y - d r e a m t o g e t h e r a b o u t w h a t o u r e n g i n e e r i n g will b e like in t h e h e y d a y of t h e c h e m i c a l sciences.

I n t h e first p l ace , w e will c o n q u e r t h e a i r , n o t o n l y b e c a u s e p l a n e s a n d rocke ts will r ise a b o v e t h e c louds , t o a n a l t i t u d e of 50 t o 100 kilo-

3 8 6

m e t r e s a n d will fly a t speeds e x c e e d i n g t h e veloci ty of s o u n d , b u t also b e c a u s e c h e m i s t r y will m a s t e r t h e a i r a n d will s u b o r d i n a t e it t o t h e p o w e r of m a n .

A t l a rge p l a n t s s ca t t e r ed t h r o u g h o u t t h e w o r l d , h e l i u m will b e e x t r a c t e d f r o m t h e a i r , t h e a i r will b e d i v i d e d i n t o o x y g e n a n d n i t r o g e n a n d w h o l e r ivers of l i qu id o x y g e n will flow a l o n g ar t i f ic ia l ly cooled p ipes to l a r g e i r on a n d steel mills, w h e r e t h e s m e l t i n g of m e t a l in b las t -f u r n a c e s will b e c o m e as s i m p l e as e v a p o r a t i o n of w a t e r in a l a b o r a t o r y t e s t - t ube .

S i m i l a r p l a n t s will p r o d u c e p u r e n i t r o g e n t r a n s f o r m e d by p o w e r f u l e lec t r ic d i scha rges i n t o n i t r i c ac id . L i fe -g iv ing n i t r o g e n will b e used as fer t i l izer fo r o u r f ields o n a ve ry l a r g e scale a n d will d o u b l e a n d t r e b l e t h e i r c rops . O t h e r p ipes of t h e s a m e ins ta l l a t ions of t h e a i r i n d u s t r y wil l c a r r y s t r e a m s of n o b l e ga se s—l iqu id n e o n , k r y p t o n a n d x e n o n — t o e lec t r ic b u l b - m a n u f a c t u r i n g p l a n t s .

B u t even m o r e w o n d e r f u l will b e t h e v i c to ry ove r t h e layers of o z o n e w h i c h a r e f o r m e d u n d e r t h e i n f l u e n c e of t h e u l t r a -v io le t r ays of t h e ^ s u n a t a l t i t udes of h u n d r e d s of k i lomet res .

W e k n o w t h a t these layers of o z o n e e n v e l o p t h e e a r t h , as i t were , b y a c o n t i n u o u s b l a n k e t , r epe l l ing r a d i o w a v e s a n d b lock ing t h e v iv i fy ing a c t i o n of t h e u l t r a -v io l e t rays .

N o w , i m a g i n e this f a n t a s t i c p i c t u r e : e n o r m o u s e lect r i f ied c o l u m n s of a m m o n i a c c o m p o u n d s rise t o a h e i g h t of severa l h u n d r e d k i lomet res , i .e. , t o t h e f a m o u s o z o n e l a y e r ; t h e o z o n e b r e a k s u p , f ree w i n d o w s a r e f o r m e d in it a n d t h r o u g h t h e m t h e s u n sends p o w e r f u l s t r e a m s of u l t r a -v io l e t e l e c t r o m a g n e t i c waves . I n s o m e p laces t h e y des t roy life, in o the r s t h e y i m p a r t a m i g h t y fo rce t o it a n d serve as t h e source of n e w , l i fe-giving e n e r g y .

B u t t h e c o n q u e s t of t h e e a r t h ' s i n t e r i o r seems e v e n m o r e f an tas t i c . T h e o c e a n of m a g m a bo i l i ng u n d e r o u r feet , t h e colossal a m o u n t s

of h e a t c o n c e a l e d in t h e e a r t h ' s en t r a i l s wil l al l c o m e w i t h i n t h e r e a c h of m a n .

By specia l m a i n s r u n n i n g to a d e p t h of 20 t o 30 k i lomet res m a n wil l r e a c h t h e l ayers h e a t e d t o 500 a n d e v e n i , ooo° C . ; h e will u t i l ize t h e h e a t of t h e e a r t h ' s i n t e r i o r i n his t h e r m a l s t a t ions ; h e will s top d e s t r o y i n g forests a n d wil l cease uselessly b u r n i n g coal w h i c h is so necessa ry for c h e m i c a l processes ; h e will n o l o n g e r s p e n d oil for t h e r -m a l ins ta l la t ions .

25* 3 8 7

Mil l ions of ca lor ics will c o m e to t h e e a r t h ' s su r f ace a l o n g these pipes. T h e y will h e a t m a n ' s houses , fac tor ies a n d e n t i r e r eg ions wi th the i r ho t b r e a t h ; t hey will m e l t t he ice of t h e p o l a r coun t r i e s a n d will c h a n g e t h e c l i m a t e . P o w e r f u l r e f r i ge r a to r s sca t t e red t h r o u g h o u t t h e deser ts will t r a n s f o r m t h e m in to f lour i sh ing oases.

Bu t even this will n o t b e e n o u g h fo r m a n . M a n will n o t .be c o n -t e n t w i t h t he h e a t t h a t will s p r e a d a l o n g t h e e n t i r e su r f ace of t he e a r t h a t his c o m m a n d a n d will r e m o v e t h e defec ts of t h e s u n ; h e will b r i n g to t h e su r face t h e w e a l t h c o n c e a l e d in t h e i n t e r io r of t he e a r t h .

A n e w s tage in t he s t rugg le for m a s t e r i n g t h e i n t e r i o r of t h e e a r t h is a l r e a d y b e g i n n i n g in t he Sovie t U n i o n in k e e p i n g w i t h M e n d e -leyev 's b r i l l i an t p r ed i c t i ons .

I n t he e a r t h ' s en t ra i l s inaccess ib le to m i n i n g m a n is n o w b u r n i n g coal , a n d t h e p r o d u c t s of c o m b u s t i o n rise a l o n g p ipes to t h e su r f ace a n d a r e u t i l i zed b y i n d u s t r y . T h i s does n o t r e q u i r e e i t he r m i n e s o r t h e h a r d w o r k of dr i l lers , h e w e r s a n d w h e e l e r s ; a u t o m a t i o n , m e c h a n i -z a t i o n a n d r e m o t e c o n t r o l m a k e it possible t o u t i l ize t he coa l reserves w i t h o u t go ing d o w n in to t h e mines .

M a n is a l r e a d y e x t r a c t i n g s u l p h u r f r o m d e e p u n d e r g r o u n d deposi ts . S t e a m mel ts t h e s u l p h u r in t h e in t e r io r of t h e e a r t h , a n d its l iqu id s t r e a m s p o u r o u t to t he e a r t h ' s s u r f a c e ; n o w if w e p u m p s t e a m h e a t e d to 500 or 6oo° C . i n to veins, i n to c o n c e n t r a t i o n s of h e a v y m e t a l sul-ph ides , t h e p ipes m a d e of a n e w s tab le m a t e r i a l will b r i n g us t h e sul-ph ides of silver, lead a n d z inc , r a t h e r t h a n m e r e s u l p h u r .

P o w e r f u l layers of s lates will b e b u r n t in t h e i n t e r io r of t h e e a r t h a n d will yield useful gases to t he su r face . Sal ts will b e dissolved a n d b r o u g h t t o t h e e a r t h ' s su r f ace in t he f o r m of solut ions . S t r o n g ac id solu t ions will dissolve n a t u r a l subs t an ces a n d give us salts for t he e lec t ro ly t ic p lan t s . All of o u r e a r t h will be p i e rced b y mi l l ions of steel p ipes w h i c h will be e x t r a c t i n g t he subs t ances r e q u i r e d by m a n f r o m va r ious dep th s .

The v ic to ry o v e r . m a t t e r will be even m o r e decis ive w h e n c h e m i s t r y learns to col lect t h e d ispersed a t o m s of u r a n i u m a n d to ut i l ize t he i r ene rgy .

Physicists n o w tell us t h a t t h e wor ld reserves of u r a n i u m e n e r g y a r e t r e m e n d o u s . By l e a r n i n g to spl i t these d i s i n t e g r a t i n g u r a n i u m a t o m s , m a n will bu i ld n e w eng ines w h i c h will serve flawlessly a n d

3«>!

will r u n for t h o u s a n d s of yea r s o n e n d f o r m i n g a source of f a b u l o u s e n e r g y w h i c h will d r ive p l anes a n d ships al ike.

T h e e n t i r e e n e r g y of t h e w o r l d will be p l aced a t t h e service of m a n in n e w c h e m i c a l ins ta l la t ions . T h e rays of t h e s u n fa l l ing so uselessly o n t h e e a r t h ' s su r f ace will b e c a u g h t u p by e n o r m o u s m i r r o r s a n d will b e t r a n s f o r m e d i n t o h e a t . So l a r k i t chens in C a l i f o r n i a a n d in t he U . S . S . R . , t h e first e x p e r i m e n t s in h a r n e s s i n g t h e e n e r g y of t h e sun , will b e c o m e e v e r y d a y p rac t i ce .

T h e sources of t h e w h i t e a n d b l u e coal will b e fu l ly u t i l i zed ; the i r e n e r g y will b e c a u g h t b y e n o r m o u s s ta t ions a l o n g all sea coasts a n d r i v e r - b a n k s . M a n will b e c o m e m a s t e r of such e n o r m o u s q u a n t i t i e s of e n e r g y , t h a t h e will b e a b l e t o p e r f o r m real mi rac les .

A n d t h e n m a n will m a s t e r space , d i s t a n c e a n d t ime . S p e e d s of severa l t h o u s a n d s of k i lomet res p e r h o u r will b e c o m e t h e u sua l t h i n g ; t he dis-t ances b e t w e e n cities a n d o t h e r cen t re s of h a b i t a t i o n will b e r e d u c e d to a m i n i m u m a n d will cease to d i v i d e peop le . N e w f o r m s of life a n d a n e w social o r g a n i z a t i o n of t h e w o r l d will e rase all e a r t h l y b o u n d a r i e s . T h e life of m a n will b e c o m e t h e m a i n ob jec t ive of c r ea t ive scient i f ic e n d e a v o u r . M a n will l e a r n to spli t a t o m s b y fine m e t h o d s ; b y m e a n s of r a d i o a c t i v e rays a n d e m a n a t i o n s f r o m e n o r m o u s cyc lo t rons m a n will b e a b l e to d o a n y t h i n g he likes w i t h t h e a t o m s ; h e will be a b l e t o b r e a k t h e m u p i n t o s e p a r a t e pieces, t r a n s f o r m t h e h e a v y a t o m s i n t o l igh t ones a n d , con t r a r iw i se , t h e l igh t a t o m s i n t o h e a v y ones .

By ar t i f ic ia l ly p r o d u c i n g v a r i o u s types of a t o m s , m a n wil l l e a rn to u t i l ize t h e m . M a n wil l b e a b l e to i n t r o d u c e t h e a t o m s w h i c h live on ly a s econd o r a m i n u t e i n t o t h e o r g a n i s m as n e w r e m e d i e s to fight v i ruses a n d p a t h o g e n i c b a c t e r i a . H e wil l m a s t e r t h e l iv ing cell by c o n t r o l l i n g i t w i t h t h e a id of t h e n e w chemis t ry . B u t for his p o w e r f u l c h e m i c a l processes h e will a lso b e a b l e to u t i l ize m i c r o - o r g a n i s m s . M a n a l r e a d y g rows m a n y of t h e usefu l b a c t e r i a h e needs in ge la t ine c o n t a i n e d i n smal l t e s t - tubes a t ins t i tu tes of m i c r o b i o l o g y .

H e will b e a b l e to p r o d u c e t h e m in i m m e n s e q u a n t i t i e s a n d to s t rew t h e m ove r his f ields. T h e b a c t e r i a will g ive t h e fields f e r t i l i z e r—ni t r i c a c i d — a n d b y d e c o m p o s i n g g y p s u m will e x t r a c t s u l p h u r . M a n will t r a n s f o r m b a c t e r i a i n t o a v i ta l force , i n t o a p o w e r f u l c h e m i c a l a g e n t a n d by us ing t h e m , h e will l e a r n t o e x t r a c t t h e m e t a l s d i spersed in t he seas as it is d o n e b y t h e i n d i v i d u a l smal l a c a n t h a r i a w h o a b s o r b s t r o n t i u m f r o m m a r i n e solut ions .

3 8 9

I n his s t rugg le lor t h e e a r t h ' s i n t e r io r m a n will m a k e use of t h e en t i r e mass of rocks. T h e r e will b e n o w a s t e p r o d u c t s , n o u n u s e d ta i l -ings. E v e r y t h i n g will serve i n d u s t r y ; all of M e n d e l e y e v ' s Pe r iod i c T a b l e will b e u t i l i zed , a n d t h e m o s t w i d e s p r e a d e l emen t s—si l i con a n d a l u m i n i u m — w i l l b e c o m e t h e basis of life.

T h e n a m e " s u p e r - r a r e " subs t ances will n o l o n g e r m a k e a n y sense. T h e s e subs t ances will f o r m p a r t of o u r e v e r y d a y life. W i t h t he i r a id we shal l d e v e l o p T V screens a n d f r o m o u r o w n r o o m s w e shal l b e a b l e to ta lk to d i s t a n t a u d i e n c e s w h i c h w e shal l see o n t h e sc reen w i t h o u r o w n eyes. T h e ra res t e l e m e n t s will serve fo r c h e m i c a l r eac t i ons w h i c h a t l a rge c h e m i c a l p l a n t s will b e a b l e to t r a n s f o r m subs t ances i n to p r o d u c t s r e q u i r e d for life.

O r g a n i c c h e m i s t r y is b e c o m i n g v e r y i m p o r t a n t . I n s t e a d of t h e h u n d r e d s of t h o u s a n d s of c a r b o n c o m p o u n d s k n o w n t o d a y , m a n will p r o d u c e mi l l ions of n e w s t r u c t u r e s w h e n h e l ea rns t o use in his n e w ins ta l la t ions low t e m p e r a t u r e s close to a b s o l u t e zero , as wel l as t e m -p e r a t u r e s of mi l l ions of degrees a n d pressures of h u n d r e d s of t h o u s a n d s of a t m o s p h e r e s .

Moscow State University on Lenin Hills

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T h i s will b e a n e w c h e m i s t r y of c a r b o n . T h i s will n o t on ly b e t he plas t ics f r o m w h i c h w e c a n m a n u f a c t u r e a n y t h i n g f r o m b u t t o n s t o l i g h t w e i g h t p l anes , n o t on ly s y n t h e t i c r u b b e r w h i c h is b e g i n n i n g suc-cessfully t o r e p l a c e n a t u r a l r u b b e r , n o t on ly t h e r e m a r k a b l e dyes w h i c h h a v e r e n d e r e d t h e p l a n t a t i o n s of i nd igo u n n e c e s s a r y ; no , these will b e en t i r e ly n e w subs tances , ve ry close t o t h e r ea l o r g a n i c mo le -cule , t o p r o t o p l a s m , to p r o t e i n . . . . T h e s e will b e a r t i f ic ia l n u t r i t i v e subs t ances w h i c h will d o a w a y w i t h t h e s u p e r f l u o u s c o m p l e x c h e m i c a l l a b o r a t o r i e s i n t h e o r g a n i s m s of a n i m a l s .

T h e n e w s y n t h e t i c c h e m i s t r y will also be a b l e to u t i l ize o t h e r e l e m e n t s in o r d e r to b u i l d t h e s a m e c o m p l e x c o m p o u n d s t h a t o r g a n i c c h e m i s t r y h a s b e e n a b l e t o c o n s t r u c t f r o m c a r b o n , o x y g e n a n d h y d r o g e n . I c a n a l -r e a d y i m a g i n e t h e n e w molecu le s of si l icon, g e r m a n i u m , b o r o n a n d n i t ro -g e n in t h e r e m a r k a b l e c o m p o u n d s w h i c h t h e chemis t s h a v e b e e n ab l e t o p r o d u c e in r e c e n t yea r s b y b u i l d i n g t h e b e n z e n e r i n g n o t f r o m c a r b o n o r h y d r o g e n , b u t f r o m t w o o t h e r e l e m e n t s of t h e e a r t h — n i t r o g e n a n d b o r o n .

Bu t for c h e m i s t r y t o m a s t e r t h e w o r l d r e q u i r e s e n o r m o u s scient if ic w o r k ; it needs p o w e r f u l a n d n u m e r o u s scient i f ic ins t i tu tes w i t h pe r f ec t ins ta l l a t ions of h i g h pressures a n d t e m p e r a t u r e s w h i c h m u s t m e r g e w i t h t h e l a b o r a t o r i e s of fac tor ies .

A n d h e r e in these n e w pa l ace s of sc ience v ic to ry shal l b e w o n b y n e w a n d d a r i n g m e n a r m e d w i t h b o l d scient i f ic f a n t a s y a n d b u r n i n g w i t h a f i re of n e w ques ts .

T h i s is h o w I p i c t u r e to myse l f t h e f u t u r e in t h e l igh t of t o d a y . B u t I took t h e co lours for m y p i c t u r e f r o m n a t u r e t h a t s u r r o u n d s us a n d f r o m o u r k n o w l e d g e . T h e p i c tu re s of t h e d i s t a n t f u t u r e will b e even m o r e ma je s t i c , b u t to p a i n t t h e m w e n o w lack words , co lours a n d images . . . .

T h e a i m of o u r s t o r m y ques t s is t h e h a p p i n e s s of h u m a n i t y . T h e n e w life wil l b e b o r n as a resu l t of v i c to ry ove r n a t u r e a n d over t h e ine r tness of m a n himself .

M a n h a s ^ h a r d a n d s t u b b o r n s t rugg le a h e a d of h i m , b u t t h e mi le-s tones of t h e f u t u r e h a v e a l r e a d y b e e n p l a c e d a n d t h e ob jec t ives o u t l i n e d . T h e s t rugg le for n a t u r e , fo r t h e m a s t e r y of h e r forces, fo r t h e t r ans -f o r m a t i o n of al l t h a t is useless i n t o usefu l th ings will b e o n e of t he p o w e r f u l levers in t h e c r e a t i o n of a n e w life.

END OF BOOK

W c h a v e c o m e to t he e n d of t h e book . Y o u a n d I h a d to c h a n g e in to smal l w a n d e r i n g a t o m s in o r d e r t o r u n t h r o u g h t h e c o m p l e x p a t h s of m i g r a t i o n s of t h e e l emen t s , t o look i n t o t h e i n t e r i o r of t h e e a r t h a n d even a t t h e h o t celest ial bod ies , t o see t h e b e h a v i o u r of v a r i o u s a t o m s in t h e un ive r se a n d in t h e h a n d s of m a n , a n d to f ind o u t w h a t t h e y d o i n i n d u s t r y a n d in a g r i c u l t u r e .

T h e a t o m s t r ave l a l o n g w a y in t he i r h i s to ry a n d w e d o n o t k n o w e i the r its b e g i n n i n g o r its e n d . T h e b i r t h of t h e a t o m s a n d t h e b e g i n n i n g of the i r m i g r a t i o n s o n e a r t h a r e still a m y s t e r y t o us. N o r a r e t he i r f u t u r e fates, t he i r fa tes in t h e c o m p l e x f u t u r e of o u r p l a n e t c l ea r to us.

W e only k n o w t h a t s o m e a t o m s d i s a p p e a r b e y o n d t h e l imits of t h e e a r t h a n d a r e d i spe r sed i n in t e r s t e l l a r s p a c e w h e r e t h e r e is n o m o r e t h a n o n e neg l ig ib le a t o m p e r c u b i c m e t r e a n d w h e r e on ly so smal l a p a r t of s p a c e is o c c u p i e d b y t h e m t h a t i t w o u l d h a v e t o b e expressed b y io"30.

W e k n o w t h a t o t h e r a t o m s b e c o m e d i spe r sed in t h e e a r t h ' s c rus t , in its soils, w a t e r s a n d o c e a n s ; still o the r s s lowly a n d g r a d u a l l y r e t u r n to its in t e r io r , sub j ec t to t h e laws of g r a v i t y .

S o m e a t o m s a r e c o n s t a n t , i n v a r i a b l e a n d as d u r a b l e as p u r e , w h i t e ivory b i l l i a rd ba l l s ; o the r s a r e , o n t h e c o n t r a r y , as res i l ient as r u b b e r balls , c o n t r a c t w h e n co l l id ing w i t h e a c h o t h e r a n d i n t e r l a c e in s o m e c o m p l e x s t r u c t u r e s s u r r o u n d e d b y e lec t r ic fields; still o the r s c o m -ple te ly d i s in t eg ra t e , nuc l e i a n d all , e m i t t i n g e n e r g y a n d c h a n g i n g to s t r a n g e gases whose l i fe -span is prec ise ly d e t e r m i n e d b y t h e l aws of d i s i n t e g r a t i o n a n d is m e a s u r e d b y mi l l ions of yea r s for some , yea r s

3 9 2

Minera log ica l M u s e u m o£ the U.S.S.R. A c a d c m y of Sciences

for others and seconds or even negligible fractions of a second for still others.

The world around us is built of about 100 chemical elements, but what great multiformity they produce, how the features of these atoms vary and how their combinations differ!

Only now are we beginning to read in a new manner these remarkable pages in the history of the earth's chemical elements. Geochemistry has only just slightly opened the door into a new world of nature; hard and persistent work has only just started; the behaviour of each element in the earth's crust has only begun to be observed, but we must already keep a record of the behaviour of each atom, thoroughly examine its characteristic features and learn about its merits and de-fects; in a word, we must make so detailed and profound a study of

393

e a c h a t o m as to b e a b l e to t r a c e its fates , i .e. , t h e h i s to ry of t h e un iverse , f r o m t h e s e p a r a t e fac ts .

E a c h l ink in th is h i s tor ica l c h a i n is d e p e n d e n t o n t h e as ye t u n k i i q w n p r o p e r t i e s of t h e a t o m , wh i l e c o m p l e x a n d p r o f o u n d laws g o v e r n its fa tes i n t h e cosmos, o n e a r t h a n d in t h e h a n d s of m a n a l ike .

B u t it is n o t o u t of m e r e cur ios i ty t h a t w e w a n t to t r a c e t h e p a t h s t r ave l l ed b y t h e a t o m s ; it is n o t on ly b e c a u s e w e w a n t t o k n o w h o w t h e y b e h a v e o n e a r t h ; w e m u s t l e a r n t o c o n t r o l t h e m in a m a n n e r r e q u i r e d b y m a n for his t e chn ica l , e c o n o m i c a n d c u l t u r a l progress .

Enge l s sa id w e m u s t s t u d y n a t u r e in o r d e r to r e s h a p e it . I t is j u s t this t h a t cons t i tu tes t h e b ig a n d h o n o u r a b l e p r o b l e m of geochemis t s .

Yes, w e m u s t m a s t e r t h e a t o m s c o m p l e t e l y a n d b e a b l e to d o al l w e w a n t w i t h t h e m , for e x a m p l e , t o p r o d u c e s u p e r - h a r d al loys, i.e., a l loys h a r d e r t h a n d i a m o n d s ; b u t t o d o this w e m u s t k n o w h o w t h e a t o m s a r r a n g e themse lves in t he i r c o m p l e x s t ruc tu re s .

W e m u s t l e a r n t o d iv ine t h e p r o p e r t i e s of t h e c o m p o u n d s of m e t a l s ; we w a n t a n d m u s t b e a b l e n o t on ly t o t ry , b u t t o k n o w fo r sure .

W e m u s t o b t a i n a n d p r o d u c e t h e g rea t e s t possible q u a n t i t i e s of s u c h a t o m s as ce s ium a n d t h a l l i u m w h i c h easily give off the i r o u t e r elec-t rons . W i t h these w e w a n t t o b u i l d t h e f inest T V sets smal l e n o u g h to fit in a p o c k e t o r in a n o t e b o o k , a n d w o n d e r f u l t a l k ing m o t i o n -p i c t u r e c a m e r a s t h e size of a n o r d i n a r y book .

I n a w o r d , w e w a n t to s u b j u g a t e t h e e n t i r e a t o m , t o s u b o r d i n a t e it to o u r will , to t h e will of v ic to r ious m a n w h o is t r a n s f o r m i n g al l t h e r e d o u b t a b l e a n d h a r m f u l n a t u r a l forces i n t o usefu l ones . W e w a n t to m a k e all n a t u r e , t h e e n t i r e M e n d e l e y e v t a b l e of e l e m e n t s serve t h e needs of w o r k i n g h u m a n i t y .

T h e a foresa id cons t i tu tes t h e p u r p o r t a n d a i m of g e o c h e m i c a l w o r k ; t h a t is w h y w e w a n t to u n d e r s t a n d a n d secure t h e a t o m .

W i t h these w o r d s w e a r e b r i n g i n g o u r l o n g s tory to a n e n d . But , d e a r f r i ends , c a n t h e r e ever b e a n e n d to sc ience o r t o s tud ies?

Le t us b e pe r fec t ly f r a n k a b o u t it . H e r e , a t t h e v e r y e n d of o u r b o o k we , essential ly, find ourselves

a t t he v e r y b e g i n n i n g of o u r k n o w l e d g e ; even if w e r e a d th is b o o k several t imes , c a r e fu l l y sc ru t in i ze a l l t h e p i c t u r e s in it a n d t ry to r e m e m -b e r t h e b e h a v i o u r of t h e i n d i v i d u a l a t o m s w e shal l still h a v e t o a d m i t w e a r e on ly a t t h e ve ry b e g i n n i n g .

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STUDY MATURE!

We shall have to read and think and work a lot more before we get an insight into the mysteries of nature around us.

To begin with we must study the basic sciences—chemistry, physics, mineralogy and geology. We cannot circumvent these sciences and in order to become good students of the natural resources we must thoughtfully reread books on tHe principles of the chemical and miner-alogical sciences.

We must read books carefully, delve thoughtfully into the fate of each element, study its behaviour in the earth, in water, in the air, in industry and in agriculture, and Mendeleyev's Periodic Table will always be our guiding star. Let us look at this table printed in this book or, what is even better, draw it on a large sheet of paper, put a chemical symbol and the atomic weight of a chemical element in each box and underneath each element write its content in the earth's crust and hang it in our rooms so that we always have it before our eyes.

Mendeleyev's Periodic Law will teach us a great deal. It will show us how the atoms are related to each other not only

in the periodic table, but also in nature itself.

L e n i n g r a d O r d e r of Lenin Min ing Ins t i tu te

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E x t e r i o r of the Che rnyshov M u s e u m of Geo log ica l Prospec t ing in L e n i n g r a d

Academic i an F . Che rnyshov M u s e u m of Geolog ica l P rospec t ing in L e n i n g r a d . H a l l of Mine ra l s

Not only books, maps and tallies, however, teach us chemistry and geochemistry. We can learn about the new ideas in chemistry in mineralogical museums where the exhibits in mineralogy and geo-chemistry in which the samples are frequently arranged according to separate chemical elements teach us a lot.

Large smelters and chemical mills also teach us chemistry, mineralogy and geology.

Anyone who has visited the Magnitogorsk Works will for ever remember what happens to iron ore and how first carbon-rich iron and then real steel are born in special shops from a complex com-bination of chemical elements processed in blast-furnaces. In Soli-kamsk we can learn about the chemical and geochemical fates of potassium and magnesium. At the superphosphate plants in Leningrad, Voskresensk (near Moscow), the Urals, the Ukraine and in other places we can see how apatites and phosphorites are transformed by means of sulphuric acid into fertilizer for our socialist fields.

By observing the processes in the fire-breathing furnaces of the Chelyabinsk ferro-alloy plants we shall come to understand how molten magma is born in the interior of the earth and how substance is crystallized from this magma.

In a word, separate pages from the history of atoms are continuously rewritten at all large plants; these include the mixing of the atoms of various metals in complex proc-esses and the extraction of different substances from them, which arc later blended again in new combi-nations with other atoms in order to produce alloyed steels, com-plex superphosphates, salts of po-tassium, manganese, vanadium and zirconium.

Industrial processes make ever more extensive use of chemistry. Metallurgical Plant

H97

G e o c h e m i s t s tudying rock o u t c r o p - h a r d e n e d l ava s t reams

We are no longer content with grinding a stone into a pavement block or an arrow-head; we now strive to change it chemically in order to get the most valuable quality and combination of various sub-stances.

We cast fine blocks for our new, improved pavements; we change the natural processes and transform natural substances into new values.

Today we are living not only in an epoch of chemical transformations, but also in a period of state-planned development of cheinicai research and chemical industry.

Chemical processes surround us on al! sides and we must keep an eye on them and be able to divine them.

Nature itself, its deposits of metals, salts and ores also teach us geochemistry and give us new ideas in mineralogy. Nowhere will the young investigator learn the laws of chemical transformations as he will from nature itself, and we therefore appeal to all of them to study the chemical processes of the earth spring arid summer, winter and autumn

398

By sc ru t i n i z ing t h e b l a c k clays of t h e J u r a s s i c depos i t s n e a r M o s c o w w e shal l see h o w in ea r ly s p r i n g t h e g o l d e n spark le t s of p y r i t e in t h e m a r e a b s o r b e d by t h e f a d e d l i gh t -g reen salts of vitr iols. W e shall see a g r a n d p i c t u r e of c h a n g e s a n d t r a n s f o r m a t i o n s of i r o n ores in M o u n t M a g n i t n a y a pi t w h e r e a t o n e t i m e h u g e f o r m a t i o n s of m a g n e t i t e o n t h e e a r t h ' s su r f ace b e g a n to c h a n g e first i n to b r o w n masses of t h e m i n e r a l n o n t r o n i t e a n d w e r e l a t e r c o v e r e d w i t h b r o w n -r e d a n d rus ty i r on oxides .

E v e r y w h e r e , i n m i n e s a n d q u a r r i e s , on t h e tops of m o u n t a i n r a n g e s a n d i n t h e d e e p val leys a l o n g r ivers , we see h o w s u b s t a n c e is b e i n g t r a n s f o r m e d , h o w o n e m i n e r a l c h a n g e s i n t o a n o t h e r a n d h o w a n e w s u b s t a n c e is r e p l a c e d b y a still o t h e r s u b s t a n c e . W e m u s t o n l y b e c a r e f u l i n o u r o b s e r v a t i o n s a n d w e shal l soon no t i ce t h a t e v e r y t h i n g c h a n g e s , s o m e t i m e s slowly a n d qu i e t l y , s o m e t i m e s s u d d e n l y , sub jec t t o t h e g r e a t l aws of n a t u r e . " E v e r y t h i n g is fluid," t h e a n c i e n t G r e e k p h i l o s o p h e r s sa id . " E v e r y t h i n g c h a n g e s , " say t h e geochemis t s of o u r t ime .

S U P P L E M E N T

26

THE GEOCHEMIST IN THE FIELD

INTRODUCTION

This chapter consists of two parts. In the first part we set forth a number of practical suggestions for the geochemist who is prospecting for minerals and is making a geochemical study of some region. The second part briefly describes the basic methods in the sequence that should be observed by the geochemist in his field work.

Both the first and second parts are based on principles now closely adhered to by prospectors; scientific field work is generally comf posed of three parts: the preparatory stage, the investigation itsel-and the transport and treatment of the material.

All these three parts are, no doubt, equally important and each of them requires attention and a thoughtful attitude.

Tents of geologists on the edge of the Kara-Kum Desert

26* 4°3

" H e who knows a lot and thinks a lot travels well," said a certain traveller and scientist, while another quite rightly added that the sharpest and the most important instrument an investigator must have at his disposal is his eye, which must not let even the most negli-gible phenomena escape because they not infrequently conceal exten-sive and important inferences.

P ART ONE

E Q U I P M E N T

/

The problem of equipment in field work is very important to the geochemist because, in addition to the usual geological equipment, he will also need a number of other instruments for physical and chemi-cal research. In this case it is necessary, first of all, to consider the means of conveyance on hand in the given region and the weight and size of the equipment. If a shortage of good equipment is sometimes dangerous for an expedition, in a number of cases, on the other hand, superfluous equipment is a drawback because it renders the movements of the expedition difficult and creates hardships that retard it and even prevent it from reaching certain inaccessible regions.

The total equipment of a prospector must primarily include different types of hammers. Sedimentary and soft rocks require a hammer which combines the properties of a hammer proper and a light pick; its handle must be approximately 40 cm. long and so fixed that its

Mineralogical magnifying glasses of different degrees of magnification

4 0 4

narrow end will fit the hand while the wider end will prevent the hammer from coming loose in work. In the regions of hard rocks, the prospector should have a heavier hammer (weighing I to 2 kg.) with a handle about 70 cm. long. Centimetres should be marked on the handle in order that the investigator always have accurate scales for measurement at hand. In addition, extensive work requires a sledge hammer weighing up to five kg. and a small lightweight hammer with a short handle of about 20 to 30 cm. for knocking off small pieces or for shaping the samples. A set of chisels of various shape and size is required in addition to the hammers. The rest of the equipment should include a magnifying glass (magnifying no more than eight times), a mountain compass, a tape-measure, a pen-knife, a notebook and pencil, specially prepared and numbered labels 6 x 4 cm. in size, a lot of wrapping paper, some small glass jars for collecting valuable fragile samples and crystals, and strong boxes of different sizes; for dry substances it is important to have a set of small, numbered canvas bags.

In addition to the afore-said equipment, it is necessary to have a camera, an aneroid barometer and a set of coloured pencils for making geological and geochemical diagrams.

East Pamirs. Upper reaches of the Lyangar River

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It is always good to have small bottles with acids of various con-centration, good charcoal, plat inum wire, soda and borax. For work of a more permanent nature this elementary equipment should be supplemented by a number of special instruments.

The packing and distribution of the equipment is a very serious affair. Part of it must be packed in strong, moisture-proof bags fit for being carried on the back (knapsacks), the other part must be packed in boxes suitable for the methods of transportation planned in the given region, and this requires a maximum of attention and experience to avoid blunders.

P A C K I N G C O L L E C T E D M A T E R I A L S

The question of packing and transporting the collected mineralogical materials is very serious and must be given thorough consideration.

Careful packing and wrapping of each sample in separate paper with a label in it forms one of the "musts" of a good collection. You must make it your rule never to wrap several samples into one paper,

Steep loess bank of the Angren River near Tashkent

406

h o w e v e r s m a l l t h e y m a y b e ; e a c h s a m p l e m u s t a l w a y s b e w r a p p e d

s e p a r a t e l y . N e g l i g e n c e i n p a c k i n g o f t e n d e s t r o y s w e l l c o l l e c t e d m a t e r i a l s ,

e s p e c i a l l y s a m p l e s o f s o f t m i n e r a l s . W e s h o u l d , t h e r e f o r e , d i s t i n g u i s h

t h e d e l i c a t e a n d s o f t s a m p l e s f r o m t h e h a r d o n e s a n d p a c k t h e m s e p a -

r a t e l y . E a c h s a m p l e m u s t b e w r a p p e d i n t w o o r t h r e e s h e e t s o f p a p e r ,

b u t t h e s e s h e e t s m u s t , u n d e r n o c i r c u m s t a n c e s , b e f o l d e d t o g e t h e r .

T h e l a b e l f o r e a c h s a m p l e , f o l d e d i n t w o , s h o u l d n o t b e p u t d i r e c t l y

o n t h e s a m p l e , b u t r a t h e r a f t e r t h e f i r s t l a y e r o f p a p e r ; t h e l a b e l s m u s t

b e i n s c r i b e d i n p e n c i l ( b u t , u n d e r n o c i r c u m s t a n c e s , i n i n d e l i b l e p e n -

c i l ) . B r i t t l e a n d d e l i c a t e b r u s h e s o f c r y s t a l s m u s t first b e c o v e r e d

b y t h i n c i g a r e t t e p a p e r a n d a c o t t o n t a m p o o n a n d o n l y t h e n w r a p p e d

i n l a r g e s h e e t s o f p a p e r .

T h e m a t e r i a l s c o l l e c t e d b y a n e x p e d i t i o n m u s t b e p a c k e d i n a s e r i e s

o f s t a g e s , e a c h s t a g e t r e a t e d v e r y c a r e f u l l y . T h e first s t a g e i s t h e d a i l y

c o l l e c t i o n a n d t r a n s p o r t a t i o n o f t h e m a t e r i a l s t o t h e c a m p . I w o r k e d

o u t t h i s m e t h o d p e r s o n a l l y d u r i n g m y fifty y e a r s o f e x p e r i e n c e . I n

c o l l e c t i n g g e o c h e m i c a l a n d m i n e r a l o g i c a l m a t e r i a l a l l s a m p l e s f o u n d

b y a c e r t a i n g r o u p o f w o r k e r s m u s t b e c a r r i e d t o s o m e d e f i n i t e p l a c e

( n e a r t h e c a m p ) i n m u c h l a r g e r q u a n t i t i e s t h a n i s r e q u i r e d . T h e n ,

a t t h e e n d o f e a c h w o r k d a y ( i n t h e e v e n i n g ) a l l o f t h e c o l l e c t e d m a t e r i a l

i s s o r t e d , s h a p e d , t h e b e s t t y p i c a l s a m p l e s a r e s e l e c t e d a n d t e m p o r a r i l y

c a r e f u l l y p a c k e d i n k n a p s a c k s . I n t h e p e r m a n e n t c a m p , t h e s a m p l e s

a r e s t o r e d i n a d e p e n d a b l e a n d d r y p l a c e a n d a t t h e e n d o f a c e r t a i n p e r i o d

o f w o r k t h e y a r e a g a i n e x a m i n e d a n d w r a p p e d i n p a p e r f o r s u b s e q u e n t

p a c k i n g i n s t r o n g b o x e s w i t h t h e i d e a t h a t e a c h b o x w e i g h n o m o r e

t h a n 5 0 k g . P a c k i n g i n t o l a r g e r b o x e s i s n o t r e c o m m e n d e d b e c a u s e

o f t h e d a n g e r o f c r u s h i n g t h e s t o n e s ; b e s i d e s , d u r i n g t r a n s p o r t a t i o n

a n d r e l o a d i n g v e r y h e a v y b o x e s m a y e a s i l y b e d a m a g e d . T h e m a t e r i a l s

s h o u l d b e s h i p p e d b y t h e m e m b e r s o f t h e e x p e d i t i o n t h e m s e l v e s .

L e a v i n g t h e s a m p l e s i n c a r e o f s o m e o f t h e l o c a l i n h a b i t a n t s p u t s t h e

c o l l e c t i o n s i n j e o p a r d y a n d t h e y e i t h e r g e t i n t o t l f e h a n d s o f t h e p r o s p e c -

t o r v e r y l a t e , o r n o t a t a l l .

U p o n a r r i v a l o f t h e b o x e s t h e m a t e r i a l s m u s t b e c a r e f u l l y a s s o r t e d

a n d t h e s a m p l e s p l a c e d t o g e t h e r w i t h t h e l a b e l s i n t o c o r r e s p o n d i n g

b o x e s , b e c a u s e a c o n f u s i o n o f t h e l a b e l s m a y l e a d t o i r r e p a r a b l e d a m a g e

a n d n o t i n f r e q u e n t l y t o w r o n g a n d d a n g e r o u s c o n c l u s i o n s .

T h e f i r s t q u e s t i o n t h a t a r i s e s d u r i n g a c o l l e c t i o n i s : h o w m u c h s h a l l

w e t a k e a n d i n w h a t s h a p e ? T h i s q u e s t i o n i s r a t h e r h a r d t o a n s w e r ,

4 0 7

and a good collcction of mineralogical material can be ensured only by long experience and extensive knowledge of nature. Of course the prospector needs at least a modicum of artistic sense in order that the picked sample reflect by its form and colours precisely the mineral for which it was taken. Some samples must, therefore, never be given definite shape, while for others certain sizes (approximately 9 X 12 or 6 X 9 cm.) and shapes are desirable.

COLLECTION OF MATERIALS IN GEOCHEMICAL PROSPECTING

Geochemical prospecting and geochemical methods of research require that special material be collected. Since the subsequent work of geochemists is connected with special mineralogical, chemical, spectroscopic and X-ray studies, the collection of materials is a problem of prime importance and the success of geochemical analysis very largely depends on the quality and organization of the collection.

What must a collection of this type yield? 1) In the first place, a sufficient amount of materials not only for

optical studies, but also for chemical analysis; in some cases detailed chemical analysis is preceded by concentration of the minerals during which the unnecessary admixtures are separated. Scores of samples of the most typical rocks and mineral combinations are, there-fore, needed.

2) Mineralogical studies also require a collection of separate minerals to find out the sequence in which minerals are liberated and in order that good pure samples of the most important minerals may be selected for analysis.

3) I t is necessary to collect mate-rials not only for laboratory studies Crystals of black tourmaline

4 0 8

but also for retaining typical museum samples. This is important both for demonstrative purposes and because large typical samples make it possible to compare these minerals with samples of similar minerals, but from other deposits.

Comparative analysis is one of the research methods used by naturalists. A geochemist must not repeat the mistakes of the old mineralogical school; he must seriously consider even the slightest manifestations of every chemical element; even the Crystals of gypsum thinnest crusts, products of weather-ing, must be collected as thoroughly as the beautiful ores with good crystals.

As a rule, prospectors are generally advised to take as much material as possible. It is better that they throw out later all that is superfluous rather than not collect all of the material required by the complex of minerals and chemical elements of the region studied.

In collecting samples one must never be sure he will come to the same place again and will collect additional new material. This does not always work out, and the collection is frequently incomplete, casual and of little value.

RECORDING OBSERVATIONS

The question of recording observations in field work is very important and serious. A certain scientist used to say quite justly that a traveller and explorer must carry a pencil tied to a string around his neck because the closer you have the pencil within your reach, the more you will write with it. The records must be made by two methods. In the first place, it is desirable accurately to inscribe on each label enclosed with the sample not only where and when the sample was found, but also some data on the conditions under which

4 0 9

Crystals of r ed ga rne t in mica s la te

it was obtained. The more exactly the place of the find is indicated, the easier it will be subsequently to utilize the collected material.

The main records, however, are made in the field notebook and keeping the book in the best pos-sible order must be the object of the prospector's constant concern. The success of many explorations depends on how carefully, thoughtfully and fully the field journals are kept. The observations must be recorded, first of all, at the place of work; the records must include all ob-servations made in the given place and whatever thoughts occurred to the prospector at that time. A summary of all the material must be given at the end of the day with

diaries kept of what was done during that time. Diagrams of the places where the work was done and the separate samples were taken should be made by the prospector in the notebook personally.

The completeness and accuracy of records in the notebook generally serve as the best index of the work, and one of the blunders of field workers is excessive reliance on their memory. Data added in the field book or on the labels by memory are a very dangerous method which not infrequently renders the collection valueless and leads to wrong inferences.

It will be observed that it is very difficult to keep a good field journal . Entries can usually be made in it only in the evening, at the end of a hard day in the field when the prospector is already tired and wants to rest. One must frequently force oneself to spend at least fifteen minutes on recording the observations made in the field during the day. I remember I also sometimes neglected my journal because I was too tired. In these cases it is best to take a day's rest and devote several hours to a calm and business-like correction of the journal.

4 1 0

F i e l d j o u r n a l s m u s t b e k e p t p a r t i c u l a r l y c a r e f u l l y ; t h e y m u s t n o t

b e r e l i n q u i s h e d e i t h e r d u r i n g w o r k o r a f t e r i t b e c a u s e t h e y a r e t h e

b a s i c d o c u m e n t w h i c h m u s t a l w a y s b e c a r r i e d a l o n g w i t h t h e o t h e r

m o s t i m p o r t a n t d o c u m e n t s o f t h e e x p e d i t i o n .

A f t e r r e t u r n i n g f r o m t h e e x p e d i t i o n a n d s o r t i n g o u t t h e c o l l e c t i o n s

w e c o m e t o t h e s e c o n d p a r t o f o u r w o r k , i . e . , t o s u m m i n g u p t h e r e s u l t s

o f t h e field w o r k .

I b e l i e v e i t i s v e r y i m p o r t a n t a n d c o n s i d e r a field r e p o r t i n m a n y

r e s p e c t s m o r e i m p o r t a n t t h a n t h e final r e p o r t , b e c a u s e i t u s u a l l y

o b j e c t i v e l y s u m m a r i z e s t h e d i r e c t field o b s e r v a t i o n s a n d i s , t h u s , m o r e

v a l u a b l e t h a n a d e t a i l e d final r e p o r t w h i c h i s i n f l u e n c e d b y t h e

l i t e r a t u r e r e a d , b y t h e o p i n i o n s o f o t h e r p r o s p e c t o r s a n d b y a n u m b e r

o f e x t r a n e o u s c o n s i d e r a t i o n s .

T h e r e p o r t m a d e u n d e r t h e first i m p r e s s i o n s o f t h e t r i p i s n o t i n f r e -

q u e n t l y m u c h m o r e c o r r e c t a n d p r o f o u n d f r o m t h e p o i n t o f v i e w o f

p o s i n g t h e p r o b l e m s t h a n t h e l a t e r s t u d i o u s l y t h o u g h t - o u t a n d e l a b o -

r a t e d s u m m a r y .

PART TWO

METHODS AND SEQUENCE OF WORK

B e f o r e l e a v i n g f o r t h e field t h e g e o c h e m i s t m u s t d o s o m e p r e l i m i n a r y

w o r k i n a d d i t i o n t o p r e p a r i n g h i s e q u i p m e n t w h i c h w e h a v e a l r e a d y

d i s c u s s e d . T h i s p r e l i m i n a r y w o r k c o n s i s t s i n t h e f o l l o w i n g .

F i r s t o f a l l , h e m u s t r e a d t h e l i t e r a t u r e o n t h e g i v e n r e g i o n a n d t h e

g i v e n p r o b l e m . I f t h e p r o s p e c t o r i s s e a r c h i n g f o r a d e f i n i t e c h e m i c a l

e l e m e n t h e m u s t n e c e s s a r i l y s t u d y i n d e t a i l i t s p r o p e r t i e s a n d i t s c o m -

p o u n d s . I n a d d i t i o n t o r e a d i n g t h e a v a i l a b l e l i t e r a t u r e t h e g e o c h e m i s t

m u s t , i n a l l c a s e s , m a k e a d e t a i l e d m u s e u m s t u d y o f t h e s a m p l e s t y p i c a l

o f t h e g i v e n r e g i o n a n d o f t h e m i n e r a l s w h i c h c h a r a c t e r i z e t h e e l e m e n t ,

i . e . , t h e o b j e c t o f h i s p r o s p e c t i n g . I t i s p a r t i c u l a r l y i m p o r t a n t t h a t t h e

i n v e s t i g a t o r o b t a i n d e t a i l e d t o p o g r a p h i c a l a n d g e o l o g i c a l m a p s o r

c o p i e s o f t h e m , i n o r d e r t h a t h e m a y m a r k i n c o l o u r e d p e n c i l t h e r o u t e

h e h a s t r a v e l l e d a n d t h e l o c a t i o n s o f t h e m o s t i n t e r e s t i n g m i n e r a l s

o n t h e s e m a p s .

B e f o r e d e p a r t i n g f o r t h e e x p e d i t i o n , t h e p r o s p e c t o r m u s t n e c e s s a r i l y

m a k e a d e t a i l e d s t u d y o f a l l t h e m e t h o d s o f field r e s e a r c h a n d k n o w

4 1 1

Characteristic relief in Dzhalal-Abad Region, Kirghiz S.S.R.

precisely not only how to use the instruments the geochemist takes along, but also how to repair them.

The second stage of work begins upon the arrival of the prospector on location. First of all, he must find out what is known about the given region in the local scientific societies, museums, libraries and schools. He must collect information among the local population about all the places where ore is mined and where there are natural outcrops. In a number of cases it is very important to analyze the geo-graphical names which, not infrequently, point at the existence of mines or production in the given territory; for example, in Central Asia, the word " k a n " means a mine, "kumysh"—silver, "kalba"—tin or bronze, etc. If a house is being built or a road paved, the prospector should find out-where the material is brought from and where the new road bridges or a railway line are built. O n state and collective farms he must ascertain where they dig wells, where they obtain clay for their stoves and lime or paint for their homes.

The local population frequently remembers that research parties had worked in the given region before, and many old people who know the region very well remember the ores found in particular

4 1 2

places. In some regions it is very important to ascertain the existence of old mines, dumps of ores and slags, remains of smelting furnaces, etc.

Of course, most of the material for the preliminary acquaintance with the mineralogy and geochemistry of a region is obtained not so much from natural outcrops as from artificial excavations, dumps near mines and workings which offer the mineralogist and geochemist indispensable and often perfectly fresh material. Ore deposits accu-mulate enormous quantities of the substances which accompany the ore and in the dumps of mines it is not infrequently possible to collect interesting material by examining the new output for a period of many days and by analyzing the minerals in daylight in the freshly broken-off samples. The dumps and heaps of mined ore and stone generally offer the mineralogist or geochemist much more valuable material than the underground workings where it is often hard to conduct accurate observations.

In open-cast mining and in pits it is very useful to talk to the workers, question them about the samples they encounter and focus their atten-tion on interesting things, asking them to put away whatever strikes

Mining phosphorite ore at the Kara-Tau Mine (Kazakh S.S.R.)

4 1 3

their eye. I t is possible and nec-essary to get the local population interested by letting the people in on your work and by telling them of the use of the minerals which may be found. The creation of a definite public opinion, a sympathy and cooperation on the part of the local population is one of the most important factors in the success of prospecting. The local population becomes inter-ested and even children bring samples of pebbles and boulders from the river. It must be said that the greatest discoveries of new deposits are not infrequently made by the local population and the local amateurs.

In each outcrop, quarry, working and mine the geo-chemist must try to collect the

samples of all mineral bodies encountered there and pay attention to their large accumulations and negligible traces which may indicate some particular geochemical processes.

The collection of materials must, naturally, be accompanied by ob-servations of the minerals imbedded in the rock, their correlations, age, etc. The primary acquaintance of the region enables the prospector to make a correct approach to its geochemical study. The following paragraphs are devoted to these problems of a purely research character.

The geologist and petrographer begin their work in the field with a study of the general geological situation, the tectonics and the relation-ships of rocks; this requires, in the first place, that the entire territory should be studied as a whole before a detailed study of any concrete sector is begun.

The work of the geochemist usually proceeds differently; he must begin his work essentially with concrete material, i.e., with the very deposit. He must begin his research from the heaps of the mined ore

Sarez Mountain Lake in the Pamirs formed after enormous landslide in the mountains (Tajik S.S.R.)

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a n d t h e d u m p s o f c o u n t r y r o c k w i t h a r e a d y k n o w l e d g e o f t h e g e n e r a l g e o l o g i c a l l a y o f t h e l a n d . T h i s i n d i c a t e s t h e r a t h e r s h a r p d i f f e r e n c e i n t h e m e t h o d s o f a p p r o a c h t o t h e w o r k o f g e o l o g i s t s a n d g e o c h e m i s t s i n a n e x p e d i t i o n o r e x c u r s i o n .

U p o n a r r i v a l i n s o m e d e p o s i t t h e g e o l o g i s t i m m e d i a t e l y g o e s t o a d r i f t o r m i n e t o e x a m i n e t h e f a c e s ; h e a l s o e x a m i n e s , i n t h e f irs t p l a c e , t h e o u t c r o p o f s e p a r a t e r o c k s , n a t u r a l o u t c r o p s , e t c .

T h e g e o c h e m i s t and'- m i n e r a l o g i s t g o , first o f - a l l , t o t h e o r e h e a p s a n d d u m p s . T h e y m u s t g o i n t o t h e s t o p e o n l y w h e n t h e i r e y e l e a r n s t o d i s t i n g u i s h s e p a r a t e m a t e r i a l s i n t h e d a y l i g h t b e c a u s e d e t e r m i n a t i o n o f m i n e r a l s p e c i e s i n t h e a r t i f i c i a l l i g h t i n g o f t h e s t o p e is a v e r y h a r d t a s k a n d is p o s s i b l e o n l y w i t h l o n g e x p e r i e n c e . O n l y a f t e r a t h o r o u g h s t u d y o f t h e m i n e r a l s i n h e a p s a n d d u m p s n f u s t t h e g e o c h e m i s t b e g i n s t u d y i n g t h e m o r e g e n e r a l g e n e t i c a n d g e o c h e m i c a l p r o b l e m s f o r w h i c h p u r p o s e h e e x a m i n e s t h e n a t u r a l o u t c r o p s a n d m i n e f a c e s a n d s t u d i e s a n y s k e t c h e s t h a t m a y b e a v a i l a b l e .

T h i s m a k e s i t p e r f e c t l y c l e a r w h y t h e m i n e r a l o g i s t a n d g e o c h e m i s t u p o n a r r i v i n g a t a m i n e u s u a l l y g o first t o t h e c o u n t r y r o c k d u m p s r a t h e r e v e n t h a n t o t h e o r e h e a p s .

I h a v e p e r s o n a l l y o b s e r v e d t h a t t h e l o c a l t e c h n i c a l a n d e n g i n e e r i n g p e r s o n n e l is f r e q u e n t l y n o t o n l y s u r p r i s e d , b u t a l s o v e r y m u c h d i s p l e a s e d w h e n , u p o n m y a r r i v a l , I g o t o t h e d u m p s r a t h e r t h a n t o t h e w o r k i n g s . W e m u s t n o t f o r g e t t h a t w e c a n s o l v e t h e m o s t c o m p l i c a t e d p r o b l e m s o f a d e p o s i t a n d u n d e r s t a n d i t s g e n e s i s o n l y b y a d e t a i l e d s t u d y o f a l l o f t h e o b s e r v e d m i n e r a l c o m p l e x e s , t h e i r i n t e r r e l a t i o n s , t h e i r r e l a t i o n s w i t h t h e l a t e r a l r o c k s , e t c .

T h u s , t h e s e q u e n c e o f t h e w o r k o f a g e o c h e m i s t d u r i n g t h e first c o l l e c t i o n o f s c i e n t i f i c m a t e r i a l a p p e a r s t o u s a s f o l l o w s : a d e t a i l e d e x a m i n a t i o n o f t h e d u m p s a n d t h e n o f t h e o r e h e a p s ; l a t e r , o f t h e f a c e s i n o p e n - c a s t w o r k i n g s a n d o u t c r o p s ; o n l y a f t e r a l l t h a t s h o u l d h e e x a m i n e t h e u n d e r g r o u n d w o r k i n g s a n d s t u d y t h e i n t e r r e l a t i o n s h i p s o f t h e m i n e r a l s i n t h e f r e s h u n d e r g r o u n d s t o p e s .

A s p r e v i o u s l y s t a t e d , t h e g e o c h e m i s t m u s t c o l l e c t m a t e r i a l s a n d c o n c u r r e n t l y a n a l y z e a l l m i n e r a l o g i c a l a n d g e o c h e m i c a l i n t e r r e l a t i o n s ; i t is , t h e r e f o r e , n e c e s s a r y t h a t h e c a r e f u l l y c o m p a r e a l l h i s o b s e r v a t i o n s . I r e c a l l t h a t , w h e n I a d v a n c e d t h e t h e o r y o f t h e r e l a t i o n o f p e g m a t i t e p r o c e s s e s t o t h e f o r m a t i o n o f e m e r a l d s i n t h e E m e r a l d M i n e s I m e t w i t h o s y m p n a t h y f o r a l o n g t i m e u n t i l s e v e r a l v e r y s m a l l c r y s t a l s

* i 5

of columbite confirmed that we were dealing with typical granite pegmatites.

In thinking over his observations the geochemist must mentally establish relationships between sep-arate minerals, reconstruct the conditions under which they were formed, basing himself on his ex-perience, subject all the data to a comparative analysis and, thus, grad-ually evolve some working hypothesis about the genesis of the deposit in question. Such a hypothesis is abso-lutely necessary for subsequent pros-pecting, but it must not be allowed to obscure the facts themselves. If the facts disagree with the hy-pothesis, the latter must be rejected. This work requires the most pro-found self-criticism and self-analysis, because success in prospecting con-sists in the ability to draw out of

small and hardly perceptible facts inferences which may be able to connect all phenomena to each other and to suggest those that are still unknown. Any working hypothesis is good only as long as it suggests new directions.

I am consciously focusing the reader's attention on this problem, because field workers are very frequently loath to give up their first working hypothesis even when new facts are at variance with it.

One more principle, which, unfortunately, has lately been somewhat neglected. The prospector must clearly distinguish the fact itself and his observation, on the one hand, from the theoretical and general conclusions, on the other. Both in his field and final reports the prospector must sharply separate these two parts so that everyone may see where the factual material of observations ends and where the logical and theoretical constructions of the author begin. Young prospectors should be warned against putting the concrete factual material in the back-

In the Pamirs. At the source of the Murgab River

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ground and becoming fascinated with the final conclusion, because in this case the conclusions hang in the air.

This is why we must especially persistently emphasize the necessity of accurate and painstaking observation of natural phenomena.

In the field the prospector must make note of every trifle that strikes his eye during observation. He must transform his field notebook into a constant diary of his own thoughts and observations, for only thus will he be able to make correct conclusions and decisions. Besides, he must sharply distinguish between the character of work and notes taken during the first year of visiting a particular deposit or region and that of the subsequent years. During the first visit it is especially necessary to accumulate purely factual material; during the second visit the pros-pector faces the necessity of checking on the work in his hypothesis; finally, during the third visit, he runs into problems of a general nature and it is usually precisely the third year that brings discoveries and suggests the direction of accurate prospecting. These periods may be cut short, but this depends on the experience of the prospector and on the extent to which the given deposits or region have been studied from the geo-logical and mineralogical points of view.

The final conclusions are considerably expedited if the prospector analyzes beforehand the minerals and rocks he encounters during his field work. Portable geochemical laboratories and the possibility of sending certain samples to near-by laboratories for quantitative analysis in large measure facilitate the field studies and enable the pros-pector to expedite final conclusions.

I t should be clear from the foregoing that the keeping of records is of prime importance.

27

BRIEF INFORMATION ABOUT CHEMICAL ELEMENTS

Actinium ( A c ) . A t o m i c n u m b e r — 89 , a t o m i c w e i g h t — 2 2 7 . D i s c o v e r e d in 1899 b y D e b i e r n e in p i t c h - b l e n d e . R a d i o a c t i v e p r o d u c t of u r a n i u m d i s i n t e g r a t i o n w i t h a 2 0 - y e a r h a l f -life p e r i o d . As a r e su l t of s u b s e q u e n t d i s i n t e g r a t i o n a c t i n i u m success ive ly f o r m s a series of r a d i o a c t i v e ele-m e n t s k n o w n as t h e a c t i n i u m series. T h e final m e m b e r of th i s ser ies is n o r l - r a d i o a c t i v e l e a d w i t h a n a t o m i c w e i g h t of 207. V e r y l i t t l e is k n o w n a b o u t a c t i n i u m a n d its c o m p o u n d s as y e t .

Actinoids. G r o u p of c h e m i c a l ele-m e n t s fo l l owing a c t i n i u m a n d v e r y closely r e s e m b l i n g e a c h o t h e r c h e m -ical ly . L ike t h e r a r e - e a r t h g r o u p , o r i a n t h a n o i d s , th i s g r o u p m u s t c o n t a i n 15 c h e m i c a l e l e m e n t s f r o m N o . 89 t o N o . 103; t w e l v e of t h e m h a v e a l r e a d y b e e n d i s c o v e r e d o r p r o d u c e d a r t i f i c i a l l y ; these i n c l u d e a c t i n i u m , t h o r i u m , u r a n i u m , n e p -t u n i u m . p l u t o n i u m , a m e r i c i u m , c u r i u m , b e r k e l i u m , c a l i f o r n i u m , e i n s t e i n i u m , f e r m i u m a n d m e n d e l e -v i u m . T h e first t h r e e of these o c c u r in n a t u r e .

T h e e l e m e n t s of th is g r o u p a r e u n i t e d u n d e r t h e n a m e of " a c t i n o i d s " ( " a c t i n i d e s " ) . T h e i r c h e m i c a l p r o p -er t ies ve ry m u c h r e s e m b l e those of t h e I a n t h a n o i d s a n d t h e y arft a l l c r o w d e d i n t o a s ingle b o x in t h e 3 r d

g r o u p of M e n d e l e y e v ' s P e r i o d i c T a b l e j u s t b e l o w t h e r a r e - e a r t h g r o u p .

Alabamine. D . M e n d e l e y e v be l i eved t h e r e w a s a n e l e m e n t ( e k a i o d i n e ) w i t h a n a t o m i c n u m b e r of 8 5 a n d d e s c r i b e d its p r o p e r t i e s . D i s c o v e r y of a n e l e m e n t w i t h t h e a t o m i c n u m b e r 8 5 w a s r e p o r t e d i n A m e r i c a in 1931, t h e e l e m e n t b e i n g n ^ m e d a l a b a m i n e ; t h e d i s c o v e r y w a s n o t c o n f i r m e d , h o w e v e r , a n d e l e m e n t 8 5 d i d n o t r e t a i n t h e n a m e a l a b a m -ine . See astatine.

Aluminium (A l ) . A t o m i c n u m -b e r — 1 3 ; a t o m i c w e i g h t — 2 6 . 9 8 . S i l v e r y - w h i t e , v e r y l i gh t m e t a l ; c o n s t i t u e n t of c lays , f e ld spa r s , m i c a s a n d m a n y o t h e r m i n e r a l s . M o s t a b u n d a n t c l e m e n t in t h e e a r t h ' s c rus t a f t e r o x y g e n a n d s i l icon. T h e e a r t h ' s c rus t c o n t a i n s 7 .5 p e r c e n t of it b y w e i g h t . T h e m a i n m a s s of a l u m i n i u m is c o n c e n t r a t e d in a l u m o s i l i c a t e s , m i n e r a l s c o m p o s e d of a l u m i n i u m , s i l icon, o x y g e n a n d c e r t a i n m e t a l s . B a u x i t e s — h y d r o u s ox ides of a l u m i n i u m — a r e e spec ia l ly r i c h in a l u m i n i u m . A l u m i n i u m is p r o d u c e d m a i n l y f r o m b a u x i t e a n d f r o m n e p h e l i n c . I t s a l loys a r e e x t e n -sively u sed in a i r c r a f t - b u i l d i n g . Fi rs t o b t a i n e d i n its p u r e s t a t e b y VVohler i n 1827. T h e n a m e s t e m s f r o m t h e w o r d alum.

4 1 8

Americium ( A m ) . A t o m i c n u m -b e r — 9 5 : a t o m i c w e i g h t of t h e s t ab l e s t i s o t o p e w i t h a ha l f - l i fe p e r i o d of a b o u t 10 ,000 y e a r s is 243 . F i r s t o b t a i n e d a r t i f i c i a l ly by b o m b a r d m e n t of u r a n i u m w i t h a l p h a p a r t i c l e s in 1945. F i v e i so topes a r e k n o w n t o d a y . I n its c h e m i c a l p r o p -e r t i es i t is v e r y s i m i l a r t o r a r e -e a r t h m e t a l s .

Antimony ( S b ) . A t o m i c n u m b e r — 5 1 : a t o m i c w e i g h t —121 .76 . K n o w n s ince a n t i q u i t y . P r o d u c e d in its f r ee s t a t e b y Basil V a l e n t i n e in t h e 15th c e n t u r y . V e r y b r i t t l e m e t a l . O c c u r s in c o m b i n a t i o n w i t h s u l p h u r . U s e d as a c o n s t i t u e n t in t y p e m e t a l a n d in m e d i c i n e . A n a d d i t i o n of a n t i m o n y to l e a d g r e a t l y i n -c r e a s e s its h a r d n e s s , w h i c h , is t a k e n a d v a n t a g e of in t h e m a n u f a c t u r e of t y p e m e t a l a n d bu l l e t s . A n t i m o n y c o m p o u n d s a r e used in t h e m a t c h , r u b b e r a n d glass i ndus t r i e s .

Argon ( A r ) . A t o m i c n u m b e r — 1 8 ; a t o m i c w e i g h t — 3 9 . 9 4 4 ; b e l o n g s t o t h e g r o u p of i n e r t gases w h i c h f o r m n o c o m p o u n d s e i t h e r w i t h e a c h o t h e r o r w i t h a n y o t h e r s u b s t a n c e s , a n d t h u s s h a r p l y d i f f e r f r o m al l o t h e r e l e m e n t s . O w e s its n a m e to its p a s s i v i t y : a r g o n m e a n s " i n a c t i v e " in G r e e k . D i s c o v e r e d by R a m s a y a n d R a y l e i g h in 1894. E n c o u n t e r e d as a c o n s t i t u e n t of t h e a i r w h i c h c o n t a i n s a b o u t o n e p e r c e n t of it. U s e d for filling l u m i -nescen t t u b e s : e m i t s a b lu i sh l i g h t .

Arsenic (As) . A t o m i c n u m b e r — 3 3 ; a t o m i c w e i g h t — 7 4 . 9 1 . Br i t t l e , b r o w n - b l a c k vo la t i l e m e t a l w i t h a ga r l i c - l ike o d o u r . T h e n a m e of t h e e l e m e n t s t e m s f r o m t h e w o r d arsenicon, m e a n i n g m i n e r a l d y e . K n o w n s ince h o a r y a n t i q u i t y . S u b l i -m a t e s w i t h o u t m e l t i n g a t 6 3 3 ' C . M e l t s a t 8 1 8 G . a n d u n d e r a p r e s s u r e of 3 6 a t m o s p h e r e s . A r s e n i c a n d its s o l u b l e sal ts a r e p o i s o n o u s . U s e d in a l loys w i t h l e a d a n d c o p p e r : f o r m s a c o n s t i t u e n t of t h e s u b s t a n c e s used in fighting

a g r i c u l t u r a l pes t s ( f u n g i c i d e s ) ; e m -p l o y e d in glass m a n u f a c t u r e for d e c o l o u r i z i n g glass.

Astatine ( A t ) . A t o m i c n u m b e r — 8 5 ; a t o m i c w e i g h t of its l onges t -l ived i s o t o p e w i t h a ha l f - l i f e p e r i o d of 8 . 3 h o u r s is 210 . F i r s t o b t a i n e d in 1940 b y b o m b a r d m e n t of b i s m u t h w i t h a l p h a p a r t i c l e s . N a m e d a f t e r astatos, t h e G r e e k w o r d m e a n i n g " u n s t a b l e . " 20 i so topes a r e k n o w n . I ts p r o p e r t i e s q u i t e c o i n c i d e w i t h D . M e n d e l e v e v ' s p r e d i c t i o n s ; M e n d e l c y e v h a d n a m e d it e k a i o d i n e .

Barium ( B a j . A t o m i c n u m b e r — 5 6 ; a t o m i c weigh t - —137.36. Sil-v e r v - w h i t e m e t a l a s h a r d as l e a d . D i s c o v e r e d in 1774 b y S c h e e l e ; f irst p r o d u c e d in its p u r e s t a t e by D a v y in 1808. The n a m e c o m e s f r o m t h e m i n e r a l b a r i t e , f r o m w h i c h it w a s p r o d u c e d (bams — h e a v y ) . G o l o u r s t h e flame a c h a r a c -te r i s t ic y e l l o w - g r e e n . I ts sal ts a r e used as a g o o d w h i t e p a i n t .

Berkelium (Bk) . A t o m i c n u m b e r 97 . P r o d u c e d a r t i f i c i a l l y b y b o m -b a r d m e n t of t h e i s o t o p e of a m e r i c -i u m w i t h a n a t o m i c w e i g h t o f 241. T h e ha l f - l i fe p e r i o d s of t h e b e r k e l i u m i so topes t h u s f a r dis-c o v e r e d d o not exceed a few h o u r s . N a m e d a f t e r t h e c i ty of Berke ley in t h e S t a t e of C a l i f o r n i a ( U . S . A . ) .

Beryllium (Be) . A t o m i c n u m b e r — 4 : a t o m i c w e i g h t - - 9 . 0 1 3 . V e r y h a r d b u t l igh t w h i t e m e t a l (its spec i f ic g r a v i t y is 1 .85) : s t a b l e in t h e a i r . D i s c o v e r e d in [797 b y Y a u q u e l i n a n d n a m e d by h i m g l u c i n u m b e c a u s e of t h e swee t i sh taste, of its salts . T h i s n a m e h a s pers i s ted on ly i n F r a n c e . T h e w o r d " b e r y l l i u m " c o m e s f r o m t h e m i n e r a l be r y l . Used for a l loys w i t h c o p p e r ( b e r y l l i u m b r o n z e s ) a n d o t h e r m e t a l s : m a k e s these, a l loys h a r d as steel a n d " t i r e l e s s " u n d e r stress ( w a t c h s p r i n g s ) . L a r g e c o n c e n t r a t i o n s of b e r y l l i u m m i n e r a l s a r e r a r e .

Bismuth (Bi) . A t o m i c n u m b e r — 8 3 ; a t o m i c w e i g h t — 2 0 9 . R e d d i s h - w h i t e ,

27* 4 ' 9

b r i t t l e , f u s i b l e m e t a l . C o m p o u n d s of b i s m u t h w e r e k n o w n in a n t i q -u i t y b u t a t t h a t t i m e i t w a s n o t d i s t i n g u i s h e d from l e a d ; first i s o l a t e d in i t s n a t i v e s t a t e b y a l c h e m i s t Basi l V a l e n t i n e i n t h e 1 5 t h c e n t u r y . F o r m s p a r t of t h e a l l o y s u s e d in p r i n t i n g a n d in d i f f e r e n t fire-fight-i n g d e v i c e s ; i n t e r e s t i n g fo r i t s s u p e r c o n d u c t i v i t y of c u r r e n t a t t e m p e r a t u r e s a p p r o a c h i n g a b s o l u t e z e r o .

Boron (B) . A t o m i c n u m b e r — 5 : a t o m i c w e i g h t — 1 0 . 8 2 . D i s c o v e r e d in 1808 b y D a v y in E n g l a n d a n d b y G a y - L u s s a c a n d T h e n a r d in F r a n c e . T h e n a m e c o m e s f r o m t h e w o r d " b o r a x . " C r y s t a l l i n e b o r o n i s o l a t e d f r o m t h e a l l o y w i t h a l u -m i n i u m is a l m o s t a s h a r d a s d i a m o n d . O c c u r s a s b o r i c a c i d a n d b o r a x a n d in c e r t a i n s i l i c a t e s ( sa l t s of s i l ic ic a c i d ) . U s e d m a i n l y for t h e m a n u f a c t u r e of e n a m e l s a n d i n m e d i c i n e . T h e c o m p o u n d s o f b o r o n w i t h c a r b o n a n d n i t r o g e n a r e e x t r a o r d i n a r i l y h a r d .

Bromine !Br . A t o m i c n u m b e r — 3 5 ; a t o m i c w e i g h t - 7 9 . 9 1 6 , D i s c o v e r e d b y B a l a r d in 1826 a n d n a m e d b r o m i u m (bromos— s t i n k i n g ) b e c a u s e of i ts u n p l e a s a n t o d o u r . B r o m i n e is a d a r k - b r o w n h e a v y l i q u i d ; l ike a l l t h e h a l o g e n s it is e x t r a o r d i n a r i l y a c t i v e a n d e n t e r s i n t o c o m b i n a t i o n w i t h m o s t of t h e e l e m e n t s . R e a c t s p a r t i c u l a r l y v i g o r o u s l y w i t h m e t a l s . P r o d u c e s s e v e r e b u r n s u p o n c o n -t a c t w i t h t h e s k i n . E n c o u n t e r e d m a i n l y in c o m p o u n d s w i t h p o t a s s i u m , s o d i u m a n d m a g n e s i u m . T h e s a l t - l a k e s of t h e C r i m e a a r e r i c h i n b r o m i n e . U s e d i n m e d i c i n e a n d in t h e p h o t o i n d u s t r y .

Cadmium ( C d ) . A t o m i c n u m b e r — 4 8 ; a t o m i c w e i g h t — 1 12.41 . S i l v e r y -w h i t e m e t a l d i s c o v e r e d b y S t r o h -m e y e r in 1 8 1 7 ; n a m e d e r i v e d f r o m t h e G r e e k w o r d cadmes—zinc o r e . C l o s e l y r e s e m b l e s z i n c in p r o p -e r t i e s a n d a l w a y s a c c o m p a n i e s i t i n n a t u r e . U s e d i n s t e a d of z i n c

f o r p l a t i n g i r o n , in a l l o y s w i t h c o p p e r f o r e n h a n c i n g t h e s t r e n g t h of c o p p e r w i r e s ; in f u s i b l e a l l o y s a n d y e l l o w p a i n t m a n u f a c t u r e .

Calcium ( C a ) . A t o m i c n u m b e r — 2 0 ; a t o m i c w e i g h t — 4 0 . 0 8 . A l k a l i n e -e a r t h m e t a l . D i s c o v e r e d b y D a v y a n d B c r z e l i u s in 1809 . N a m e c o m e s f r o m t h e w o r d calx—soft s t o n e ( l i m e s t o n e ) ; m a l l e a b l e , r a t h e r h a r d w h i t e m e t a l ; m e l t s a t a b o u t i ioo ' C . a n d b o i l s a t 1 , 2 4 0 ' C . ; a b u n d a n t in n a t u r e i n t h e f o r m of c a r b o n a t e s , s u l p h a t e s a n d s i l i ca t e s . I t s a v e r a g e c o n t e n t i n t h e e a r t h ' s c r u s t is 3 . 4 p e r c e n t . O n l y 4 e l e m e n t s ( O , Si , A1 a n d F e ) a r e e n c o u n t e r e d i n n a t u r e i n l a r g e r a m o u n t s t h a n c a l c i u m . M e t a l l i c c a l c i u m h a s n o t f o u n d a n y s p e c i a l a p p l i c a t i o n a s y e t .

Californium ( C f ) . A t o m i c n u m -b e r — 9 8 . A r t i f i c i a l l y o b t a i n e d b y b o m b a r d m e n t of t h e i s o t o p e o f c u r i u m ( a t o m i c w e i g h t — 2 4 2 ) w i t h a l p h a p a r t i c l e s . T h e h a l f - l i f e p e r i o d of c a l i f o r n i u m ( a t o m i c w e i g h t — 2 4 6 ) is 3 5 h o u r s . N a m e d a f t e r t h e S t a t e of C a l i f o r n i a , U . S . A .

Carbon ( C ) . A t o m i c n u m b e r — 6 ; a t o m i c w e i g h t — 1 2 . o i l . K n o w n s i n c e e a r l y a n t i q u i t y . N a m e d e r i v e d f r o m L a t i n carbo—coal. O c c u r s i n t h e f o r m of d i a m o n d s , g r a p h i t e , c o a l , v a r i o u s h y d r o c a r b o n s (oil a n d n a t u r a l g a s e s ) a n d i n o r g a n i c s u b -s t a n c e s . M o s t of i t , h o w e v e r , is i n c a r b o n a t e s ( sa l t s of c a r b o n i c a c i d ) — l i m e s t o n e s , m a r b l e s , e t c . , a s w e l l a s in s o l u t i o n s w i t h w a t e r a n d a i r ( i n t h e f o r m o f c a r b o n d i o x i d e ) . A p p l i c a t i o n s : d i a m o n d — f o r b o r i n g , c u t t i n g a n d g r i n d i n g g lass , f o r d e c -o r a t i o n s ; g r a p h i t e — a s a r e f r a c t o r y m a t e r i a l ( g r a p h i t e c r u c i b l e s ) , l u b r i -c a n t , p o w d e r , in p e n c i l s , i n r h e o -s t a t s a n d i n e l e c t r o d e s f o r a r c e l e c t r i c f u r n a c e s ; c o a l a n d oi l a r e u s e d a s f u e l , a s o n e of t h e m o s t i m -p o r t a n t s o u r c e s of e n e r g y . C a r b o n b l a c k is u s e d i n p a i n t s ( I n d i a n i n k ) . C o a l p r o c e s s i n g y i e l d s n u m e r o u s

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c h e m i c a l p r o d u c t s i n c l u d i n g a n i l i n e ; d r u g s — a s p i r i n a n d s t r e p t o c i d e ; sac -c h a r i n e ; e x p l o s i v e s — t r i n i t r o t o l u e n e , •etc.

Cassiofieium ( C p ) . N a m e used in s o m e c o u n t r i e s for t h e e l e m e n t l u t e c i u m . See lutecium.

Cerium (C'.e). A t o m i c n u m b e r — 5 8 ; a tomic , w e i g h t — 1 4 0 . 1 3 . R a r e - e a r t h e l e m e n t . D i s c o v e r e d in 1803 b y H i s i n g e r , K l a p r o t h a n d B e r z e l i u s a n d n a m e d a f t e r t h e s m a l l p l a n e t C e r e s . C e r i u m f o r m s p a r t of t h e m i x t u r e u s e d in t h e m a n u f a c t u r e of flints fo r c i g a r e t t e - l i g h t e r s , in m e d i c i n e , a n d in a r t i l l e r y for t r a c e r shel ls . I t is e x t r a c t e d f r o m m o n a z i t e as a b y - p r o d u c t in t h e p r o d u c t i o n of t h o r i u m .

Cesium ( C s ) . A t o m i c n u m b e r — 5 5 ; a t o m i c w e i g h t — 1 3 2 . 9 1 . Alka l i m e t a l . Spec i f i c g r a v i t y — 1 . 8 7 : m e l t i n g p o i n t 2 8 . 5 C . N a m e d a f t e r t h e s k y - b l u e c o l o u r of t h e s p e c t r a l l ines c h a r a c t e r i s t i c of c e s i u m (cac-sius in L a t i n — b l u e sky ) . F i rs t of t h e e l e m e n t s d i s c o v e r e d b y s p e c t r a l ana lys i s ( B u n s e n in 1860). C o l o u r s t h e test flame v io le t . O n l y o n e c e s i u m m i n e r a l — p o l l u c i t e — i s k n o w n . C e -s i u m is u s e d as t h e m a i n c o n s t i t u e n t in pho toce l l s .

Chlorine (CI ) . A t o m i c n u m b e r — 1 7 : a t o m i c w e i g h t — 3 5 . 4 5 7 . D i s c o v e r e d b y S c h e e l e in 1774 : n a m e d e r i v e d f r o m t h e w o r d chloros—green. Ye l -l o w - g r e e n gas h e a v i e r t h a n a i r . O c -c u r s in sal ts of s o d i u m a n d p o t a s s i u m d isso lved in t h e w a t e r s of t h e o c e a n , o r i n r o c k sal t ( N a C l ) depos i t s . O n e of t h e ba s i c e l e m e n t s of t h e c h e m i c a l i n d u s t r y m a i n l y for t h e p r o d u c t i o n of c h l o r i d e of l i m e : p l a y s a v e r y i m p o r t a n t p a r t in t h e m a n u f a c t u r e of p a i n t s , m a n y d r u g s a n d po i son gases . L a r g e q u a n t i t i e s of c h l o r i n e a r e u sed in b l e a c h i n g f a b r i c s a n d p a p e r , in s t e r i l i z ing d r i n k i n g w a t e r a n d in f i g h t i n g a g r i c u l t u r a l pes t s . S o d i u m c h l o r i d e ( N a C l ) is used in e n o r m o u s a m o u n t s in food ( eve ry h u m a n b e i n g c o n -

s u m e s f r o m 2 to t o kg . of sa l t a y e a r ) .

Chromium ( C r ) . A t o m i c n u m b e r — 2 4 ; a t o m i c w e i g h t 52 .01 . Dis -c o v e r e d b y V a u q u e l i n in 1798 w h i l e h e w a s d e c o m p o s i n g t h e m i n e r a l c r o c o i l e b r o u g h t b y Pa l l a s f r o m t h e U r a l s . N a m e s t e m s f r o m t h e G r e e k w o r d chrome—colouring b e c a u s e of t h e m o t l e y c o l o u r s of its d i f f e r e n t c o m p o u n d s . V e r y b r i t t l e , h a r d a n d v e r y s t a b l e a g a i n s t a i r a n d w a t e r : spec i f ic g r a v i t y — 7 . 1 ; m e l t s a t 1 ,765: C . M o s t f r e q u e n t l y e n c o u n t e r e d in t h e m i n e r a l c h r o -m i t e . U s e d m a i n l y in t h e steel i n d u s t r y . C h r o m i u m steels a r e k n o w n for t h e i r h a r d n e s s a n d d u r a b i l i t y ; t h e y a r e used for t h e m a n u f a c t u r e of tools a n d g u n t u b e s . O t h e r m e t a l s a r e c h r o m i u m - p l a t e d in o r d e r t o p r e v e n t t h e m f r o m c o r r o s i o n .

Cobalt ( C o ) . A t o m i c n u m b e r - - 2 7 : a t o m i c w e i g h t — 5 8 . 9 4 . D i scove red b y B r a n d t in 1735 a n d n a m e d a f t e r t h e w o r d cobold. m e a n i n g m o u n t a i n sp i r i t o r g n o m e . R a t h e r h a r d g r e y i s h - w h i t e , m a l l e a b l e a n d d u c t i l e m e t a l ; m e l t s a t 1,490" C . ; m a g n e t i c , b u t less so t h a n i r o n ; in a p u l v e r i z e d s t a t e c a p a b l e of a b s o r b i n g l a r g e a m o u n t s of h y d r o g e n : r e s e m b l e s i r o n phys i ca l l y a n d c h e m i c a l l y . O c c u r s in m e t e o r -i tes (in a l loys w i t h n icke l a n d i ron) a n d in t h e e a r t h ' s c rus t in c o m -b i n a t i o n w i t h a r s e n i c a n d s u l p h u r . U s e d in t h e p r o d u c t i o n of spec i a l steels, as a b l u e d y e for glass a n d e n a m e l s a n d as a ca t a ly s t in p r o -d u c i n g m o t o r fue l f r o m coa l .

Copper ( C u i . A t o m i c n u m b e r 2 9 ; a t o m i c w e i g h t — 6 3 . 5 4 . R e d , m a l -l e a b l e m e t a l . K n o w n s ince ea r ly a n t i q u i t y . N a m e d a f t e r t h e I s l a n d of C y p r u s b e c a u s e of t h e ex tens ive p r o d u c t i o n of c o p p e r w a r e s on t h e i s l and in a n t i q u i t y . O c c u r s m a i n l y in c o m b i n a t i o n w i t h sul-p h u r , m o r e r a r e l y n a t i v e . U s e d in its p u r e f o r m in e l ec t r i ca l e n g i n e e r -i n g a n d is o n e of t h e bes t c o n d u c t o r s

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of h e a t a n d e lec t r ic i ty ; a lso wide ly used in al loys w i th t in a n d z inc (brass) .

Curium ( C m ) . A t o m i c n u m b e r — 96. P r o d u c e d ar t i f ic ia l ly in 1944. E igh t isotopes of c u r i u m a r e k n o w n t o d a y . T h e longest - l ived i so tope is t he o n e w i t h t he a t o m i c w e i g h t of 24-). Its hal f - l i fe is m o r e t h a n 500 yea r s ; c h e m i c a l l y res. nbles the r a r e - e a r t h e lements . N a m e d in h o n o u r of M a r i e a n d P ie r re C u r i e a n d of F r e d e r i c a n d I r e n e J o l i o t -C u r i e .

Dvi-manganese. See rhenium. Dysprosium ( D y ) . .Atomic n u m -

b e r — 6 6 ; a t o m i c w e i g h t — 1 6 2 . 4 6 . R a r e - e a r t h e l e m e n t . D i scovered by Lecoq d e B o i s b a u d r a n in 1886. N a m e d a f t e r t h e G r e e k w o r d dysprositos—difficult of access.

Einsteinium ( E n ) . A t o m i c n u m -ber 99. R a d i o a c t i v e e l e m e n t of the ac t i n ide series. Syn thes ized b y a g r o u p of A m e r i c a n physicists in 1953. Five isotopes of e i n s t e i n i u m h a v e b e e n o b t a i n e d t o - d a t e . N a m e d in h o n o u r of the g r e a t G e r m a n scientist A. E ins te in .

Ekaalumininm. See gallium. Ekaborun. See scandium. Ekacesium. See francium. Ekaiodine. See astatine. Ekamanganese. See technetium. Ekasilicon. See germanium. Erbium (E r ) . A t o m i c n u m b e r — 6 8 ;

a t o m i c w e i g h t — 1 6 7 . 2 . R a r e - e a r t h e l e m e n t . Discovered by M o s a n d e r in 1843 a n d n a m e d a f t e r t h e t o w n of Y t t e r b y .

Europium ( E u j . A t o m i c n u m b e r — 6 3 ; a t o m i c w e i g h t — 1 5 2 . R a r e -e a r t h e l e m e n t . D i scovered by D e -m a r g a y in i g o i . I ts salts a r e col-o u r e d p ink .

Eermium ( F m ) . A t o m i c n u m b e r —100. R a d i o a c t i v e e l e m e n t of t he ac t i n ide series. O b t a i n e d in t he U . S . A . in 1953 by fission of t h e p r o d u c t s resu l t ing f r o m i r r a d i a t i n g u r a n i u m wi th a m o m e n t a r y s t r e a m of neu t rons . N a m e d in h o n o u r

of the I t a l i a n physicist E . F e r m i . F o u r isotopes of f e r m i u m w i t h a ha l f - l i fe p e r i o d of 30 m i n u t e s to 16 h o u r s h a v e been synthes ized t o - d a t e .

Fluorine (F ) . A t o m i c n u m b e r — 9 ; a t o m i c we igh t —19.00 . H a l o g e n -fami ly n o n - m e t a l . I n its f ree s t a t e it w a s first i so la ted b y Moi s san in 1886 t h o u g h it h a d been t a k e n for a n e l e m e n t by .Ampere as ea r ly as 1810. T h e n a m e s tems f r o m the n a m e of the m i n e r a l fluorite. N o r m a l l y it is a gas , g reen i sh -ye l low in its h e a v y layers . Specif ic g r a v i t y — 1 . 1 1 ( l i q u i d ) ; mel t s a t — 223° G . : boils a t 188 C. F inds n o a p p l i c a t i o n in its f ree s t a te . H y d r o f l u o r i c ac id is w ide ly used in c h e m i c a l l a b o r a t o r i e s as w e l l as in e t c h i n g glass.

Francium ( F r j . .Atomic n u m b e r — 8 7 : first d i scovered b y t he F r e n c h -w o m a n M . Percy in 1939 in the n a t u r a l r a d i o a c t i v e series of ac t in -i u m d i s i n t e g r a t i o n ; la te r p r o d u c e d ar t i f ic ia l ly . T h e br ief exis tence of t he isotopes of f r a n c i u m m a k e s it d i f f icu l t t o s tudy its c h e m i c a l p r o p -ert ies. T h e a t o m i c we igh t of o n e of its isotopes is 223. In its p rope r t i e s it is ak in to ces ium a n d is o n e of t he mos t ac t ive meta l s . N a m e d a f t e r t h e n a t i v e l a n d of the invest i-g a t o r . T h e exis tence of f r a n c i u m was a s s u m e d by D . M e n d e l e y e v w h o desc r ibed it u n d e r t h e n a m e of ekaces ium.

Gadolinium ( G d ) . A t o m i c n u m b e r — 6 4 ; a t o m i c w e i g h t — > 5 6 . 9 . R a r e -e a r t h e l e m e n t . D i scovered by M a r i -g n a c in 1880; n a m e d a f t e r t he m i n e r a l g a d o l i n i t e in 1886.

Gallium ( G a ) . A t o m i c n u m b e r — 3 1 ; a t o m i c w e i g h t — 6 9 . 7 2 . O n e of t he e l e m e n t s whose p r o p e r t i e s w e r e p r e d i c t e d by D . M e n d e l e y e v (eka-a l u m i n i u m ) . D i scove red by L e c o q d e B o i s b a u d r a n in 1875 by t he spec t ra l m e t h o d a n d n a m e d in h o n o u r of F r a n c e w h o s e old n a m e was Ga l l i a . S i lve ry -whi te soft m e t a l

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w i t h v e r y low m e l t i n g t e m p e r a t u r e of 2 9 . 8 G . (me l t s in t h e h a n d ) , b u t w i t h a b o i l i n g t e m p e r a t u r e of 2 , 3 0 0 C . ; sol id g a l l i u m is l i g h t e r t h a n l i q u i d g a l l i u m a n d t h e r e f o r e floats in its o w n m e l t ; b e l o n g s t o t h e r a r e d i s p e r s e d e l e m e n t s ; u sed in t h e m a n u f a c t u r e of t h e r m o -m e t e r s for m e a s u r i n g h i g h t e m -p e r a t u r e s a n d l u m i n o u s c o m p o u n d s ; a lso u sed in t h e p r o d u c t i o n of o p t i c a l m i r r o r s .

Germanium ( G e ) . A t o m i c n u m -b e r — 3 2 ; a t o m i c w e i g h t — 7 2 . 6 0 . O n e of t h e r a r e s t e l e m e n t s w h o s e p r o p -er t ies w e r e p r e d i c t e d b y D . M e n -d e l e y e v (ekas i l i con) . D i s c o v e r e d in 1886 b y W i n k l e r b y t h e s p e c t r a l m e t h o d . Possesses b o t h m e t a l l i c a n d n o n - m e t a l l i c p r o p e r t i e s . F i n d s a p p l i c a t i o n in r a d i o - e n g i n e e r i n g for t h e m a n u f a c t u r e of l u m i n o u s c o m p o u n d s a n d for t h e p r o d u c t i o n of spec ia l sor t s of glass.

Glucinum (G l ) . See beryllium. Gold ( A u ) . A t o m i c n u m b e r — 7 9 ;

a t o m i c w e i g h t — 1 9 7 . 2 . K n o w n s ince h o a r y a n t i q u i t y . M a l l e a b l e a n d sof t m e t a l ; resists o x i d a t i o n ; dissolves o n l y i n a q u a r e g i a ; does n o t r e a d i l y f o r m c o m p o u n d s w i t h o t h e r e l e m e n t s ; o n l y its a l loys w i t h s i lver a n d its c o m p o u n d s w i t h s e l e n i u m a n d t e l l u r i u m a r e k n o w n . Spec i f i c g r a v i t y of c h e m i -ca l ly p u r e go ld is 19.3 (of n a t i v e g o l d c o n t a i n i n g f r o m 15 t o 25. p e r c e n t s i l v e r — 1 5 to 16). M e l t s a t 1 ,060° C . a n d bo i l s a t 2 ,677° C . T h i n l eaves of go ld s h o w u p g r e e n . G o l d is a c u r r e n c y m e t a l a n d this c o n s t i t u t e s its m a i n v a l u e . I ts t e c h n i -ca l a p p l i c a t i o n s a r e i n s i g n i f i c a n t ; c o n t a c t s , g o l d - p l a t e d a r t i c les , p h o t o g -r a p h y a n d m e d i c i n e .

Hafnium ( H f ) . A t o m i c n u m b e r — 7 2 ; a t o m i c w e i g h t — 1 7 8 . 6 . T h o u g h a m o r e a b u n d a n t e l e m e n t t h a n go ld o r s i lver a n d its c o n t e n t in s o m e m i n e r a l s a m o u n t s t o 30 p e r c e n t , it w a s d i s c o v e r e d o n l y in 1923 b y C o s t e r a n d H c v e s y . T h i s

w a s d u e t o t h e e x t r a o r d i n a r y r e s e m -b l a n c e of its c h e m i c a l p r o p e r t i e s t o those of z i r c o n i u m f r o m w h i c h h a f n i u m c a n b e s e p a r a t e d on ly w i t h d i f f i c u l t y . M e t a l l i c h a f n i u m is ve ry h a r d a n d h a s a h igh m e l t -i n g p o i n t ( a b o u t 2 .200 C . i . I n t h e f o r m of ox ides k c o n s t i t u t e s p a r t of t h e a l loys used in t h e m a n u -f a c t u r e of e l e c t r o n va lve f i l a m e n t s . F i n d s l i m i t e d use in t h e r a d i o i n d u s t r y as s u p e r - f i r e p r o o f m a t e r i a l . I t s n a m e c o m e s f r o m t h e a n c i e n t n a m e of t h e D a n i s h c a p i t a l — C o p e n h a g e n ( H a f n i a ) .

Helium ( H e ) . A t o m i c n u m b e r — 2 ; a t o m i c w e i g h t — 4 . 0 0 3 . N o b l e gas. F i r s t s p e c t r o s c o p i c l ines d i s c o v e r e d b y J . J a n n s e n in 1868 in t h e a t m o s -p h e r e of t h e s u n . O n e a r t h d is -c o v e r e d b y R a m s a y in 1895; the l a t t e r i so la ted this gas f r o m t h e m i n e r a l c leve i te . T h e n a m e c o m e s f r o m t h e w o r d helios—sun. S e c o n d l igh tes t of al l gases a f t e r h y d r o g e n ; it is 8 t i m e s as l ight as a i r . F o u n d in t h e a t m o s p h e r e a n d t o g e t h e r w i t h o t h e r n a t u r a l gases in t h e i n t e r i o r of t h e e a r t h ; f o r m e d d u r i n g r a d i o a c t i v e d i s i n t e g r a t i o n of e l e m e n t s ; t h e a l p h a p a r t i c l e w h i c h c o m e s flying o u t of t h e a t o m i c n u c l e i of r a d i o a c t i v e e l e m e n t s is a pos i t ive ly c h a r g e d n u c l e u s of h e l i u m ; u sed t o g e t h e r w i t h h y d r o g e n for filling d i r i g i b l e s ; p r e -v e n t s t h e l a t t e r f r o m e x p l o d i n g . L o w e s t t e m p e r a t u r e on e a r t h , n e a r l y — 2 7 3 ° C . , h a s b e e n o b t a i n e d b y e v a p o r a t i n g h e l i u m .

Holmium ( H o ) . A t o m i c n u m b e r — 6 7 ; a t o m i c w e i g h t — 1 6 4 . 9 4 . R a r e -e a r t h e l e m e n t . D i s c o v e r e d b y t h e S w e d i s h c h e m i s t C l e v e in 1879. H o l m i u m sal ts a r e p i n k - c o l o u r e d . N a m e d a f t e r t h e S w e d i s h c a p i t a l S t o c k h o l m .

Hydrogen ( H ) . A t o m i c n u m b e r — 1 ; a t o m i c w e i g h t — 1 . 0 0 8 . L i g h t e s t a n d first e l e m e n t in t h e p e r i o d i c s y s t e m of e l e m e n t s . C o n s t i t u t e s a b o u t 1 p e r c e n t of t h e e n t i r e m a s s of t h e e a r t h ' s

4 2 3

c rus t , i n c l u d i n g w a t e r a n d t h e a i r . Co lou r l e s s gas , f o u r t e e n t i m e s as l igh t as a i r . D i s c o v e r e d in t h e first h a l f of t h e 16th c e n t u r y by-P a r a c e l s u s as a resu l t of t h e r e a c t i o n b e t w e e n s u l p h u r i c a c i d a n d i r o n . I n 1766 C a v e n d i s h d i s c o v e r e d its p r o p e r t i e s a n d p o i n t e d o u t its d i f f e r e n c e s f r o m t h e o t h e r gases . Lavo i s i e r w a s t h e first t o p r o d u c e h y d r o g e n f r o m w a t e r in 1783 a n d to p r o v e t h a t w a t e r w a s a c h e m i c a l c o m p o u n d of h y d r o g e n a n d o x y g e n . O n t h e e a r t h h y d r o g e n o c c u r s o n l y in c o m p o u n d s — i n w a t e r , oil a n d in t h e t issues of l iv ing ce l l s : in its f r ee s t a t e it is f o u n d in ins ign i f -i c a n t q u a n t i t i e s in t h e u p p e r l aye r s of t h e a t m o s p h e r e : a l so l i b e r a t e d d u r i n g v o l c a n i c e r u p t i o n s . S p e c -t ro scop ica l l y d i s c o v e r e d in t h e s u n a n d in t h e s ta rs . A c c o r d i n g t o m o d e r n c o n c e p t i o n s , t h e s u b s t a n c e of t h e c o s m o s consis ts of 30 to 50 p e r c e n t f r ee h y d r o g e n w h o s e a t o m is t h e p r i n c i p a l b u i l d i n g br ick of t h e u n i v e r s e . I n a d d i t i o n to h y d r o g e n w i t h a n a t o m i c w e i g h t of 1 t h e r e a r e t w o r a r e i so topes w i t h a t o m i c w e i g h t s of 2 a n d 3 w h i c h in c o m b i n a t i o n w i t h o x y g e n y ie ld " h e a v y w a t e r . " H y d r o g e n is used for f i l l ing d i r ig ib l e s a n d b a l l o o n s in w h i c h it ac t s as t h e l i f t ing force b e c a u s e it is l i g h t e r t h a n a i r . I n a u t o g e n o u s w e l d i n g its f l a m e d e v e l o p s a t e m p e r a t u r e of u p to 2 ,000" C . ; it is a lso u sed in t h e c h e m i c a l i n d u s t r y for p r o d u c i n g a r t i f i c ia l oil f r o m coa l .

Illinium ( I I ) . A n e l e m e n t w i t h a n a t o m i c w e i g h t of 61 w a s de -s c r i b e d u n d e r this n a m e . T h e f ac t of its d i s cove ry w a s n o t c o n f i r m e d . See promethium.

Indium ( I n ) . A t o m i c n u m b e r — 4 9 ; a t o m i c w e i g h t — 1 1 4 . 7 6 . R a t h e r r a r e d i spe r sed e l e m e n t . D i s c o v e r e d b y t h e s p e c t r a l m e t h o d b y R e i c h a n d R i c h t e r in 1863; n a m e d a f t e r t h e d a r k - b l u e , i n d i g o - c o l o u r e d l ines in its s p e c t r u m . S i l v e r y - w h i t e m e t a l

s o f t e r t h a n l e a d in its f r ee s t a t e ; n o m i n e r a l s r i c h in i n d i u m a r e k n o w n ; o r e s of m a n y m e t a l s c o n -t a i n i n s i g n i f i c a n t a d m i x t u r e s of its c o m p o u n d s , e spec ia l ly w i t h z inc . Best m e t a l fo r t h e m a n u f a c t u r e of m i r r o r s .

Iodine ( I ) . A t o m i c n u m b e r — 5 3 ; a t o m i c w e i g h t — 1 2 6 . 9 2 . D i s p e r s e d e l e m e n t . T y p i c a l n o n - m e t a l . U s u a l l y sol id , vo la t i l e a n d eas i ly s o l u b l e i n a n u m b e r of so lvents . D i s c o v e r e d b y C o u r t o i s in 1811. P r o d u c e d in i n d u s t r y from C h i l e a n s a l t p e t r e in a m o u n t s of u p t o 1,000 t o n s a y e a r : a l so e n c o u n t e r e d in m i n e r a l oil w a t e r s a n d e x t r a c t e d f r o m s e a w e e d s . N a m e d e r i v e d f r o m t h e G r e e k w o r d iodis—violet b e c a u s e of t h e c o l o u r of its v a p o u r s . F i n d s ex t ens ive a p p l i c a t i o n in m e d i c i n e , r o e n t g e n o t h e r a p y , m a n u f a c t u r e of p o l a r i z i n g glass, p h o t o g r a p h y a n d in dyes .

Iridium ( I r ) . A t o m i c n u m b e r — 7 7 ; a t o m i c w e i g h t - - 1 9 3 . 1 . O n e of t h e h e a v i e s t m e t a l s (specif ic g r a v i t y — 22 .4 ) . D i s c o v e r e d b y T e n n a n t i n p l a t i n u m ores in 1803. N a m e d e r i v e d f r o m t h e w o r d iridis—iridescent ( b e c a u s e of t h e p a r t i c o l o u r e d so lu t i ons of its sal ts : n o t e d for its g r e a t h a r d n e s s a n d c h e m i c a l s t ab i l -i t y ; m e l t s a t 2 . 4 5 4 C . : c h e m i c a l l y c losely r e s e m b l e s r h o d i u m ; o c c u r s as a f e l l o w - t r a v e l l e r of p l a t i n u m ; u s e d in its p u r e s t a t e for c r u c i b l e s , h i g h - t e m p e r a t u r e e l ec t r i c f u r n a c e s a n d t h e r m o e l e m e n t s ; a lso e x t e n -sively u sed in a l loys .

Irm ( F e ) . A t o m i c n u m b e r — 2 6 ; a t o m i c w e i g h t — 5 5 . 8 5 . K n o w n s ince e a r l y a n t i q u i t y . Eas i ly ox id izes a n d f ree ly c o m b i n e s w i t h o t h e r e l e m e n t s a n d is, t h e r e f o r e , h a r d t o o b t a i n in its p u r e s t a t e . M e t a l l i c i r o n is s t ee l -g rey a n d m a l l e a b l e : h a s t h e h i g h e s t m a g n e t i c p r o p e r t i e s of all m e t a l s . C o m p o u n d s of i r o n a n d c a r b o n (steels, c o n t a i n i n g f r o m 0 .2 t o 2 p e r c e n t c a r b o n , a n d p i g i rons c o n t a i n i n g f r o m 2 .5 to 4 p e r

4 2 4

c e n t c a r b o n ) f o r m t h e bas is of t h e i r o n a n d steel i n d u s t r y of o u r a g e . T h e p r i n c i p a l o res a r e h e m a t i t e — Fe. ,0 : 1 ) m a g n e t i t e — F e 3 0 4 , i r o n c a r -b o n a t e o r s i de r i t e — F e C O , a n d h y d r o u s ox ides of i r o n — F e . , 0 : l n H 2 0 . T h e e a r t h ' s c r u s t c o n t a i n s 4 .7 p e r c e n t i r o n ; t h e cosmos c o n t a i n s m o r e . R o c k s w i t h m o r e t h a n 30 p e r c e n t i r o n a r e i r o n ores .

ICrypton ( K r ;. A t o m i c n u m b e r — 3 6 : a t o m i c w e i g h t — 8 3 . 6 6 . I n e r t gas d i s c o v e r e d b y R a m s a y a n d T r a v -ers in 1898; n a m e d e r i v e d f r o m t h e G r e e k w o r d kryplos, m e a n i n g h i d d e n . O c c u r s as a c o n s t i t u e n t of t h e a i r in w h i c h it is c o n t a i n e d in neg l i g ib l e q u a n t i t i e s .

Lanthanum ( L a ) . A t o m i c n u m -b e r — 5 7 ; a t o m i c w e i g h t — 1 3 8 . 9 2 . R a r e - e a r t h e l e m e n t . D i s c o v e r e d b y M o s a n d e r in 1839; n a m e d e r i v e d f r o m t h e G r e e k w o r d lanthenein, m e a n i n g h i d e ; c o n s t i t u e n t of t h e a l l oy u sed for " f l i n t s " in c i g a r e t t e -l igh te r s .

Lanthanoids ( l a t h a n i d e s ) . S e e rare-earth elements.

Lead ( P b ) . A t o m i c n u m b e r — 8 2 : a t o m i c w e i g h t — 2 0 7 . 2 1 . K n o w n s ince e a r l y a n t i q u i t y . B lu i sh -g rey , sof t , h e a v y m e t a l . Spec i f i c g r a v i t y 11 .34; m < " h s a t 3 2 7 0 G . H a s m a n y uses. U s e d ch ie f ly in t h e m a n u -f a c t u r e of c a b l e s h e a t h i n g a n d s t o r a g e - b a t t e r y p l a t e s ; a l a r g e a m o u n t of it is u sed in t h e m a n u -f a c t u r e of bu l l e t s a n d sho t . C o n -s t i t u e n t of m a n y a l loys : b a b b i t s , t y p e m e t a l s , e t c . C o m p o u n d s of l e a d a r e u s e d as a w h i t e p a i n t . O c c u r s m a i n l y in ga l c f i a ( P b S ) f r o m w h i c h l ead is e x t r a c t e d .

Lithium (L i ) . A t o m i c n u m b e r — 3 ; a t o m i c w e i g h t — 6 . 9 4 0 . T h e l ightes t m e t a l . L i g h t e r t h a n w a t e r (specif ic g r a v i t y — 0 . 5 3 4 ) . D i s c o v e r e d b y A r f -v e d s o n in 1817; n a m e d e r i v e d f r o m t h e G r e e k w o r k lithos—stone. Be longs t o t h e g r o u p of a l k a l i m e t a l s a n d is k n o w n for its ve ry h i g h c h e m i c a l a c t i v i t y ; c losely

r e s e m b l e s p o t a s s i u m a n d s o d i u m c h e m i c a l l y . I ts sal ts c o l o u r t h e test flame b r i g h t r ed . E n c o u n t e r e d o n l y in c o m p o u n d s ; t r a c e s of it a r e f o u n d in t h e w a t e r s of m a n y m i n e r a l sp r ings . U s e d in t h e m a n u -f a c t u r e of b a t t e r i e s for s u b m a r i n e s , in spec ia l a l loys a n d in w e l d i n g a l u m i n i u m w a r e s .

Lutecium ( L u ) . A t o m i c n u m b e r — 7 1 ; a t o m i c w e i g h t — 1 7 4 . 9 9 . R a r e - e a r t h e l e m e n t . D i s c o v e r e d s i m u l t a n e o u s l y by U r b a i n in F r a n c e a n d b y A u e r in G e r m a n y . 1 h e f o r m e r n a m e d it l u t e c i u m a f t e r t h e old n a m e of P a r i s ; t h e l a t t e r g a v e it t h e n a m e of c a s s i o p e i u m . Bo th n a m e s a r e u sed in l i t e r a t u r e . T h e n a m e used in t h e Sovie t U n i o n is l u t e c i u m .

Magnesium ( M g ) . A t o m i c n u m -b e r — 1 2 ; a t o m i c w e i g h t — 2 4 . 3 2 . A l k a l i n e - e a r t h m e t a l . D i s c o v e r e d by e lec t ro lys is b y D a v y in 1808. N a m e d a f t e r t h e m i n e r a l magnesia alba. ( M a g n e s i a is a loca l i ty in G r e e c e ; alba m e a n s w h i t e . ) A b u n d a n t in n a t u r e ; c o n s t i t u t e s 2 .5 p e r cen t of t h e w e i g h t of t h e e a r t h ' s c rus t a n d is a c o n s t i t u e n t of c a r b o n a t e a n d s i l ica te rocks . E n o r m o u s a m o u n t s of d isso lved m a g n e s i u m sal ts a r e f o u n d in s e a - w a t e r : l ight (specif ic g r a v i t y — 1 . 7 4 ) a n d m a l l e -a b l e ; v e r y a c t i v e c h e m i c a l l y , b u t s t a b l e in a l loys . H a s f o u n d c o n -s i d e r a b l e a p p l i c a t i o n in t h e a i r c r a f t i n d u s t r y in t h e f o r m of m a g n e s i u m -a l u m i n i u m al loys .

Manganese ( M n j . A t o m i c n u m -b e r — 2 5 ; a t o m i c w e i g h t — 5 4 . 9 3 . A s i l ve rv -wh i t e , h a r d m e t a l . Dis-c o v e r e d b y Schee l e in 1774 ill t h e m i n e r a l p v r o l u s i t e ( n a t i v e m a n -g a n e s e d i o x i d e s o m e t i m e s ca l l ed black m a g n e s i a , h e n c e t h e n a m e of t h e e l e m e n t ) . V e r y a b u n d a n t in n a t u r e ; f o r m s a c c u m u l a t i o n s of b lack p v r o l u s i t e in m a r i n e s e d i m e n t s . Used in m e t a l l u r g y for i m p r o v i n g t h e q u a l i t y of s teel , in t h e p a i n t i n d u s t r y a n d in m a n y b r a n c h e s of t h e c h e m i -ca l i n d u s t r y .

42")

Masurium. D i s c o v e r y of a n ele-ment . w i t h t h e a t o m i c n u m b e r of 43 w a s r e p o r t e d i n 1924. T h i s d i s co v e ry is n o t r e c o g n i z e d t o d a y . See lechnelium.

Mendelevium ( M v ) . A t o m i c n u m -b e r — 1 0 1 . O b t a i n e d in t h e U . S . A . in 1955 b y b o m b a r d i n g e i n s t e i n i u m 253 w i t h h i g h - e n e r g y a l p h a p a r t i -cles. N a m e d in h o n o u r of t h e R u s s i a n c h e m i s t D . M e n d e l e y e v .

Mercury ( H g ) . A t o m i c n u m b e r — Bo; a t o m i c w e i g h t — 2 0 0 . 6 1 . T h e on ly m e t a l f o u n d in a l i q u i d s t a t e u n d e r n o r m a l c o n d i t i o n s . K n o w n s ince e a r l y a n t i q u i t y . L a t i n n a m e ( h y d r a r g y r u m ) s t e m s f r o m t h e G r e e k w o r d s hydor argyros — l i qu id s i lver . Sol idif ies a t — 3 9 - 3 C . ; boi ls a t 357 ' ' C . Spec i f ic g r a v i t y — 1 3 . 6 . Dis -solves m a n y m e t a l s (go ld , s i lver , c o p p e r a n d t in) y i e l d i n g l i qu id a n d sol id a l loys ca l l ed a m a l g a m s . I ts v a p o u r s a r e v e r y p o i s o n o u s . Used in filling v a r i o u s i n s t r u m e n t s (for e x a m p l e , t h e r m o m e t e r s ) , in m e d i c i n e , in e x t r a c t i n g g o l d f r o m ores a n d in m a n u f a c t u r i n g m e r c u r y f u l m i n a t e , o n e of t h e m o s t i m p o r t a n t d e t o n a t o r s . E n c o u n t e r e d in t h e m i n e r a l c i n n a b a r ( H g S j .

Molybdenum ( M o ) . A t o m i c n u m -b e r — 4 2 ; a t o m i c w e i g h t — 9 5 . 9 5 . G r e y i s h - w h i t e m e t a l , h a r d a n d m a l -l eab le a t a h i g h t e m p e r a t u r e . Dis-c o v e r e d b y H j e l m in 1782, b u t p u r e m o l y b d e n u m w a s p r o d u c e d b y M o i s s a n o n l y in 1895. T h e n a m e s t e m s f r o m t h e G r e e k w o r d molybdos, m e a n i n g l e a d , b e c a u s e of t h e r e s e m b l a n c e of t h e l a t t e r t o t h e m i n e r a l m o l y b d e n i t e . F o u n d m a i n l y as m o l y b d e n i t e o r m o l y b d e -n u m d i s u l p h i d e ( M o S 2 ) , a m i n e r a l w h i c h e x t e r n a l l y r e s e m b l e s g r a p h i t e . M e t a l l i c m o l y b d e n u m is u s e d in steel a l loys to m a k e t h e m v e r y h a r d a n d d u r a b l e . I ts a l l oy w i t h t u n g s t e n r e p l a c e s p l a t i n u m . Also used as a n a n t i c a t h o d e in R o e n t g e n t u b e s a n d for t h e a n c h o r s t h a t s u p p o r t t h e t u n g s t e n f i l a m e n t in

e l ec t r i c b u l b s . C o m b i n e s w i t h c a r b o n to f o r m t h e c a r b i d e M o C 2 , a v e r y h a r d p r o d u c t .

Neodymium ( N d ) . A t o m i c n u m -b e r — 6 0 ; a t o m i c w e i g h t — 1 4 4 . 2 7 . R a r e - e a r t h e l e m e n t . D i s c o v e r e d b y A u e r in 1885 as a resu l t of s p l i t t i n g d i d y m i u m . f o r m e r l y c o n s i d e r e d a n e l e m e n t , in t w o : n e o d y m i u m — n e w t w i n — a n d p r a s e o d y m i u m . N e o d y m -i u m sal ts a r e p i n k - r e d .

Neon ( N e ) . A t o m i c n u m b e r — 1 0 ; a t o m i c w e i g h t — 2 0 . 1 8 3 . N o b l e gas d i s c o v e r e d b y R a m s a y a n d T r a v e l s in 1898 s i m u l t a n e o u s l y w i t h k r y p t o n a n d x e n o n . N a m e d e r i v e d f r o m t h e G r e e k w o r d neos—new. E n c o u n t e r e d as a neg l i g ib l e a d m i x t u r e in t h e a i r . U s e d for filling gas - l i gh t l a m p s ( n e o n l a m p s ) w h i c h e m i t a r e d l igh t .

Neptunium ( N p ) . A t o m i c n u m -b e r — 9 3 . F i r s t of t r a n s u r a n i u m ele-m e n t s . P r o d u c e d a r t i f i c i a l ly in 1940 b y b o m b a r d m e n t of u r a n i u m w i t h n e u t r o n s . R a d i o a c t i v e . 12 i so topes a r e k n o w n t o d a y ; t h e longes t - l i ved i s o t o p e is t h e o n e w i t h a n a t o m i c w e i g h t of 2 3 7 : its ha l f - l i fe is 2.2 m i l l i o n y e a r s . C h e m i c a l l y r e s e m b l e s u r a n i u m . N a m e d a f t e r t h e p l a n e t N e p t u n e . O c c u r s in neg l i g ib l e q u a n -ti t ies.

Nickel (N i ) . A t o m i c n u m b e r — 2 8 ; a t o m i c w e i g h t — 5 8 . 6 9 . S i l v e r y - w h i t e , r a t h e r h a r d m e t a l . T h e n a m e s t ems f r o m t h e m i n e r a l Kupfernickel w h i c h m e a n s w o r t h l e s s c o p p e r . D i s c o v e r e d b y C r o n s t e d t in 1751. M e l t s a t 1 ,455 C . O c c u r s in c o m b i n a t i o n w i t h s u l p h u r o r in s i l i ca te ores . W i d e l y u sed for n i c k e l - p l a t i n g , in t h e m a n u f a c t u r e of spec ia l steels a n d as a c a t a l y s t .

Niobium ( N b ) . A t o m i c n u m b e r — 4 1 ; a t o m i c w e i g h t — 9 2 . 9 1 . G r e y i s h -w h i t e , h a r d a n d m a l l e a b l e m e t a l . D i scov e r e d b y H a t c h e t t m 1801 a n d n a m e d c o l u m b i u m b y t h e d i s c o v e r e r . I n 1846 R o s e d i v i d e d c o l u m b i u m i n t o t w o e l e m e n t s — n i o b i u m a n d t a n t a l u m . T h e n a m e

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columbium persis ts in A m e r i c a , w h i l e niobium p r e v a i l s in t h e E u r o p e a n c o u n t r i e s . N a m e d a f t e r t h e n y m p h N i o b e . t h e d a u g h t e r of T a n t a l u s . O b t a i n e d in its p u r e s t a t e in 1907 ; e x t r a o r d i n a r i l y s t a b l e a g a i n s t v a r i o u s c h e m i c a l i n f luences . F o u n d closely a s soc ia t ed w i t h t a n t a l u m a n d t i t a -n i u m . U s e d in spec ia l a l loys a n d in s teels fo r t h e m a n u f a c t u r e of v e r y i m p o r t a n t w e l d e d s t r u c t u r e s s ince t h e a d d i t i o n of n i o b i u m g r e a t l y e n h a n c e s t h c s t r e n g t h o f w e l d e d s e a m s . E m p l o y e d in t h e p r o d u c t i o n o f s u p e r -h a r d a l loys : o f fe r s se r ious a d v a n t a g e s for e l e c t r o - v a c u u m e n g i n e e r i n g .

Nitrogen ( N ) . A t o m i c n u m b e r — 7 ; a t o m i c w e i g h t — 1 4 . 0 0 8 . C o l o u r l e s s g a s c o n s t i t u t i n g 4 / 5 of t h e v o l u m e of t h e s u r r o u n d i n g a i r . F i r s t i nd i -c a t i o n s of t h e ex i s t ence of n i t r o g e n as a s e p a r a t e s u b s t a n c e w e r e m a d e b y R u t h e r f o r d (1772) , b u t it w a s o n l y L a v o i s i e r w h o p r o v e d t h a t it W a s a n e l e m e n t a n d w h o g a v e it t h e n a m e of a z o t e ( t h e G r e e k for " l i f e l e s s " ) . T h e L a t i n n a m e N i t r o -g e n i u m a n d t h e m o d e r n E n g l i s h n a m e n i t r o g e n o r i g i n a t e d f r o m nitron

s a l t p e t r e a n d g e n u s . I n a d d i t i o n t o t h e a i r . n i t r o g e n is f o u n d in all l iv ing o r g a n i s m s , as wel l as in t h e f o r m of t h e s a l t p e t r e s , i .e. , t h e n i -s t r a t c of s o d i u m a n d p o t a s s i u m . F r e e n i t r o g e n is used in e lec t r i c l a m p s ; its c o m p o u n d s a r e of e n o r m o u s i m -p o r t a n c e as fer t i l izers a n d as c o n -s t i t u e n t s of explos ives .

Osmium ( O s ) . A t o m i c n u m b e r — 76 ; a t o m i c w e i g h t — 1 9 0 . 2 . Be longs to t h e g r o u p of p l a t i n u m m e t a l s . D i s c o v e r e d b y T e n n a n t in 1803 : n a m e d e r i v e d f r o m t h e G r e e k w o r d nsme—odoriferous b e c a u s e t h e va -p o u r s of o s m i c a n h y d r i d e smel l of r o t t e n r a d i s h . C h e m i c a l l y v e r y s t a b l e e l e m e n t . Spec i f i c g r a v i t y of 22 .48, is t h e h ighes t of all t h e s u b s t a n c e s o n e a r t h . M e l t s a t 2 .500 ' C . O c c u r s in its n a t i v e s t a t e t o g e t h e r w i t h p l a t i n u m . A l loy of o s m i u m a n d i r i d i u m is u n c o m m o n l y

h a r d a n d is used for tips of f o u n t a i n p e n s .

Oxygen ( O ) . A t o m i c n u m b e r 8 : a t o m i c w e i g h t — 1 6 . 0 0 0 0 . The n a m e l i t e ra l ly m e a n s " a c i d f o r m e r . " Dis-c o v e r e d b y Pr ies t ley in 1 774. E x t r a o r -d i n a r i l y a b u n d a n t in n a t u r e , con -s t i t u t i n g 4 9 . 5 p e r cen t of t h e e a r t h ' s c rus t by w e i g h t . P l ays a n e n o r m o u s p a r t in n a t u r a l p rocesses : c o n s t i t u e n t of w a t e r , mos t m i n e r a l s a n d o r g a n i s m s : w i d e l y used in m e t a l -l u r g y (in t h e s m e l t i n g of p i g i r o n ) , in a u t o g e n o u s w e l d i n g a n d in a n u m b e r of b r a n c h e s of t h e c h e m i c a l i n d u s t r y : l i qu id o x y g e n or l iqu id ai t a r e used as p o w e r f u l explosives .

Palladium ( P d ) . A t o m i c n u m b e r — 4 6 ; a t o m i c w e i g h t - 106.7. E l e m e n t of t h e p l a t i n u m g r o u p . D i scove red by W o l l a s t o n in 1803 a n d n a m e d in h o n o u r of t h e smal l p l a n e t ( a s t e ro id ) Pa l l a s . Softest a n d mos t m a l l e a b l e of all t h e e l e m e n t s of t h e p l a t i n u m g r o u p . R e m a r k a b l e for its ab i l i t y to a b s o r b t r e m e n d o u s a m o u n t s of h y d r o g e n ( u p to 300 v o l u m e s p e r o n e v o l u m e of t h e m e t a l ) w h i l e r e t a i n i n g its m e t a l l i c a p p e a r a n c e b u t i n c r e a s i n g in v o l u m e . Used in j e w e l l e r y b e c a u s e of its b e a u t y .

Phosphorus ( P ) . .Atomic n u m -b e r — 1 5 ; a t o m i c w e i g h t 30 .975 . R e c e i v e d its n a m e b e c a u s e of its l u m i n e s c e n c e ( f r o m t h e ( J r eek w o r d s phos—light a n d photos b e a r i n g ) . D i s c o v e r e d by B r a n d t in 1669. Spec i f ic g r a v i t y 1 .83; me l t s a t 4 4 C . ; boi ls a t 280 .5 ' C . T h e f o l l o w i n g va r i e t i e s a r e k n o w n : ye l low p h o s p h o r u s , r e d p h o s p h o r u s : in 1914 B r i d g e m a n p r o d u c e d b l a c k p h o s p h o r u s . A b u n d a n t in t h e e a r t h ' s c r u s t in t h e f o r m of p h o s p h a t e s ; c o n s t i t u e n t of n u m e r o u s m i n e r a l s : a p a t i t e , t u r q u o i s e , i r on p h o s p h a t e s , c o p p e r p h o s p h a t e s , e t c . U s e d in t h e m a n u f a c t u r e of m a t c h e s , in t h e p r o d u c t i o n of smoke - sc r eens , k i n d l i n g s u b s t a n c e s , e tc . P h o s p h o -r i tes a n d a p a t i t e a r e t h e m o s t im-

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p o r t a n t r a w m a t e r i a l s fo r t h e p r o -d u c t i o n of p h o s p h o r u s - c o n t a i n i n g fer t i l izers .

Platinum ( P t i . A t o m i c n u m b e r — 7 8 ; a t o m i c w e i g h t — 1 9 5 . 2 3 . C h i e f e l e m e n t of t h e p l a t i n u m g r o u p . D i s c o v e r e d by A n t o n i o U l l o a in 1838 in t h e g o l d - b e a r i n g s a n d of t h e P i n t o R i v e r ; as a n i n d e p e n d e n t e l e m e n t d e s c r i b e d b y W a t s o n i n 1750. N a m e s t e m s f r o m t h e S p a n i s h w o r d plalina, a d i m i n u t i v e o f p l a t a — si lver . Spec i f ic g r a v i t y — 2 1 . 4 ; m e l t s a t 1 ,773.5 C . S h i n i n g , m a l l e a b l e m e t a l ; does no t c h a n g e in t h e a i r even w h e n h e a t e d t o t h e h i g h e s t poss ible t e m p e r a t u r e . As a r e f r a c -to ry a n d c h e m i c a l l y s t a b l e e l e m e n t f i nds ex tens ive a p p l i c a t i o n in sc ien-tific a n d t e c h n i c a l l a b o r a t o r i e s . O c -c u r s n a t i v e . M i n e d m o s t l y in p l a c e r d e p o s i t s .

Plutonium ( P u ) . A t o m i c n u m -b e r — 9 4 . Firs t a r t i f i c i a l ly p r o d u c e d in 1941 b y b o m b a r d m e n t of u r a -n i u m w i t h d e u t e r i u m — n u c l e i of h e a v y h y d r o g e n . R a d i o a c t i v e . 12 isotopes a r c k n o w n t o d a y . T h e longes t - l ived i so tope is t h e o n e w i t h a n a t o m i c w e i g h t of 242 . I t s ha l f -life is 5 0 0 , 0 0 0 yea r s . I s o t o p e 239 is t h e bas ic p r o d u c t fo r o b t a i n i n g a t o m -ic e n e r g y : c h e m i c a l l y r e s e m b l e s u r a -n i u m . N a m e d a f t e r t h e p l a n e t P l u t o . F o u n d as a neg l i g ib l e a d -m i x t u r e in n a t i v e u r a n i u m ores ( a b o u t 1 a t o m of p l u t o n i u m p e r 140,000 mi l l ion a t o m s of u r a n i u m ) .

Polonium ( P o ) . A t o m i c n u m b e r — 8 4 : a t o m i c w e i g h t — 2 1 0 . 0 . R a d i o -ac t ive e l e m e n t . D i s c o v e r e d b y M a r i e C u r i e in 1898 a n d n a m e d in h o n o u r of h e r n a t i v e P o l a n d . H a s n o t b e e n p r o d u c e d in its p u r e s t a t e . C h e m i c a l l y v e r y closely r e s e m b l e s t e l l u r i u m a n d is a m e m b e r of t h e u r a n i u m series of r a d i o a c t i v e ele-m e n t s . I ts ha l f - l i fe is 137.6 days_

Potassium ( K ) . A t o m i c n u m b e r — 19; a t o m i c w e i g h t — 3 9 . 0 9 6 . F i r s t i so la ted by e lect rolys is f r o m c a u s t i c p o t a s h by D a v y in 1807. L a t i n

n a m e ( k a l i u m ) c o m e s f r o m t h e a r a b i c w o r d alkali; E n g l i s h n a m e — f r o m p o t a s h . D o e s n o t o c c u r n a t i v e b u t is v e r y a b u n d a n t in s i l ica tes a n d h a l i d e s . T h e p o t a s s i u m i s o t o p e h a v i n g a n a t o m i c w e i g h t of 40 is r a d i o a c t i v e . P o t a s s i u m is a s i lvery-w h i t e m e t a l , sof t as w a x ; ox id izes r a p i d l y in t h e a i r a n d is, t h e r e f o r e , k e p t in k e r o s e n e . M e l t s a t 6 3 . 5 ' C „ boi ls a t 762° C . I t is l i g h t e r t h a n w a t e r (specif ic g r a v i t y — 0 . 8 6 2 ) . W i t h s o d i u m y ie lds a n a l l o y w h i c h is l i q u i d a t u s u a l t e m p e r a t u r e s a n d w h i c h c a n r e p l a c e m e r c u r y i n t h e r m o m e t e r s . M e t a l l i c p o t a s s i u m finds v e r y l i t t le a p p l i c a t i o n b e c a u s e it is r e p l a c e d b y c h e a p e r s o d i u m .

Praseodymium ( P r ) . A t o m i c n u m -b e r — 5 9 ; a t o m i c w e i g h t — 1 4 0 . 9 2 . R a r e - e a r t h e l e m e n t . D i s c o v e r e d t o g e t h e r w i t h n e o d y m i u m b y A u c r in 1885. N a m e d e r i v e d f r o m t h e G r e e k w o r d s praseos a n d didymos— g r e e n t w i n . I t s sal ts a r e g r e e n .

Promethium ( P m ) . A t o m i c n u m -b e r — 6 1 . I n M c n d e l e y e v ' s p e r i o d i c s y s t e m l o c a t e d in t h e g r o u p of r a r e - e a r t h e l e m e n t s . C h e m i c a l l y i so la ted f r o m f r a g m e n t s of u r a n i u m fission as a r e l a t i v e l y l o n g - l i v e d i so tope , w i t h a n a t o m i c n u m b e r of 147. I t s ha l f - l i fe is c lose t o 4 y e a r s . N a m e d in h o n o u r of t h e m y t h o l o g i -ca l t i t a n P r o m e t h e u s .

Protactinium ( P a ) . A t o m i c n u m b e r — 9 1 ; a t o m i c w e i g h t — 2 3 1 . S i lve rv -w h i t c m e t a l . R a d i o a c t i v e e l e m e n t . D i s c o v e r e d b y H a l i n a n d Lise M e i t n e r in 1917. I n 1927 Gros se i so la ted a f r a c t i o n of a g r a m of f r ee p r o t a c t i n i u m . N a m e d e r i v e d f r o m t h e G r e e k w o r d s protos a n d actinos—first r a y . O c c u r s t o g e t h e r w i t h u r a n i u m a n d is o n e of t h e p r o d u c t s of its d i s i n t e g r a t i o n . I t s ha l f - l i fe is 3 , 2 0 0 y e a r s .

Radium ( R a i . A t o m i c n u m b e r — 8 8 ; a t o m i c w e i g h t — 2 2 6 . 0 5 . S i lve ry m e t a l w h i c h d e c o m p o s e s w a t e r a t o r d i n a r y t e m p e r a t u r e . R a d i o a c t i v e e l e m e n t of t h e u r a n i u m series

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d i s c o v e r e d b y t h e C u r i e s in p i t c h - b l e n d e in 1898. N a m e de -r i ved f r o m t h e w o r d radius—ray. C h e m i c a l l y v e r y c lose ly r e s e m b l e s b a r i u m a n d it is, t h e r e f o r e , v e r y h a r d t o s e p a r a t e t h e sal ts of r a d i u m f r o m t h o s e of b a r i u m . T h e m o s t r e m a r k a b l e p r o p e r t y of r a d i u m is its h i g h r a d i o a c t i v i t y , seve ra l m i l l i o n t imes t h a t of u r a n i u m . R a d i u m e m i t s a l p h a , b e t a a n d g a m m a r ays . T h e sa l ts of r a d i u m a r e l u m i n o u s ; t h e r a y s it emi t s , in a d d i t i o n t o a c t i n g o n p h o t o - p l a t e s , p r o d u c t -m a n y c h e m i c a l r e a c t i o n s , d e s t r o y a n i m a l o r g a n i s m s a n d kill b a c t e r i a . T h e a b i l i t y of r a d i u m i n c e s s a n t l y to l i b e r a t e l a r g e a m o u n t s of energy-is p a r t i c u l a r l y a s t o u n d i n g . I ts h a l f -life is 1 ,580 y e a r s . U s e d in m e d i c i n e for t r e a t i n g c a n c e r a n d l u p u s .

Radioactive elements. C h e m i c a l ele-m e n t s c o n t i n u o u s l y e m i t t i n g inv is ib le r a y s w h i c h l ike X - r a y s p e r m e a t e t h r o u g h v a r i o u s s u b s t a n c e s , m a k e t h e a i r e l e c t r o c o n d u c t i v e a n d b l a c k e n p h o t o - p l a t e s , e tc . , a r e ca l l ed r a d i o -a c t i v e . R a y s e m i t t e d b y r a d i o a c t i v e e l e m e n t s a r e d i v i d e d i n t o a l p h a r ays , b e t a r a y s a n d g a m m a , r ays . P o t a s s i u m i s o t o p e w i t h a n a t o m i c w e i g h t of 40 , o n e of t h e i so topes of r u b i d i u m , i n d i u m , l a n t h a n u m , sa-m a r i u m , a n d r h e n i u m , u r a n i u m , t h o r i u m , p o l o n i u m , r a d i u m , p r o t a c -t i n i u m a n d al l t r a n s u r a n i u m ele-m e n t s h a v e r a d i o a c t i v e p r o p e r t i e s .

Radon ( R n ) . A t o m i c n u m b e r — 8 6 ; a t o m i c w e i g h t — 2 2 2 . 0 . H e a v i e s t n o b l e g a s ; p r o d u c t of r a d i o a c t i v e t r a n s f o r m a t i o n of r a d i u m . S h o r t -l i v e d : its ha l f - l i fe is 3 . 8 5 d a y s ; t r a n s f o r m e d i n t o h e l i u m a n d sol id s u b s t a n c e r a d i u m A. D i s c o v e r e d b y D o r n i n i g o o . T h e n a m e s t e m s f r o m t h e s a m e r o o t as t h e w o r d radium. W a s a l so c a l l e d r a d i u m e m a n a t i o n a n d n i t o n . U s e d in t r e a t i n g c a n c e r .

Rare earths ( T R ) . Box 57 of M e n d e l e y e v ' s P e r i o d i c T a b l e c o n -t a i n s n o t o n e e l e m e n t , a s d o t h e o t h e r boxes , b u t 15 c lose ly r e l a t e d

e l e m e n t s . T h e i r a t o m i c n u m b e r s r u n f r o m 57 to 71. These e l e m e n t s a r e u n i t e d u n d e r t h e g e n e r a l t i t le of r a r e e a r t h s 01 " r a r e - e a r t h " e l e m e n t s o r , f ina l ly , l a n t h a n o i d s ( l a n t h a n i d e s ) . T h e r a r e e a r t h s i n c l u d e l a n t h a n u m , c e r i u m , p r a s e o d y m i u m , n e o d y m i u m , p r o m e t h i u m , s a m a r i u m , e u r o p i u m , g a d o l i n i u m , t e r b i u m , d y s p r o s i u m , h o l m i u m , e r b i u m , t h u l i u m , y t t e r -b i u m a n d l u t e c i u m . Y t t r i u m ( N o . 39) is a l so c o n s i d e r e d o n e of t h e r a r e -e a r t h e l e m e n t s . T w o g r o u p s of r a r e e a r t h s a r e d i s t i n g u i s h e d : y t t r i a n a n d c c r i a n . Al l t h e r a r e e a r t h s a r e v e r y m u c h a l ike in t h e i r p r o p e r t i e s . I n t h e i r f r ee s t a t e t he se m e t a l s h a v e v e r y h i g h m e l t i n g p o i n t s ; t h e y d e c o m p o s e w a t e r a t o r d i n a r y t e m p e r -a t u r e . I n n a t u r e t h e y a r e a l w a y s e n c o u n t e r e d m i x e d w i t h e a c h o t h e r . I t is v e r y d i f f i c u l t t o d i v i d e t h e r a r e e a r t h s . M o n a z i t e is t h e m a i n r a r e -e a r t h c o n t a i n i n g m i n e r a l . O n l y c e r i u m h a s so f a r a c q u i r e d p r a c t i c a l i m p o r t a n c e . T h e h i s t o r y of t h e d i s c o v e r y of i n d i v i d u a l r e p r e s e n t a -t ives of t h e r a r e e a r t h s is r a t h e r c o m p l i c a t e d . T h e ex i s t ence of a " n e w e a r t h " w a s first e s t a b l i s h e d b y G a d o l i n i n 1794; t h e last of t h e r a r e e a r t h s t o b e d i s c o v e r e d w a s l u t e c i u m ; p r o m e t h i u m ( N o . 61) was a r t i f i c i a l l y p r o d u c e d r e c e n t l y . A d -d i t i o n a l i n f o r m a t i o n o n t h e i nd i -v i d u a l e l e m e n t s of t h e r a r e - e a r t h g r o u p wil l b e f o u n d u n d e r t h e i r n a m e s .

Rhenium ( R e ) . A t o m i c n u m b e r — 7 5 ; a t o m i c w e i g h t — 1 8 6 . 3 1 . O n e of t h e m o s t d i spe r s ed e l e m e n t s dis-c o v e r e d b y M . a n d M m e . N o d d a c k o n l y in 1925. N a m e d a f t e r t h e R h i n e R i v e r . I t s p r o p e r t i e s h a d b e e n p r e -d i c t e d b y D . M e n d e l e y e v . w h o n a m e d it d v i m a n g a n e s e . I n e x t e r n a l a p p e a r a n c e m e t a l l i c r h e n i u m re-s e m b l e s p l a t i n u m . I t is o n e of t h e h e a v i e s t a n d m o s t r e f r a c t o r y ele-m e n t s . T h e m e t a l is p a r t i c u l a r l y v a l u a b l e for t h e e l ec t r i ca l i n d u s t r y b e c a u s e it is used in t h e m a n u f a c t u r e

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of f i l a m e n t s for e l ec t r i c b u l b s w h i c h a r e m o r e d u r a b l e t h a n t u n g s t e n f i l a m e n t s . I t is a l so used in a l loys . O c c u r s in t h e m i n e r a l m o l y b d e n i t e in a m o u n t s w h i c h d o n o t e x c e e d o . o o o o i p e r c e n t .

Rhodium ( R h ) . A t o m i c n u m b e r — 4 5 ; a t o m i c w e i g h t —102 .91 . E l e m e n t of t h e p l a t i n u m g r o u p . D i s c o v e r e d in 1804 by W o l l a s t o n ; n a m e d e r i v e d f r o m t h e G r e e k w o r d rhodon—pink b e c a u s e , of t h e c o l o u r of its salts . O c c u r s n a t i v e t o g e t h e r w i t h t h e p l a t i n u m e l e m e n t s . A n a l l oy of p l a t i n u m a n d r h o d i u m is u sed in t h e m a n u f a c t u r e of i n s t r u m e n t s for m e a s u r i n g h i g h t e m p e r a t u r e s ( t h e r -m o c o u p l e s ) .

Rubidium ( R b ) . A t o m i c n u m b e r — 3 7 ; a t o m i c w e i g h t — 8 5 . 4 8 . E l e m e n t of t h e a lka l i g r o u p . D i s c o v e r e d b y Bunsen in 1861 by s p e c t r a l ana lys i s . N a m e d a f t e r t h e c h a r a c t e r i s t i c r e d l ines of t h e s p e c t r u m (rubidus—dark-r e d ! . In its p r o p e r t i e s it is v e r y close to s o d i u m a n d p o t a s s i u m . Speci f ic g r a v i t y 1 .52; m e l t s a t 39 C . ; boils a t 696'" C . O c c u r s in e x t r e m e l y d i spe r sed s t a t e ; t h e l a rges t a m o u n t s ( u p t o o. 1 p e r c e n t ) a r c f o u n d in a m a z o n i t e ( g r e e n f e l d s p a r ) ; a p p r e c i a b l e q u a n t i t i e s of it a r e f o u n d in t h e m i n e r a l c a r n a l l i t e . R u b i d i u m is r a d i o a c t i v e ; it e m i t s o n l y b e t a r ays a n d is t r a n s f o r m e d i n t o s t r o n -t i u m . I t s ha l f - l i fe is 70 .000 m i l l i o n yea r s .

Ruthenium ( R u ) . A t o m i c n u m b e r — 4 4 ; a t o m i c w e i g h t — 1 0 1 . 7 . P l a t i n u m e l e m e n t . D i s c o v e r e d in 1844 b y t h e R u s s i a n sc ient is t K l a u s in t h e c i ty of K a z a n a n d n a m e d in h o n o u r of R u s s i a ( R u t h c n i a in L a t i n m e a n s R u s s i a ) . Br i t t le . Spec i f i c g r a v i t y — 12.26; me l t s a t 1,950 ' C . O c c u r s t o g e t h e r w i t h o t h e r e l e m e n t s of t h e p l a t i n u m g r o u p . I t is e x t r e m e l y r a r e a n d h a s t h e r e f o r e f o u n d n o a p p l i -c a t i o n .

Samarium ( S m ) . A t o m i c n u m b e r — 6 2 ; a t o m i c w e i g h t — 1 5 0 . 4 3 . R a r e -e a r t h e l e m e n t . D i s c o v e r e d b y L e c o q

d e B o i s b a u d r a n in 1879 a n d n a m e d a f t e r t h e m i n e r a l s a m a r s k i t e . I t c o l o u r s t h e flame of t h e v o l t a i c a r c a p i n k - r e d . I t is r a d i o a c t i v e ; e m i t s o n l y a l p h a r ays a n d is t r a n s f o r m e d i n t o n e o d y m i u m .

Scandium (Sc ) . A t o m i c n u m b e r — 2 1 ; a t o m i c w e i g h t — 4 4 . 9 6 . O n e of t h e m o s t d i s p e r s e d e l e m e n t s . I t s ex i s t ence w a s a s s u m e d b y D . M e n -d e l e y e v in 1871. D i s c o v e r e d b y Ni l son in 1879 b y s p e c t r a l ana lys i s . I t s p r o p e r t i e s a r e n o t v e r y wel l k n o w n . N a m e d a f t e r t h e S c a n d i -n a v i a n P e n i n s u l a .

Selenium (Sc). A t o m i c n u m b e r — 3 4 ; a t o m i c w e i g h t — 7 8 . 9 6 . Dis -c o v e r e d b y Berze l ius in 1817; n a m e d e r i v e d f r o m t h e G r e e k w o r d selene— m o o n . C o n d u c t s e l ec t r i c c u r r e n t , its r e s i s t a n c e v a r y i n g w i t h d e g r e e of i l lu-m i n a t i o n . The use of s e l e n i u m in p h o t o e l e c t r i c cells is b a s e d m a i n l y o n this p r o p e r t y . I n c h e m i c a l p r o p e r t i e s it is close t o s u l p h u r a n d , espec ia l ly , t o t e l l u r i u m . Spec i f ic g r a v i t y — 4 . 8 ; m e l t s a t a i 7 ° C . ; boi ls a t 6 8 8 ° C . F o u n d in a d i spe r s ed s t a t e as a s m a l l a d m i x t u r e in s u l p h u r . I n a d d i t i o n t o pho to -ce l l s , s e l e n i u m is u sed i n e lec t r i ca l e n g i n e e r i n g , in t h e r u b b e r a n d glass i n d u s t r i e s a n d in te le-v is ion . H o w e v e r , i ts uses a r e ex-t r e m e l y l i m i t e d .

Silicon (Si ) . A t o m i c n u m b e r — 1 4 ; a t o m i c w e i g h t — 2 8 . 0 6 . S e c o n d m o s t a b u n d a n t c l e m e n t ( a f t e r o x y g e n ) . N e v e r o c c u r s n a t i v e , b u t in c o m -b i n a t i o n w i t h o x y g e n ( k n o w n as s i l ica—SiO; , ) o r sal ts of silicic a c i d (s i l icates) . Q u a r t z a n d its n u m e r o u s v a r i e t i e s a r e c o m p o s e d of s i l ica . T h e m o s t i m p o r t a n t t e c h n i c a l p r o d -uc ts , s u c h as glass , p o r c e l a i n , ce-m e n t a n d b r i c k , l ike t h e m a i n r o c k s — g r a n i t e , b a s a l t , syen i t e , e tc . , cons is t , p r i m a r i l y , of s i l icates . Dis -c o v e r e d b y G a y - L u s s a c a n d T h c n a r d in 1810, b u t its n a t u r e as a n e l e m e n t w a s e s t a b l i s h e d b y Berze l ius o n l y in 1825. T h e n a m e c o m e s f r o m t h e w o r d silex m e a n i n g s tone .

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Silver ( A g ) . A t o m i c n u m b e r — 4 7 ; a t o m i c w e i g h t — 1 0 7 . 8 8 . N o b l e m e t a l . K n o w n s ince e a r l y a n t i q u i t y . P u r e s i lver is w h i t e , v e r y sof t a n d d u c t i l e . Spec i f i c g r a v i t y — 1 0 . 5 ; m e l t s a t 9 6 0 . 5 C . ; in i ts p r o p e r t i e s r e s e m b l e s go ld a n d c o p p e r ; does n o t c h a n g e in t h e a i r a n d is v e r y m a l l e a b l e . Best c o n d u c t o r of h e a t a n d e l ec t r i c -i ty . O c c u r s n a t i v e a n d in c o m -b i n a t i o n w i t h s u l p h u r a n d c h l o r i n e . S i lve r a l loys se rve for t h e m a n u f a c t u r e of h o u s e w a r e s , j e w e l r y a n d s i lver co ins . T h e L a t i n n a m e ( a r g e n t u m ) s t e m s f r o m t h e S a n s k r i t w o r d argenos—clear.

Sodium ( N a ) . A t o m i c n u m b e r — 1 1 ; a t o m i c w e i g h t — 2 2 . 9 9 7 . S i lve ry -w h i t e m e t a l , a s sof t a s w a x ; ox id izes in t h e a i r (is k e p t in ke ro sene ) a n d is l i g h t e r t h a n w a t e r (speci f ic g r a v -i t y — 0 . 9 7 1 ) . D i s c o v e r e d b y D a v y in 1807 b y e lec t ro lys is of c a u s t i c s o d a ; D a v y ' s e x p e r i m e n t s w e r e suc -cessfu l ly r e p e a t e d in P e t e r s b u r g b y t h e R u s s i a n c h e m i s t S e m y o n V l a s o v . L a t i n n a m e ( n a t r i u m ) d e r i v e d f r o m t h e A r a b i c w o r d natron m e a n i n g s o d a , a lka l i . E n g l i s h n a m e d e r i v e d f r o m " s o d a . " A b u n d a n t in n a t u r e i n t h e f o r m of s i l ica tes a n d h a l i d e s . S o d i u m a n d its sa l ts a r e w i d e l y used i n i n d u s -t ry ( c o m m o n sa l t , s o d a , G l a u b e r ' s sal t , e t c . ) .

Strontium ( S r ) . A t o m i c n u m b e r — 3 8 ; a t o m i c w e i g h t — 8 7 . 6 3 . Be longs to a l k a l i n e - e a r t h m e t a l s . D i s c o v e r e d in 1790 b y C r a w f o r d . M e t a l l i c s t r o n t i u m is s i l ve ry -wh i t e , v e r y a c t i v e c h e m i c a l l y a n d is, t h e r e f o r e , e n -c o u n t e r e d o n l y i n c o m b i n a t i o n . C o l o u r s t h e test flame r e d . U s e d in p y r o t e c h n i c s a n d i n t h e s u g a r in -d u s t r y .

Sulphur (S) . A t o m i c n u m b e r — 1 6 ; a t o m i c w e i g h t — 3 2 . 0 6 6 . K n o w n s ince h o a r y a n t i q u i t y . H a s seve ra l v a r i -e t i e s : r h o m b i c , m o n o c l i n i c a n d a m o r p h i c . The c rys ta l s of s u l p h u r a r e l igh t ye l l ow . V e r y a b u n d a n t i n n a t u r e b o t h in its n a t i v e s t a t e a n d in t h e f o r m of s u l p h i d e o res

a n d s u l p h a t e s ( g y p s u m , a n h y d r i t e , e t c . ) . U s e d for p r o d u c t i o n of sul-phur ic . a c i d , in d e s t r o y i n g ag r i -c u l t u r a l pes ts ( p h y l l o x e r a ) a n d in t h e r u b b e r i n d u s t r y . C o n s t i t u e n t of h u n t e r s ' p o w d e r , m a t c h e s , B e n g a l l ights , u l t r a m a r i n e ( b l u e d y e j . Also used in m e d i c i n e .

Tantalum ( T a ) . A t o m i c n u m b e r — 7 3 ; a t o m i c w e i g h t — 1 8 0 . 9 5 . R a r e e l e m e n t . D i s c o v e r e d in 1802 b y E k e b e r g a n d n a m e d in h o n o u r of t h e G r e e k m y t h i c a l h e r o T a n t a l u s . Eas i ly m a c h i n e d a n d k n o w n lot-its e x t r a o r d i n a r y r e s i s t ance t o v a r i o u s c h e m i c a l i n f luences . 'Phis p r o p e r t y is u t i l i zed in t h e m a n u f a c t u r e of v a r i o u s i m p o r t a n t c h e m i c a l a p -p a r a t u s a n d s u r g i c a l i n s t r u m e n t s . T h e a l loys of t a n t a l u m a n d c a r b o n a r e n o t e d for t h e i r e x t r e m e h a r d n e s s w h i c h m a k e s t h e m ve ry v a l u a b l e in t h e m a n u f a c t u r e of c u t t i n g tools a n d dr i l l s . O c c u r s a l w a y s t o g e t h e r w i t h n i o b i u m a n d f r e q u e n t l y w i t h ti-t a n i u m .

Technetium ( T c ) . A t o m i c n u m b e r — 4 3 ; t h e first c h e m i c a l e l e m e n t p r o -d u c e d a r t i f i c i a l ly . S y n t h e s i z e d b y K . P e r r i e r a n d I'). S c g r e in 1937 b y b o m b a r d m e n t of m o l y b d e n u m w i t h t h e n u c l e i of t h e h e a v y i so tope of h y d r o g e n — d e u t e r o n s . 17 of its iso-t o p e s a r e k n o w n t o d a y . T h e longes t -l ived i s o t o p e is t h e o n e w i t h a n a t o m i c w e i g h t of 99 . C h e m i c a l l y a k i n t o r h e n i u m a n d m a n g a n e s e . N a m e s t e m s f r o m t h e G r e e k w o r d technetos—artificial, to m a r k t h e f ac t t h a t it w a s t h e first a r t i f i c ia l ly p r o -d u c e d e l e m e n t . I t s p r o p e r t i e s ex-a c t l y c o i n c i d e w i t h those p r e d i c t e d b y D . M e n d e l e y e v , w h o h a d . n a m e d th i s e l e m e n t e k a m a n g a n e s e .

Tellurium ( T e ) . A t o m i c n u m b e r — 5 2 : a t o m i c w e i g h t — 1 2 7 . 6 1 . Dis-c o v e r e d in 1782 b y F . M t i l l e r ; K l a p r o t h c o n f i r m e d th i s d i s cove r y in 1789 a n d g a v e t h e e l e m e n t its n a m e f r o m t h e L a t i n w o r d telluris— e a r t h . C h e m i c a l l y r e s e m b l e s s u l p h u r a n d . . e spec ia l ly , s e l e n i u m . F i n d s

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l imi t ed use in t h e c e r a m i c s i n d u s t r y , in c o l o u r i n g glass a n d as a n a d d i t i o n t o g a s o l i n e i n o r d e r t o a c c e l e r a t e c o m b u s t i o n in t h e eng ines .

Terbium ( T b ) . A t o m i c n u m b e r — 6 5 ; a t o m i c w e i g h t — 1 5 9 . 2 . R a r e -e a r t h e l e m e n t . D i s c o v e r e d b y M o -s a n d e r in 1843. N a m e d a f t e r a s m a l l t o w n Y t t e r b y n e a r w h i c h t h e r a r e - e a r t h m i n e r a l s w e r e f o u n d for t h e tirst t i m e .

Thallium ( T l ) . A t o m i c n u m b e r — 81 ; a t o m i c w e i g h t — 2 0 4 . 3 9 . Discov-e r e d b y C r o o k e s in 1861 b y s p e c t r a l ana lys is . N a m e d e r i v e d f r o m t h e G r e e k w o r d thallus—green t w i g b e c a u s e of t h e g r e e n c o l o u r of its s p e c t r a l l ines. M e t a l l i g h t e r t h a n l ead a n d v e r y v o l a t i l e ; m e l t s a t 302 0 . a n d co lou r s t h e test flame g r e e n . E n c o u n t e r e d in a d i s p e r s e d s t a te . T h e p r i n c i p a l r a w m a t e r i a l is t h e dus t p r o d u c e d d u r i n g t h e a n n e a l i n g of t h e s u l p h i d e ores of c e r t a i n m e t a l s . U s e d as a c o n s t i t u e n t in a c i d p r o o f a l loys , in t h e m a n u -f a c t u r e of o p t i c a l glass a n d in p h o t o -cells.

Thorium ( T h ) . A t o m i c n u m b e r — 9 0 ; a t o m i c w e i g h t — 2 3 2 . 1 2 . O n e of 1 h e mos t i m p o r t a n t r a d i o a c t i v e ele-m e n t s . D i s c o v e r e d b y Berze l ius in 1828 a n d n a m e d a f t e r T h o r , t h e S c a n d i n a v i a n g o d of w a r . R a d i o -ac t iv i ty of t h o r i u m w a s e s t a b l i s h e d in 1898 b y C u r i e - S k l o d o w s k a a n d S c h m i d t . I n its f r ee s t a t e it is a m e t a l ; speci f ic g r a v i t y - - i 1 .7; m e l t s a t 1 ,842 J C . E x t e r n a l l y r e s e m b l e s p l a t i n u m . I t s ha l f - l i fe is 13,000 mi l l i on yea r s . I n d i s i n t e g r a t i n g t h o -r i u m f o r m s t h e t h o r i u m scr ies of r a d i o a c t i v e e l e m e n t s , t h e last m e m -b e r of w h i c h is l e a d w i t h a n a t o m i c w e i g h t of 208. M o n a z i t e a n d t h o r i t e a r e t h o r i u m ' s ch ief m i n e r a l s . M o n a -z i te is e x t r a c t e d f r o m m o n a z i t e -c o n t a i n i n g s a n d s . T h o r i u m o x i d e is v e r y i m p o r t a n t for i n c a n d e s c e n t gas m a n t l e s . L i k e u r a n i u m t h o r i u m spli ts a n d l i b e r a t e s a l a r g e q u a n t i t y of a t o m i c e n e r g y .

4 3 2

Thulium ( T u ) . A t o m i c n u m b e r — 6 9 ; a t o m i c w e i g h t — 1 6 9 . 4 . R a r e -e a r t h e l e m e n t . D i s c o v e r e d b y C l e v e in 1880 ; n a m e d e r i v e d f r o m t h e w o r d Thulia, t h e a n c i e n t n a m e of S c a n d i n a v i a . T h e salts of t h u l i u m a r e g r e e n .

Tin ( S n ) . A t o m i c n u m b e r — 5 0 ; a t o m i c w e i g h t — 1 1 8 . 7 0 . O n e of t h e first m e t a l s k n o w n to m a n s ince e a r l y a n t i q u i t y ( b r o n z e a g e ) . I n its f r ee s t a t e q u i t e a m a l l e a b l e a n d d u c t i l e s i l v e r y - w h i t e m e t a l ; spec i f ic g r a v i t y — 7 . 2 8 ; m e l t s a t 2 3 2 0 C . Be low 18' C . c h a n g e s to its g r e y v a r i e t y . W h e n s h o r t s t icks of t i n a r e b e n t t h e y p r o d u c e a c h a r a c -ter is t ic c r a c k l e p r o b a b l y b e c a u s e of t h e f r i c t ion of t h e i n d i v i d u a l c rys ta l s a g a i n s t e a c h o t h e r . U n -a f f e c t e d b y w a t e r a n d a i r ; o w i n g t o th i s p r o p e r t y it is w i d e l y u sed for p l a t i n g i r o n (so-cal led w h i t e m e t a l u t i l i z ed ch ie f ly for food c a n s ) . I t s a l l o y s — b a b b i t a n d b r o n z e — a r e v e r y i m p o r t a n t . E n c o u n t e r e d m a i n l y as t h e m i n e r a l cass i t e r i t e ( S n 0 2 ) .

Titanium ( T i ) . A t o m i c n u m b e r — 2 2 ; a t o m i c w e i g h t — 4 7 . 9 0 . S i lve ry -w h i t e . v e r y h a r d a n d b r i t t l e m e t a l . V e r y a b u n d a n t e l e m e n t : c o n s t i t u t e s 0 .6 p e r c e n t of t h e w e i g h t of t h e e a r t h ' s c r u s t . D i s c o v e r e d b y K l a p r o t h in 1795, b u t p r o d u c e d in its p u r e s t a t e o n l y in 1857 b y W o h l e r a n d S a i n t e - C l a i r e Dev i l l e a n d n a m e d in h o n o u r of t h e m y t h o l o g i c a l h e r o . Spec i f i c g r a v i t y — 4 . 5 ; m e l t s a t 1 ,800 ' C . P r a c t i c a l i m p o r t a n c e of t i t a n i u m is e spec ia l ly g r e a t i n m e t a l l u r g y : a ids in c o m p l e t e l y r e -m o v i n g o x y g e n a n d n i t r o g e n f r o m m o l t e n steel d u e t o w h i c h t h e s m e l t -i n g is r e m a r k a b l y v in i fo rm; i m p a r t s h a r d n e s s a n d e las t i c i ty t o s teel . M e t a l l i c t i t a n i u m is s t a b l e in s h a r p t e m p e r a t u r e v a r i a t i o n s a n d m a y b e ex t ens ive ly u sed in h i g h - s p e e d av i -a t i o n . T i t a n i u m o x i d e serves for t h e m a n u f a c t u r e of v e r y g o o d w h i t e p a i n t .

Transuranium elements. R a d i o a c t i v e e l e m e n t s fo l lowing u r a n i u m in M e n -de leyev ' s p e r i o d i c sys tem w i t h a t o m i c n u m b e r s of 93 a n d u p . H a v e a l l b e e n o b t a i n e d ar t i f ic ia l ly . T h e first t o b e s t u d i e d w a s n e p t u n i u m (in 1939). S ince t h e i r l i fespan is m u c h b r i e f e r t h a n t h e age of o u r p l a n e t t h e y w e r e n o t d i scove red u n d e r n a t u r a l cond i t ions . T h e t r a n s u r a -n i u m e l e m e n t s k n o w n t o d a y a r e : n e p t u n i u m , p l u t o n i u m , a m e r i c i u m , c u r i u m , b e r k e l i u m , c a l i f o r n i u m , e in s t e in ium, f e r m i u m a n d m e n -d e l e v i u m .

Tungsten ( W ) . A t o m i c n u m b e r — -74; a t o m i c w e i g h t — 1 8 3 . 9 2 . H e a v y (specific g r a v i t y — 19.1), s i lve ry-whi te m e t a l w i t h a h igh m e l t i n g p o i n t (3 )37°° C . ) . D i scove red b y Schee l e in w o l f r a m i t e in 1 7 8 3 ; o b t a i n e d in its p u r e s t a t e b y W o h l e r on ly in 1850; does n o t ox id ize a n d does n o t dissolve in ac ids w i t h t he excep t i on of a q u a r e g i a ; re -f r a c t o r y ; b e c a u s e of t he ab i l i ty of t u n g s t e n t o b e d r a w n i n t o w i r e d o w n t o 0 .01 m m . th ick it is used in t h e m a n u f a c t u r e of filaments for e lec t r ic b u l b s ; also used in h igh - speed steel a n d s u p e r - h a r d al loys w h i c h a r e ca l l ed p o b e d i t e , " W i e D i a m a n t " a n d c a r b o l o y , in t h e m a n u f a c t u r e of c h e m i c a l l a b o r a t o r y - w a r e a n d for c o n t a c t s as a s u b s t i t u t e for t he m o r e expens ive p l a t i n u m . P o b e d i t e is a lmos t as h a r d as d i a m o n d a n d is used for d r i l l i ng t h e h a r d e s t rocks.

Uranium ( U ) . A t o m i c n u m b e r — 92; a t o m i c w e i g h t — 2 3 8 . 0 7 . R e -f r ac to ry , s i lve ry-whi te m e t a l . O n l y r ecen t ly o c c u p i e d t he last p l a c e in t h e p e r i o d i c t a b l e of e l emen t s . Dis-cove red in p i t c h - b l e n d e by K l a p r o t h in 1789, b u t p r o d u c e d in its p u r e s t a t e ' b y Pe l igo th in 1841. Speci f ic g r a v i t y — 1 8 . 7 ; me l t s a t 1 , 6 9 0 ° C . ; r a d i o a c t i v e . W h i l e s t u d y i n g u r a n i u m B e c q u e r e l d i scovered t h e p h e n o m -e n o n of r ad ioac t i v i t y in 1898. N a t i v e u r a n i u m h a s severa l isotopes. T h e i so tope w i t h a n a t o m i c w e i g h t

of 238 p r eva i l s ; t h e r e is 0 .7 p e r c e n t of t h e i so tope w i t h a n a t o m i c w e i g h t of 235. Because of its r a d i o -ac t i ve d i s i n t e g r a t i o n u r a n i u m 238 f o r m s e l emen t s of t h e u r a n i u m series w h i l e u r a n i u m 235 f o rms t he ac t in -i u m series. T h e e n d p r o d u c t of t h e u r a n i u m series is l e a d w i t h a n a t o m i c w e i g h t of 206; t h a t of t h e a c t i n i u m series is l ead w i t h a n a t o m i c w e i g h t of 207. U r a n i u m 235, w h e n its nuc l eus is b o m b a r d e d b y slow n e u t r o n s , is easily split i n t o t w o n e a r l y e q u a l f r a g m e n t s l iber -a t i n g a n e n o r m o u s q u a n t i t y of a t o m i c ene rgy . N a m e d a f t e r t he p l a n e t U r a n u s , d i scovered shor t ly be fo re t h e d iscovery of this ele-m e n t .

Vanadium ( V ) . A t o m i c n u m b e r — 23; a t o m i c w e i g h t — 5 0 . 9 5 . Steel-g r e y m e t a l , v e r y h a r d , b u t n o t b r i t t l e . D i scove red in 1830 b y Se f s t rdm a n d n a m e d in h o n o u r of t h e goddess V a n a d i s . I t is q u i t e a b u n d a n t b u t f o u n d on ly in a dis-pe r sed s t a t e ; p r o d u c e d f r o m t i t ano -m a g n e t i t e ores a n d f r o m b i t u m i n o u s sha les ; used m a i n l y in t he p r o d u c t i o n of h i g h - g r a d e steel d i s t ingu i shed for its d u r a b i l i t y , res i l ience a n d tensi le s t r e n g t h ; also used as a ca ta lys t in t h e c h e m i c a l i ndus t ry , as a d y e in ce ramics , for t o n i n g p r i n t s in p h o t o g -r a p h y , a n d in m e d i c i n e .

Virginium. U n d e r this n a m e Allison d e s c r i b e d a n e l e m e n t w i t h t h e a t o m i c n u m b e r of 87. T h e fac t of t h e dis-cove ry w a s n o t c o n f i r m e d . See Francium.

Xenon ( X e ) . A t o m i c n u m b e r — 5 4 ; a t o m i c w e i g h t — 1 3 1 . 3 . N o b l e gas d i scove red b y R a m s a y a n d T r a v e r s i n 1898 a t t he s a m e t i m e as k r y p t o n a n d n e o n . N a m e comes f r o m t h e G r e e k w o r d xenos, m e a n i n g a l ien . O c c u r s as a neg l ig ib le c o n s t i t u e n t of t h e a i r . I t is 4 .5 t imes as h e a v y as a i r .

Ytterbium ( Y b ) . A t o m i c n u m b e r — 70; a t o m i c w e i g h t — 1 7 3 . 0 4 . R a r e -e a r t h e l e m e n t . D i scovered in 1878

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b y M a r i g n a c w h o e s t a b l i s h e d t h a t t h e e l e m e n t e r b i u m c o n t a i n e d a " n e w e a r t h . " T h e n a m e c o m e s f r o m t h e s m a l l S w e d i s h t o w n of Y t t e r b y .

Yttrium ( Y ) . A t o m i c n u m b e r — 3 9 ; a t o m i c w e i g h t — 8 8 . 9 2 . V e r y close t o t h e l a n t h a n o i d f a m i l y i n p r o p -e r t i es a n d o w i n g t o c o m m o n o c c u r -r e n c e w i t h t h e m in n a t u r e is c o n -s i d e r e d o n e of t h e r a r e e a r t h s . O c c u r s i n l a r g e q u a n t i t i e s in t h e m i n e r a l s x e n o t i m e a n d g a d o l i n i t e . D i s c o v e r e d b y G a d o l i n i n 1794 a n d first o b t a i n e d i n its p u r e s t a t e b y W o h l e r in 1828. T h u s f a r its p r a c t i c a l uses h a v e b e e n r a t h e r i n s i g n i f i c an t .

Zinc ( Z n ) . A t o m i c n u m b e r — 3 0 ; a t o m i c w e i g h t — 6 5 . 3 8 . D i s c o v e r e d b y P a r a c e l s u s in t h e 16 th c e n t u r y . R e -ce ived its n a m e f r o m t h e G r e e k w o r d linko m e a n i n g w h i t e f i l m ( t he sal ts of

z i n c a r e w h i t e ) . M e t a l l i c z i n c is g r e y -i s h - w h i t e a n d r a t h e r s t a b l e a g a i n s t t h e a c t i o n of w a t e r a n d a i r . O c c u r s m a i n l y i n t h e m i n e r a l s p h a l e r i t e ( Z n S ) . U s e d i n i r o n - p l a t i n g (ga l -v a n i z e d i r o n ) , a n d in a l loys w i t h c o p p e r (b ra s s ) . T h e w h i t e sa l ts of z i n c a r e u s e d as a p a i n t a s we l l a s in m e d i c i n e .

Zirconium ( Z r ) . A t o m i c n u m b e r — 4 0 ; a t o m i c w e i g h t — 9 1 . 2 2 . Dis -c o v e r e d b y K l a p r o t h i n 1789 a n d n a m e d a f t e r t h e m i n e r a l z i r c o n . Z i r c o n i u m o x i d e is v e r y r e f r a c t o r y ; m e l t s a t 3 , 0 0 0 ° C . ; e x t r a o r d i n a r i l y s t a b l e a g a i n s t c h e m i c a l a c t i o n . Be-c a u s e of t he se p r o p e r t i e s it is u sed as a h i g h l y r e f r a c t o r y m a t e r i a l . A l so u s e d as a n a d d i t i o n t o p i g i r o n be -c a u s e it i m p r o v e s its c a s t i n g p r o p e r -t ies. O c c u r s i n z i r c o n a n d c o m p l e x s i l icates .

GLOSSARY

Abrasives o r abrasive materials—very h a r d s u b s t a n c e s w h i c h , w h e n p u l v e r -i zed , y i e ld s h a r p - e d g e d g r a i n s . A b -ras ives a r e u s e d for c u t t i n g , s a w i n g , d r i l l i n g , s h a r p e n i n g , g r i n d i n g , po l i sh -i n g a n d o t h e r t y p e s of m a c h i n i n g m e t a l s , s tones , glass, e tc . T h e m o s t i m p o r t a n t natural a b r a s i v e s a r e : d i a m o n d , c o r u n d u m , g a r n e t , flint, q u a r t z , s a n d s t o n e a n d p u m i c e ; arti-

ficial-. s y n t h e t i c c o r u n d u m (e l ec t ro -c o r u n d u m a n d a l u n d u m ) ; c a r b o -r u n d u m (al loys of q u a r t z a n d c a r -b o n ) ; s t a l in i t e , w o l o m i t e (a l loys of t u n g s t e n a n d c a r b o n ) a n d b o r o n c a r b i d e . T h e t e c h n i c a l i m p o r t a n c e of a b r a s i v e s is e n o r m o u s .

Acetylene—gas r e s u l t i n g f r o m t h e a c t i o n of w a t e r o n c a l c i u m c a r b i d e . B u r n s w i t h a b r i g h t w h i t e flame; w i d e l y u s e d i n o x y g e n o u s c u t t i n g , g a s - w e l d i n g of f e r r o u s a n d n o n -f e r r o u s m e t a l s a n d i n s o l d e r i n g .

Adit—horizontal o r s l igh t ly in -c l i ned m i n e w o r k i n g w i t h o n e e n d c o m i n g o u t t o t h e s u r f a c e . Cross sec t ion of a n a d i t is t r a p e z o i d a l , ova l o r r o u n d .

Agate—striped s t r a t i f i ed c h a l c e d -o n y w i t h l a y e r s of d i f f e r e n t c o l o u r s ( w h i t e , r e d , b l a c k , e t c . ) . See chalcedony.

Agricola—Latinized n a m e of G e o r g B a u e r ( 1 4 9 4 - 1 5 5 5 ) , G e r m a n p h y -s i c i an , m i n e r a l o g i s t a n d m e t a l l u r g i s t . H i s w o r k On Mining s e r v e d as a n a i d in t h e t e c h n i q u e s of m i n i n g a n d

m e t a l l u r g y for a p e r i o d of t w o c e n -tu r i e s .

Alaite—-very r a r e , b e a u t i f u l r e d m i n e r a l ; n a t u r a l v a n a d i c a c i d ( V 2 0 6 - H j O ) . F o u n d in C e n t r a l As ia .

Alchemy—medieval n a m e of c h e m -is t ry . T h e p re - sc i en t i f i c p e r i o d in t h e d e v e l o p m e n t of c h e m i s t r y is u s u a l l y r e f e r r e d t o as a l c h e m y .

Alpha rays. See alpha particles. Alpha particles—helium ions e m i t -

t e d b y s o m e r a d i o a c t i v e s u b s t a n c e s . O n p a s s i n g t h r o u g h a s u b s t a n c e t h e a l p h a p a r t i c l e s i o n i z e i t ; o n s t r i k i n g fluorescent o r p h o s p h o r e s c e n t s u b -s t a n c e s t h e y c a u s e t h e m to lu -m i n e s c e . U p o n c o n t a c t w i t h h u m a n o r a n i m a l sk in t h e y p r o d u c e b u r n s w h i c h a r e h a r d t o h e a l . Also a b l e t o p r o v o k e c e r t a i n c h e m i c a l r e a c t i o n s .

Alumina—aluminium o x i d e ( A ] , 0 : , ; . F o r m s p a r t of m a n y rocks a n d m i n e r a l s ( a lumos i l i ca t e s ) . T e c h n i c a l l y o b t a i n e d m a i n l y f r o m b a u x i t e . O c c u r s n a t i v e as c o r u n d u m , e tc .

Alumosilicates—silicates in w h i c h a l u m i n i u m o x i d e , i .e. , a l u m i n a , p l a y s a n essen t ia l p a r t .

Alums—chemical c o m p o u n d s r e p -r e s e n t i n g d o u b l e sal ts of s u l p h u r i c a c i d . I n n a t u r e m o s t f r e q u e n t l y e n c o u n t e r e d in t h e f o r m of a l u m i n -i u m ( a l u n i t e ) a n d fe r r i c (ha lo -t r i c h i t e ) a l u m s .

Alundum—alumina ( A 1 2 0 3 ) . P r o -d u c e d a r t i f i c i a l ly f r o m n a t u r a l a l u -

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mos i l i ca t e s o r b a u x i t e s . See abrasive materials.

Alunite o r a l u m r o c k — w h i t e o r r e d - b r o w n m i n e r a l , n a t u r a l s u l p h a t e of p o t a s s i u m a n d a l u m i n i u m .

Amber—fossilized t a r of c o n i f e r o u s t rees m a i n l y of t h e T e r t i a r y P e r i o d , h a r d e n e d i n t o d e n s e m a s s . C o l o u r s r a n g i n g f r o m m i l k y , h o n e y - y e l l o w a n d b r o w n t o d a r k - o r a n g e a n d r e d d i s h . Br i t t l e , b u t eas i ly g r o u n d a n d p o l i s h e d . B u r n s w i t h a r o m a t -ic o d o u r . U s e d in t h e c h e m i c a l i n d u s t r y , i n e l e c t r i c a l e n g i n e e r i n g a n d for m a n u f a c t u r e of v a r i o u s a r t -icles.

Amethyst—transparent, v io le t -c o l o u r e d m i n e r a l ; v a r i e t y of q u a r t z . See quartz.

Ampangabeite—rare, b r o w n - r e d , r a d i o a c t i v e m i n e r a l ; t a n t a l o - n i o -b a t e of u r a n i u m , i r o n , e tc . F i r s t f o u n d o n M a d a g a s c a r .

Amphibole o r horn-blende—dark-g r e e n , g r e e n i s h - b l a c k o r b l a c k -b r o w n m i n e r a l w i t h g lassy lus t r e . A r o c k - f o r m i n g m i n e r a l of t h e s i l ica te class. E n c o u n t e r e d in c o n -t i n u o u s g r a n u l a r a n d fibrous masses .

Angstrom—unit of l e n g t h c o r r e -s p o n d i n g t o 0 .00000001 c m . o r i o—8 c m . D e s i g n a t e d b y A . U s e d m a i n l y in op t i c s t o m e a s u r e t h e l e n g t h of l i g h t - w a v e s a n d i n a t o m i c phys ics . N a m e d a f t e r t h e S w e d i s h sc ient i s t A n g s t r o m w h o w a s t h e first t o i n t r o d u c e th i s v a l u e i n t o p r a c t i c e i n 1868.

Aneroid. See barometer. Anion. See ion. Antimonite, antimony glance o r

stibnite—native a n t i m o n y t r i s u l p h i d e S b , S 3 , l e a d - g r e y m i n e r a l w i t h m e t a l -l ic lus t re , f r e q u e n t l y w i t h a p a r t i -c o l o u r e d o x i d e t i n t . E n c o u n t e r e d in n e e d l e - s h a p e d c rys ta l s a n d in d e n s e masses . U s e d for p r o d u c t i o n of a n t i m o n y .

Anthracite—grade of c o a l c h a r a c t e r -i zed b y h i g h e s t c a r b o n c o n t e n t ( u p t o 9 6 p e r c e n t ) .

Antimony glance. See antimonite.

Apatite—mineral; c a l c i u m p h o s -p h a t e c o n t a i n i n g fluorine a n d c h l o -r i n e . U s e d for p r o d u c t i o n of p h o s -p h a t i c fe r t i l i ze r .

Aquamarine—transparent v a r i e t y of b e r y l c o l o u r e d b l u e - g r e e n s h a d e s of s e a - w a t e r ( f r o m t h e L a t i n w o r d s : aqua—water, mare—sea); v a l u e d as a p r e c i o u s s t o n e .

Aragonite—mineral c o r r e s p o n d i n g t o c a l c i t e ( C a C 0 3 ) i n c o m p o s i t i o n , b u t d i f f e r i n g f r o m it b y t h e a r r a n g e -m e n t of its a t o m s a n d b y its p h y s i c a l p r o p e r t i e s . C o l o u r — w h i t e , ye l low, g r e e n o r v io le t . D e n s e f o r m a t i o n s i n t h e s h a p e of s p h e r i c a l ool i tes , as we l l a s m a n y s t a l ac t i t e s a n d s t a l a g m i t e s f o u n d in caves , a r e c h a r a c t e r i s t i c of a r a g o n i t e . U s u a l l y f o r m e d f r o m h o t a n d c o l d w a t e r s .

Argonauts—seafarers o n t h e s h i p Argo, h e r o e s f r o m t h e a n c i e n t G r e e k l e g e n d s w h o sa i l ed t o K o l c h i s ( n o w T r a n s c a u c a s u s ) u n d e r t h e l e a d e r s h i p of J a s o n in q u e s t of t h e g o l d e n fleece. T h e m y t h a b o u t t h e A r g o -n a u t s is a r e f l e c t i o n of t h e h i s t o r y of e a r l y G r e e k c o l o n i z a t i o n ( 8 t h -6 t h c e n t u r i e s B. C . ) .

Aristotle (384-322 B . C . ) — g r e a t a n c i e n t G r e e k p h i l o s o p h e r . Aris-to t l e ' s w o r k s c o v e r e d a l l b r a n c h e s of k n o w l e d g e of his t i m e : logic , p s y c h o l o g y , n a t u r a l sc ience , h i s t o r y , pol i t ics , e th i c s a n d es the t i cs . N o n e of his w o r k s h a v e s u r v i v e d ; o n l y s e p a r a t e e x c e r p t s c i t e d b y a n c i e n t a u t h o r s a r e k n o w n .

Asbestos—group n a m e of a n u m -b e r of fine-fibre m i n e r a l s , m a g n e -s i u m si l icates . T h e fibres r e a c h 5 a n d m o r e c m . in l e n g t h . Asbes to s is u s e d for p r o d u c t i o n of f i r e p r o o f f a b r i c s , for t h e r m a l a n d e l ec t r i c i n s u l a t i o n , fo r v a l u a b l e fireproof m a t e r i a l s , e tc .

Astrophysics—branch of a s t r o n o m y s t u d y i n g t h e p h y s i c a l s t a t e a n d c h e m i c a l c o m p o s i t i o n of ce les t i a l b o d i e s a n d i n t e r s t e l l a r m a t t e r .

Asphalt—hard b r o w n i s h o r l u s t r e -less b l a c k b i t u m e n , f r e q u e n t l y

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m e r e l y h a r d e n e d o x i d i z e d oil . Sof-tens a t 70 t o u o ° C . a n d t h e n me l t s . T h e r e a r e n a t i v e a n d a r t i f i c i a l a s p h a l t s .

Atmosphere—gaseous shel l of t h e e a r t h . T h r e e l a y e r s a r e n o w d i s t i n -g u i s h e d in t h e a t m o s p h e r e : 1) t r o p o s p h e r e , 2) s t r a t o s p h e r e a n d 3) i o n o s p h e r e .

Atoll—coral-island i n t h e f o r m of a c o n t i n u o u s o r b r o k e n r i n g s u r r o u n d i n g a l a g o o n . E n c o u n t e r e d in t h e o p e n sea , a r r a n g e d s ing ly o r in a r c h i p e l a g o e s .

Atom ( f r o m t h e G r e e k w o r d m e a n i n g indivisible)—minutest p a r -t ic le of a c h e m i c a l e l e m e n t . U n t i l t h e m i d d l e of t h e 19th c e n t u r y t h e a t o m w a s b e l i e v e d t o b e a n a b s o l u t e l y ind iv i s ib l e a n d i n v a r i -a b l e p a r t i c l e of s u b s t a n c e . I n t h e b e g i n n i n g of t h e 20th c e n t u r y i t w a s d e m o n s t r a t e d t h a t t h e a t o m w a s ind iv i s ib l e o n l y c h e m i c a l l y .

Aztecs—one of t h e p r o m i n e n t I n d i a n p e o p l e s i n M e x i c o . T h e c o n q u e s t of M e x i c o b y t h e S p a n i a r d s in 1519-21 t e rmina ted the independ-e n t d e v e l o p m e n t of th i s p e o p l e .

Baikalite—dark, d u l l - g r e e n v a r i e t y of a l i m e - f e r r u g i n o u s s i l ica te , d i o p -s ide f r o m L a k e Ba ika l .

Barite o r heavy spar—heavy, o p a q u e m i n e r a l ( B a S 0 4 ) , b a r i u m s u l p h a t e . Co lou r l e s s , o r m o r e f r e -q u e n t l y c o l o u r e d ye l low, r e d , b l u i s h a n d o t h e r t in t s . W i d e l y u s e d i n t h e m a n u f a c t u r e of w h i t e p a i n t s , c h e m i c a l p r e p a r a t i o n s , e t c .

Barometer ( f r o m t h e G r e e k w o r d s baros—gravity a n d metreo—I m e a s -u r e ) — m e t e o r o l o g i c a l i n s t r u m e n t u s e d i n m e a s u r i n g a t m o s p h e r i c p r e s -s u r e .

T h e r e a r e m e r c u r y a n d m e t a l {aneroid) b a r o m e t e r s .

Basalt—black o r b l a c k - g r e e n i g n e o u s r o c k p o u r e d o u t t o t h e e a r t h ' s s u r f a c e o r u n d e r w a t e r i n a m o l t e n s t a t e . Cons i s t s of m i n e r a l s r i c h i n m a g n e s i u m a n d

i r o n . F o r m s s e p a r a t e h e x a g o n a l c o l u m n a r s t r u c t u r e s .

Basaltic bed—according t o c e r t a i n m o d e r n p e t r o g r a p h e r s basa l t s a r e t h e in i t i a l m a t e r n a l m a g m a w h i c h f o r m s a b a s a l t i c shel l t h a t u n d e r l i e s t h e h a r d e a r t h ' s c r u s t .

Bauxite—white, s o m e t i m e s r e d -d i s h , a r g i l l a c e o u s rock cons i s t i ng of h y d r o u s c o m p o u n d s of a l u m i n a , ox id e s of i r o n a n d t i t a n i u m . Se rves as a r a w m a t e r i a l fo r t h e p r o d u c t i o n of a l u m i n i u m .

Belomorite—moonstone f r o m t h e p e g m a t i t e ve ins of W h i t e Sea r e -g i o n s ; v a r i e t y of a l b i t e ( f e l d s p a r ) .

Bengal light—various s l o w - b u r n i n g p y r o t e c h n i c a l c o m p o u n d s p r o d u c -i n g a b r i g h t w h i t e o r c o l o u r e d flame d u r i n g c o m b u s t i o n . U s e d in i l l u m i n a t i o n s a n d fireworks. C o l o u r d e p e n d s o n t h e c h e m i c a l e l e m e n t u s e d ( for i n s t a n c e , s t r o n t i u m i m -p a r t s a r e d c o l o u r , e t c . ) .

Beryl—chief m i n e r a l fo r t h e p r o -d u c t i o n of m e t a l l i c b e r y l l i u m . C o n -sists of s i l icon, a l u m i n i u m a n d b e r y l l i u m ( u p t o 14 p e r c e n t of its o x i d e ) . Co lou r l e s s o r c o l o u r e d g r e e n i s h a n d ye l lowish t in ts . E n -c o u n t e r e d in t h e f o r m of t r a n s p a r -e n t , w e l l - c o l o u r e d v a r i e t i e s : e m e r -a l d ( b r i g h t g r e e n ) , a q u a m a r i n e ( t he c o l o u r of s e a - w a t e r ) , v o r o b i e v i t e ( p i n k i s h ) , e t c . P u r e a n d wel l -co l -o u r e d b e r y l is a p r e c i o u s s t o n e ; e m e r a l d is p a r t i c u l a r l y v a l u a b l e .

Beryllium bronze—mixture of c o p -p e r a n d b e r y l l i u m (2 t o 2 .5 p e r c e n t B e ) ; d u r a b l e , res i l i en t a n d g o o d c o n d u c t o r of h e a t a n d e lec t r ic -i ty . U s e d in t h e m a n u f a c t u r e of s p r i n g s a n d i m p o r t a n t s p r i n g y m a c h i n e - p a r t s , gea r s , cogwhee l s , b u s h i n g s a n d b e a r i n g s for se rv ice a t h i g h speeds , h i g h p res su res a n d h i g h t e m p e r a t u r e s .

Berzelius Jons Jakob ( 1779-1848) — f a m o u s S w e d i s h c h e m i s t a n d m i n e r a l o g i s t . H o n o r a r y m e m b e r of t h e P e t e r s b u r g A c a d e m y of Sc iences . H i s t e x t b o o k of c h e m i s t r y

437

a n d a n n u a l r ev i ews of c h e m i c a l p r o g r e s s (1820-47) d i s s e m i n a t e d c h e m i c a l k n o w l e d g e i n t h e f i rs t h a l f of t h e 19th c e n t u r y .

Beta rays—stream of e l e c t r o n s e m i t t e d d u r i n g d i s i n t e g r a t i o n of a t o m i c n u c l e i . C a p a b l e of i on iz -i n g gases , m a k i n g m a n y s u b s t a n c e s l u m i n e s c e n t a n d a c t i n g o n p h o t o -p l a t e s .

Biotite. See mica. Bitumen—name of a m i x t u r e of

v a r i o u s h y d r o c a r b o n s e n c o u n t e r e d in n a t u r e in t h e f o r m of gases (oil gases) , l i q u i d s (oil a n d a s p h a l t ) a n d sol id s u b s t a n c e s ( o z o c e r i t e ) . B i t u m e n s o f t e n i m p r e g n a t e v a r i o u s r o c k s : l imes tones , s la tes a n d s a n d -s t o n e s ; s u c h i m p r e g n a t e d rocks a r e ca l l ed b i t u m i n o u s .

Bituminous coal—black m i n e r a l c o n t a i n i n g f r o m 70 t o g o p e r c e n t c a r b o n . See Mineral coal.

Bolide—fire-ball s w e e p i n g ac ross t h e sky ; c a u s e d b y t h e i n v a s i o n of a m e t e o r i c b o d y f r o m i n t e r -p l a n e t a r y s p a c e i n t o t h e e a r t h ' s a t m o s p h e r e .

Borax o r lineal ( N a 2 B 4 0 7 • i o H z O ) — s o d i u m t e t r a b o r a t e . E a s i l y d is -solves m e t a l l i c ox ides a n d t h e r e f o r e serves for c l e a n i n g s u r f a c e s in sol-d e r i n g . U s e d in c e r a m i c s a n d l e a t h e r -m a k i n g , in m e d i c i n e , e t c .

Bore-hole—special p i t c h a r a c t e r -i zed b y r o u n d cross -sec t ion of a v e r y s m a l l d i a m e t e r a n d c o n s i d e r -a b l e l e n g t h . B o r e d b y m e a n s of a pe r cus s ion or r o t a t o r y too l . M a d e t o d e t e r m i n e t h e e x t e n t a n d q u a l i t y of m i n e r a l depos i t s , fo r e x t r a c t i o n of oil, w a t e r , s u l p h u r , e tc . T h e y r e a c h a d e p t h of m o r e t h a n 5 , 0 0 0 m e t r e s .

Boric acid ( H 3 B 0 3 ) — w e a k a c i d . E n c o u n t e r e d in t h e m i n e r a l sas-solite. W h i t e s c a l e - s h a p e d c rys ta l s .

Boulders—fragments of rocks , m a i n l y g r a n i t e s , q u a r t z i t e s , l i m e -s tones a n d o t h e r s , m e a s u r i n g f r o m 10 c m . to 10 m . a n d m o r e in d i a -m e t e r . F o r m e d b y w e a t h e r i n g of

rocks a n d b y g l a c i a l a c t i v i t y . U s e d for p a v i n g s t ree t s a n d as a filler i n c o n c r e t e s t r u c t u r e s ; l a r g e b o u l -d e r s a r e u s e d for m o n u m e n t p e d e s -ta ls .

Boyle, Robert ( 1 6 2 7 - 1 6 9 4 ) — f a m o u s E n g l i s h c h e m i s t a n d phys i c i s t .

Bronze—nowadays a n a l l oy of c o p p e r a n d v a r i o u s o t h e r e l e m e n t s , m a i n l y m e t a l s . O n l y a f e w d e -c a d e s a g o t h e t e r m bronze d e s i g n a t e d a l loys of c o p p e r a n d t in a l o n e .

Brown coal—variety of m i n e d coa l . C o n t a i n s 50 t o g o p e r c e n t c a r b o n a n d i n c o m b u s t i o n y ie lds q u i t e a lo t of a s h a n d s u l p h u r . W i d e l y u s e d as f u e l .

Calcite o r limespar—white, c o l o u r -less o r s l igh t ly c o l o u r e d m i n e r a l — c a l c i u m c a r b o n a t e ( C a C 0 3 ) , f r e -q u e n t l y w i t h v a r i o u s a d m i x t u r e s . O c c u r s in e x c e l l e n t l y f o r m e d crys ta ls , g r a n u l a r a n d c o m p a c t masses , s t r a t i -fied f o r m s , i n s t a l ac t i t e s a n d s t a l a g -mi t e s . T h e p e r f e c t l y t r a n s p a r e n t ca l -c i te w h i c h d o u b l e s t h e i m a g e v i e w e d t h r o u g h i t is ca l l ed Iceland spar. S o m e rocks consis t e n t i r e l y o r a l m o s t e n t i r e l y of ca l c i t e as , fo r e x a m p l e , m a r b l e s , l i m e s t o n e s a n d c h a l k .

Calory—unit of h e a t . L a r g e c a l o r y is t h e a m o u n t of h e a t r e q u i r e d t o ra i se t h e t e m p e r a t u r e of 1 ki lo-g r a m m e of w a t e r b y i ° C . ; s m a l l c a l o r y is t h e a m o u n t of h e a t re -q u i r e d t o r a i s e t h e t e m p e r a t u r e of 1 g r a m of w a t e r b y i ° C .

Carat—measure of w e i g h t of p r e -c ious s t o n e s ; e q u a l s 2 0 0 m i l l i g r a m s .

Carbides—chemical c o m p o u n d s of m e t a l s a n d c a r b o n p r o d u c e d b y t h e a c t i o n of c o a l o n m e t a l s o r o n t h e i r ox ides .

Carbonates—salts of c a r b o n i c a c i d . V e r y a b u n d a n t in n a t u r e .

Carlsbad stone—solid d e p o s i t s of c a l c i u m c a r b o n a t e f r o m h o t m i n e r a l s p r i n g s in K a r l o v y V a r y ( C a r l s b a d ) in C z e c h o s l o v a k i a . (See aragonite.)

Carnallite—transparent, r e d d i s h m i n e r a l ; h y d r o u s c h l o r i d e of p o t a s -

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s i u m a n d m a g n e s i u m . D e l i q u e s c e s i n t h e a i r . S o u r c e of p o t a s s i u m fe r t i l i ze r a n d of m e t a l l i c m a g n e s i u m .

Cassiterite o r tinstone—mineral r a n g -i n g in c o l o u r f r o m b r o w n to b l a c k ; t i n o x i d e ( S n 0 3 ) c o n t a i n i n g u p t o 79 p e r c e n t t i n . C h i e f t i n o r e .

Cation. See ion. Cat's eye—greenish t r a n s p a r e n t

q u a r t z s h o t w i t h silk b e c a u s e of t h e i n c l u s i o n of a sbes tos fibres. I t s s t r ipes p l a y b e a u t i f u l l y , e spec ia l -ly w h e n it is g r o u n d w i t h c a b o -c h o n .

Caves o r c a v e p h e n o m e n a — r e l i e f s t y p i c a l of t e r r a i n s f o r m e d b y rocks s o l u b l e in w a t e r a n d p e r v i o u s t o i t — l i m e s t o n e s , d o l o m i t e s a n d g y p -s u m . As a r e su l t of l i x iv i a t i on of t h e r o c k s b y u n d e r g r o u n d w a t e r , c r a t e r s a n d ex t ens ive c losed ho l lows a r e f o r m e d o n t h e s u r f a c e a n d cav i t i e s a n d c a v e s i n t h e i n t e r i o r . I n t he se r e g i o n s r ive r s f r e q u e n t l y flow i n t o c rev ices a n d c r a t e r s , r u n u n d e r g r o u n d anel t h e n c o m e o u t t o t h e s u r f a c e a g a i n . C a v e p h e n o m e n a a r e we l l d e v e l o p e d i n t h e C r i m e a , in t h e U r a l s a n d i n s o m e r e g i o n s of Si-b e r i a .

Cavity—natural s t o r e - h o u s e i n p e g m a t i t e ve ins . B e a u t i f u l l y f o r m e d c rys ta l s of v a r i o u s m i n e r a l s f r e -q u e n t l y g r o w o n t h e wa l l s .of these cavi t ies .

Celestite—beautiful s k y - b l u e m i n -e r a l ; s t r o n t i u m s u l p h a t e ( S r S 0 4 ) . U s e d for p r o d u c t i o n of s t r o n t i u m sal ts .

Cement — c a l c i n e d m i x t u r e of l i m e s t o n e a n d c l ay . W i t h w a t e r c e m e n t h a r d e n s i n t o s t r o n g s t o n y m a s s . M a n u f a c t u r e d i n e n o r m o u s q u a n t i t i e s a n d u s e d for b u i l d i n g p u r p o s e s .

Ceramics ( f r o m t h e G r e e k w o r d ceramos—clay)—articles m a d e of b a k e d c l a y a n d its c o m p o u n d s w i t h m i n e r a l a d d i t i o n s . C e r a m i c w a r e s i n c l u d e b u i l d i n g b r i c k , t i le , f a c i n g s labs , c l i nke r , w a t e r a n d c a n a l i z a t i o n m a i n s , fire- a n d a c i d -

p r o o f a r t ic les , p o t t e r y , m a j o l i c a , f a i e n c e a n d p o r c e l a i n . C e r a m i c s b e g a n t o b e p r o d u c e d as p r i m i t i v e b a k e d a r t i c l e s in t h e s t o n e a g e .

Chalcedony—mineral of a l l poss ib le co lou r s , a l a t e n t - c r y s t a l l i n e fibrous v a r i e t y of q u a r t z . E n c o u n t e r e d in f o r m of n o d u l e s a n d s t a l a g m i t e s . S e m i - t r a n s p a r e n t a n d t r a n s l u c e n t . U s e d for t e c h n i c a l w a r e s , a s a s e m i - p r e c i o u s s t o n e a n d in t h e m a n u f a c t u r e of v a r i o u s a r t i c les .

I ts s t r i p e d va r i e t i e s a r e ca l l ed agates.

Chalcopyrite—brass-yellow m i n e r a l c o n t a i n i n g 35 p e r c e n t c o p p e r , 35 p e r c e n t s u l p h u r a n d 30 p e r c e n t i r o n . O n e of t h e m a i n c o p p e r ores .

Chalk—white, sof t , fine-earth sed i -m e n t a r y r o c k of o r g a n i c o r ig in . F o r m e d b y a c c u m u l a t i o n of m i c r o -scop ic shells a n d consis ts m a i n l y of c a l c i u m c a r b o n a t e .

U s e d in g l a s s , . c e m e n t , r u b b e r , p a p e r a n d p a i n t i ndus t r i e s , as w r i t i n g m a t e r i a l , e tc .

Chlorites—minerals; h y d r o u s a l u -mos i l i c a t e s of m a g n e s i u m in w h i c h p a r t of t h e m a g n e s i u m o x i d e a n d a l u m i n a is r e p l a c e d b y i r o n o x i d e s ; c o l o u r — a l l s h a d e s of g r e e n t o b l a c k ; b io t i t e s , h o r n - b l e n d e s a n d p y r o x e n e s m o s t f r e q u e n t l y c h a n g e t o ch lo r i t e s . T h e m i n e r a l is l a m e l l a r l ike m i c a , b u t is non - r e s i l i en t .

Chwmite—heavy b l a c k or b r o w n -b l a c k m i n e r a l . E n c o u n t e r e d in d e n s e a n d g r a n u l a r masses . O r e for t h e p r o d u c t i o n of c h r o m i u m .

Chrysoberyl—transparent g r e e n m i n e r a l c o n t a i n i n g b e r y l l i u m a n d a l u m i n i u m w i t h a n a d m i x t u r e of i r o n a n d s o m e t i m e s c h r o m i u m ( B e A l j O j ) . R a r e p r e c i o u s s t o n e (chrysos—golden, beryllos—beryl).

Cinnabar—red m i n e r a l w i t h a d a -m a n t i n e l u s t r e ; m e r c u r i c s u l p h i d e . C h i e f m e r c u r y o r e .

Clay—sedimentary r o c k cons i s t ing m a i n l y of h y d r o u s silicic c o m p o u n d s of a l u m i n i u m a n d f r e q u e n t l y c o n -

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t a i n i n g m i n u t e s t p a r t i c l e s of v a r i o u s m i n e r a l s ; p l a s t i c a n d c a p a b l e of f o r m i n g a p u t t y - l i k e m a s s w h e n m i x e d w i t h w a t e r . U s e d i n b u i l d i n g , p o t t e r y , e tc .

Cleopatra—last Q u e e n of E g y p t (69-30 B . C . ) .

Cteveite—mineral c o n t a i n i n g u r a -n i u m a n d c e r t a i n a m o u n t of r a r e e a r t h s . W h e n h e a t e d l i b e r a t e s l a r g e a m o u n t s of h e l i u m i n c l u d e d in t h e m i n e r a l as a r e su l t of r a d i o a c t i v e d i s i n t e g r a t i o n of u r a n i u m . Sc ien t i s t s d i s c o v e r e d t h e e x i s t e n c e of h e l i u m o n e a r t h for t h e first t i m e b y s t u d y i n g t h e l i b e r a t i o n of g a s f r o m c leve i te . U n t i l t h e n h e l i u m w a s k n o w n to exist o n l y i n t h e s u n .

Columbite—brown-black, o p a q u e , r a r e m i n e r a l — t a n t a l o - n i o b a t e of i ron a n d m a n g a n e s e . S o u r c e of t a n t a l u m a n d n i o b i u m . O c c u r s m a i n l y i n p e g m a t i t e ve ins .

Concentrate—the v a l u a b l e m i n e r a l s e p a r a t e d f r o m a n o r e u n d e r g o i n g a speci f ic t r e a t m e n t .

Concentration—preliminary p r o -cessing of a m i n e r a l in o r d e r t o s e p a r a t e it f r o m va lue l e s s r o c k s ( g a n g u e ) o r o t h e r m i n e r a l s .

Concrete—artificial r o c k y c o n g l o m -e r a t e m a t e r i a l ; h a r d e n e d m i x t u r e of a b i n d i n g a g e n t ( c e m e n t ) , w a t e r a n d n a t u r a l o r a r t i f i c i a l r o c k y fi l lers ( s a n d , fine s lag , g r a v e l a n d c r u s h e d s t o n e ) .

Coral reefs—rocky u n d e r w a t e r ( o r r i s ing a b o v e t h e w a t e r ) r ee f s f o r m e d m a i n l y b y l i m e s t r u c t u r e s of c o r a l co lon ies . A b u n d a n t o n l y in t r o p i c a l seas n e a r c o n t i n e n t a l coas t s a n d i s l ands o r in s h a l l o w sec t ions of t h e o p e n sea .

Corals—or c o r a l p o l y p s — m a r i n e a n i m a l s , c o e l e n t e r a t e s . L i v e p r i n -c i p a l l y i n co lon ies a n d l e a d a s e d e n t a r y life. T h e s k e l e t o n is m a d e of s e p a r a t e l i m e cells.

Corundum—mineral cons i s t i ng of a l u m i n i u m o x i d e ( A 1 2 0 3 ) . E x -c e p t i o n a l l y h a r d ; s c r a t c h e s a l l m i n e r -als e x c e p t d i a m o n d s . I t s t r a n s p a r e n t

u n i f o r m l y c o l o u r e d c rys t a l s a r e u s e d as p r e c i o u s s tones . R e d c o r u n d u m is k n o w n as ruby, t h e b l u e v a r i e t y — as sapphire.

Cosmic speed—speed a t w h i c h a ce les t ia l b o d y m o v e s t h r o u g h s p a c e ; i t is m a n y t i m e s as h i g h as t h e k n o w n s p e e d s a t w h i c h v a r i o u s b o d i e s m o v e o n e a r t h .

Cosmic rays—rays w h i c h p e n e t r a t e i n t o t h e a t m o s p h e r e o f t h e e a r t h , c a r r y e n o r m o u s e n e r g y a n d , t h e r e -fo re , h a v e h i g h p e n e t r a t i n g p o w e r . T h e n a t u r e of c o s m i c r a y s is n o t v e r y we l l k n o w n as y e t .

Cretaceous period—geological p e r i o d t e r m i n a t i n g t h e m e s o z o i c e r a in t h e f o r m a t i o n of t h e e a r t h ' s c r u s t . S u b d i v i d e d i n t o t w o e p o c h s — l o w e r a n d u p p e r c r e t a c e o u s e p o c h s . T h e m a r i n e s e d i m e n t s of th is p e r i o d a r e e spec ia l ly n o t e d for d e p o s i t s of p o w e r f u l l a y e r s of w r i t i n g c h a l k .

Crocus—natural o r a r t i f i c i a l a b r a -s ive m a t e r i a l ; u s e d i n p o l i s h i n g m e t a l s , o p t i c a l a n d o t h e r glass , b u i l d i n g a n d d e c o r a t i v e s t o n e .

Cryolite—very r a r e s n o w - w h i t e m i n e r a l — a l u m i n i u m a n d s o d i u m fluoride ( N a 3 A l F 6 ) . I n t h e m o l t e n s t a t e it dissolves a l u m i n i u m o x i d e , t h e r e f o r e it is u s e d i n e lec t ro lys is of m e t a l l i c a l u m i n i u m , as we l l as i n p r o d u c t i o n o f glass a n d f a i e n c e . I t is n o w m a n u f a c t u r e d a r t i f i -c ia l ly .

Crystal—geometrically r e g u l a r s t r u c t u r e of a t o m s o r ions l o c a t e d i n t h e p o i n t s of a c r y s t a l l a t t i c e . T h e w o r d crystal w a s u s e d l o n g b e f o r e o u r e r a a n d m e a n t r o c k c r y s t a l w h o s e o r i g i n w a s t h e n c o n n e c t e d w i t h p e t r i f i e d ice . S u b s e -q u e n t l y th i s w o r d b e g a n t o b e u s e d t o s ign i fy a l l m i n e r a l s of a n a t u r a l p o l y h e d r a l f o r m . C r y s t a l s a r e s t u d i e d b y c r y s t a l l o g r a p h y .

Crystallography—science a b o u t c rys -t a l s ; s t u d i e s t h e i r s h a p e s , o p t i c a l , e l ec t r i ca l , m e c h a n i c a l a n d o t h e r p r o p e r t i e s , a s we l l a s p r o b l e m s c o n n e c t e d w i t h t h e o r i g i n a n d

4 4 0

g r o w t h of c rys t a l s a n d t h e i r d e p e n d -e n c e o n d i f f e r e n c e s i n c h e m i c a l c o m p o s i t i o n .

Curie-Sklodowska, Marie ( 1867-1 9 3 4 ) — o u t s t a n d i n g sc ient is t , o n e of t h e f o u n d e r s of t h e t h e o r y of r a d i o -a c t i v e s u b s t a n c e s . F i r s t w o m a n p r o -fessor a t S o r b o n n e ( F r a n c e ) . Dis-c o v e r e d p o l o n i u m a n d r a d i u m ( 1 8 9 6 ; .

Cyaniding—method of e x t r a c t i n g g o l d f r o m rocks . By th i s m e t h o d finely-dispersed g o l d is d i s so lved in a q u e o u s so lu t i ons of p o t a s s i u m c y a n i d e .

Darwin. Charles Robert ( 1 8 0 9 - 1 8 8 2 ) — g r e a t E n g l i s h n a t u r a l i s t , c r e a t o r of t h e m a t e r i a l i s t t h e o r y of h i s t o r i ca l d e v e l o p m e n t of l iv ing n a t u r e — D a r -w i n i s m . F o u n d e r of sc ien t i f ic e v o l u -t i o n a r y b i o l o g y . A u t h o r of t h e Origin of Species a n d o t h e r books . H i s h i s to r i c c o n t r i b u t i o n w a s t h a t h is t h e o r y h e l p e d in t h e v i c t o r y of m a t e r i a l i s m o v e r i d e a l i s m in c o g n i -t i o n of l iv ing n a t u r e .

Dernocritus ( a b o u t 4 6 0 - 3 7 0 B . C . ) — g r e a t G r e e k m a t e r i a l i s t ph i l o s -o p h e r .

Deoxidizers—materials a d d e d t o l i q u i d s tee l a f t e r t h e a d m i x t u r e s h a v e b u r n e d o u t in o r d e r t o r e d u c e t h e a m o u n t of f e r r o u s o x i d e d i sso lved i n t h e m e t a l , t h i s b e i n g n e c e s s a r y b e c a u s e f e r r o u s o x i d e causes r e d s h o r t n e s s . D e o x i d i z e r s u s u a l l y c o n t a i n t h r e e e l e m e n t s t h a t r e d u c e t h e f e r r o u s o x i d e — c a r b o n , m a n g a n e s e ar id sili-c o n .

Deuterium ( f r o m t h e G r e e k w o r d m e a n i n g " s e c o n d " ) — h e a v y i s o t o p e of h y d r o g e n H 2 . T h e m a s s of t h e d e u t e r i u m a t o m is a b o u t t w i c e t h a t of t h e a t o m of u s u a l h y d r o g e n a n d e q u a l s 2 . 0 1 4 7 1 . W i t h o x y g e n f o r m s h e a v y w a t e r D . , 0 a n d p e r o -x i d e D 2 0 2 , w h i c h is m o r e s t a b l e t h a n h y d r o g e n p e r o x i d e . D i s c o v e r e d in 1932.

Diamond—crystalline v a r i e t y of c a r b o n . T h e h a r d e s t of a l l k n o w n

m i n e r a l s in n a t u r e . Co lour le s s o r s l igh t ly c o l o u r e d ; r a r e l y b l a c k . F i n e p r e c i o u s a n d t e c h n i c a l s t o n e . F o r m e d f r o m m o l t e n rocks a t h i g h p ressures a n d t e m p e r a t u r e .

Dialomaceous seaweeds ( d i a t o m e a e ) o r s i l ic ious s e a w e e d s — m i c r o s c o p i c u n i c e l l u l a r s e a w e e d s w i t h a r m o u r ( t un i c ) i m p r e g n a t e d w i t h sil ica. A b u n d a n t in f resh a n d s e a - w a t e r s t h r o u g h o u t t h e w o r l d . R o c k - f o r m i n g o r g a n i s m s ; f o r m t h i c k depos i t s of d i a t o m i t e ( d i a t o m a c e o u s sed i -m e n t s ) a n d k i e s e l g u h r ( i n f u s o r i a n e a r t h ) . T h e s e a c c u m u l a t i o n s — d i a l o -rnites a n d k i e s e l g u h r — a r e of g r e a t e c o n o m i c i m p o r t a n c e as b u i l d i n g m a t e r i a l s a n d a b r a s i v e s .

Diorite—igneous g r e e n i s h - g r e y rock . Cons is t s of p l a g i o c l a s e a n d h o r n - b l e n d e , s o m e t i m e s w i t h b io t i t e a n d q u a r t z ( q u a r t z d i o r i t e ) . I t s g r e a t t o u g h n e s s a n d h a r d n e s s m a k e it a g o o d b u i l d i n g m a t e r i a l .

Disthene—mineral. See kyanite. Dokuchayev, Vasily ( 1 8 4 6 - 1 9 0 3 ) —

g r e a t R u s s i a n n a t u r a l i s t , f o u n d e r of m o d e r n soil s c i ence a n d c o m p l e x n a t u r e s tud ie s . D o k u c h a y e v ' s m e t h -o d s h a v e f o r m e d t h e bas is of sc ien t i f ic g e o g r a p h y . Russian Cherno-zem (1883) is his c lass ical w o r k .

Dolomite—white, g r e y , o r s l igh t ly c o l o u r e d m i n e r a l ; c a l c i u m a n d m a g n e s i u m c a r b o n a t e . C o n t a i n s 54 p e r c e n t C a O a n d 4 4 p e r c e n t M g O .

T h e t e r m d o l o m i t e a l so s ignif ies a d e n s e s e d i m e n t a r y r o c k c o m p o s e d m a i n l y of g r a i n s of t h e m i n e r a l d o l o m i t e . O c c u r s in m a r i n e depos i t s of d i f f e r e n t geo log i ca l p e r i o d s . U s e d as fireproof m a t e r i a l , a s flux in b l a s t - f u r n a c e s m e l t i n g , in t h e c h e m i -ca l i n d u s t r y a n d i n b u i l d i n g .

Earth's crust - -lithosphere—the o u t e r h a r d shel l of t h e c r u s t w h i c h is t h e o r e t i c a l l y s u p p o s e d t o b e o n l y 15 t o 17 k i l o m e t r e s t h i c k ( f r o m t h e s u r f a c e ) .

S o m e sc ient i s t s b e l i e v e it t o b e as m u c h as 60 k i l o m e t r e s t h i ck .

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Electron—elementary particle car-rying charge of negative electricity. Component part of atom. In the atom electrons revolve along definite orbits around the positively charged atomic nucleus. The number of electrons in an atom corresponds to the atomic number of the chemi-cal element.

Electronic microscope—up-to-date microscope using a stream of elec-trons instead of a ray of light making it possible to magnify the object up to a million times.

Electroscope—instrument for detect-ing or roughly measuring the electric tension between two bodies.

Emanation—gaseous products of disintegration of radioactive ele-ments.

Emerald. See beryl. Euclase—very rare, transparent,

blue or bluish-green mineral of the silicate group; very close to beryl. Beautiful precious stone.

Face—wall of a stope being worked upon.

Fans—long and gently-sloping deposits of rocks washed and trans-ported by water and carried out to plains.

Feldspar—most abundant group of minerals constituting about 50 per cent by weight of the entire earth's crust; chief constituent of most rocks; aluminium silicates of sodium, potassium and calcium. Depending on composition divided into 1) potassium feldspars (orthoclase and microline) and 2) sodium-calcium feldspars (plagioclases).

Fluorescence—luminescence of a substance which is not due to heating, but to irradiation of its surface by solar rays, light of the voltaic arc, ultra-violet or X-rays. Luminescence ceases immediately upon removal of the influence.

Fluor spar. See fluorite. Fluorite or fluor-spar—mineral

transparent to opaque; most fre-quently coloured various shades

of violet, green, blue and grey, with glassy lustre; chemically cal-cium fluoride. Used in metallurgy as flux which lowers the temperature of metal smelting, in the chemical industry—for production of hydro-fluoric acid, for impregnating sleep-ers, in ceramics and in glass manufacture. Transparent crystals are used in optics and are known as optical fluorite. More beautiful samples are used in the manufac-ture of various articles. The earthy pink-violet variety of fluorite is called ratovkite.

Flux—mineral substances added to ore to facilitate smelting of the latter and to separate the metal from the molten gangue (slag). Quartz, limestone, fluorite and other minerals and rocks may serve as fluxes.

Foraminifera—unicellular protozoa with a shell made up in most cases of calcium carbonate (CaCO a ) ; occur in marine sedimentary depos-its of all geological periods; some foraminifera are important for esti-mating the geological age of rocks.

Fulgurites—small tubes, the thick-ness of a finger, burned out or caked in sand by an electric dis-charge in the form of lightning.

Gabbro—Plutonic magmatic rock. Rich in iron, calcium and magne-sium and poor in silicious acid. Black, greenish or grey. Excellent building material.

Gadolinite—black or greenish-black rare mineral; complex silicate of rare-earth elements.

Galaxy or galactic system—accu-mulation of stellar systems com-posed of many thousands of red-hot stars. Our sun, for example, belongs to the Milky Way Galaxy, where it forms only one of the luminescent stars among tens of thousands of others.

Galena, or lead glance—grey mineral with silver lustre (PbS) containing up to 86 per cent lead. Contains

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silver as a constant admixture and is frequently a valuable silver ore. Used for the manufacture of red lead, production of lead, white lead and glazing; also used in radio-engineering.

Galvanometer—highly sensitive electric measuring instrument.

Gamma rays—electromagnetic ema-nation with very short waves. Arise during disintegration of the atoms of radium and other radioactive substances. Resemble X-rays, but have greater penetrating power.

Garnets—very abundant group of hard minerals including many varie-ties (class of silicates) of different colours with a pronounced glassy lustre. Certain garnets are used as decorations as well as abrasive material.

Gedroits, Konstantin ( 1 8 7 2 - 1 9 3 2 ) — Soviet soil scientist and agrochemist; academician since 1929. Founder of the theory of soil colloids and their role in the formation of the soil and in its fertility.

Geode—round, oval and more rarely, lentil-shaped cavities in rock; minerals crystallize on their walls.

Genesis—origin. In mineralogy the theory of genesis (origin of minerals) aims at finding the way and con-ditions under which minerals are formed and at studying their subse-quent changes.

Geological era—largest time unit in geological chronology correspond-ing to a geological group. Four « eras are distinguished: Archaic, Paleozoic, Mesozoic and Cainozoic.

Geophysics—complex of sciences about the physical properties of the earth and of the physical processes occurring in it.

Glacier—natural mass of ice flow-ing like an ice-river slowly down the slope of a mountain or down a valley by gravity. In its movement the glacier destroys its bed, pol-ishes the projections in its bed,

scratches them with fragments of rock frozen into the ice, transports them over considerable distances and deposits tremendous quantities of rock fragments, rounded boulders (moraines), etc. Upon reaching the region of melting the mountain glacier gives rise to rapid rivers.

Gneiss—metamorphic schistous rock. Akin to granite in composition. Used as building material.

Goethite—yellow-reddish or black-brown brittle mineral; hydrous iron oxide. Used as an iron ore along with other iron oxides.

Golitsyn, Boris ( 1862 -1916)—Rus-sian physicist, academician; founder of seismology and author of numer-ous scientific papers.

Granite—igneous rock of crystal-line-granular structure. Consists of' quartz, feldspar, mica and sometimes of horn-blende. Has different colours from white to black or from light pink to dark red. Because of its strength, beauty and the ability to produce large monoliths, it is a very valuable building, facing, sculptural and acid-resistant mate-rial.

Graphite—soft, oily to the touch and soiling mineral; variety of crystalline carbon ranging in colour from black to steel-grey. Melts above 3,000° C.; acid- and alkali-resistant. Used in the foundry for the manufacture of crucibles, electrodes, dry cells, and for paints, pencils, etc.

Grey copper ores—name of a group of minerals whose chief represent-atives are tennantite or copper arsenide and tetrahedrite or copper antimonide. Tetrahedrites are used along with other minerals in smelting copper.

Gypsum — mineral and mono-mineral sedimentary white or slightly coloured rock ( C a S 0 4 . 2 H 2 0 ) . Very abundant in nature and widely used for building, decor-ative and plastic work and for

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manufacture of cement; also used in medicine for surgical casts and in agronomy for improving the soils. Alabaster and selenite are varieties of gypsum.

Half-life—the time required for half the initial number of atoms of radioactive elements to disinte-grate. Each radioactive element has its own constant half-life period. These periods range from a fraction of a second to thousands of millions of years.

Halite (or common salt)—rock salt—NaCi (sodium—39.39 per cent, chlorine—60.61 per cent). Salty to the taste. The name "halite" is connected with the Greek word halos meaning salt. Since it is used in the food, it has been given the name of common salt. Deliques-cence in humid air is due to the presence of admixtures.

Rock salt was formed in the past geological periods on the floors of former water basins. This salt is now found in massive form among rocks. In addition, salt is also deposited on the surface of the earth, mainly in steppe and desert regions, in (he form of films, so-called efflores-cences.

Heraclilus of Ephesus (about 530-470 B.C.)—outstanding ancient Greek materialist philosopher. His philos-ophy was exhaustively and scientif-ically analyzed in the works of the classics of Marxism-Leninism.

Herodotus (about 484-425 B.C.) —ancient Greek historian known as the Father of History. Author of the unfinished History of Greco-Persian Wars.

Hershel, John (1792-1871) —English astronomer, son of William Hershel, outstanding English astronomer.

Homer—legendary epic poet of ancient Greece.

Horn-blende. S e e amphibole. Humboldt, Alexander Friedrich

Wilhelm (1769-1859)—outstanding German naturalist and traveller.

Humic acids—acid part of humin substances constituting the natural humus of the soil. These complex organic substances play an im-portant part in plant growth.

Iceland spar. See calcite. Igneous rocks. See magmatic rocks. Ilmenite or ferrous titanate—black,

opaque, semi-metallic mineral ( I V n 0 3 ) . Important ore for tita-nium production.

Ion—atom, molecule, part of mole-cule or group of molecules carrying a positive or negative electric charge. In electrolysis positively-charged ions move towards the cathode and are called cations (for example, the metal in a salt, the hydrogen in an acid), while ions, charged negatively, move towards the anode and are known as anions. The mutual attraction of the ions with opposite charges is the reason they combine into molecules.

Ionization—transformation of neutral particles (molecules, atoms) in any medium into particles carry-ing a positive or negative electric charge, i.e., into ions.

Iron ores—mineral substances con-taining from 25 to 70 per cent iron. Include various compounds of iron and oxygen: hematite, magnetite, brown hematite and its varieties (limonite, limnite, hydro-goethite, etc.), goethite, siderite (iron spar), ferruginous quartzite. etc. Compounds of iron and sulphur are not fit for production of the metal.

Isotopes—varieties of chemical ele-ments with different atomic weights, differing in mass numbers from the atoms but having the same nuclear charge and, therefore, occupying the same place in Mendeleyev's periodic-system.

Jasper—variety of chalcedony with extensive mixtures in the form of a- finely-dispersed dye. Encoun-tered in large concentrations. The durability and hardness of jasper,

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the beauty and vat m y of its shades make this stone technically and artistically valuable.

Joliot-Curie. Frederic (born in 1900) —outstanding French physicist, one of the most prominent scientists in the field of nuclear physics, eminent progressive public figure and winner of the International Lenin Prize For Strengthening Peace among the Nations. Chairman of the Peace Council. Member of the Communist Party since 1942.

Kaolin—porcelain clay; name derived from the Chinese word kaolong (mountain with kaolin de-posits) ; light-coloured, more fre-quently light, loose, fine-grained clay consisting almost entirely of the mineral kaolinite. Pure kaolin is highly fireproof and melts at 1,750° C. Formed by decomposition of rocks rich in feldspar. Used in faience-porcelain, paper, rubber, chemical and other branches of industry.

Kaolinite—opaque, lustreless white mineral Al 2 (0H) 4 (S i . , 0 5 ) . Contains about 40 per cent alumina (alu-minium oxide), silica and water.

Kimberlite—dark, almost black magmatic rock, consisting mainly of olivine, brown mica and py-roxene which hardened in large explosion cratcrs; in South Africa and in America it contains crystals of diamond.

Kunzite—transparent, light-lilac or pink variety of the mineral called spodumene, a silicate of lithium and aluminium. Used as a precious stone.

Kursk magnetic anomaly—vast terri-tory near the city of Kursk where a considerable deviation of the magnetic needle is observed; the deviation is caused by large magnetite deposits.

Kyanite or disthene—mineral of beautiful blue shades, nearly trans-parent. Contains about 60 per cent aluminium oxide. Used as a highly

fire- and acid-proof material, while the transparent and beautifully coloured varieties of kyanite are faceted.

Labrador—bluish-grey or black iridescent (resembling a peacock feather) mineral of the feldspar group.

Labradorite—mixed crystalline rocks consisting chiefly of labra-dor. Fine building and decorative stone.

Laccolith—shape in • which mag-matic rocks are deposited in the earth's crust. i.e., flat-convex bodies resembling a loaf of bread or the cap of a mushroom. Magma hardened before reaching the earth's surface and arched the overlying layers. Freed by weathering and erosion of the overlying sedimentary rocks it forms low mountains, for example, Beshtau and Mashuk (North Caucasus), Ayu-Dag (the Crimea), etc.

Lagoon—shallow gulf or bay separated from the sea (or lake) by alluvial sand or clay. Depending on the climate of the region the lagoon may have salty or saltish water; the salinity of the water is sometimes due to the fact that sea-water periodically breaks into the lagoons. Organic world of the lagoons is always poorer than that of the sea.

Laterite—or red earth—red clay-like products of rock disintegration in humid subtropical regions. Con-tain iron and aluminium oxides. Externally resemble brick and are used in building, hence, the name from the Latin later—brick.

Lava—fiery liquid mass (magma) pouring out of volcanic craters or fissures on to the earth's surface. O n hardening forms various vol-canic rocks. The latter are deposited in the form of streams (on the slopes of volcanoes) or as crusts (when pouring out of fissures) sometimes covering vast areas.

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Lavoisier Anioine (] 743-1794) —great French chemist. For his work of compiling the mineralogical atlas of France was elected member of the French Academy of Science.

Lead glance. See galena. Leucite—white or greyish mineral

of the silicate group containing aluminium and potassium. Fre-quently forms sphere-like polyhedrons with twenty-four sides. Encountered as a constituent of intrusive rocks. Attempts are now being made to extract potassium and metallic alu-minium from leucite.

Liebig, Justus von (1803-1873)—one of the most prominent chemists of the 19th century. Founder of agronomii; chemistry and soil science. Made very important contributions to organic chemistry.

Limespar. See calcite. Limestone—sedimentary rock of

white, grey and other colours com-posed of calcium carbonate (CaCO,): frequently an accumula-tion of the remains of skeletons and shells. Very abundant in the earth's crust; forms enormous layers. Used in building, cement, chemical and metallurgical industries, in agrono-my, and in other branches of the national economy.

Limonile—colloid precipitate of different hydrates of ferric oxides of variable composition. Used as an iron ore. See iron ore.

Lithosphere. See earth's crust. Lucretius Cams (99-55 B.C.) —

brilliant Roman poet and philos-opher. In his poem On the Nature of Things he set forth the philosophy of atomistic materialism.

Magma—(Greek to dough)—fiery liquid molten mass under the hard crust of the earth. In chemi-cal composition it is a complex molten silicate. Owing to changes in temperature, pressure and other factors magma divides into separate sections; these sections differ in

composition; in hardening each o them produces a special rock.

Magmatic or igneous rocks—rocks formed from molten magma as the latter cooled and hardened. Divided into intrusive or Plutonic rocks, i.e., hardened in the interior of the earth (granite, peridotite, gabbro, etc.) and extrusive rocks, i.e., formed from the magma which poured out to the earth's surface, as during volcanic eruptions (ande-site, basalt, liparite, etc.).

.Magnesite—white or slightly coloured mineral; magnesium car-bonate. Excellent refractory material for metallurgical furnaces, etc.

Magnetite or loadstone—black, opaque mineral consisting of ferric and ferrous oxides; highly magnetic, sometimes forms whole mountains (Magnitnaya and Vysokaya moun-tains in the Urals). Most important iron ore. See iron ores.

Manganese ores are various man-ganese oxides accumulated amid sedimentary rocks.

Most important manganese-ore minerals are psilomelane, pyrolusite and manganite.

.\latble—general name of fine-or medium-crystal granular lime-stones and dolomites capable of being polished.

Marbles are' noted for the diver-sity of their colours and patterns. Valuable and important building, technical, facing and decorative material. Snow-white and pink marbles are used for sculpture.

Marble onyx—veined deposits of variously coloured calcite. Used as beautiful decorative stone.

Mar!—sedimentary rock consist-ing of clay and limestone mixed in various proportions (argillaceous and calcareous marl).

Marl containing 75 to 80 per cent calcium carbonate and 20 to 25 per cent clay is fit for production of Portland cement without any

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additions (cement marl or natural cement).

Mass-spectrograph—instrument by means of which it is possible to estimate the number of isotopes in different chemical elements.

Mendclevite—rare black mineral containing niobium and tantalum.

Mercury Julminaie—Hg(ONC)2. White or grey poisonous crystalline substance. Explodes readily on being struck, rubbed or heated as well as under the action of certain concen-trated acids. Dangerous in use. Used as an explosive.

Metamorphic rocks—rocks of mag-matic or sedimentary origin, their mineralogical and chemical com-position and structure changed (metamorphosed) after their forma-tion ; divided into rocks of Plutonic metamorphism (crystalline shales, micaceous shales, gneisses, etc.), contact metamorphism (corniferous rocks, tourmaline shales, etc.) and partly remelted rocks.

Metamorphism. See metamorphic rocks.

Meteor—light phenomenon in the form of a shooting star caused by the invasion of a small hard granule weighing a fraction of a gram from interplanetary space into the atmosphere of the earth.

Meteoric body—solid iron or stony mass weighing from a fraction of a gram to many thousands of tons and moving around the sun in interplanetary space as an inde-pendent celestial body. In invading the atmosphere of the earth the meteoric body produces a meteor or bolide and sometimes ends by falling on the earth.

Meteorite—iron or stony mass fall-ing on the earth; remnant of a meteoric body which has not fully disintegrated in the earth's atmos-phere.

Meteoritics—special branch of science studying meteorites and the

conditions under which they fall on the earth.

Mica—group of chemically com-plex minerals: alumosilicates of alkalis, magnesium and iron. It is a characteristic ability of mica to split into very thin sheets. Chief micas: white mica or muscovite— transparent, light and potassic; black or biotite— from translucent to opaque, rich in iron and magnesium. Encountered in crystals, sometimes of very large size. Valuable electric-insulation material.

Micaceous shale—schistous rock consisting mainly of mica and quartz with a small amount of feldspar.

Alicron—o.ooi millimetre. Migration of elements—shift and

redistribution of chemical elements in the earth's crust as a result of which an element is dispersed in some parts and concentrated in others.

Mineial coal—product of large accumulations of various organic (mainly vegetable) remains gradu-ally changed in the course of geological periods. Encountered in layers interspersed with clays, sand-stones and other rocks. Layers range from a fraction of a centimetre to several metres thick. Varieties: anthracite, bituminous coal and brown coal.

Alineral oil, petroleum or liquid bitumens — brown, dark-green or black, sometimes almost colourless liquid. Easily recognized by odour resembling kerosene. Main consti-tuents of petroleum are carbon and hydrogen which form compounds— hydrocarbons—of extraordinarily diverse composition. Mineral oil occurs in layers and pockets and saturates loose or porous sedi-mentary rocks. It plays an uncom-monly important part in various branches of the national economy and is used chieflv as fuel. Refin-

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ing produces various valuable prod-ucts—benzine, kerosene, gasoline, lubricants, asphalt, explosives, etc., etc.

Mineral spring—spring with large amounts of inorganic substances dissolved in its waters.

Molecule—minutest particle of substance which cannot be further divided without destruction of its physical and chemical identity. A molecule consists of atoms number-ing from one (noble gases) to thousands (proteins).

Molybdenite—lead-grey mineral with metallic lustre. Chemically molybdenum disulphide (MoS2). Chief molybdenum ore.

Monomineral—consisting of some one mineral.

Morion—almost black rock crystal; its fine fragments, however, appear brown. When carefully heated (baked in bread) becomes light, turning yellow; jewellers take advantage of this property. Further heating may deprive it of all colour. Composition of the colour and its origin are still unknown. See quartz.

Mosaics—artistic pattern made of particoloured pieces of stone, glass, wood, bone and other materials closely adhering to each other.

Mountain sickness (altitude sick-ness)—morbid state as a result of climbing to high altitudes, due to the action of low atmospheric pressure on man.

Murmanite—rare violet-coloured mineral; titanosilicate of sodium from the pegmatites of nepheline syenites.

Muscovite. See mica. Narzan—mineral spring in the

city of Kislovodsk. The salts dissolved in its water and the large amount of free carbonic acid give it valuable medicinal properties.

Nephelite, nepheline or eleolite— greyish-white or greenish mineral

with glassy or oily lustre; alumosili-cate chemically rich in alkalis.

Xephelite can be used as an aluminium ore in the chemical industry (production of soda, alums, etc.), in the abrasive, porcelain, glass and leather (it replaces tanning materials) industries, in the manu-facture of waterproof fabrics, in impregnating wood, as a fertilizer, etc.

Nephelitic syenite—rock erupted from the interior of the earth and containing nephelite, feldspar, pyroxene and amphibole, but never any quartz. Occurs relatively rarely; largest concentration is found on Kola Peninsula.

Nephrite—milky-white, grey, apple-green, sometimes dark, almost black-green mineral. I-ime-, magne-sium-and iron-containing amphibole. Opaque, but somewhat translucent in thin sheets. Takes polish well. Very valuable, strong and viscous material; consists of microscopic-ally interlaced fibres. Used as building and partly as technical stone.

Neptune—i) god of water, rivers, streams and rain water in the mythology of ancient Rome. With the development of sea-trade Nep-tune became the god of the sea and the patron off seafarers; a) the eighth planet in the solar system: discovered in 1846.

Neptunism—theory of the origin of all rocks (including igneous rocks) from aqueous sediments, very popular with geologists at the end of the 18th and the beginning of the 19th centuries.

Nero (37-68 A. D.i Roman emperor.

Neutron—elementary particle carrying no electric charge; its weight equals that of the proton. The atomic weight of a chemical element corresponds to the sum of the protons and neutrons in

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the atom. The neutrons and protons together constitute the nucleus of the atom.

Nontronile—rare apple-green mineral of earthy appcarancc con-sisting essentially of hydrous iron silicate; product of weathering of primary silicate.

Ochre—yellow earthy products of oxidation of heavy metals (for instance, vanadic, tungsten, ferric, chromic, lead and other ochres).

In the paint trade—dyes of iron hydrates with different water content and of different shades, from earthy-yellow to red.

Octane number—conventional measure of resistance to explosion of liquid fuel. Octane number of iso-octane is too; that of the very highly detonating heptane is 0. Most types of fuel arrange them-selves between iso-octane and hep-tane.

Olivine or peridot—yellow-green, olive-coloured or yellow-brown translucent mineral with glassy glance. Silicate of iron and magne-sium.

The transparent golden-green crystals are known as chrysolite and are faceted.

Olivinic rocks—igneous rocks from the interior of the earth with the mineral olivine as their chief con-stituent.

Onyx—variety of agate; consists of layers of different colours, white and black, white and red, etc. The layers are flat and the bands straight; used for making cameos, etc.

Opal—mineral of amorphic (non-crystalline, glass-like) structure; silica with variable water content. Noted for great variety of appear-ance. Chief varieties—transparent, iridescent and evenly-coloured (noble opal, hyalite, hyclrophane, fire opal, etc.), ordinary opals— non-iridescent and not quite trans-parent (milky, waxy, etc.! and

semi-opals—slightly translucent or opaque containing mechanical ad-mixtures (agate, jasper, chalcedonic opals, etc). Abundant in nature; precipitated in hot and cold waters. Large amounts of opaline sub-stance accumulate on sea floors as a result of vital activity of ma-rine animals and plants (radiolarians. sponges, diatomaceac, etc.).

Ore—mineral or rock containing sufficient useful material to make its processing profitable.

Ore deposits—natural accumula-tions of ore in the earth's crust which by their beds, extent and percentage of metal content render their exploitation profitable.

Orpimenl—arsenic sulphide, yellow mineral usually encountered in leafy and columnar masses.

Orthoclase. See feldspar. Osmic iridium—rare platinum

mineral; natural alloy of osmium and iridium.

Outcrop—place where rocks, veins and mineral deposits actually come out to the surface of the earth. Outcrops may be natural and artificial (clearings).

Paleozoic era—ancient era in the history of the earth or era of ancient life. Subdivided into five periods: Cambrian, Silurian, Devonian, Carbon-iferous and Permian. Minerals formed on the territory of the U.S.S.R. during the Paleozoic era are very abundant.

Pegmatite—I ) vein rocks of various composition formed from residual part of magma saturated with volatile and fusible elements. Peg-matite formations may be connected with various rocks, but granite pegmatites are particularly well known. They are noted for very large segregations of feldspar, quartz, dark and white mica and not infrequently for accumulations of precious stones and rare minerals; 2) regular growth of quartz through orthoclase with the formation of

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structures resembling ancient charac-ters.

Peridotite—dark-grey or black crystalline igneous rock consisting of olivine and pyroxene. Rich in iron and magnesium.

Permian system—layers formed during final period of Paleozoic era; follows Carboniferous period. Name stems from Perm Region where this system is most fully developed and where it was first described.

Permian Sea—sea of the Permian system.

Petrified tree—pseudomorphosis of chalcedony, quartz and opal in a tree.

Petrography—division of geology studying the composition and struc-ture of rocks.

Phenacite—bright wine-yellow, sometimes pale pink-red, transpar-ent to semi-transparent mineral; beryllium silicate.

Phosphates—compounds of phos-phorus and various metals. In nature most frequently encountered in combination with calcium and fluorine: apatite, phosphorite, etc.

Phosphorite—variety of the mineral apatite of a sedimentary-organogenic origin. Appears as crock- or spheri-cally-shaped concretion with radial structure. Valuable mineral fertilizer if it does not contain much clay and limestone.

Plagioclase. See feldspar. Pliny the Elder (24-79 A.D.) —

Roman scientist. Died during the eruption of

Vesuvius. His 36-volume .Xatural History, a sort of encyclopaedia, has come down to our days. In addition to books on biology, botany and medicine it also includes books on cosmography, mineralogy and even the history 01" art.

Pluto—1) god of the underworld in the mythology of ancient Greece; 2) ninth planet in the solar system; discovered in 1930.

Plutonism—theory that all rocks resulted from the action of under-ground heat, popular at the end of the 18th century.

Polarizing microscope—microscope adapted to studies of crystalline substances. Used mainly for study-ing rocks and minerals.

Polaroid—film or plate made of special crystals polarizing natural light.

Polymetallic ore—ore containing several metals, most frequently copper, zinc, lead and silver.

Porphyries—general name of all rocks with large crystals and large grains of minerals (feldspar, quartz) immersed in the main mass which consists of smaller grains.

Proton—elementary particle of substance carrying a positive electric charge. Protons together with neu-trons form the nucleus of the atom. The number of protons in the nucleus equals that of the negatively charged electrons and, consequently, the atomic number of the chemical element.

Protuberances or prominences—pro-jections on the surface of the sun consisting of heated gases, mainly, calcium and hydrogen. Easily observed during full solar eclipse in the form of fire fountains and eruptions near the edge of the solar disk. Outside eclipses they can be observed only by means of a spectroscope.

Pseudomorphosis—mineral forma-tions of crystalline structure or form atypical of the given mineral. These minerals assume the external form of other minerals, fossillized trees and shells.

Pyrite—iron sulphide; gold-coloured mineral consisting of 46.7 per cent iron and 53.3 per cent sulphur. Very abundant mineral used mainly for the manufacture of sulphuric acid, green vitriol, alum and sulphur.

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Pyrites—coloured sulphide com-pounds of copper and iron (also of nickel and cobalt! with metallic lustre. The term came into science from miners who distinguished pyrites from glances, i.e.. sulphide compounds of the same metals, but of grey and white colours. Examples — copper pyrite and copper glance (chalcocite).

Pyroxenes chemically-complex sil-icates rich in iron, calcium and magnesium; colours—grey, yellowish and green up to black. Glassy lustre. Pyroxene has many varieties (ensta-tite. bronzite. hypersthene, diopside etc.). Augite is the usual representa-tive of this group of minerals.

Quartz—hard, colourless, white or variously-coloured mineral (S i0 2 ) . Important constituent of many rocks; one of the most abundant minerals in the earth's crust. Occurs in excellently formed crystals as well as in granular and continuous masses. Varieties: transparent quarty.es—rock crystal, amethyst, smoky quartz or smoky topaz, citrine; semi-transparent—morion, milky, grey, etc.: opaque—ordinary white, ferruginous, etc. Widely used in the manufacture of physical and optical instruments, in precision mechanics, in radio-engineering, in the glass and ceramics industry, etc.: valu-able as a precious and industrial stone.

Radioactivity— physical phenome-non whose essence consists in the fact that (he atoms of some chemical elements, found mainly at the end of the periodic system, are capable of spontaneous disintegration. As a result of such radioactive dis-integration atoms of one element are transformed into those of another.

Radio!arions—microscopically small unicellular organisms belonging to the protozoa. Remarkable for the uncommon variety of their skeletons consisting chiefly of silica.

Raf>a—brine; water saturated with salts dissolved in it in amounts exceeding those in sea-water ; formed in individual closed water reservoirs subject to constant intense evapora-tion.

Ratovkile. See ftuorite. Rock crystal transparent variety

of quartz. Occurs in the form of beautiful hexahedra! crystals. Used in radio-engineering. See quartz.

Rocks—natural accumulations of minerals united by a common process of formation and possessing more or less constant composition and structure. Divided into mag-matic. sedimentary and metamor-phic, depending on origin.

Rock salt. See Halite. Roentgen, Wilhelm Konrad (1845-

1923)—well-known German physi-cist. His name won particular fame after his dicovery in 1895 of a special form of radiant energy, the so-called X-rays.

Ruby—red variety of corundum used in jewellery, for bearings in watches, meters, etc. Also produced artificially. See corundum.

Rutherford, Ernest (1871-1937)— most prominent English experi-mental physicist who studied the structure of atoms and radioactive processes.

Rut He—mineral—titanium dioxide \ T i O , i: forms reddish-brown crys-tals. Sometimes encountered grown into quartz in the form of fine fibres, so-called "Venus' hair."

Saline—soil saturated with salts to the extent that their crusts or crystals colour it white.

Saltpetre—potassium or sodium ni-trate. Occurs in desert regions in thin white crusts on the earth's surface, on rocks, etc. Used as fertilizer and for production of explosi ves.

Samarskite—rare, velvety-black mineral of the niobate and tantalatc group.

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Sand—disintegrated, loose rock formation consisting of rounded or angular grains of separate minerals (quartz, feldspar, etc.) ranging from 2 to 0.02 mm. in size.

Origin —product of disintegration, transport and deposit of formerly existing rocks.

Sands are worked for various purposes. Depending on their tech-nical uses the following sorts are distinguished: building, glass, mould-ing, grinding, filtering sands, etc.

Sapphire. See corundum. Sarder—ancient name (sard) of red

chalcedony ranging from light to deep shades, as well as from brown-red to brown.

Scale—crust formed on the surface of a molten metal (iron, copper) when air has access to it while it is being processed. The com-position of the scale is inconstant and depends on the temperature and the excess of air during its for-mation.

Scheele, Karl Wilhelm (1742-1786) —outstanding Swedish chemist. Dis-covered oxygen, chlorine and man-ganese.

Scheelite—opaque greyish-yellow mineral with oily lustre, calcium tungstate ( C a W 0 4 ) . Under the action of ultraviolet rays shows beautiful greenish-blue colour. Mined for production of tungsten, one of the most important elements in metallurgy.

Secondary minerals—minerals origi-nated in deposits near the earth's surface as a result of the decom-position of primary minerals under the action of subsoil waters and the oxygen of the air.

Sedimentary rocks—stratified rocks formed as a result of precipitation of mineral substances chiefly from water under the action of gravity, for example, limestones, sandstones, etc.

Seismograph or seismometer—instru-ment for registering and measuring

the waves (shocks) produced in the earth and in engineering structures by earthquakes, explosions, trans-port, factory machinery, etc.

Seismology—science about earth-quakes.

Serpentine—dense green rock of secondary origin consisting of ser-pentinite, magnetite, cnromite, etc.; often shows green, black, grey, white, red and yellow spots which make it look like snake skin.

Serpenlinite—hydrous magnesium silicate containing small amounts of iron, chromium and nickel; abun-dant mineral ranging in colour from onion-green to reddish-green. Used as ornamental stone.

Shales—rocks which independent of their origin are characterized by a fine-layer structure and well-pronounced slatiness, i.e., ability to divide into more or less thin, flat and parallel layers or sheets; may stem from sedimentary and from magmatic rocks by means of metamorphism.

Shors—saline formed in place of a dried-out lake with clearly pro-nounced lakeside line.

Silicates—large group of minerals representing substances containing silicon and a number of other elements (natural salts of various silicic acids). In the earth's crust silicates comprise the largest group of minerals, including feldspars, micas, horn-blendes, pyroxenes, kao-lin minerals, etc.

Silt—sediment on the floor of water reservoirs consisting mainly of minutest clayey particles less than 0.01 mm. in size. Soft ground with a low viscosity and rich in water is usually called silt.

Smaragd—old name of emerald. Soffioni—volcanic gas streams con-

taining hydrogen sulphide and car-bon dioxide, as well as a small amount of ammonia and methane. The best-known soffioni are found in Toscania (Italy). They contain

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boric acid which is extracted for industrial purposes. The steam of the soffioni is used for heating.

Soil science—science about the origin and development of the soil, the process of development of its fertility and the methods of influ-encing the soil for crop improve-ment.

Soils —surface formations con-nected with the weathering of rocks and remade by water, air and various processes in the vital activity of plants and animals.

Spectral analysis— highly sensitive method of determining chemical composition of complex substances by studying their spectra.

Spectroscope—instrument for study-ing optical spectra.

Sphalerite or zinc-blende —yellow, brown-red, green and black mineral with adamantine lustre. Compound of zinc and sulphur (Zn, Fe)S.

Mined for production of zinc. Sphalerite stems from the Greek word sphaleros—deceptive.

Stalagmites—formations on the floors of underground caves or galleries formed by drops of water saturated with carbonates falling from the ceiling. Gradually grow from the floor of the cave upward.

Stalactites—masses of calcite and other cylinder-shaped minerals (re-sembling icicles 1 hanging down from the ceilings and tops of walls in lime rock of underground caves and galleries.

Step-bearing—support made of a very hard mineral, mainly ruby (natural and synthetic). Used in precision mechanisms. Supports rap-idly-revolving parts. Rubies in watches serve as an example.

Stibnite. See antimonite. Slope—part of a mine working

where minerals are being extracted. Slrabon (63 B.C.-20 A.D.I —

famous Greek philosopher and his-torian. Travelled extensively through Asia Minor. Syria, Egypt, Italy and

Greece. His work Geography in 17 volumes has nearly fully come down to our days: the work has been translated into all languages, in-cluding Russian.

Sublimation—transformation of sub-stance from crystalline state directly (i.e., without melting) into vapour.

Suess, Eduard (1831-1g14 j —Aus-trian geologist. His basic scientific work Face of the Earth influenced the development of many branches of geology.

Superphosphate—mineral fertilizer; mixture mainly of calcium sulphate and calcium phosphate. Superphos-phate is the most widespread ferti-lizer.

Supersonic wares mechanical os-cillations with a frequency above the upper limit of auditory per-ception.

Syenite —light-coloured igneous crystalline rock consisting mainly of feldspars and horn-blende.

Differs from granite by absence of quartz. Named after the city of Syene in Egypt.

Talc—magnesium silicate, one of the softest minerals, coloured silvery-white, greenish and yellowish: has oily lustre and is shot with mother of pearl; oily to the touch.

Used in the form of powder for hygienic purposes and as a filler in the rubber, paper, paint and other branches of industry; its dense variety is called steatite or soapstone and is used in the form of slabs as fire- and acid-proof material and as an electric insulator.

Tectites—small glassy bodies found in many parts of the world. Their origin is still problematic. Some scientists believe them to be meteor-ites.

Tectonics— branch of geology study-ing rock deposits and their various irregularities.

Test pit—shallow, vertical shaft-like excavation sunk for prospecting for mineral deposits.

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Tiger's eye -ye l low-brown and brown-black quartz shot with gold owing to inclusions of horn-blende fibres.

Timiryazev. Klementy (1843-1920)— great Russian scientist and revolu-tionary, prominent botanist and physiologist, ardent propagandist of Darwin's evolutionary theory.

Tinstone. See cassiterite. Toluene—chemical compound ob-

tained from coal tar and coke-furnace gases. Basic raw material for pro-duction of saccharine: used in manufacture of dyes. Nitrating of toluene produces trotyl, one of the most important explosives.

Topaz —transparent, translucent and opaque, colourless, wine-yellow, greenish, blue and pink mineral with glassy lustre. Chemically alu-minium fluosilicate. Its transparent beautifully formed crystals are used as precious stones.

Tourmaline—mineral of very com-plex and variable composition— alum-borosilicate of calcium, iron and magnesium. Colours vary ex-traordinarily. Has several varieties. Used as precious stone and as thermo-and piezoelectrical raw material.

Tsiolkovsky, Konstantin (1857-1937) —outstanding Russian scientist and self-taught inventor; devoted all his life to scientific work in the field of rocket-flying.

Turquoise—beautiful blue and bluish-green opaque mineral with a dull lustre; phosphate of copper and aluminium. Used for decorative purposes.

L'ltrabasic rocks—rocks especially rich in such metals (bases) as magnesium, calcium and ferrous oxide; contain 45 per cent silicon dioxide. All noted for dark (green or black) colours, are heavy and formed from melts in the deepest interior of the earth's crust.

Ultra-short waves — electromagnetic oscillations with a wave-length of less than 10 metres.

Ultraviolet rays—general term for electromagnetic waves with wave-lengths of 40,000 A to 100 A.

Uvarovite—chrome garnet of emer-ald-grecn colour.

Vacuum—space devoid of matter in a closed vessel.

Vauquelin, Louis Nicolas (1763-1829)—French chemist. Discovered chromium in Siberian red-lead ore in 1797. The same year found the oxide of a formerly unknown metal, beryllium, in the mineral beryl. Made extensive studies of substance of plant and animal origin.

Vein—fissure in rocks fiiled with some mineral crystallized from the magma or from hot or cold solu-tions.

Venus'' hair—rock crystal, smoky quartz or amethyst including rutile and other fibrous minerals.

Vernadskite—very rare mineral be-longing to the group of basic hydrous sulphates of copper. Encountered in the crater of Vesuvius.

Volcanic (or real) tuff—rock of pressed volcanic ash. Colour ranges from greyish and delicate violet to black.

Weathering—destruction of rocks and minerals by the physical and chemical action of the air and water.

Wolframite—brownish-black min-eral whose composition includes tungsten, iron and manganese. Con-tains up to 50 per cent tungsten and yields 95 per cent of its world output. Used in the manufacture of steel and paints.

X-rays or Roentgen rays—short-wave electromagnetic emanations discov-ered by W. K. Roentgen in 1895. Have extraordinarily extensive application in science and engineer-ing. The structure of atoms and molecules is studied by means of X-rays. Used in analyzing substance for the purpose of discovering par-ticular elements in it. Also widely used in medicine.

Zinc-blende. See sphalerite.

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