t 68 TIlE FltkNlfLli~ JOUB.I'~AI~ AND

ties only ; that the early growth of the plants may be prbmoted, ~rim. ~mt excessiw~., and cor-~sequently injurious, luxuriance being given° For transplanted peas, I should pret~a" at poor and light soil ; so that the roots mi,,_:ht lm led, as they w.uh[ bc under suclt circumstances° {o confine then~selves to n;trvow limits: and the plants consequentl3 be brought i. an early maturity.

Note [ql the S~crclur]/. hi a l,'l¢,'v rl~ceived t}'om Mr. Knight~ dated tim 27th of ,Tune, lie

mcliti.~s that .c had then seen the, full result of Iris expe.rimen{ on tim mode ~>f,aNir,~ early pc.as, above descril lcd. 'f'he plants so h'c'aEed had 1, educed :t very abundant crop at least twche days caviler than lhose scmn at he st .e t m in t m usual way~ alld with a m~ch I,mr. vapid succession of produce.

O~ the: 31im:ra/ t/i.~lorg oj (;old, aml the septcralicm of iL from Ea'ct/~g and ,%Tm~q I;odics~ by ~?hter~ Alercw:y, 4"c. 1],,1 Che &re %V~,1a~x,~. Imwls, M, D.

(Continued from p, 81.)

There ace sundry European rivers which roll pat'tldes of ~o}d with flwk' sands ill no great quantity, yet such~ that the neigbourmg inha- bitants, at certain :~easons~ ti ld th'eir aeemmt ir,~ collecting them. M, de l{e; tu/nul ' , ill an ess',~/)' in tile French Memoirs for 1718, drawn up fcom malen'i;ds ftnnished by the iutendants of the several provinces~ in puvsu:mct, of lilt: orders'of the fluke nfOrleans~ gives ;m account of ten vivvl',~ .v vi~ulcAs in ih~ tcrrilovies of Vl'ztliCl:. tl'at have gold mixed wilh their sands in certain parts of theh' course : the Rhin'~; fiom .Ih isac &m~l to Strasburg, sparingly ; from thence to PhilipsburF~ move abund;mdv ; and most of all so b.:tween Fort Louis and Gcrliie.- sheim. The llhone~ in the Pals de Gex~ from the cm.qlux of the Arveo from which it i~ suH:,osed to receive its gold, to about live league~, lower down: the rivulets of" Ferriet and Benagues~ which rise fi'o,ii the heights ml the left hand of the descent ti'om Varilhere to Pahniers: tile A rlege, ~turigera; about Paimiers, below where it receives the two fore~olng rivulets : the Garonn% some leagues ti'oni Tottlouse, below where it receives the Arieze: tim Salat, Wilich rises, its the _,kriege, ~n the Pyrennees: t to Cez~e and Garden, which come from the Ce- vennes, and the l)oux, in the Franche-Compte. The last of these 'Avers is the poorest, the gold havinz hitherto been collected from it, ~ah/e,r in the way of curios'fry than width a lucrative view : the greatest cwar~tities are obtained from tile Rhine, not that this is really the rich- vs~, but m~ account of its sands being the most industriously searched ; tbr s,,mc of tim others, particularly the Ceze and Garden, appear to bc at least equal to it in richness. The quantity got flora the Rhine, uT arl account ~f near two leu.,~ues beh)w Strasburg~ is said to amount i. no more than fbur or live'-ounces in a year: this is tile quantity tn'ought to the magistrates of Strasbm'g, who farm out the right of col

AMEa~CAN M~CHAmCS ~ ~AGAZmE. 1 0 9

let'.tlng it, on condition of its being sold to them, at a price consider~ ably under its value ; so that it may be presumed that a part is other. wis~e disposed of, and that the quantity really obtained, is considerably greater.

There are many.other rivers reported to yield gold ; as the Tagus, the Danube, the Elbe, tile 0der, the Inn, the Sala, &c. The Schwartz, in the county of Schwartzburg, in Upper Saxony, is said to be rich in this metal, and its sands to be worked with great profit: Stahl mentions a piece found in it, as broad as a middling bean, though not so thick, and supposes that the Sala receives a l l i t s gold from this river; the gold of the Sala bein~ found only below where the Schwartz enters it, and being less plentiful, a ~ in-smaller grains. I t is gen¢, rally reckoned that the gold parti-~l'es, in all auriferous rivers, are washed out by the stream from such rich beds, and afterwards rest or settle where the current is languid, or in places where they escape its three: fl'onl what particular sources the gold in diflhrent rivers pru- ceeds, does not seem to have been examined.

The richest parts of rivers, within the extent in which they roll gold, are. those where their com'se is slow and uninterrupted, where they widen or change their direction: the most favourab~e season is when the water has s-fl)sided after a flood. The appearance of the sand a~ords a u..~elul m;~,rk of dtstlngmslnng the richest spots; the gold being al ways mosi. plentiful where the sai~d is reddish or blaekish~ or of a cutour s~m~(.wh;tt difli~rent fl'om what it is seen elsewhere ; not thai the red or black sands have any natural connexion with the gold, but on acco,lnt of tl~eir beirlg moreponderous than the white; sothat the same cause which determines the particles of gold, determines these also, to subside. The black sand abounds with iron, being vigorously attracted by the magnet; the red, viewed in a microscope, appears, as Reaumur observes, a beautiful congeries of coloured crys- tals, imitatin~ all the gems known to the jeweller, among which, those of the rubyand hyacinth tints are the most common; whence the reddish colour of the sand to the naked eye: the particles of gohl are of irregular figures, but constantly flat~ smooth, and with the edges rounded off.

Some goht has been discovered in Britain at diffhrent times, though, hitherto, in little quantity. Instances are mentioned in Houghton's Collections, from Camden, Sibbald, and Gerard de Malines, of gold found in Scotland, about the head of the Clyde, in Crawford-moor; and Boyle says, he had fl'om some part of Scdtland, divers large grains of gold, taken up near the s:,.rface Of the earth, over a lead nfine ; one of which, clear from spar, weighed two hundred and one grains. Mr. Boyle had aist) an English fin ore, wherein there lay, in little cells, a number of small leaves or chips of gold : he observes, that, though the tinmen, unable to separate them to profit, usually melted both metals together, yet he was assured, that one person advantageously employed his children to pick out the gold fl'om the ore, sIdlfully broken. Some earlier writers also menti(m gold found in the tin ores of Cornwall ; and about the beginning of the present century (1700) a patent is said to have been obtained" ti)r separating gold and silver

roE. l l . ~ N o . 5.~Sr:~'r~:~InL% 1826. o~

170 ' r i l e FRANKLIN JOURNAL AND

from. tin, by precipitation in a reverberatory furnace, with some pe- cuhar ttuxes 9' what success this scheme met with, I have not learnt. Mr. Borlase, in his natural history of Cornwall, gives an account ot some tin ore, abounding with a yellow matter, which was taken by the wm'kmeu It,,- tmmdiC : some bits of the yellow matter, one of which "was at vein, as large as a goose quill, included in a stone, the size of a watnu{, produced on bein~ melted an ounce of pure gold : he men- tions several other pieces of~considerable bulk, and gives a. figure of one found h) 1756, wei~hin~ three hundred and seventy-six ~rainso It is supposed to be cfi6fl?' }he stream tin, (that is, tlw. tin ore'found in detached pieces on the sides of hills,) whicl~ co~liain~ gold ; that all nf this sort contains more or h.,~ nf it ; anti that both tl~e ~)!(l and thl ore have been brought from ei~;ewhere by torceI~ts of water, and de- posited where they are now found, like the ~old sat..ds ~)f rivers.

Boyle conieetures that, besides the grains Of goht Miic5 lie detached among saud~, there may be many particles so minute, and closely fixed to {he sand, as no(to I)e perceivable by the eye, or separable b}" the common melliods of washin~ or ~)ickin~'; that n{any small pc.'-tions of the metal may be incorporated also witl~ the bodv ~f ~he sand, and that by skil['ul management they might be extract(d. Experiments, he says, c(miirmed him in this persuasion : later experiments have ~'erified it, and shown the existence of gold in sands, to be even more extensive than he seems to ha,:e apprehended. Many of the commot~ sands~ particularly the yellow, red, black, and those of a black colouv inclining to ~-iolet, appear to be rich in .cold: Becher and Cramer l)resume d~at there is no sand in nature e~i~irely fi'ee fi'om it. Hello{ rehttes, that in eleven assays of one kind of' sand, made by M. Liehe. recht, [~y a process described in the sequel, the yield of noble metal turned out constantly ti'om 840 to 844 grains on the quintal, or 9'21~ 600 grains, exclusiv(i of what remained in the scoriae, which were still llmml to be rich ; that dittbrent parcels of sand, taken up at no great distance from olle another, differed in degree of t'ichness, some havin~ .attorded above I000 ~ralllS, others only o50, and others yiehlina' none by the treatment which had succeeded so well fi)r the rest ; an~(l that of the metal thus obtained fi'om sands, two-thirds are commonly gc.!d. and the rest silver. Yet, notwithstandinz the ~t'eat richness of these sands, no means have hitherto been disco"vereff of availin~ ourselves el the metal they eontam~ or of extracting it to advantage m the large way. Be{hey, indeed, undertook to obtain gold with profit from the common sea" sands, and entered into engagements with the states of Holland, for establishing a mineral work on this foundation; but thouglx experiments made on little quantities, promised very consideratSle g.:tin, and though on trial in the large, is likewise said to have proved su.cc}~.ssful, yet, as he conmmnicated the whole process to the com- m~ssmn(!rs appointed to examine the a~air, and, as lie has shown, that such a work might be carried on more advantageously in Holland than in o!her parts of Europe, its never having been prosecuted in thdland, aIIbrds a strong presumption of its not being suiticiently luo crative. The existence of gold in sands, is, nevertheless~ aa interesting

AMERICAN MECIlANICS ~ MAGAZINE, 171

|'act, at least to the philosopher; and fiu'ther examination may, perhaps~ tint| means of making it lul'n to accOUnt.

'though grid has i)een but lately discovered, or expected in these minerals, iu which it is so common and so plentiful, their unpromising appearance having given little encouragement to examine them, there are others, whose ~ tlattering colour has-raised great expectations, but which have m~t been f, mnd, upon experiment, to yield any gold. The yellow pyritm, or march, sites, and other minerals of a golden colour, or c<mEnin~ ~,,ld-coloured specks, have, by some, been regarded as ores or matnac~s of ~old, and accordingly submitted to operations as fruitless as expensive : their losing their colour in the fire, or changiog it to a yelbm~, soon discovers that their tinging nmtter is not gold, but Sll D 1111;. o r ~ f e l ' r t l r i n 0 u s e a l x There are indeed, pyrita? which con- tam grad, and m quantity suthcmnt to deserve notice. Ilenckel, m the 19~t1; chapter of his pyritolo~,i., gives an account of some assays of minerals of this kind, brouei~t from the iIungarian mines, one of which viehled on the centner, 7~r 1600 ounces, half an ounce of noble metal(of which one-fifth was gold, and the rest silver : fi.om the same quantity of another, he obtained no less than sixty ounces of silver, and eight ounces and a half of ~ohl: but the gohl- ~ as he observes is by no means proper to the pyri{es, o," an esseX{tin(part of its compo- sition, having been only casually intermixed, as it is in stones and other minerals, in the g~fld mines.

Many have been deceived also, by some of the talcs : of which there is one species, naturally of a gray colour, which in a moderately strong fire, changes to a gold yellow; and another, naturally of a glittering ~ol~l colou~', which receives no change fl'om moderate'fire" both these . . . . . • bothes have a further resemblance to gold, m imparting a deep yellow tincture to strong aqua-regia. By repeated digestion in fresh aqua- red.is all the colourin~ matter may be extracted', and the earthy part tef't white ; but the solution yields no gold, and is found to be no other than a solution of iron. Reaumur observes, that spangles of the yel- low talc are frequent in the sands of some rivers, and-that they may readily be distinguished fi-om gohl, which they have often been taken tbr, by viewing them with a magnifying glass ; the gold particles found in rioters being constantly smooth, witlx the edges rounded, w ~ile the talk s ones; are rugged and sharp-edged.

[TO BE CONTINUED°]

FROM TIIE GLASGOW 3[ECHJk~ICS ~ .~[£GAZI~}~.

ESSAYS ON B L E A C H I N G . ~y J,)~s t~:xsiE, A. M. Lecturer on Philosophy, &c. &c. London,

No. I. tIislory of the drt.

SECTION I ,

Bleaching may be defined, the art of whitening cloth, and other ar- ticles of manufacture, by depriving them of such colouring materiala