The preservation of Niagara Falls

234 Matthews: [J. F. I.,

t i t r a t i o n w i t h o u t h a v i n g the r e a g e n t a t a n y t i m e in c o n t a c t w i t h the air .

A n o t h e r c h e m i c a l m e t h o d , ba sed s o m e w h a t o n t he s a m e idea as the p r e c e d i n g one , is t he use of a s o l u t i o n of t i t a n o u s ch lo r -

ide as the r e d u c i n g r e a g e n t . T h i s is a s t r o n g r e d u c i n g a g e n t ,

c a u s i n g t he c o m p l e t e d e c o l o r a t i o n of a l a r g e n u m b e r of dye so- l u t i ons , a n d in m a n y cases g i v i n g a v e r y s a t i s f a c t o r y e nd r eac -

t i on . T h e s a m e p r e c a u t i o n s m u s t be e m p l o y e d in t he t i t r a t i o n as m e n t i o n e d in t he case of s o d i u m h y d r o s u l p h i t e . T h i s

m e t h o d a lso has the s a m e l i m i t a t i o n s as t he p r e c e d i n g o n e in

t h a t it is o n l y s e r v i c e a b l e for th~ c o m p a r i s o n of d i f f e r e n t s a m - ples of the s a m e dye.

PRODUCTION OF STONE IN ~9o4.

A report on the stone industry in I9o 4 is among the recent publications of the United States Geological Survey. It is published as an extract from the volume of "Mineral Resources of the United States, I9O4," and is intended for general distribution.

The total value of stone reported in 19o 4 was $74,200,360, which is a gain ot $1,254,453 over the value of stone in I9O3, when it amounted to $72,945,9o8 The corresp,onding gain in I9o 3 over I9O2, when the figures were $69,83o,35 I, was $3,II5,557. In x9o2 the gain over ~9or, when the total value was $6o,- 275.762, was $9,554, 589; and in I9OI the gain was $I2,267,o23 over I9OO.

In I9O4, granite, marble, and limestone increased in value, while slate and sandstone decreased.

Granite showed the largest increase. In I9o4 its total value, including that of trap rock, was $Io,992,983; in I9O 3 it was $I8,436,o87, a gain of $7,443,- Io4 for I9o 4. The granite production increased from $i5,6o3,793 in I9O 3 to $I7,I69,437 in I9O4, a gain of $I,565,644; and the trap rock from $2,732,294 in I9o3 to $2,823,546 in I9O4, a gain of $91,252.

Sandstone, including bluestone, decreased in value from $II,262,259 in I9O3 to $IO,295,933 in I9O4, a loss of $966,326. The value of bluestone in- cluded in the sandstone was $I,779, 457 in I9O3, and $I,791,729 in I9o4, an in- crease of $I2,272. The sandstone figures decreased from $9,482,802 in I9o 3 to $8,504,204 in I9O4, a loss of $978,598.

The value of marble increased from $5,362,686 in I9O 3 to $6,297,835 in I9o4, a ain of $935,I49.

This late output was valued at $6,256,885 in I9O3, and at $5,617,I95 in I9O4, a loss of $639,69o.

The limestone output remained nearly the same, being valued at $31,627,- 99I in i9o3, and $31,996,415 in I9o4, a gain of $368,424 in I9O4.