228 DESCRIPTIONS OF MINERALS. 
north of trail from Mono Lake, is a deposit, 10 miles long 
by 7 wide, of borates and other salts, chiefly borax, calcium 
Horate, sodium sulphate, and common salt. ‘The large de- 
posits of ‘* priceite ” in Southern Cregon, and of ulexite, in 
the ‘‘ Cane Spring District,” 20 miles west of San Bernar- 
dino, and at the Columbus Marsh, are other sources of 
pdorax. The amount of borax received at San Francisco 
during the year 1876 was 5,180,910 pounds, and in 1877, 
4,154,209 pounds. 
Nitre.—Potassium Nitrate. 
~ Trimetric. In modified right rhombic prisms. J:/= 
118° 50".. Usually in thin white subtransparent crusts, and 
in needleform crystals on old walls and in caverns. Taste 
saline and coolime, .. 2. ,G=1.97- 
Composition. K,0; N=Nitrogen pentoxide (N, O;) 53-4, 
potash 46°6. Burns vividly on a live coal. 
Diff. Distinguished readily by its taste and its vivid ac- 
tion on a live coal; and from sodium nitrate, which it most 
resembles, by its not becoming liquid on exposure to the 
air. 
Nitre, called also saltpetre, is employed in making gun- 
powder, forming 75 to 78 per cent. in shooting powder, “and 
62 in mining powder. The other materials are suiphur (10 
per cent., for shooting powder to 20 for mining) and char- 
coal (12 to 14 for shooting powder and 18 for mining). It 
is also extensively used in the manufacture of nitric and 
sulphuric acids ; also for pyrotechnic purposes, fulminating 
powders, and sparingly in medicine. 
Obs. Occurs in many of the caverns of Kentucky and 
other Western States, scattered through the earth that 
forms the floor of the cave. In procuring it, the earth is 
lixiviated, and the lye, when evaporated, ” yields the nitre. 
India is its most abundant locality, where it is obtained 
largely for exportation. 
Spain and Egypt also afford large quantities of nitre for 
commerce. This salt forms on the cround i in the hot weather 
succeeding copious rains, and appears in silky tufts or efflo- 
rescences ; these are brushed up by a kind of broom, lixi- 
viated, and after settling, evaporated and crystallized. In 
France, Germany, Sweden, Hungary, and other countries, 
there are artificial arrangements called nitriaries or nitre 
beds, from which nitre is obtained by the decomposition 

