200 DESCRIPTIONS OF MIN:RALS. 
This salt (but the artificially prepared) is extensively 
used in the manufacture of soap and glass, and for many 
other purposes. 
Trona. A hydrous sodium sesquicarbonate occurs in the province 
of Suckenna, in Africa, between Tripoli and Fezzan, where it forms a 
fibrous layer an inch thick beneath the soil. It is abundant at a lake 
in Maracaibo, 48 miles from Mendoza; and forms an extensive bed in 
Churchill County, Nevada. 
Thermonatrite. A hydrous sodium carbonate of the formula Na, 
@,C+aq. An anhydrous sodium carbonate is stated to exist native. 
“Gag iy-Lussite. Occurs in white brittle monoclinic crystals. Com- 
position $Naj}CaO,C+2 aq. From Lagunilla, in Maracaibo, and Lit- 
tle Salt Lake, near Ragtown, in Nevada. 
AMMONIUM. 
The salts of ammonia are more or less soluble in water, 
and are entirely and easily volatilzed before the blowpipe. 
When treated with caustic lime or potassa, ammonia 1s lib- 
erated, and is recognized by its odor and the reaction of the 
vapors on test papers. : 
Salmiak.—Sal Ammoniac, Ammonium Chloride. 
Occurs in white crusts or efflorescences, often yellowish 
or gray. Crystallizes in regular octahedrons. ‘Translucent 
—opaque. ‘laste saline and pungent. Soluble in three parts 
of water. 
Composition. N H,Cl=Chlorine 66:3, ammonium 33°7= 
100. Gives off the odor of ammonia when powdered and 
mixed with quicklime. 
Obs. Occurs in many volcanic regions, as at Etna, Vesu- 
vius, and the Sandwich Islands, where it is a product of 
volcanic action. Occasionally found about ignited coal 
seams. 
The sal ammoniac of commerce is manufactured from 
animal matter or coal soot. It is generally formed in chim- 
neys of both wood and coal fires. In Egypt, whence the 
greater part of this salt was formerly obtained, the fires of 
ane peasantry are made of the dung of camels ; Gein the soot 
which contains a considerable portion of the ammoniacal 
salt is preserved and carried in bags to the works, where it. 
is obtained by sublimation. Bones and other animal mat- 
ters are used in France. A liquid condensed in the gas 
works, is also used in its production. 

