230 DESCRIPTIONS OF MINK HALS. 



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 2 

 O s C-j-aq. An anhydrous sodium carbonate is stated to exist native. 



Gay-Luss-ite. Occurs in white brittle monoclinic crystals. Com- 

 position -i-Xa^Ca 3 C+2|aq. From Lagunilla, in Maracaibo, and Lit- 

 tle Salt Lake, near Eagtown, in Nevada. 



AMMONIUM. 



The salts of ammonia are more or less soluble in water, 

 and are entirely and easily volatilized before the blowpipe. 

 When treated with caustic lime or potassa, ammonia is 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. Taste saline and pungent. Soluble in three parts 

 of water. 



Composition. XH 4 Cl= Chlorine 66*3, ammonium 33*7= 

 100. Gives off the odor of ammonia when powdered and 

 mixed with quicklime. 



Ohs. 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 

 the peasantry are made of the dung of camels : and 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. 



