SAL ANMO'NIAC (known in chemistry as IITIMMCIILORATE OF AMMONIA) is an article of considerable importance in the materia medica. It is obtained on a large scale by decomposing with common salt (chloride of sodium) the sulphate of ammonia. which is formed in the manufacture of coal gas, or the carbonate of ammonia, obtnined by the distillation of bones. It is sold in large, crystalline, grayish-white, semi-transparent cakes, convex on one side, and concave on the other. It is inodorons, but possesses an acrid, • bitter, and nauseous taste. Its specific gravity is 1.95; it volatilizes without decomposition when heated, and is freely soluble in water. Its aqueous solution, when hva t ed. with caustic potash, evolves gaseous ammonia; and when treated with nitride of silo eis-yields a white, curdy precipitate of chloride of silvtr. This salt is largely given in France and Germany in eases of pneumonia and of inflammation of the serous mem branes, in mucous diarrhea. in chronic rheumatism and gout. and in passive dropsies. Neligan recommends it in eases of low fever, in subacute laryngitis, in chronic affections of the liver. and in facial neuralgia. It may be giveu in doses varying from 10 to 30 grains. dissolved in some aromatic water. As a local external application, it is of great value in prmnoting the ahsorption of effused blood; and there is probably no remedy so effectual for that common but disfiguring affection popularly known as a black eye, as a moderately strong solution of this salt, kept constantly applied as a lotion. If it is
desired to apply cold to any part of the body. an excellent refrigerant (q.v.) may be obtained by dissolving 5 parts of this salt and 5' parts of niter in 16 parts of water.
Sal ammoniac is employed for various purposes in the arts. It is used in soldering, and in the tinning of copper and iron to prevent the oxidation of the surface to be tinned. It is exported from Britain to Russia, where it is used by dyers.
It occurs as a mineral, as an efflorescence on the surface of rocks, or as a sublimate in fissures, crystallized in small crystals, or forming crusts, stalactites, etc. It is found in volcanic regions, but is produced during the time of the quiescence of active volca noes, rather than during their eruptions. It occurs in Britain, near burning beds of coal. It is found in Persia, Tartary, Siberia, and many other countries, where there are no active volcanoes. Formerly all Europe was supplied with it from the neighborhood of the temple of Jupiter Ammon in Egypt, whence its name.