AMMONIAC. This substance is a gum resin, ob tained from a plant of the genus ferula. Dioscorides says, it is the juice of a kind of ferula, growing in Bar bary, and that the plant which produces it was called agasyllis. Pliny calls the plant, whence it flows, met o peon ; and says, the gum took its name from the temple of Jupiter 4112711011, in the western part of Egypt, now the kingdom of Barca, near which it was said to grow. Olivier, after a careful examination of the seeds of this ferula, which he had an opportunity of seeing in Persia, is of opinion, that it is a new species. It grows to the eastward of the Caspian Sea, among the mountains in the vicinity of Samarcand and Bokara; but it appears also to grow in Africa; for the gum which it produces exported in considerable quantities from Alexandria in Egypt. It is als, brought Iront the East Indies. It occurs in small pieces, which are agglutinated together; internally it has a white, and externally a yellowish co lour. Its specific gra% ity is 1,207. Its smell is some
what like that of galbanum, but more agreeable. Its taste is a nauseous sweet, mixed with hitter. It does not melt. Water dissolves a portion of it; the solution is milky, but gradually lets fall a resinous portion. One half is soluble in spirit of wine. It is soluble in alkalis. It is much to be regretted, that we has e no accurate descriptions of the different gums, gum-resins, ac. We would recommend to chemists, and writers on the mate ria medIca, the adoption of a language similar to that in vented by Werner for minerals, in their descriptions of the different natural and artificial productions, which arc the objects of their inquiries.
Sonic assert, that this gum was used by the ancients for incense in their sacrifices. It enters as a compo nent part into several medicinal compositions; of Which an account will be given in the article MEDI e A. (1)