lxxii

Elements of Pharmacy.

Part I.

By the action of concentrated sulphuric acid, they emit awhite vapour; and they are cppable of supporting combustion.Officinal: Nitrates of potass and of silver.

312. The carbonates always preserve their alkaline proper-ties in some slight degree. They are decomposed by all theacids, forming a brisk effervescence, which is colourless. Thecarbonates of the metals very much resemble their oxides.Officinal: Carbonates of baryta, of lime, of magnesia, of po-tass, of soda, of ammonia, of zinc, of iron.

313. Borates are verifiable; and their concentrated solu-tions afford, when heated with the strong sulphuric acid, bril-liant lamellated crystals. Officinal: Sub-borate of soda.

314. The sulphites, by the action of heat, furnish sulphur,and become sulphates. They are also converted into sulphates,with effervescence, and exhalation of sulphurous vapours, by.the sulphuric, nitric, muriatic, and other acids, and by expo-sure to the atmosphere gradually, when dry, and very quickly,when dissolved. Officinal: Sulphate of potass with sulphur.

315. The sulphates form sulphurets, when heated to rednesswith charcoal, and iurnish copious precipitates with solutionsof baryta. Officinal: Sulphates of baryta, potass, soda, zinc,copper, iron mercury.

316. The phosphites are fusible, and, when heated in closevessels, furnish a little phosphorus, and become phosphates.When heated in the open air, they emit a phosphorescentlight, and often flashes of flame, accompanied by a strongsmell of garlic, and a thick white vapour, and are convertedinto pho-phales.

317. The phosphates are crystallizable, fixed, fusible, vitri-fiable, and phosphorescent. They are not decomposed bycharcoal. They are soluble in nitric acid, without efferves-cence, and precipitable from that solution by lime water.Officinal : Phosphate of soda.

318. The arsenites are decomposed by heat, and by all theacids.

319. The arsenates are decomposed by charcoal at a hightemperature.

320. The mohjbdates are generally colourless and soluble,and are precipitated light brown by prussiate of potass.

321. The chromatrs are of a yellow or orange colour.

322. Columbate of potass resembles boracic acid in its ap-pearance.

323. Acetates are very soluble in water; are decomposedby heat, by exposure of their solutions to the air, and by thestronger acids. Officinal .- Acetate of potass, lead, zinc,mercury.