ALUMINA

(Lat.), n. f, A%(a%l)-u2(u)'mitn-at. Fr., alumine, Ger,, Thonerde. It., allumina. Sp., a limina, Aluminium oxide, Al;Oy, a substance isomorphous with the higher oxides of iron and chromium, A. oceurs native, and very nearly pure, in the form of hexagonal prismatic crystals of corundum, varieties of which, distinguished chiefly by their color, are the sapphire, ruby, oriental topaz, oriental amethyst, oriental emerald, ete. A colorle variety is called hyaline corundum. Emery is an opaque variety contain- Ing oxide of iron. Crystallized a., both in the form of the ruby and In that of the sapphire has been prepared artificially, and a, may also be obtained as a white powder or a hard amorphous ma , Next to the diamond, crystalline a. is the hardest substance known, Sp. gr., 35-3°9. A. acts as a weak base, and in the presence of stronger bases as an acid-forming oxide. See ALUMINATE. In the older chemical nomenclature of salts, the compounds of aluminium with oxy-acids were described as salts of a.; e. g., aluminium sulhate Was called sulphate of a. For these salts see ALUMINIUM. A. eat been used in medicine as an absorbent and given in diarrhoea and dysentery in doses of 7 to 8 grains, [B, 2, 3, 46.]—Acetas aluminæ, A. acetate. See ALUMINIUM acetate.—A. acetic a. See the major list.—A. acidnlo-sulphur lea cam kali. Potash alum, [L 63.}—1\. ammonia to-sulphuric a. Ammonia alum. [L, 63.] —A. depurata. Pure a. obtained by the decomposition of aluminjum sulphate at a red heat. [L, 63.]—A. dihydrate. See ALUXINrum oxytetrahydrat aminz et ammon iæ sulphas. Ammonia alum. [L, 45.|—Aluminze et pota æ sulphas. Potash alum.—Alumiue et sodæ sulphas. Sodium alum—Aluminæ sulpha See ALUMINIUM sulphate.—Aluminz sulphas acic lus cum pota a. Potash alum. [L, 45.1—Aluminæ sulph fas us. See ALUMEN exsiccatum.—Aluminæ tanuas. The a, tan: nate of Harrison. [B.] See ALUMINIUM tannate.—A. hydrata Ger. Ph. (1st ed.), Ru . Ph.]. Aluminium trihydrate. |B, 95.]—A. hydrata siliciea. Kaolin. [B, 108.|—A. hydrate. See ALUM 1Vx hydrate.—A. hydriea (Aust. Ph., Hung. Ph.]. Aluminium trihydrate. [B, 95.]—A. hydrochloric a. Aluminium chloride. [L, 57.] A. hypochlorosa. See the major list.—A. kalina sulphuriea. Potash alum. [L, 63.|—A. monohydrate. See ALUmisium oxydihydrate.—A. muriatiea. Aluminium chloride. [L, 63.j—A. natri sulphuriea. Soda alum. [L.]—A. pur a. See A. depurata,—A. sulfuric a, A. sulphate, A. sulphuric a. See ALUMINIUM sulphate and A. suLFuRIc A—A. tannate |Harrison]. See ALUMINIUM tannate.—A. trihydrate. See ALUMINIUM trihydrate.—Colloidal a. See ALUMINIUM oxy tetra hydrate. —Hydrated a. See ALUMINIUM hydrate.—Hyper sulphas aluminz et pota æ. Potash alum. [L, 85.]—Oxydum alumluæ hydratum. Aluminium trihydrate. [B, 108.]—Sulfas aluminæ. Aluminium sulphate. [L, 57.]—Sulfas alum i. et lixiviæ anhydrata. See ALUMEN exsiccatum.—Sulfas aluminæ et lixi cum aqua, Sulphas acid us alumiuæ et pota æ. Potash alum. {L, 57, 85.]-Sulphas aluminæ acetatus. Fr., pierre médicamenteuse. Syn.: lapis medic a mentos us. A preparation made by macerating alum, litharge, and Armenian bole each 2 parts, red oxide of iron 1 part, pota ium nitrate 4 parts, and ammonium chloride 1 part in vinegar, evaporating to dryne , and calcining [Sp. Ph. (1798), Würzb. Ph. (1795)]. The Brunswick Ph. (1777) an¢ Würtemberg Ph. (1798) substituted lead ca bonate for litharge, and 8 parts of zine sulphate for the pota ium nitrate, and omitted the red oxide of iron. The Sard in i an Ph. (1773) ordered 3 parts of the red oxide of iron and omitted the Armenian bole, the pota ium i and the ammonium chloride. [L, 85.]—S us cum pota a. Potash alum. ie 1 …il minæ et pota æ exsiceatus [Belg. Ph.j, Su fusus. See ALUMEN exsiccatum.—Super sulphas aluminæ et pota æ. Potash alum. (L, 85.]