([alpha].) _Oxide of Bismuth _(Bi^{2}O^{3}).--This oxide is a light yellow powder, fusible at a red heat, insoluble in caustic potash and ammonia. It is the base of the salts of bismuth. Its hydrate is white, and easily soluble in acids. The addition of water causes these solutions to become milky, because they are decomposed into a soluble acidulous and an insoluble basic salt of bismuth. ([beta].) _Peroxide of Bismuth_ (BiO^{2}) is a dark-colored powder, completely soluble in boiling nitric acid, and yielding oxygen; produces, with hydrochloric acid, chlorine gas. It can be heated up to the temperature of 620° without being decomposed; but, exposed to a temperature of 630° it yields oxygen. Mixed with combustible substances, it glows with brightness. ([gamma].) _Bismuthic Acid _(Bi^{2}O^{5}) is a brown powder similar to the peroxide, but is converted by boiling nitric acid into a green, scarcely soluble substance (Bi^{2}O^{3}, Bi^{2}O^{5}). Its hydrate is of a red color. BLOWPIPE REACTIONS.--Metallic bismuth is converted, when exposed upon platinum wire to the flame of oxidation, into a dark brown oxide, which turns light yellow while cooling. It is slowly volatilized when heated, and a yellow sublimate of oxide is produced upon the charcoal. Oxide of bismuth melts upon platinum foil in the flame of oxidation very easily into a dark-brown liquid, which changes to a light yellow while cooling. By too strong a heat, it is reduced and penetrates the platinum foil. Upon charcoal, in the flame of oxidation and of reduction, it is reduced to metallic bismuth, which melts into one or more globules. By a continued blast they are slowly volatilized, and produce a yellow sublimate of oxide upon the charcoal, beyond which a white sublimate of carbonate of bismuth is visible. These sublimates disappear in the flame of reduction, but without communicating any color to it. _Borax_ dissolves oxide of bismuth upon platinum wire, in the flame of oxidation, easily to a clear yellow bead, which appears colorless after cooling. By the addition of more oxide, the hot bead becomes orange. It turns more yellow while cooling, and when cool is opalescent. Upon charcoal in the flame of reduction, the bead becomes turbid and greyish colored. The oxide is reduced with intumescence to the metallic state, and the bead becomes clear again. The addition of tin promotes the reduction. _Microcosmic Salt_ dissolves oxide of bismuth upon platinum wire, in the flame of oxidation, to a yellow bead, which becomes colorless after cooling. By the addition of more oxide, the bead is yellowish-brown while hot, and colorless after cooling, but not quite transparent. This bead becomes enamelled when heated by the intermittent flame; also, by the addition of still more of the oxide, after it is cooled.