in cubes. It is brittle, and may be readily pulverized.
It melts at 476 deg., and is volatilized at a white heat. It is soluble in
nitric acid, and forms the nitrate of bismuth.

([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 deg. without being decomposed; but, exposed to a
temperature of 630 deg. 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