BISMUTH is a brittle metal of a crystalline texture, and of a white color tinged with a faint red hue. It is found native in Cornwall, France, and Sweden. where it occurs in veins or fissures passing throug,l, other rocks. The principal natural source is an impure metal; but it is likewise found in combination with oxygen. sulphur, and arsenic. The pure metal is obtained by heating the impure native 11. in iron tubes in a furnace, when the metal volatilizes. and the vapor, condensing into a liquid in a somewhat 'cool part of the tube, runs intoa receiving-vessel, and is ultimately transferred to molds, where it solidifies with a crystalline texture. B. is represented by the chemist by the symbol 131; has the atomic weight or equivalent of 213, and has the specific gravity of 9783 to 9883 (water=1000). The metal II. is seldom employed by itself in the arts. The alloys of B. are of considerable commercial importance. In combination with tin, B. forms an alloy possessing great sonorousness, and therefore suitable for bells. The alloy of 8 of B., 5 of lead. and 3 of tin, fuses at 202' F., and therefore melts in boiling water; and the alloy of 2 of 13., 1 of lead, and 1 of tin, at 200.75' F. Either of the latter alloys is entitled to the term fusible albyy, and when mixed with some mercury, becomes still more fusible, and may then be used in forming molds for toilet-soaps, and in taking casts.
B. forms several compounds of service in the arts and in medicine; it combines with oxygen to form several oxides, of which the teroxide is time most important. It may be prepared by evaporating the solution of the ternitrate of 13. to dry
ness, and then heating, when the nitric acid escapes, and leaves the teroxide of B. as a yellowish powder. It is employed in the porcelain manufacture as an agent for fixing the gilding, and for increasing time fusibility of fluxes, at the same time neutralizing the colors which are often communicated by them. The ternit•ate of B. is prepared by acting upon the metal B. with a mixture of one part of commercial nitric acid and one part of water, and applying heat. The subnitrate or basic nitrate of B. receives the names of Pearl White, Pearl Powder, Blanc de Ford, Blanc d'Espagne, Ilajestery of B., and .Perlweiss and Schminkweiss (German). It is used as a cosmetic, but is apt to become gray in tint, and even brown or black, when sulphureted hydrogen, often evolved from sewers, cesspools, and drains, comes in contact with it.
The subnitrate of 13., the only medicinal preparation formed from this metal, acts as a local irritant and caustic poison on animals. On man, when given in small doses, it acts locally as an astringent. diminishing secretion. On account of the frequent relief given by it in painful affections of the stomach, where there is no organic disease, but where sickness and vomiting take place, accompanied by cramp or nervous disorder, it is supposed to act on the nerves of this viscus as a sedative. It has also been denomi nated tonic and antispasmodic. Vogt says, that when used as a cosmetic, it has been known to produce a spasmodic trembling of the face, ending in paralysis.