BISMUTH

From Agepedia

BISMUTH is a metal called, by artists, tin glass, a name obviously derived from the French etain de glace. It is found both pure and mineralized by sulphur, oxygen and arsenic.Native bismuth occurs in the veins of primitive mountains, and is accompanied by ores of lead, silver, and sometimes of cobalt and nickel. It exists in reticulated, lamellar, or amorphous masses; is soft, and of a white color, occasionally tinged with red. Spe* cific gravity, 9. It is found in many countries,in France, England, Sweden, Bohemia and the U. States,but its chief locality is at Schneeberg, in Saxony, from whence the supply of bismuth, in commerce, is principally derived. To procure the metal, the ore requires merely to be reduced to convenient fragments, and heated in furnaces, when the bismuth separates from the earthy matter in which it is engaged, and flows out into castiron moulds prepared for its reception.Bismuth, when pure, has a reddishwhite color, is harder than lead, and is easily broken under the hammer, by which it may even be reduced to powder. It melts at 470° or 480°, and crystallizes, on cooling, with great regularity, in the form of cubes. When kept in a state of fusion, at a moderate heat, it is covered with an oxyde of a greenishgray or brown color; at a higher temperature, it enters into a feeble combustion, forming a yellow powder, called flowers of bismuth.It combines, by fusion, with a great number of metals, communicating to them brittleness and fusibility. The mixture discovered by Newton, and produced by melting together 8 oz. bismuth, 5 oz, lead and 3 oz. tin, fuses at 202°. From it are made toy spoons, which melt on being employed to stir very hot tea. A stili more fusible compound was invented by Mr. Dalton, composed of 3 parts tin, 5 lead and 10^ bismuth, which melts at 197°. The addition of a little mercury renders it even more fusible, and fits it to be used as a coating to the inside of glass globes. An alloy of equal parts of tin and bismuth melts at 280°; a less proportion of bismuth adds to the hardness of tin, and hence its use in the formation of pewter. Equal parts of tin, bismuth and mercury form the mosaic gold, used for various ornamental purposes. 1 part of bismuth, with 5 of lead and 3 of tin, forms plumbers' solder, a compound of great importance in the arts. Bismuth is also used by letterfounders in their best typemetal, to obtain a sharp and clear face for their letters. Bismuth combines with sulphur, and forms a bluishgray sulphuret, having a metallic lustre. The same compound is found native in small quantity, and is called, in mineralogy, bismuth glance.Nitric acid dissolves bismuth with great readiness. The solution is decomposed on the addition of water, and a white substance, called magestens of bismuth, is precipitated, which consists of a hydrated oxyde, united to a small proportion of nitric acid. This precipitation, by the addition of water, being a peculiarity of bismuth, serves as an excellent criterion of this metal. The magestens of bismuth, from its whiteness, is sometimes employed to improve the complexion, as well as the pearl powder, a similar preparation, differing only by the mixture of a little muriatic acid with the nitric acid in effecting the solution of the bismuth. The liberal use of either, however, is highly prejudicial to the skin. They are, besides, liable to be turned black by the vapors evolved from nearly all putrefying substances.The chloride of bismuth, formerly termed butter of bismuth, is formed by pouring bismuth, in fine powder, into chlorine gas, or by depriving the muriate of bismuth of its water of crystallization by heat.