Bismuth.. This metal is principally prepared in Germany, and, as imported, generally contains both arsenic and copper. It is a crystalline metal, very brittle, of a reddish white color; melts at about 500° Fahr., volatilizes at a strong heat, and the fumes form crystalline scales (flowers of bismuth). It burns when strongly heated in the air, and has a specific gravity of about 9.8. The addition of bismuth to other metals lowers their melting point in an extraordinary manner, making it a useful ingredient in the composition of type-metal and solders. (See No. 3499 (Solder for Tin), etc.)

3345. To Purify Bismuth

3345.    To Purify Bismuth. Dissolve crude bismuth in nitric acid, and concentrate the solution by evaporation. Then pour the clear solution into a largo bulk of distilled water, and a white powder (sub-nitrate of bismuth) will be precipitated. Collect the precipitate and digest it for a time in a little caustic potash, to dissolve away any arsenious acids that may be present; next wash and dry the sub-nitrate; heat it with about 1/10 its weight of charcoal in an earthen crucible, and the pure bismuth will be found at the bottom of the crucible. (Makins.)

3346. To Separate Bismuth from Lead

3346.      To Separate Bismuth from Lead. Dissolve the mixed metal in nitric acid; add caustic potash in excess, and the oxides of bismuth and lead will be precipitated, but the lead oxide will be at once re-dissolved by the alkali. The oxide of bismuth can then be separated by filtration, washed, and ignited. (Makins.)                             •