[895] E. Légar, Bull. de la Soc. Chim., vol. iv., 1888, 91.
(7) Van Kobell’s test, as modified by Hutchings,[896] and proposed more especially for the detection of bismuth in minerals, is capable of being applied to any solid compound suspected of containing the metal:—A mixture of precipitated and purified cuprous iodide, with an equal volume of flowers of sulphur, is prepared, and 2 parts of this mixture are made into a paste with 1 part of the substance, and heated on a slip of charcoal on an aluminium support by the blowpipe flame. If bismuth be present, the red bismuth iodide will sublime, and on clean aluminium is easily distinguishable.
[896] Chem. News, vol. xxxvi. p. 249.
There are many other tests, but the above are sufficient.
§ 818. Estimation of Bismuth.—The estimation of bismuth, when in any quantity easily weighed, is, perhaps, best accomplished by fusing the sulphide, oxide, or other compound of bismuth, in a porcelain crucible with cyanide of potassium; the bismuth is reduced to the metallic state, the cyanide can be dissolved out, and the metallic powder washed (first with water, lastly with spirit), dried, and weighed.
Mr. Pattison Muir has shown[897] that bismuth may be separated from iron, aluminium, chromium, and manganese, by adding ammonia to the acid solutions of these metals.