BISMUTH. 
§§ 847-850-] 
One of the best of these is based upon the brown colour which ferro- 
cyanide of potash produces in very dilute solutions of copper. A 
standard copper solution is obtained by dissolving sulphate of copper in 
a litre of water, so that each c.c. contains 0-1 mgrm. Cu, and a solution 
of ferrocyanide of potash in water is prepared, strength 4 per cent. It 
is also convenient to have a solution of nitrate of ammonia, which is 
found to render the reaction much more delicate. 
The further details are on the well-known lines of colorimetric 
estimations. 
3. BISMUTH. 
§ 847. Bismuth, Bi = 210 ; specific gravity, 9*799 ; fusing-point, 264° 
(507*2° F.).—Bismuth, as obtained in the course of analysis, is either a 
black metallic powder or an extremely brittle bead of a reddish-white 
colour. The compounds which it will be necessary to briefly notice are 
the peroxide and tersulphide. 
§ 848. The peroxide of bismuth, Bi 2 0 3 = 468—specific gravity, 8*211 ; 
Bi, 89*64 per cent. ; 0, 10*36 per cent.—as prepared by igniting the car¬ 
bonate or nitrate, is a pale lemon-coloured powder, which can be fused 
without loss of weight, but is reduced on charcoal, or in a stream of 
carbon dioxide, to the metallic state. It is also reduced by fusion with 
potassic cyanide or by ignition with ammonium chloride. 
§ 849. The Sulphide of Bismuth, Bi 2 S 3 = 516—Bi, 81*25 per cent. ; 
S, 18*75 per cent.—occurs, in the course of analysis, as a brownish- 
black or quite black precipitate, insoluble in water, dilute acids, alkalies, 
alkaline sulphides, sulphate of soda, and cyanide of potassium, but 
dissolving in moderately concentrated nitric acid with separation of 
sulphur. It continually increases in weight when dried in the ordinary 
way, and is completely reduced when fused with cyanide of potassium. 
§ 850. Preparations of Bismuth used in Medicine and the Arts. 
1. Pharmaceutical Preparations:— 
Bismuthi Subnitras, Bi0N0 3 .H 2 0.—A heavy white powder, insol¬ 
uble in water, and responding to the usual tests for bismuth and nitric 
acid. The formula should yield 77 per cent, of bismuth oxide. Com¬ 
mercial preparations, however, vary from 79 to 82 per cent. 
Bismuth Lozenges (Trochisci bismuthi) are composed of subnitrate 
of bismuth, magnesia carbonate, precipitated lime carbonate, and 
“ rose basis.” Each lozenge should contain 0*15 grm. (2J grains) of 
subnitrate of bismuth. 
Solution of Citrate of Bismuth and Ammonia (Liquor Bismuthi et 
Ammoniae citratis), a colourless neutral or slightly alkaline fluid, 
responding to the tests for bismuth and ammonia. As an impurity 
lead may be present, citric acid being so frequently contaminated with 
