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Proceedings of the Boyal Society 
of bismuth in conjunction with Hoffmeister and Bobbs ( Chem . Soc. 
Jour., 1881 ; Proc., p. 21), I had occasion to prepare Boedeker’s 
salt ; a slight study of its properties proved it to be a compound 
of no little interest. When a concentrated aqueous solution of 
potassium cyanide is added to a solution of metallic bismuth in 
excess of nitric acid, and the mixture is boiled, a brownish-red solid 
and a more or less dark red liquid are obtained, and quantities of 
hydrocyanic acid are evolved. When the excess of nitric acid is 
nearly neutralised by potash before addition of potassium cyanide, 
the colour of the solid is a much lighter brown, and the supernatant 
liquid is nearly or quite colourless. When a large excess of nitric 
acid is present, no solid, but only a red liquid, is produced. After 
very many trials, this method of preparation was abandoned, and 
potassium cyanide solution was added to a solution of crystallised 
bismuth nitrate, in the minimum quantity of dilute nitric acid : 
much more constant results were thus obtained. Various prepara- 
tions of the puce-coloured salt were made, using varying quantities 
of bismuth nitrate and potassium cyanide ; in each case the puce- 
coloured precipitate was washed with boiling water until the 
washings were free from cyanogen and from potassium ; in one or 
two instances the precipitate was also boiled with extremely dilute 
sulphuric acid (about 1 : 300), and again washed free from acid, 
The temperatures at which the various preparations were dried are 
noted in the following table. 
Inasmuch as Boedeker states that he failed to obtain evidence of 
cyanogen in the new salt described by him, and as an examination 
for cyanogen by the ordinary tests confirmed this result, I was con- 
vinced that the salt must be an oxide of bismuth. 
Bismuth was determined by heating over a Bunsen lamp, whereby 
the salt was decomposed with production of bismuthous oxide ; the 
loss of weight (of the dehydrated salt) gave, as I supposed, the 
amount of oxygen in excess of that required to form Bi 2 0 3 . Water 
was determined by heating in a current of dry air, and determining 
the increase of weight of a calcium chloride tube attached to the 
apparatus in which the salt was heated. 
2. The following table contains the analytical results ob- 
tained: — 
