563 
of Edinburgh, Session 1881-82. 
production of bismuthous nitrate, sulphate, or chloride. When 
sulphuric acid is employed as solvent, the salt which separates 
after concentration is probably BiHS0 4 .3H 2 0 (47 - 9 per cent, 
bismuth was obtained instead of 45 *95 per cent, required by 
this formula). The specific gravity of bismuth oxycyanide at 20° 
is 4 -6 4 referred to water at the same temperature (mean of 
4 '6 7 and 4*61 ; weighings done in benzene, specific gravity at 
20° = 0-8804). 
6. Bismuth oxycyanide is readily acted on by hot, and more 
slowly by cold, concentrated aqueous potash, with production of a 
very deep red liquid. So far as I have examined this action, 
about 75 per cent, of the oxycyanide is invariably converted into 
the oxide Bi 4 0 7 , while 25 per cent, goes into solution. This change 
appears to be independent of the quantity of potash, provided there 
be excess, and of the time of action of the hot liquid on the oxy- 
cyanide. 
When the strongly alkaline red liquid is neutralised, preferably 
by hydrochloric acid, a reddish-brown flocculent precipitate is 
formed, which, after washing with hot water, contains the whole 
of the bismuth originally in solution, but is free from potassium. 
When the precipitate has been dried at 100°, it appears as a nearly 
black hard cystalline substance resembling magnetic oxide of iron, 
and is now only dissolved by long-continued boiling in strong acids, 
with formation of deep red liquids, which are scarcely decomposed 
except by evaporation to dryness. This salt is strongly decomposed 
when heated to redness in air, with production of bismuthous oxide; 
heated in a limited supply of air a portion remains as metallic 
bismuth; the salt contains a considerable quantity of water; it is 
unchanged, otherwise than that it loses water, at 300°. It may be 
readily dissolved and decomposed by treatment with bromine and 
aqueous potash. 
I have made many analyses of this peculiar substance, but the 
results show great variations ; inasmuch, however, as the prepara- 
tion of this substance in quantity involves the use of much 
potassium cyanide, which is an extremely disagreeable reagent* to 
work with, especially when added to hot acid liquids, and the ex- 
penditure of a great deal of time, I think it may be well to put on 
record a synopsis of the results obtained. 
VOL. xi. 3 z 
