28 Mr. kirwan’s Experiments and Observations on 
Bifmuth in marine acid. 
400 grs. of fpirit of fait, whofe fpecific gravity is 1,220, 
diflolved only 3 or 4 grs. of bifmuth. 
Nickel in vitriolic acid. 
100 grs. of concentrated vitriolic acid diffolve about 4 of 
nickel, with the affiftance of a ftrong heat. The calces of 
nickel are much more foluble. 
Nickel in nitrous acid. 
100 grs. of nickel require for their folution 112 grs. of ni- 
trous acid, whofe proportion to water is as 1 to 1 1 or 12, 
affifted with a moderate heat. A concentrated acid a6fs fo rapidly 
that much is diffipated. The produT of nitrous air is 79 cubic 
inches. The calces of nickel are alfo foluble in this acid. 
Nickel in marine acid. 
200 grs. of fpirit of fait, whofe fpecific gravity is 1,220, 
diflolved 4 or 5 grs. of nickel, without the affiftance of heat. 
A weaker acid diffolves lefs, and requires the affiftance of heat. 
In all thefe cafes of difficult folution more of the metal will be 
taken up by diftillation and cohobation ; but the proportion will 
be difficult to affign. 
The calces of nickel are alfo difficultly foluble in this acid. 
Cobalt in vitriolic acid. 
100 grs. of cobalt require 450 grs. of real acid, whofe pro- 
portion to its water is not lefs than 1 to T 7 ^, and a heat of 
4 270° 
