Combustion of the Diamond. 563 
of a solution of carbonic add in water, precipitated in the same 
manner lime water, and when in excess redissolved the pre- 
cipitate. To ascertain if this precipitate was exactly the same 
in composition as pure carbonate of lime, I made a sufficient 
quantity of it by pouring lime water into the recipient contain- 
ing the results of the first experiment ; and after collecting 
and drying it at the temperature of 212° Fahrenheit, I intro- 
duced a quantity of it contained in some foil of platinum through 
mercury into a glass tube filled with mercury, and I heated 
in the same manner an equal quantity of finely powdered' 
Carrara marble, and admitted to them equal quantities of so- 
lution of muriatic acid. In this trial, there was rather more 
elastic fluid disengaged from the Carrara marble than from 
the carbonate of lime from the diamond ; but on examining 
the foil of platinum after the experiment, I found that a little 
of the carbonate had not been acted upon: I tried two similar 
experiments, substituting bibulous paper instead of the metallic 
foils for infolding the carbonates; the results were such as to 
shew that both substances afforded the same quantities of 
elastic fluid. 
1 healed some of the carbonate from the diamond in a tube 
which contained potassium, and passed the potassium through 
it in vapour : there was ignition, and a substance of a dense 
black colour was formed; this substance was acted on by dilute 
muriatic acid, when it left a fine black powder which burnt 
like lamp black, and when thrown into fused nitre scintillated 
and disappeared in the same manner as powdered charcoal. 
The gas that remained in the second experiment, after the 
absorption of the carbonic acid gas, vividly supported combus- 
tion, and diminished with nitrous gas; but as the degree of 
