238 Mr. Chenevix’s Analysis of 
into a well stopped phial. A violent disengagement of caloric 
took place ; the liquor became of the same colour as with the ore, 
and contained a salt, in every respect similar to that afforded 
by the ore ; while a portion of metallic copper remained, with 
all its lustre, at the bottom of the phial. The solution was de- 
canted ; and the residuum of metallic copper weighed 7,5. Con- 
sequently, 42,5 had been dissolved, which, with 57,5 of black 
oxide, complete the hundred parts. 
No experiment could prove, in a manner more satisfactory, 
the quantity of oxygen contained in 100 parts of this suboxide; 
nor could any afford results more important, or more conclusive. 
The passage of a portion of oxygen from one part of the metal 
to another, to favour its solution, as already stated, is proved be- 
yond the possibility of doubt ; and is doubly interesting, as it is 
the inverse of what happens to the ore when treated by phos- 
phoric acid. 
In the experiments of M. Proust, he has estimated the quan- 
tity of oxygen, contained in 100 parts of this oxide, to be 1 7. This 
proportion was calculated upon the deficit of a single analytic 
experiment, made upon the salt of muriate of suboxide of cop- 
per, after having determined the quantity of acid, of water, and 
of metallic copper. But, first, the salt cannot easily be obtained 
(as I have before observed) in a state sufficiently certain to be 
relied on, in an experiment of this nature; and, in the next 
place, it is probable, as happens in almost every analysis, that 
the deficit was greater than the real quantity of oxygen. For, 
the agreement between the analytic and synthetic experiments 
I have just stated, seems to confirm 1 1,5 to be more exactly the 
proportion. 
When, in the dry way, the above proportions of metallic 
