2 36 Mr. Chenevix’s Analysis of 
the natural oxide. When alone and dry, it is much more per- 
manent in its nature, than when combined with muriatic acid; 
but any part of it that happens to be in contact with a filter, 
becomes green, and then blackish, leaving a mark of the same 
shade upon the paper. Were it not for this property of chang- 
ing, it might be of use in the art of painting ; for the colour is 
extremely beautiful, and would be highly valuable, if durable. 
The precipitate caused in the muriate of copper, by the car- 
bonates of potash and soda, is of a brighter yellow, and is a real 
carbonate of suboxide of copper. But, if ammonia is poured, at 
first in a small quantity, into the above solution, the precipitate 
is blue ; and, upon adding an , excess of the precipitant, the 
whole is redissolved, and the liquor is like any other ammoniacal 
solution of copper. 
In order, however, to determine in what state the copper was 
dissolved by that alkali, I poured some ammonia upon 100 parts 
of this suboxide, in a well-closed phial. The liquor became blue; 
and I expected to find that part of the ore had been reduced* 
as with phosphoric acid ; but the residuum was entirely soluble 
in muriatic acid, with the usual phenomena. 
A spirituous tincture of galls, poured into muriate of 
suboxide of copper, afforded no precipitate, owing, I suppose, 
to the excess of acid ; but, sulphurated hydrogen gas threw 
down a black, and prussiate of ammonia a lightish brown, 
precipitate. 
I endeavoured to obtain muriate of suboxide of copper, by 
evaporation, and by distillation in a retort ; but, as I could per- 
ceive the liquor constantly assume a bluish tinge, I could not 
reckon upon the purity of the salt, sufficiently to submit it to 
analysis. 
