Mr. Chenevix’s Analysis of 
copper, that is thrown down. In order to effect, in this salt, a 
decomposition similar to that which takes place in muriate of 
bismuth, or of antimony, it is necessary to draw off the first 
liquor, and then proceed to wash copiously. The precipitate 
will by degrees assume an orange colour, which, as we shall 
presently see, is the real appropriate colour of this oxide of 
copper, prepared in the humid way. 
It is evident also, from this precipitation, that this oxide of 
copper combines with muriatic acid by a very slender affinity. 
As it did not appear to me, that I should obtain any thing 
very satisfactory from this combination with muriatic acid, I 
resolved to try some other acids. Sulphuric, phosphoric, oxalic, 
citric, acetic, tartareous, and acetous acids, were each poured 
upon known quantities of the ore, and kept in bottles com- 
pletely filled and well stopped, in order to prevent any absorp- 
tion of atmospheric oxygen. The liquors generally became 
blue ; and, upon trial, were found to contain the common and 
well known salts of copper, composed of the respective acid, and 
the oxide of copper containing 20 per cent, of oxygen ; while 
a large portion of the ore appeared to remain in its original state. 
But, as I was certain, that there could be no decomposition in 
most of these acids, under the above circumstances, and more- 
over, that no oxygen could be taken in from the atmosphere, it 
became a matter of no smallinte rest, to examine from what 
source the metal dissolved had acquired the necessary quan- 
tity of oxygen to favour its solution, and afford the usual salt 
of copper, in which it is oxidated in the proportion of 20 per 
pent. 
I repeated, with all the above acids, the experiments tending 
to satisfy that enquiry ; but, as the results from all were nearly 
