18 Copper \ 
iron with a little alumine and silex. The ammoniated so* 
lution which now only contained copper, was supersatu- 
rated with sulphuric acid, and the copper separated by 
iron. 
The first residue untouched by the nitric acid (amount- 
ing to more than half the ore) was then digested with mu- 
riatic acid, which dissolved nearly half, leaving a residue 
which by subsequent fusion with alkali was found to be 
silex, still holding a minute portion of silver* The mu- 
riatic solution was evaporated, during which it deposited 
a few small crystals of muriat of silver, after which water 
was added, which separated an abundant white oxyd, 
which was found by various trials to be antimony. 
Oxyds and Carbonated Oxyds of Copper . 
The purest native ox yd of copper is the red octohedral 
ore from Cornwall. This appears to consist of nothing 
but copper and oxygen, but, according to Mr. Chenevix f 
the copper here exists in a less state of oxygenation than 
in any other known ore of this metal. 
One hundred parts were totally dissolved in nitric acid 
with copious effervescence of nitrous gas. The pure blue 
solution was evaporated to dryness, muriatic acid was ad~ 
ded, and a second time evaporated to expel the remaining 
nitric acid, and convert the salt to a muriate This latter 
diluted with water gave up 88.5 of copper to a plate of 
iron immersed. Hence it is found to consist of 88.5 of 
copper and 11.5 oxygen. The particulars of this analysis 
will be further noticed when describing the oxyds and 
muriat of copper. 
The pure carbonated oxyds of copper consist of car^ 
bonic acid, oxygen, copper and water. With almost any 
acid they effervesce strongly, and give out their carbonic 
acid. 
Fontana was the first who clearly shewed the presence 
• Phil. Trans, for 1801 . 
