202 Mr. Chenevix’s Analysis of 
No. VI. First species of the preceding Paper. One hundred 
parts, exposed to a low red heat, lost much more than any 
of the other kinds; the deficit amounted to 35. The usual 
treatment gave 49 of oxide of copper, and only 14 of arsenic 
acid. I repeated this analysis, with some portions which 
had not been exposed to heat, and never found more than 14 
of arsenic acid. This arseniate contains, 
Oxide of copper - - - - 49 
Arsenic acid ----- 14 
Water ------ 35 
”98 
No. VII. Tellow hematitic copper ore * (See page 371.) 
One hundred parts of this ore, boiled with dilute nitric acid, 
left a yellowish white residuum, which weighed 17. These 17, 
exposed to a degree of heat sufficient to volatilize the sulphur, 
left 3, which were silica. The liquor from which this resi- 
duum had been separated by filtration, upon being tried for all 
the different metals, and particularly for arsenic, afforded no 
traces of any thing but copper and iron. A copious precipitate 
took place by the affusion of ammonia ; the copper was redis- 
solved by adding an excess; and then obtained by volatilizing 
that alkali, and boiling with potash, after the filter had sepa- 
rated the iron already precipitated. The contents are, 
Sulphur - h - - - — 12; 
Silica - - - - - - r 5 
Copper, which I believe to be in the metallic state 30 « 
Oxide of iron - - - - 53 
160 
* This and the following (No. VIII.) being the matrices upon winch the arse- 
niates of copper and of iron are generally found, I thought it right to give an analysis 
of them also. 
