200 
Mr. Chenevix’s Analysis of 
they yielded a quantity of arseniate of lead, corresponding to 
30 of arsenic acid ; and I obtained 54 of oxide of copper. 
Therefore, this variety contains, 
Oxide of copper - - - - 54 
Arsenic acid ----- go 
Water ------- 16 
100 
No. III. Var. 2 of the third species. One hundred parts. 
exposed to a low red heat, lost 18 of water. The 82 remaining, 
boiled with potash, left a residuum of a blackish brown colour, 
which weighed 51, and which, examined by the different 
reagents, was found to be oxide of copper, without mixture. 
The supernatant liquor, and the liquor which washed the 51 
precipitated, being neutralized and evaporated together, left a 
precipitate, by nitrate of lead, which weighed 88, and, by the 
proportions of arseniate of lead, established above, indicated 
29 of arsenic acid. The proportions in this variety are there- 
fore as follows : 
Oxide of copper - - - — 51 
Arsenic acid ----- 29 
Water ------ 18 
“98 
No. IV. Var. 5 of the third species. This gave, by one or 
other of the two methods, already described and applied, as 
follows : 
Oxide of copper - - - - 50 
Arsenic acid - - - - - 29 
Water ------- 21 
100 
