1816.] Scientific Intelligence. 401 
I was able in this way to separate completely the soluble part of the 
verdigris from the insoluble. The insoluble portion, being dried 
in the open air, weighed 54-8 grains: of course 45°7 grains had 
been dissolved. 
The solution consisted entirely of acetate of copper, and was 
composed of 
Black oxide of copper ....+--- ii, ofthog 20 
Acetic acid ws... eee ee ee ee reese 2.0 12°85 
32°85 
“Hence it is obvious that this portion of acetate of copper in th 
verdigris was combined with 12°85 grains of water. . et 
“’The insoluble portion, which weighed 54°3 grains, consisted 
chiefly of subacetate of copper, but contained likewise some car= 
bonate of copper. This carbonate | found could be separated from 
the subacetate by means of diluted sulphuric acid; for the carbonate 
is much more soluble in this acid than the subacetate.- The analysis 
made-in this way, however, cannot entirely be depended upon, as 
it somewhat overrates the quantity of carbonate of copper; because 
the whole dissolved in the sulphuric acid during the effervescence is 
considered as carbonate, though part of it probably is subacetate. 
My analysis gave the following quantities :— 
Subacetate of copper .....+-+++-- .. 23°36 
Carbonate of copper....+-+++++ee+--- 12°10 
Water eerecvevreeeseoeeseov es ee ee ee oe 18°84 
54°30 
By dissolving 100 grains of verdigris in water by means of 
sulphuric acid, and throwing down the copper from the solution by 
a cylinder of zinc, I obtained 38 grains of copper very nearly. Mr. 
Benicke informed me that 14,107 lbs. of copper were converted in 
his manufactory into 41,830 lbs. of verdigris. Hence the copper 
in 100 grains of verdigris ought to be only 33°72 lbs. From this 
it is obvious that the verdigris loses weight by keeping. The 
portion which I examined had stood for some time wrapped up in 
paper in my laboratory, and probably lost a portion of its weight 
before I examined it; so that the quantity of water which I found 
in it, though considerable, was not the whole which it had con- 
tained when originally manufactured. French verdigris, accord- 
jng to the analysis of Proust, contains 
Soluble acetate of copper .......- ah PP 
Insoluble subacctate ....0+s- sees erevee 44 
XU. Iolite. 
This is a mineral which was first formed into a peculiar species 
by Werner. It was afterwards described by Cordier in the Journal 
de Physique; and Haiiy gave it the name of dichroife, because it 
