384 Miscellaneous Intelligence. 
pulverized, mixed with nitric acid in a porcelain crucible, aud heated 
ultimately to redness, it yielded 40 per cent. of black oxide of cop- 
per. Other portions were heated to a temperature sufficient to dis- 
sipate the water, but not to decompose the salt. In these cases the 
loss was never more than 10 per cent., and was very constant. In 
respect to the acid, two grammes of the salt were dissolved in four 
grammes of sub-carbonate of potash; the mixture filtered, all the 
soluble portions collected, and after being carefully neutralised by 
sulphuric acid, evaporated to dryness, and digested in alcohol. This 
solution again evaporated gave 1.8 grammes of acetate of potash, 
which containing 0.93 of a gramme of acetic acid, gives a propor- 
tion of 46.5 per cent. on the acetate of copper employed. The 
atomic composition of this salt is therefore given as nearly the fol- 
lowing :— 
Acetic acid 2 atoms = 12.7 5or percent 51 
Oxide of copper 1 _,, =heLo bt 40 
Water Si hes aa = 22:25 re 9 
When solution of crystallized acetate of copper is boiled for some 
time it is decomposed, a little acetic acid escapes, much black oxide 
of copper falls down, and when the decomposition ceases, which it 
always ultimately does, another acetate of copper is found in the so- 
lution. This decomposition takes place in close vessels, where no 
acetic acid is allowed to escape. One hundred parts of the crystal- 
line acetate deposit about 14.65 of oxide, leaving in solution 25.35 
parts in combination, with twice its weight of acetic acid. 
On continuing to boil the solution, no further deposition of oxide 
took place ; as concentration proceeded acetic acid escaped, but suf- 
ficient remained to keep all the oxide in solution. Ultimately the 
usual crystallized acetate was obtained, which when dissolved in 
water and boiled, precipitated oxide as before, so that by several 
operations the whole might be decomposed in this manner. 
Verdigris is known to be a mixture of the crystallized acetate of 
copper, and a sub-acetate. A portion of the latter was extracted by 
washing pulverized verdigris rapidly, with successive small portions 
of cold water, to avoid a decomposition afterwards to be noticed ; 
this, when dried, was analyzed in a manner somewhat like the pre- 
ceding, and found to consist of nearly 66.5 oxide, and 33.5 acid. 
Hence there are three combinations of acetic acid, and oxide of 
copper, containing, the first, 66.5, the second, 44.44, and the third 
33.34 of oxide, supposing them all dry. 
M. Vauquelin remarked also a singular decomposition of verdigris 
which takes place spontaneously, and without the assistance of heat. 
If 1 of verdigris be mixed with 500 of distilled water, and left at a 
temperature of 60° or 70° F. it gradually becomes yellow, then 
brown, and in seven or eight days no green portions are observed. 
When filtered, per-oxide is obtained, and a blue solution, which 
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