162 Mr. Richard Phillips on the [Sepr. 
In the state in which this compound is usually met with, it is 
very difficult, on account of its extreme compactness, to deter- 
mine whether it consists principally of these blue crystals, or 
whether they are merely mixed with some other acetate, or with 
hydrate of copper. 
During a visit to Birmingham in the latter part of last year, 
Mr. Badams, a manufacturer of both kinds of verdigris, showed 
me some light blue crystals of acetate of copper, which, he 
informed me, were common verdigris that had not been subjected 
to pressure by putting it into bags. Being desirous to ascer- 
tain the composition of these crystals, Mr. Badams was good 
enough to supply me with a quantity for analysis, and I shall 
now state the results of the experiments which I made upon 
them, and also upon common verdigris. 
Although these blue crystals appeared to be unbroken, their 
size was too minute to allow of their form being determined ; 
they are unalterable by exposure to the air, and so very light 
that 100 grains, when not pressed together, occupy the space of 
an ounce of water. When a small quantity of water is added to 
these crystals, they absorb it, precisely as common verdigris 
does; to determine the action of a large quantity of water, I put 
100 grains. of the crystals into a pint of it, and after occasionally 
agitating the mixture, the clear solution was poured off. To the 
insoluble residuum, half a pint of water was added ; it gradually 
became brown, and at the expiration of three days, it had the 
appearance of being completely decomposed. 
It appears then that the blue crystals are separable by water 
into a soluble acetate, and one which is insoluble, and that the 
Jatter'is decomposed even by cold water. 
I now attempted by direct experiment to ascertain the quan- 
tity of water which these crystals contain. With this view, 100 
parts were heated in a platina crucible to the temperature of 
boiling water. They became of a green colour, and lost 24 
arts: as, however, a portion of this loss was evidently derived © 
rom the expulsion of acetic acid, it was impossible to determine 
the quantity of water by direct means. 
To find the quantity of acetic acid, 100 parts of the erystals 
were boiled in water with lime. Carbonic acid gas which 
had been previously sent through water, was passed into 
the filtered solution to precipitate the excess of lime ; the solu- 
tion, after’ being heated to expel the superfluous carbonie acid, 
became neutral acetate of lime, and was decomposed by carbonate 
of soda; the carbonate of lime precipitated, bemg washed and 
dried, weighed 28°3 parts. This experiment was repeated with 
‘but littie variation in the result. 
To-ascertain the proportion of peroxide of copper, 100 parts 
of the blue crystals were heated in a platina crucible with dilute 
nitric acid ; when the nitrate of copper formed was decomposed 
by a red heat, the peroxide left, weighed 43-2 parts. This 
