418 Mr. R. Phillips's Analysis of Verdigris, [June, 



copper precipitated, and the undissolved lime, were separated 

 by the filter; through the clear solution, containing excess 

 of lime, I passed a current of carbonic acid until the lime 

 was precipitated, and I then heated the solution to separate any 

 carbonate of lime which might have been redissolved by the 

 carbonic acid. Having filtered the solution, I found it to be 

 neutral acetate of lime, and then decomposed it with carbonate 

 of soda, which gave 48*5 grs. of carbonate of lime. On repeat- 

 ing the experiment, I obtained 48*6 grs. the mean being 48*55. 

 One hundred grains of crystallized acetate of copper were dis- 

 solved in water, and boiled with excess of potash. The peroxide 

 of copper precipitated, weighed, after washing and drynig, 38*9, 



frs. On repetition I procured 39'5 grs. giving a mean of 

 9-2 grs. 

 According to Dr. Thomson, an atom of acetic acid weighs 

 63*75 ; and 1 am satisfied, from various experiments, that it is 

 very nearly correct ; and if we consider this acid to be composed 

 of three atoms of hydrogen, three of oxygen, and four of carbon, 

 as is generally admitted, it will be represented by 63*96 on Dr. 

 Wollaston's scale, agreeing almost precisely with Dr. Thomson's- 

 determination. If then 63 of carbonate of lime, the number 

 representing it on the scale, give 63*96 for acetic acid, 48*55 the 

 carbonate of lime resulting, as above described, from the treat- 

 ment of 100 grs. of acetate of copper, will indicate 49*2 of acetic 

 acid ; so that we may consider crystallized acetate of copper as 

 composed of 



Acetic acid , , 49*2 



Peroxide of copper. . . • . • , 39*2 



Leaving for water , , * ; ^ \ < '.■; 4 '..;..... 1 1*6 



100*0 .'. 



''If, as is generally admitted, peroxide of copper be a compound 

 of two atoms of oxygen 20, and one atom of copper 80, the 

 atomic constitution of verdigris will be : ■•^'' 



By theory. By experiment. 



2 atoms of acetic acid 127*92 .... 128*84 



1 atom of peroxide of copper. . . 100*00 .... 102*65 



3 atoms ofwater." ............ 33*96 30*39 



261*88 261*88 



Dr. Thotnson has lately showrt, that the salt called blue vitrioL 

 is a bisulphate of copper ; and in addition to the reasons which 

 he has assigned for this opinion, I may add that if finely divided, 

 carbonate of lime be added to a solution of it, insoluble sulphate' 

 of copper is precipitated with effervescence, and as the same 

 effects are produced with the soluble nitrate and muriate of cop-, 

 per, and with the acetate also, although very slowly, I think we 

 may conclude, that the soluble nitrate and muriate, as well as 

 the sulphate and acetate, are bisalts. 



