414 ZINC, CADMIUM, LEAD, &c. 



Copper 4 or 1 atom 

 Oxygen 1-1 atom 



3. The only other constituent of blue vitriol 

 being water, it is obvious that the salt is a com- 

 pound of 



1 atom sulphuric acid 5 

 1 atom oxide of copper 5 

 5 atoms water 5-625 



15-625 



Disuiphate 4. There exists another sulphate of copper, 

 which I formed by the following process: 31*25 

 grains of blue vitriol were dissolved in water in 

 a retort, and the solution was mixed with 10 

 grains of peroxide of copper. The retort was 

 put upon the sand bath in such a position that it 

 was kept boiling several hours every day, taking 

 care to add fresh water in proportion as that 

 liquid was dissipated ; and this was continued 

 till all the oxide of copper had totally disap- 

 peared. This happened in about a couple of 

 months ; at the same time the liquid lost its blue 

 colour, while a green coloured powder was de- 

 posited. The liquid being tested for copper by 

 ammonia, was found to contain none. It is ob- 

 vious, therefore, that the green powder contained 

 all the acid and oxide of copper in 31 '25 grains 

 of blue vitriol, together with the additional 10 

 grains of oxide added. The green powder, there- 

 fore, was a compound of 



