COPPER. 415 



Sulphuric acid 10 or 5 



Oxide of copper 20 -JO 



This powder was tasteless, insoluble in water, 

 and produced no effect on vegetable blues. It 

 was obviously a compound of 1 atom acid, and 

 2 atoms oxide, or it was a disulphate of copper. 

 5. Sulphuret of copper is easily formed by 

 heating together copper filings and sulphur, per. 

 The combination takes place suddenly when the 

 mixture has reached a certain temperature, and 

 the sulphur from being in a liquid state becomes 

 suddenly solidified. This explains the reason of 

 the ignition which takes place, and which at- 

 tracted so much of the attention of the Dutch 

 chemists. The first person who attempted to 

 determine the composition of this sulphuret with 

 the requisite precision was Berzelius. He found 

 that 10 parts of copper, when converted into sul- 

 phuret, became 12*56 parts.* Now, 10 : 2-56 : : 

 8 : 2-048 ; so that according to this experiment, 

 sulphuret of copper is composed of 



Copper 8 

 Sulphur 2-048 



The copper of commerce, which Berzelius pro- 

 bably employed in his experiment, is not quite 

 pure. I believe it is often contaminated with some 

 protoxide of copper, and always with some other 



Af handliugar, III. 187. 

 J6 



