COBALT. 363 



1 atom sulphuric acid 5 



1 atom protoxide of cobalt 4-25 

 7 atoms water . . 7'875 



17-125 



3. There seems no reason to hesitate about 

 considering this oxide as a compound of 1 atom 

 oxygen and 1 atom cobalt. On that supposition, 



the atomic weight of cobalt will be 3*25, the Atom of 

 same as the atomic weight of nickel. 



4. If protoxide of cobalt be a compound of 1 

 atom cobalt and 1 atom oxygen, it follows, that 

 100 parts of this oxide are composed of 



Cobalt . . . 76-47 



Oxygen . . . 23-53 



100-00 



Now, when the protoxide of cobalt is precipitated 

 from an acid, edulcorated and dried in the open 

 air, it absorbs oxygen during the drying, and is 

 converted into a black powder, which is the per- 

 oxide of cobalt. This peroxide dissolves with 

 effervescence in muriatic acid, while chlorine gas 

 is disengaged. When heated, it gives out oxygen 

 gas 5 and, from the experiments of Rothoff, as 

 stated by Berzelius,* it appears, that when 111 

 grains of peroxide of cobalt are heated, they are 

 converted into 100 grains of protoxide : so that 



* Annals of Philosophy, III. 356. 



