360 IRON, 



must likewise (since the salt is neutral) indicate 

 the atomic weight of protoxide of nickel. Thus 

 it appears, that sulphate of nickel is composed of 



1 atom sulphuric acid 5 



1 atofli protoxide of nickel 4-25 

 7 atoms water . 7*875 



17-125 



There is no reason to doubt that this oxide is a 

 compound of 1 atom nickel and 1 atom oxygen. 

 Atom of An atom of nickel, therefore, must weigh 3*25. 



3. Besides the protoxide of nickel there is an- 

 other oxide, having a black colour, which was 

 first pointed out by Thenard, and which he ob- 

 tained by passing a current of chlorine gas 

 through water, having protoxide of nickel sus- 

 pended in it. A portion of the oxide dissolves 

 in the muriatic acid evolved, while another por- 

 tion assumes a black colour and is converted into 

 peroxide. It will be obvious, from the account 

 given below of the constitution of this oxide, 

 that id of the protoxide of nickel must be dis- 

 solved and converted into muriate of nickel, 

 while |ds become peroxide of nickel and remain 

 undissolved. 



Atom of When peroxide of nickel is dissolved in am- 

 Ukkei. e monia, an effervescence takes place, owing to the 

 escape of azotic gas: for the peroxide is con- 

 verted into protoxide at the expense of the hy- 

 drogen of the ammonia. An effervescence also 



16 



