HJ6T0RY OE COBALT AND NICKEL. «g 



consist of arseniat. Mr. Proust found arseniat only in the 

 interior parts of some fragments. 



Hidrosulphurettcd oxide. Sulphuret of Cobalt. 



The gray oxide, the hidrat, and the carbonat, take sulphu- Hidrosulplm- 

 retted hidrogen from water, and become hidrosulphuretted ret *» 

 oxide. This is not soluble in ammonia By distillation it 

 gives out water and sulphurous acid, and the residuum is a and sulphuret. 

 sulphuret. 



The oxides heated with sulphur are converted into siu% 

 phurets. 



One hundred parts of cobalt absorb forty of sulphur $ 

 though Mr. Proust has some doubts respecting this pro 

 portion. 



Tacts touard a history of Nickel, 



Nitrat of Nickel. 



A hundred parts of the metal dissolved in nitric acid, and Nitrat of 

 distilled till they are completely decomposed, leave 125 or nickeL 

 126 of greenish gray oxide at a minimum. Nitric acid caa 

 not convert this oxide to the maximum state. 



To ascertain the purity of the oxide of nickel, it must be Test of ?t$ 

 dissolved in muriatic acid, and exposed to the action of heat. P lint V 

 If it contain a little oxide of cobalt, oxigenized muriatic 

 acid gas will be evolved ; if it be pure, more will be given 

 out. 



The gray oxide dL ss °l ves * n a ^ tne acids, and affords, the 

 same solutions as the metal itself. 



Nitrat at a Minimwn. 



If nitrat of nickel be distilled with the same precautions as Mj a i mmn 

 nitrat of copper, we obtain, as with the latter, a nitrat with nitrat, nickel 



11 ' ' • 70-4, oxigen 



excess of base, which is insoluble in water. Of this nitrat 142 17 q } acid 12. 

 parts are afforded by 100 of nickel ; so that, if we substract 

 the 25 parts of oxigen, which the metal has absorbed, we havj 

 \7 parts of acid combined with the oxide. 



vc 



Nitrate 



