558 THE MANUFACTURE OF NICKEL. 



unnoticed by chemists. If we have in solution a mixture of the sulphates 

 of nickel, cobalt, zinc, manganese, iron, and copper, we have only to 

 add to this solution in a warm state as much sulphate of ammonia as it 

 will dissolve, and then set it aside to cool. Almost every particle of 

 the nickel and cobalt will separate as a green crystallized powder and 

 leave the other metals in solution. The explanation is very simple. 

 The sulphates of nickel and cobalt form triple salts or alums with the 

 sulphate of ammonia, and these salts are absolutely insoluble in a cold 

 saturated solution of sulphate of ammonia, particularly when the 

 solution is slightly acidulous. 



I shall conclude these remarks upon nickel by stating that this 

 metal appears to possess the property of "Avelding" like iron. At my 

 request, a workman heated two small bars of nickel which had been 

 previously powdered over with borax. The bars were heated in a 

 forge, and the two hot ends "jumped" together, — that is to say, the 

 white hot ends were forcibly driven one against the other by gentle 

 blows with a hammer applied to the other ends, the symmetry of the 

 bar being preserved by blows applied laterally. Although the point of 

 junction was afterwards subjected to much twistiug, straining, and so 

 forth, with a view to test its cohesive power, yet it showed no signs of 

 weakness even after much cold hammering. — ' Newton's London 

 Journal.' 



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