16 



ON PURE NICKEL. 



The triple fait 

 decompofed by 

 carbonate of 



pouil}. 



The metal re- 

 duced. 



Arfenic and iron a little arfenic it i f 1 remains; and there may be iron likewife, 

 when we have been a little loo fparing in the addition of nitric 

 acid to the fulpharic folution of cobalt containing calx of nickel, 



I endeavoured to feparate thefe extraneous metals in the 

 humid way, but no| with complete fuccefs. I decompofed by 

 means of carbonate of potafti the triple ammoniacal fait of 

 nickel, free from iron, and as much as poflfible from cobalt : 

 the precipitate ftill was vifibly of a greenifh blue. Having 

 edulcorated it, and heated it to rednefs, it changed its colour, 

 as it loft its carbonic acid, to a blackifh gray, which however 

 inclined evidently to a green. The water of edulcoration, 

 which had a greenilli appearance, was evaporated to drynefs, 

 and the refuluum, after being heated red hot, was warned 

 again. A green powder remained, which did not lofe its co- 

 lour in the fire, and conuiled in great part of arfeniate of 

 tnckel. 



I mixed each of the two refiduums feparately with a fifth 

 part of charcoal, and expofed them to the heat of a potter's 

 furnace for eighteen hours in a cupel with a little porcelain 

 glaze. The metallic buttons obtained differed a little from 

 each other. Each endured a few blows with a hammer with- 

 out cracking; but that of the latter reiiduum was much more 

 white and fragile than that of the former, the colour of which 

 approached that of fteel and was flightly reddifh. They were 

 both attacked with avidity by nitric acid,, and they were at- 

 tracted by the magnet, but the former only weakly. 



As from feveral effects on porcelain it appeared to me pro- 

 bable, that pure nickel was a noble metal, I diifolved afrefh 

 in nitric acid the whole quantity reduced, which- amounted to 

 feveral ounces, and evaporated thefotution to drynefs. I then 

 poured water on the faline mafs, and a beautiful green folution 

 was formed ; but agreeniflvwhite refiduum remained, in which 

 I eafily deteded the prefence of iron, nickel, and arfenic 

 acid. 



The folution, which befide arfenic, contained aconfiderable 

 portion, of copper, was precipitated by carbonate of potafli, 

 and the refiduum, the colour of which was flill very lively, 

 though not fo green as that of carbonate of copper, was well 

 waflied and expofed to a white heat. This changed its apple 

 green colour to a deep green inclining to gray and brown. 

 With a flronger heat the mafs aifumed a grayer brown, and at 



the 



The refult not 

 pure nickel. 



The folution 

 precipitated and 

 expofed to a 

 ftrong heat. 



