IQH On the Separation of Nickel from Colalt. 



substance was of a greenish yellow licre ami there, and of 

 a blueish gray at the points ot'ccmtact with the craciblc. Ou 

 being bruised it gave a powder of a black gray. It was 

 mixed with a gros of sulphuric acid dilufied with five gros 

 of water. After a sufficient ebullition water wa3 added, 

 and the solution was decanted clear. The residue was 

 treated with weak sulphuric acid. There was instantly 

 a brisk disengagement of ga?', and by afterwards heating 

 this mixture it manifested tvidentlv the odour of hvdrofTL-n 

 gas. After a sufficienr ebullition water was added, and the 

 solution was decanted clear. The residue was treated anew 

 with weak sulphuric acid. This gave then ten eraius of a 

 residue, v.hich was net an oxide of cobalt, but an oxide of 

 nickel mixed with cobaitj as the solution proved in the 

 acids and amu^onia. 



The two preceding solutions were each a part anaKsed 

 by pure potash, and The precipitate was iiesides heated with 

 an excess of potash ; afterv.ards washed and dried. On 

 trial each of the precipitates discovered cobalt, which was 

 always found purer in that of the first solution ; for the so- 

 . lution in the muriatic acid, applied on paper and heated, in- 

 clined sensibly to veilow, while the precipitate of tbe second 

 solution gave a writing of a clear and jnu-e green. It is 

 astonishing that the prccipitalt of the former solution has 

 furnished niore oxygenated muriatic acid than that of the 

 second. 



The reported experiments, and some others like them, of 

 which I have not spoken, prove: 



A. That oxide of nickel, weakly or violently warmed, 

 does not take the yellow colour; and that if this colour has 

 been ohs'erved by Mr. Sehnaabert, it must depend either on 

 a certain connection of elements which entered the compo- 

 sition of his oxide, or perhaps upon a mixture of a little 

 arsenic. 



B. That we cannot, by the aid of the process of Mr. 

 Schnaubert, obtain an oxide of nickel exempt from cobalt, 

 since it does not even occasion a separation of the two 

 oxides sufficiently far to be sensible to the eye. 



C. 1 pass over in silence several experiments which I 

 haVe made for finding a sure and exact method to produce 

 this separation, because they have not conducted me to the 

 desired end, or presented me with any other interesting 

 phaenomenon : they tended chiefly to point out an acid 

 which with one of the oxides formed an insoluble salt, 

 ^nd vvjtU the pther -^ salt easily dissolved. It only remained 



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