64 Memoir on l^tckd, 



and consequently in its results, but at present carried to it4 

 utmost degree of perfection, and leading into error those 

 ifv only who are unacquainted with its resources. But all 

 doubts are removed in ree;ard to the existence of nickel, if it 

 be incontestably proved by numerous exact and authentic 

 exper.iiicnts. The case is not the same with its magnetic 

 property, in which it participates, or seems to participate, 

 \vith iron. If several chemists, along with Bergman, ascribe 

 to it this property, others contest it. Tt is still therefore a 

 question, of which we have not a definitive solution, to 

 know whether nickel is realty susceptible of attraction.; 

 especially as it is not yet certain whether it was ever ob- 

 tained in the state of its greatest purity. The chemical art, 

 indeed, does not possess the means of separating it from 

 cobalt. Those, even, employed for separating it from ar- 

 senic are liable to objection, and a rigorous analysis might 

 perhaps excite doubts in regard to those used for separating 

 it from iron. The problem to be solved, and which forms 

 the subject of this memoir, consequently is, — to separate 

 nickel exactlv from all the matters which alter it, and par- 

 ticularly from arsenic, iron, and cobalt. I mention these 

 three metals, because they arc those which may take from 

 or communicate to it the magnetic properties. 



'J'he nickel ore which I treated had been already fused 

 several times ; all the earthy matters, and a part of the 

 arsenic and sulphur, had therefore been separated frorn it. 

 Dift'crent trials, which it is needless here to repeat, proved 

 to me that it was composed of nickel, iron, cobalt, bismuth, 

 arsenic, vaud sulphur. The following is the method of ana- 

 lysis which I followed : ' 



Experiment I. 



Having reduced the ore to powder, I roasted it in a roast- 

 ing-pot until no more arsenical vapours were disengaged. 

 When the odour of garlic was no longer sensible, notwith- 

 standing the violence of afire long maintained, I put theorr 

 thus roasted and cold into a matrass with a sufficient quan- 

 tity of nitric acid. The action of the acid favoured by heat 

 became so strong, that a most violent efl'ervescence took 

 place; the vessel was filled with thick red vapours; the. 

 solution was almost instantaneous but incomplete, and 

 there remained about a sixth part of the matter employed. 

 This residuum, when separated by the filter, was washed 

 and carefullv examined. It was of a white and slightly 

 greenish colour, without savour, insoluble in water and ni- 

 \x\a acid, but soluble in muriatic acid^ and was precipitated 

 •■ I black 



