ilQQ KrCREL AW0 COBALT. 



cfent ebullition, water was added, and the folution decanted 

 The refidue oxide off clear. Tli^e relMiie was treated again with weak fulphu- 

 with'ox'^de"o'f '^'^ ^^'^' *"^ ^^^^ S^^^ ^ refidue of ten grains which vvas by 

 •obalt. no means oxide ot cobalt, but oxide of nickel mixed with 



cobalt, as its folufions in the acids and in ammonia proved. 



The two preceeding foltitions were each feparately analyfed 



by pure potaHi, and the precipitate was befides heated with 

 Each of the pre- an excefs of potalli, and then waflied and dried. At the 

 •ipitates of the proof each of ll)e precipitates afforded cobalt, which was al- 



toregoine lolu- ' ^ . - , . r , r t ■ ■ 



tions afford ways molt pure in that oi the firft folulion ; for the lolution m 

 cobalt. muriatic acid, laid on paper, and heated, inclined perceptibly 



to a yellow, while the precipitate of the fecond folution pro- 

 duced a ftain of a clear and pure green. It is flrange that 

 the firfl folution afforded more oxi-muriatic acid than the 

 fecond. 



Theftf experiments, and others made by the author, but not 

 related, prove, 



^ . A. That the oxide of nickel heated either flightly or vio- 



The expen- o f 



mentsprovethat lenlly does not alfume a yellow colour; and if this colour 

 nickel oxide ^^g obferved by M. Schnaubert, it muft have been caufed 

 does not become f,n i-i i- i ,-• ri 



yellow; caufe of by 'ome lubitances which entered into the compolition oi the 



themftakeof oxide, or perhaps by the mixture of a little arfenic, 

 on this point. B. That it is impoflible by M. Schnaubert's method, to obtain 

 It is not poflible 3" oxide of nickel exempt from cobalt; fince it does not even 

 to obtain pure effefl a feparation of the two oxides fo far as to be perceptible 



nickel m his ^ ^, 



way. to t'l^ eye- 



C. M. Bucholz hints here at feveral experiments he made 



with a view to find an acid which would form an infoluble 



fait with one of the oxides, and one eafy of folution with the 



other, but which, as they did not fucceed, he does not men- 



M. Lehman's tion ; and as the method propofed by Mr. Lehman (in the 



^oabiefome :,r^d Cadmiologia, part II, page 1 10) of fufing fifteen or twenty 



expcnfive, »nd times, to a commencement of vitrification, a mixture of nickel 



alio ^'^'"^" ' and cobalt, in order to fcorify all the cobalt, would be too 



troublefome and expenfive, as would that alfo indicated by 



Bergman {Opvfcul, Phyfic, et chem, Vol. II. p. 24-6—249) of 



repeating the iuiion three or four times with from 8 to 12 times 



the quantity of pure nitre. The procefs indicated A 4, (con- 



fifting of a partial decompofition of the aramonical nitrate of 



the procefs A 4 nickel), aloDc remained to be repeated. For this purpofe 



repeated. ^,3^;^^ 



