1813.] 



ExpmmerJs on Nlccolamm. 



113 



crystallizations The oxides dissolved in amiiiooia in paragraphs 

 (e) and ( f ), and the portion which the ammonfa would not 

 dissolve, were freed from ammonia hy washing. Sulphuric acid was 

 then poured upon the mass, which dissolved the whole, except a 

 few flocks whicii consisted of oxide of iron, and which weiglied, 

 when heated to redness, 5 milligrammes ('O/ J grain Troy), The 

 clear solution in sulphuric acid, which had an amethyst red 

 colour, was mixed with caustic ammonia, and set aside in a 

 moderate v^^armth, in order to evaporate slowly, and crystallize* 

 There shot first deep green crystals of sulphate of ammonia and 

 nickel': these heing removed, the liquid 'remained rose-red; 

 and, finally, gave a confused mass of a dark rose-red colour. 



(Ii) The green and red salts tisus ohtained were dissolved 

 separately in v;ater, and decomposed h.y boiling them with 

 caustic potash. The hydrates of nickel and cohalt thus ohtained 

 were, the first mountain green, the second hlackisli green ; but 

 being washed, Hnd heated to redness, they became both black'sh. 

 The oxide of cobalt weighed 150 milligrammes (2*31 grains), 

 it gave before the blow-pipe with borax a dark blue glass. The 

 cobalt metal was precipitated from the smalt by a polished copper 

 wire, it dissolved in nitric acid by the assistance of sugar, and 

 the solution was coiouiless. When the solution was neutralized, 

 and mixed with benzoate of ammonia, it exhibited no trace of 

 iron. With muriatic acid it gave a sympathetic ink. It was, 

 therefore, a very pure oxide of cobalt. The green salt gave, 

 after decomposition and heating to redness, a blackish oxide of 

 nickel, which weighed 2055 milligramm.es (31-65 grains). It 

 possessed the same properties as the oxide obtained in para-- 

 graph (c), ^ ■ ^ 



The portion of regulus of niccolanum examined, therefore^ 

 which originally weighed 2243 milligrammes (34 54 gr,), had 

 been decomposed into the following constituents 



M. Gr. M. Gr. 



Black oxide of nickel 2482 



Which, reckoning 0 20 for oxygen, 



gives of metallic nickel 1985 '60 



Black oxide of cobalt 150 



Which, rtxkoning 0*20 for oxygen, 



gives of metallic cobalt 120*00 



Red oxide of iron 7 



Which, reckoning 0'30 for oxygen, 



gives of metallic iron 4*90 



A trace of arsenic 



Loss . . , 132-50 



