iQi On the Separullon of Nickel from Cohalt. 



iiicktl united with oxide of cobalt. The fikercd liquor, 

 haviniT been afterwards evaporated by the heat of a stove, 

 still deposited some oxide of the same quality. The saline 

 mass of nitrate of amnioniatcd nickel, of a deep green co- 

 lour, which had been obtained by evaporation, was redis- 

 solvcd, filtered, and kept in ebullition with au excess of 

 caustic potash till the ammonia was completely evaporated. 

 Tiy this means there was slill separated a gros and a half of 

 (he oxide of nickel, which did not appear to contain any 

 tiling more than a little oxide of cobalt. 



2. As the separation was not eflected very perfectly or 

 easily by the proce^is 1 have mentioned, I made trial of sul- 

 phuric acid. Fur this end, I poured an equal quantity of 

 water on the oxide formerly obtained, and I added sulphuric 

 acid. By the aid of heat the whole was dissolved. There 

 was then disengaged, in a very evident manner, an odour 

 similar to that of oxygenated nmriatic acid, although there 

 had not been an atom of muriatic acid emplovcd. I have 

 before observed the same phaenomenon on a similar occa- 

 sion. The solution was afterwards treated with ammonia, 

 as formerly, until it was almost all redissolved: the residue, 

 which consisted of oxide of cobalt with a little oxide oi 

 nickel, had a colour of verdigris. When the solution had 

 been evaporated in a gentle heat, and was separated by 

 filtration from the deposited powder, of which the greater 

 part was oxide of cobalt, it was left to a spontaneous eva- 

 poration. It crystallized, without anv otlur separation, in 

 groups of prismatic crystals, partly of a pale green, and iu 

 crusts of an azure colour at the edges. A trial of the oxides 

 separated by potash from the solution of these crystals, as 

 well as from the mother liquors, inade it obvious that they 

 both contained cobalt nearly in the same proportion. 



3. Though in thio case the result was unsuccessful, I re- 

 solved, nevertheless, to recommence the same experiment 

 on a greater quantity, hoping that the separation might 

 better succeed by crystallization. In consequence, the oxide 

 being separated by the carbonate of potash from a solution 

 of eight ounces of ore of earthy cobalt in common nitric 

 acid (which had been bef(>rc evaporated and liltered), this 

 oxide, treated with a suflicient excess of potash to separate 

 from it. as nuich as possible, the arsenic acid which might 

 be combined with it, was dissolved in the sulphuric acid 

 weakened bv eight parts of water. Some pure annr.onia 

 ^\as added to the liquid, so as to dissolve wha.t was soluble 

 in the-precip!tate. The filtered solution was evaporated by 

 a Hjoderate ebullition, and afterwards left to spontaneous 



evaporation. 



