1822.] Method of analyzing the Ores of Nickel. 4^^ 



h. The solution, freed from iron, was mixed with excess of 

 ammonia. It became of a blue colour, without depositing 

 any thing. The oxide of nickel was precipitated by caustic 

 potash ; it weighed 11 '725 parts. It was dissolved by muriatic 

 acid, and the solution evaporated to dryness; the dry matter, 

 treated with water, left 0-1 of silica, undissolved ; the weight of 

 the oxide of nickel, was therefore, only 11-625, equal to 29*95 



Eer cent, of metallic nickel in the ore. A current of sulphuretted 

 ydrogen gas was passed through the solution of muriate of 

 nickel, which occasioned a small precipitate, that was with 

 difficulty determined by the blowpipe to be copper. 



c. The solution precipitated in />, by caustic potash, had a 

 rose coloured tint. It deposited, by evaporation, 0*37 of 

 oxide of cobalt, equal to 0*92 per cent, of metallic cobalt in the 

 ore. This cobalt contained a little copper, which I did not think 

 it worth while to separate and weigh. 



d. The solution which had deposited the oxide of cobalt,, 

 was supersaturated with muriatic acid, and evaporated to dry- 

 ness. The saline mass, treated with water, left 0*18 of silica^ 

 As I employed caustic potash, which, when treated in the same 

 manner, gave no trace of silica ; this silica was derived from 

 the nickel ore ; but as chlorine gas does not combine with 

 silica, that is to say, with the oxide of silicium ready formed, 

 it is very probable that this silica existed in the ore as arse- 

 niuret, or sulphuret of silicium. 



(B.) Examination of the Volatile Substances. 



a. The liquor which distilled was of a very deep orange co- 

 lour. When dropped into water, it became milky, and deposited 

 sulphur. The excess of chlorine, continually absorbed by the 

 water, gradually acidified the sulphur ; so that towards the end 

 of the operation very little of it remained. The bottle, which 

 served as a receiver, had a ground glass stopper, and put in 

 a place the temperature of which varied between 85° and 140"^ 

 of Fahrenheit ; after some hours' digestion, the stopper was 

 taken out, and the liquor was heated to ebullition, in order to 

 expel tlie excess of chlorine. The particles of sulphur which 

 remained unacidified, gradually attracted each other, and at 

 length formed a small globule, which, after the expulsion of 

 the gas, was evaporated : it weighed 0*55 part. 



h. The liquid was neutralized by caustic potash, without 

 being rendered turbid ; proving that no part of the chloride of 

 iron had been volatilized. It was rendered slightly acid, and 

 mixed with muriate of barytes ; it gave 38*92 parts of sulphate 

 of barytes, equivalent to 5*37 of sulphur, which, with the 0*55 

 obtained in a, makes a total of 5*92, or 19*34 per cent, of the 

 weight of the ore. 



c. The best method of obtaining the arsenic acid would 

 undoubtedly have been to precipitate it with peroxide of iron ; 



