and the Arseniate of Nickel of Allemont. 2[>7 



But as the process of analysis oxidates the several bases which 

 in the mineral in its natural state exist free from oxygen, thtt 

 component parts of this ore must be stated as follows : 



Nickel . . 0-3904 or Ar^eniurct of nickel 0-8855 

 Cobalt.. 0-0016 Arseniuret of cobalt 0035 

 Arsenic. 0-4880 Sulphuret of antimony 0-1000 



Antimony 0-OSOO ' ■ 



Sulphur ■ 0-020(.) 0-9890 



0-9890 



The pure arscniuret of nickel therefore contains 0-451 per 

 cent, of nickel, and 0-149 of arsenic, numbers differing hut littl6 

 from -44 .and -56, which are given bv calculation. 



The arseniate of nickel, which is always found at Allemont 

 adhering to arsenical nickel, appears to be derived from the 

 spontaneous decomposition of the latter. It is sometimes com- 

 pact, and of a very fine apple-green, sometimes friable and 

 greenish white. The latter varietv was analysed by fusion in a 

 silver crucible with one and a half its weight of potash, and 

 assayed for cobalt bv the process of M. Laugier mentioned above. 

 It gave the following component parts : 



Protoxide of nickel 0-362 or Arseniate of nickel 0'706 



Protoxide of cobalt 0-025 Arseniate of cobalt 0-049 



Arsenic acid . . 0-368 



Water 0-245 0-245 



1-000 1-000 



The pure arseniate of nickel therefore will consist of 0-512 

 per cent, of oxide of nickel, and 0-4S8 of arsenic acid, which is 

 nearlv the composition of the artificial sub-arseniate, that would 

 be formed by three atoms of oxide and two atoms of acid, or, 

 exactly, of 0-496 of oxide of nickel and 0-504 of arsenic acid. 



Preparation of Nickel, and Examination rf some of its Salts. 



The ore of Allemont, after being roasted til! all arsenical va- 

 pour ceased, was dissolved in nitro-u'uriatic acid, and evaporated 

 to dryness at a gentle heat. On adding water to the residue, 

 there remained much arseniate of antimony: the solution was 

 then decomposed bv common subcarhonatc of soda, till the white 

 precipitate of arseniate of antimony began to be coloured, and 

 then filtered. The li(jUor contained all the nickel, with a little 

 cobalt and arsenic acid. To separate the latter, a solution of 

 muriated j)croxide of iron was added, followed by subcarbonateof 

 soda, till the preci|)itate bei^au to show either a green or a rose- 

 colour, and the litjuor was again filtered. The subcarbotuite of 



Vol 56. No. 270. Oct, 1820. P p soda 



