341 Facts itpon which tofcund a History 



This muriate loses 55 of water. What remains is a yel- 

 low de-hydratcd muriate, which again becomes green in the 

 air, by aI)soibing water. 



The dc-hydrated muriate, when fire is applied to it, does 

 not melt : those parts only which touch the glass are decom- 

 posed : there is then an extrication of simple muriatic acid 

 afid oxygenated acid : the salt not decomposed is sublimed 

 under the form of pearl-like flowers of a golden yellow. 

 These flowers in two days absorb Immidity, and become 

 green. The muriatic acid dissolves them with difficulty. 



100 parts of muriate of nickel gave, by means of carbo- 

 nate of potash, from 61 to (52 of carbonate; which supposes 

 from 33 to 31 of oxide. 



Sulphates of Nickel. — ^Th ere are two, the one simple and 

 the other potashed. The first crystallizes in hexaedral prisms 

 terminated by«an irregular pyramid ; the second in rhomr 

 boidal prisms. 



The simple sulphate loses 46 parts out of the 100 of water. 

 The de-hydrated residue again becomes green on absorbing 

 humidity. When strongly heated for an hour, and at a 

 red heat, in a luted retort, it is partly reduced to the state of 

 sulphate with an excess of base : water takes away that part 

 which has not lost its acid. 



100 parts of ibis sulphate gave 6i of carbonate of a clear 

 green. 



The potashed sulphate loses 24-lOOdths of water. The re- 

 sidue acts like that of the sin]|)le sulphate. The potashed 

 sulphate only gives from 27 to 28 of carbonate for 100. 



The two sulphates of nickel are transparent, of a fine eme- 

 rald green ; they are unalterable in the air. M. Proust 

 thinks that the sulphate of potash is united to that of the 

 nickel in a constant proportion. 



Extraction of the Nickel on a large Scale, — Let there be 

 an ample solution of ore first calcined, and afterwards vi- 

 triolized with the residues of ether. It is requisite to sepa- 

 rate the nicke) from iron, copper, arsenic, bismuth, and 

 cobalt. The iron is at the 7naximum : in this state it has 

 Uttle affinity for the acids. We may then precipitate it to 



the 



