1822.] Method of analyzing the Ores of Nickel, 447 



H I, gives a slight vapour, v^^hich is owing to a portion of the 

 double acids which the water has not yet dissolved ; but this 

 vapour falls back again upon the surface of the water, and 

 none of it is lost. If, on the other hand, the gas is extricated 

 too quickly, the acid vapours will not have sufficient time to 

 condense, neither in the bottle, nor the long tube I K, and 

 a vapour will be seen to escape from the opening. 



During the operation, permuriate of iron sublimes in small 

 red transparent flakes, and a small quantity of which is even 

 deposited, E D. On this account, it is proper to have this 

 so long that the portion sublimed does not escape. 



Another portion of the muriate is carried by the current in 

 the direction E F. When the acids condense with the muriate, 

 there results a white crystalline matter, a small quantity of 

 which even descends into the small bulb F, which is made for 

 the purpose of preventing the muriate of iron from descending 

 into the bottle. 



This white mass is the orange coloured liquid; and when this 

 latter has been poured into the bottle, the white mass is to be 

 decomposed by a slight heat, the double acids are volatilized, 

 and the muriate of iron re-appears with its red colour. 



The operation may be discontinued when judged convenient; 

 I suffered it to contiijue 28 hours ; but I found that in the last 12 

 hours that I had gained nothing. The chlorine gas does not 

 produce a partial decomposition ; the whole of the ore com- 

 bines with it, and that which remains after the operation has 

 undergone no alteration ; it is, therefore, not at all necessary to 

 wait until all is decomposed by the operation. 



At the moment in which the operation is discontinued, a por- 

 tion of the volatilized acids still adheres to the sides of the 

 small apparatus, from the large bulb, to the opening of the tube, 

 H. To get rid of it, both bulbs are heated at the same time ; 

 but to such a degree, as not to volatihze the muriate of iron ; 

 and whilst the bulbs are cooling, a solution of carbonate of pot- 

 ash is poured through the funnel, B : this occasions a rapid dis- 

 engagement of carbonic acid gas, by which the last vapours of 

 the acids are carried off. 



When at length D E F G H is removed, C H is washed se- 

 veral times in cold water, to remove all traces of acid which 

 may adhere to it, both inside and out, and this water is to be 

 poured into the bottle. Afterwards the metalhc chlorides are 

 dissolved in water. The chloride of iron dissolves readily, but 

 the chloride of nickel resists the water at first. A drop of 

 muriatic acid ought to be added to the liquor to prevent its 

 being turbid ; after filtration, the undissolved portion is to be 

 weighed. 



This hquid contains some protomuriate of iron, mixed with 

 permuriate. It is this muriate which is first formed, and 

 which, usually enveloped in muriate of nickel, is prevented 



