158 Progress of Foreign Science. 



the muriate is carried by the current in the direction E F. 

 When the acids are condensed with the muriate, there results 

 a white and crystalline matter, a little of which descends 

 even to the small ball F, which was made to hinder the mu- 

 riate of iron from falling into the bottle. This white mass 

 is insoluble in the orange liquid. After draining oft" the latter 

 into the bottle, we may decompose the white mass by a gentle 

 heat, the double acids (chlorides) are volatilized, and the mu- 

 riate of iron re-appears with its red colour. 



Twelve hours are sufficient for finishing the operation. The 

 chlorine produces no partial decomposition ; the whole ore com- 

 bines with it, and what remains insoluble after the process has 

 suffered no change. It is not at all necessary, therefore, to 

 wait till all the powder be decomposed. 



When we stop the operation, a part of the volatile acids 

 (chlorides?) still adheres to the sides of the little apparatus, 

 from the large ball to the opening of the tube H. To clear it 

 off, we heat the two balls at once, to such a temperature only as 

 will not volatilize the chloride of iron, and during the cooling 

 of the balls, we introduce by the funnel B a solution of carbo- 

 nate of potash, which causes a rapid disengagement of carbonic 

 acid gas, by which the last acid vapours are swept away. 

 When we have finally removed D E F G H, we dip G H several 

 times in pure water, to remove the acid traces which may still 

 adhere to it, both within and without, and we pour the water 

 into the bottle. We then dissolve the metallic chlorides in 

 th(! water. That of iron is quickly dissolved, but that of nickel 

 resists the water at first. We must add to the water a single 

 drop of muriatic acid, to prevent the liquor from becoming 

 troubled. We now filter and weigh the undissolved part. 



The liquid contains muriate of protoxide of iron, mixed with 

 that of the peroxide. It is the proto-chloride of iron which 

 forms first, and which, usually enveloped in that of nickel, is 

 thereby hindered from combining with a new dose of chlorine. 

 In order, therefore, to bring the iron to the peroxide state, we 

 wo must add nitric acid, and heat to ebullition. We then satu- 

 rate with ammonia, precipitate the iron by the succinate of 

 that alkali, adding finally an excess of ammonia, to be certain 

 that no substance, insoluble in this alkali, remains in the li- 

 quid. The ammoniacal liquid must be diluted with a great 

 deal of water, as free as possible from atmospheric air ; and 

 the oxide of nickel is to be precipitated by caustic potash. 

 The oxides of cobalt and copper, remaining in the solution, are 

 deposited during the evaporation of the ammonia. The silica 

 is to be sought fo; in the alkaline liquor, by saturating this with 

 muriatic acid, and evaporating to dryness. Water re-dissolves 

 the salts, but leaves the silica. The oxide of nickel, as well as 

 that of cobalt, contains silica sometimes, which must be sepa- 

 rated by the solution of the oxide in muriatic acid, and by eva- 



