1856.] on Aluminium, 219 



tube. The anhydrous chloride was thus evolved in vapour, and 

 condensed in a suitable receiver. The apparatus contrived by M. 

 Deville for procuring this substance, and described in the memoir 

 already referred to,* was exhibited. Wohler's process of obtaining 

 aluminium from its chloride is well known. The following mo- 

 dification of that process, devised by M. Deville, was shown in 

 action. 



A tube of Bohemian glass, 36 inches long, and about one inch 

 in diameter, was placed on an empty combustion-furnace, con- 

 structed for tiie purpose. Chloride of aluminium was introduced 

 at one extremity of the tube ; at the same extremity a current of 

 dry hydrogen gas was made to enter the tube, and was sustained 

 till the operation was finished. The chloride was now gently 

 warmed by pieces of hot charcoal, in order to drive oiF any hydro- 

 chloric acid it might contain ; porcelain boats, filled with sodium, 

 were inserted into the opposite extremity of the tube ; the heat was 

 augmented by fresh pieces of glowing charcoal until the vapour of 

 the sodium decomposed that of the chloride of aluminium. Intense 

 ignition usually attends this re-action. At length the aluminium 

 was liberated in buttons, which were found in the boat adhering to 

 a substance consisting of the mixed chlorides of aluminium and 

 sodium. The boat was now transferred, with its contents, to a 

 porcelain tube, through which hydrogen gas was passed. At a red 

 heat, the double chloride distilled into a receiving vessel, attached 

 to the tube for the purpose ; the buttons of aluminium were col- 

 lected, washed with water, and subsequently fused together under a 

 tiux consisting of the double chloride. 



Another method of obtaining aluminium from the chloride has 

 been adopted with success. It is as follows : — 



4*200 grammes of the double chloride of aluminium 

 and sodium (i.e., 2*800 grammes chloride of 

 aluminium, and 1*400 grammes common salt), 



2*100 grammes of common salt, 



2*100 grammes of cryolite, 



thoroughly dry, and carefully mixed together, are to be laid in alter- 

 nate layers, with 840 grammes of sodium (cut into small pieces), in 

 a crucible lined with alumina — a layer of sodium should cover the 

 bottom of the crucible. When the crucible is filled, a little pow- 

 dered salt is to be sprinkled on its contents, and the crucible, fitted 

 with a lid, is to be introduced into a furnace, heated to redness, 

 and kept at that temperature until a reaction, whose occurrence 

 and continuance is indicated by a peculiar and characteristic sound, 

 s»hall have terminated. The contents of the crucible, having been 

 stirred with a porcelain rod, while in their liquified state — (this 

 part of the operation is essential) — are poured out on a surface of 



* Recherches sur les M6taux, &c. 



