preparing Aluminium. 239 



owing to the great diflferenee in the price, I never employed 

 more than 4 grms, of sodium to 10 grms. of kryolite. In 

 order to avoid this loss by oxidation during coohug, I tried 

 another method of preparation. 



20 grms. of kryolite were heated intensely in a gun-barrel in 

 a current of hydrogen, and then the vapour of 8 grms. of sodium 

 passed over it. This was eflfected simply by placing the sodium 

 in a little iron tray in a part of the gun-barrel, without the fire, 

 and pushed forward when the kryolite had attained the maximum 

 temperature. The operation went on very well, the whole being 

 allowed to cool in the current of hydrogen. After the treatment 

 with water, in which the fluoride of sodium dissolved very slowly, 

 I obtained a black powder, consisting for the most part of iron; 

 its solution in hydrochloric acid gave small evidence of alumina. 



The small amounts I obtained, however, should not deter 

 others from pursuing these experiments. These are the results 

 of first experiments, on which I have not been able to expend 

 much time. Now that kryolite can be procured at so very 

 moderate a price, and sodium, by the improvement in the pre- 

 paration of which Deville has performed a most important ser- 

 vice, will in future become so much cheaper, it is in the power 

 of every chemist to employ himself in the pi'eparation of alu- 

 minium, and I have no doubt in a short time methods will be 

 found afi"ording a much more profitable result. 



For the rest, I am of opinion that kryolite is the best adapted of 

 all the compounds of aluminium for the preparation of this metal. 

 It deserves the preference over chloride of aluminium and chlo- 

 ride of aluminium and sodium, and it might still be employed with 

 great advantage even if its price were to rise considerably. 



The attempts at preparing aluminium direct from alumina 

 have as yet been unattended with success. Potassium and 

 sodium appear only to reduce metallic oxides when the potash 

 and soda produced are capable of forming a compound with a 

 portion of the oxide I'cmaiuing as such. Pure potash and soda, 

 with whose properties we arc very slightly acquainted, do not 

 appear to be formed in tliis case. Since, however, alumina com- 

 bines so readily with the alkalies to form aluminates, one would 

 be inclined to believe that the reduction of alumina by the alka- 

 line metals should succeed. 



But even were it possil)le to obtain the metal direct from alu- 

 mina, it is veiy probable that kryolite would long be preferred 

 should it remain at a moderate price; for it is furnished by 

 nature in a rare state of purity, and the aluminium is combined 

 in this substance with sodium and fluorine only, which exercise 

 no prejudicial influence on the preparation of the metal, whereas 

 alumina is rarely found in nature in the pure state, and in 



