232 ANNUAL OF SCIENTIFIC DISCOVERY. 



ON TWO PROCESSES FOR THE PREPARATION OF ALUMINUM AND 

 A NEW FORM OF SIL1CIUM, BY M. DEVILLE. 



Aluminum, says M. Deville, in a recent report to the French Academy, 

 of which the most common clays contain about 25 per cent, of their 

 weight, is eminently suited to become a commonly used metal. I have 

 not hitherto published the methods which I have used to produce it, for 

 they required to be confirmed by additional experiments. I will now, 

 however, state, that all I announced at first has been confirmed since I 

 have been able to procure larger quantities of aluminum. The medals 

 which I have had struck, and the plates which I now present to the Acad- 

 emy, have suffered no alteration from the air ; some small ingots have been 

 constantly handled for months without losing their brilliancy. In fact, 

 this substance is so completely inoxidizable that it resists the action of the 

 air in a muffle heated to the temperature at which gold is assayed ; lead 

 burns and litharge melts at a heat which takes no effect upon aluminum. 

 If this metal were alloyed by lead, it evidently might be cupelled. 



Aluminum conducts electricity eight times better than iron ; conse- 

 quently as well as, if not better than, silver. The place which should 

 be given to aluminum among metals, according to the principle of M. 

 Thenard's classification, should remove it from magnesium, zinc and man- 

 ganese, where it now is.* It must form the type of a very natural group, 

 composed besides itself of chromium, iron, nickel and cobalt. They have 

 one character in common, to which I attach the greatest importance in a 

 theoretical point of view they are unattackable by weak or concentrated 

 nitric acid, in the presence of which they become passive. This passivv- 

 ness, very powerful in aluminum and chromium, whose protoxides (if 

 aluminum possesses any) have an ephemeral existence, is only mani- 

 fested by iron when in concentrated nitric acid, in which the production 

 of protoxide is impossible. It is only seen very weakly in nickel and 

 cobalt, whose sesquioxides are unstable and difficult of combination. The 

 two metals lead to manganese. 



Aluminum, like iron, cannot be alloyed with mercury, and scarcely 

 takes the least trace of lead. It gives, with copper light, very hard and very 

 white alloys, even where .there is 25 per cent, of copper in the mixture. 

 It is characterized by forming with charcoal, and especially with silicium, 

 a gray, granular and brittle casting, crystallizable with the greatest facility. 

 "When broken it forms angles, which appear to be right angles. When 

 this mixture is attacked by hydrochloric acid, the odor of the hydrogen 

 indicates the presence of charcoal. But what it especially contains is si- 

 licium, which separates from it in a pure state when we prolong the action 



*Zinc should be placed with magnesium. In the first place, zinc decomposes wnter at 

 212 deg. F. ; then, contrary to the general opinion, pure oxide of zinc is irreducible by 

 hydrogen, in the midst of which it volatilizes, forming artificial cadmia, an assemblage 

 of crystals in which may be perceived the rhombohedral form of oxide of zinc. 



