150 



ville's process, it is rated to melt at a point a little higher than that of 

 zinc. The fact is, when strictly in a metallic state, it melts or be- 

 comes tremulous and plastic, yet not quite fluid, at a low red heat; 

 but as soon as a coating of oxide, or alumina, is formed, it resists a 

 far higher degree of heat; and the reduction of that oxide is a very 

 important part of the secret of M. Deville. 



Its ductility is a very marked and important characteristic; one of 

 our specimens being rolled down to -jq\-q inch. The rolling requires 

 some care and management, and we do not feel qualified to spe^ak 

 particularly on this point, from the small samples we have had to 

 operate upon. 



Lastly, although it is out of the line of our profession, the compa- 

 rative rigidity^ or power of resisting pressure, is so very important 

 an element, in determining the uses to which a metal may be applied, 

 that we have made a trial of this also, with a very simple, though 

 apparently accurate apparatus. Rolled strips of standard silver, iron, 

 copper, zinc, and aluminum, equal in length, breadth, and thickness 

 (by a very delicate gauge in this latter measurement), were rested 

 upon cross pieces at the ends, and a pressure of given weights applied 

 precisely at the middle of the strip, to bear down to a stopping-point, 

 making but a small deflection or curve. The weights required to 

 bring each strip down to this point, were relatively as follows : 



Standard silver (composed of nine-tenths silver, one-tenth 



copper), . . . . . .114 



Wrought iron, . . . . . .154 



Copper, . . . . . . .123 



Aluminum, ...... 123 



Zinc, ....... 28 



From the foregoing particulars, any one may imagine for himself 

 what purposes this metal may be applied to. Wherever it is desira- 

 ble to concentrate strength, with as little weight as possible, this ex- 

 traordinary material will, of course, be thought of, and tried. It has 

 already been used for the beams of fine balances, and for the works 

 of watches; and some sanguine minds, which imagine that the air 

 may yet be made a highway of travel, have considered aluminum as 

 a timely oflering, for such metallic machinery as may be indispen- 

 sable. 



Very much depends, manifestly, upon the price at which this article 

 can be furnished, when the demand will justify its manufacture upon 



