418* POPULAR SCIENCE MONTHLY. 



laboratory curiosities, because of the want of adequate means of 

 obtaining them. 



It is easy, with the aid of the electric furnace, to produce abun- 

 dant meltings of chromium by reducing the sesquioxide. This 

 melting, refined, yields chromium, an unoxidizable metal very 

 different from the specimens which have been hitherto obtained. 

 It can be filed like iron, and takes a fine polish. Chromium, 

 then, more infusible than carbon, can now be used in preparing 

 alloys without the need of the intervention of f err o- chromium, 

 which has the disadvantage of containing up to ten per cent of 

 carbon. 



This preparation opens the way for the effective study of the 

 alloys of chromium. In combination with aluminum or copper, 

 it gives interesting results. Pure copper, alloyed with 0'5 per 

 cent of chromium, assumes a double resistance and suffers less 

 change than copper in contact with moist air. 



Molybdenum, previously unfused, can also be obtained in 

 notable quantities. By heating, in a continuous electric furnace, 

 a mixture of oxide of molybdenum and charcoal, a melting of the 

 metal is obtained which flows readily and can be easily molded. 

 It furnishes a definite carburet, very well crystallized. It is re- 

 fined by a new heating in the electric furnace, with an excess of 

 oxide of molybdenum. The melted metal thus obtained has a 

 fine grain and a brilliant surface. It can be filed, and forged, at 

 a red heat, upon the anvil ; and with iron it furnishes a steel that 

 can be tempered. These are all new properties. 



Tungsten has been heretofore known to chemists only as a 

 powder. Under the action of the electric arc, the oxide of tung- 

 sten is reduced by means of carbon, and gives in a few minutes a 

 well-melted bottom, covered with a fine layer of the blue oxide of 

 tungsten. This metal, which is still more infusible than chro- 

 mium and molybdenum, can be liquefied with great facility. It 

 does not seem to have a strong affinity for carbon, and is obtained 

 without special precautions as one of the purest metals we have 

 prepared. 



The different oxides of uranium can not be reduced by carbon 

 at the ordinary temperatures of our furnaces ; but when a mix- 

 ture of the sesquioxide of uranium and carbon is subjected to the 

 high temperature of the electric furnace, the reduction takes place 

 in a few instants. After cooling, an ingot may be drawn from the 

 crucible possessing a brilliant fracture and great hardness. When 

 this uranium is slightly carbureted, it presents the property of 

 striking fire in contact with flint. The particles thrown off burn 

 with an intensity and an energy far superior to those exhibited 

 by a piece of iron. 



All these simple bodies melt at more or less high temperatures. 



