M. Peligot on a Method for obtaining pure Metallic Uranium. 133 



Peligot* describes a method for obtaining pure metallic ura- 

 nium. He prepares green protochloride of uranium by the action 

 of chlorine on a mixture of an oxide of uranium and carbon at a 

 high temperature. A quantity of sodium sufficient to decom- 

 pose the protochloride of uranium is placed in a porcelain crucible 

 and on this a layer of chloride of potassium ; and this is covered 

 with a mixture of the same salt and of protochloride of vu-anium. 

 The crucible with its cover is placed in another crucible, which 

 is filled up with charcoal powder. The addition of chloride of 

 potassium has the object of rendering the action less active and 

 less instantaneous. 



The crucible is heated until the reaction is set up, which is 

 known by a sound heard at the moment ; the crucible is then 

 removed to a wind-furnace, and heated to a white heat for 15 or 

 20 minutes. When the crucible is cold, a melted slag is found 

 which contains globules of uranium. 



The metal thus prepared has a certain malleability : it is not 

 80 hard as steel ; its colour is like that of nickel or iron. 



It assumes in the air a yellowish tint in consequence of a slight 

 superficial oxidation. Heated to redness, it exhibits a sudden 

 incandescence, and becomes covered with a voluminous black 

 oxide, in the interior of which some unoxidized metal is found 

 if the heat has not been carried too far. 



Its specific gravity is 1 8'4, and it is therefore next to gold and 

 platinum, the heaviest body. The metal may also be prepared by 

 the action of aluminium on the green chloride of uranium. This 

 action is evidently due to the greater volatility of the chloride of 

 aluminium. 



]\I. de St.-Claire Devillef gives a description of two forms of 

 apparatus which he uses for the production of very high tempera- 

 tures. His description is accompanied by drawings, without which 

 it is difficult to give an adequate idea of their construction. One 

 of them is a lamp-forge which he uses in the production of high 

 temperatures in mineral analysis ; by its means a temperature very 

 near that of an iron assay may be produced ; felspar and albite 

 melt and become liquid. The fuel used is oil of turpentine, but 

 other volatile oils may also be employed. The principle of the fur- 

 nace is to increase us much as possible the surface of the carbon, 

 and to restrain the combustion within a very small height. For 

 fuel he uses cinders freed from slag and ash, and about the size of 

 a hazel-nut, by which a higher temperature is obtained than with 

 gas-coke. 



At the elevated temperature obtained by this furnace, the best 



* Com;)^<?.? 7{en(/u5, January 21, 18.5G. 



t Annales de Ckimie et de Physique, February 1856, 



