MM. Wohler and Deville on Bofon. 273 



aluminium and sodium is used, which is prepared by passing 

 chlorine over a mixture of alumina, common salt, and charcoal. 

 It is volatile and liquefiable, running like water, and becoming 

 solid when cold. The manufacture of sodium has also been 

 considerably improved. Its preparation is now as easy as that 

 of zinc, and its price ought scarcely to exceed three shillings 

 the pound. By using the mixture of carbonate of soda, chalk, 

 and charcoal, the quantity obtained is very nearly that required 

 by theory. The action of the sodium on the chloride of alumi- 

 nium is effected in a reverberatory furnace, and is so tranquil 

 that it may be carried on on a large scale, and requires only the 

 attendance of an ordinary woi'kman. At present the price of 

 aluminium, if it were not increased by accidental circumstances, 

 ought not to exceed 100 francs the kilogramme, but it will be 

 some time before it is reduced to so low a price. 



Wohler and Deville* have published the results of an investi- 

 gation on boron, in which they prove very clearly the analogy 

 that exists between this body and carbon and silicon, and they 

 show that it resembles carbon even more closely than silicon has 

 been shown to do. Like both these substances, boron exists in 

 three conditions : the amorphous, the graphitoidal, and the dia- 

 mond forms. 



Amorphous boron can be produced by the action of aluminium 

 on a large excess of boracic acid, as well as by the action of 

 sodium on boracic acid, the process of its discoverers, Gay-Lussac 

 and Thenard. 



Graphitoidal boron is best obtained by fusing fluoborate of 

 potash with aluminium, adding a mixture in equal equivalents 

 of the chlorides of potassium and sodium to serve as a flux. 

 Small masses of boruret of aluminium are obtained, which, when 

 treated with hydrochloric acid, leave boron in its second modifi- 

 cation. This presents itself in small laminse, often hexagonal, 

 of a slightly reddish colour, opake, and having the form and 

 lustre of natural graphite and graphitoidal silicon. 



The crystallized boron or diamond of boron is prepared by 

 melting together in a carbon crucible 80 grms. of aluminium 

 with 100 grms. of boracic acid. The carbon crucible is intro- 

 duced into a black-lead crucible, which is heated to the highest 

 tomjjerature of a wind-furnace in which nickel could be melted, 

 for five or six hours. The crucible is found on cooling to 

 contain two distinct layers, of which one is vitreous, consist- 

 ing of boracic acid and alumina, the other metallic, of an iron- 

 gray colour, full of blisters, and filled throughout its whole 



* Comptes Rendus, Decembers, 1856; February 16, 1857. Liebig'a 

 Annalen, January 1H57. 



Phil. Mag. S. 4. Vol. 13. No. 86. April 1857. U 



