FOREIGN CORRESPONDENCE. 



163 



Von Humboldt, " I would ask why the elementary substances that 

 compose one group of cosmical bodies, or one planetary system, may 

 not in a great measure be identical ? Why should we not adopt this 

 view, since we may conjecture that these planetary bodies, like all the 

 larger or smaller agglomerated masses revolving round the sun, have 

 been thrown off from the once far more expanded solar atmosphere, 

 and been formed from vaporous rings describing their orbits round the 

 central body ? " {Cosmos, vol. i.) 



At one of the recent meetings of the Academy of Sciences at Paris, 

 our ever-active friend M. Jobard, of Brussels, director of the Belgian 

 Mus6e d'Industrie, presented to the members a piece of anthracite 

 found in a blast-furnace, and which possessed the following properties. 

 In his amusing and instructive work of last year, entitled " Les 

 Nouvelles Inventions,'' M. Jobard speaks of a species of coal, found in 

 Belgium, that cuts glass as easily as does the diamond of a glazier. 

 But it is only alluded to once in the whole four volumes, and his 

 account of it is so short that we did not quite understand his 

 meaning. Now it is evident enough : " I have the honour," says 

 M. Jobard, " of presenting to the Academy a piece of coal which has 

 become incombustible from having passed through a blast-furnace at 

 Creuzot, in France. This coal, which was given to me by M. Mene, 

 the chemist of the establishment, was originally of a poor quality, and 

 appears to have taken some carbon from the rich coal with which it 

 was m-ixed in the furnace together with coke, and it has undergone 

 this transformation without any change in its form." 



It may be well to remark here that, when M. Jobard begins to 

 theorize on chemical subjects, he appears to be one of those who 

 belong to a region which the Germans are fond of calling "cloud- 

 land." But our friend is a good observer of facts. " This product," 

 he continues, "■ cuts glass with the noise of a glazier's diamond, which 

 proves that it is as hard as the latter (!).t and that, after being reduced 

 to powder, it may possibly serve to replace diamond-powder in the 

 workshops of lapidaries, or certain other polishing pow^ders. . . . This 

 transformed coal is not, however, isomorphous with the black dia- 

 mond j it is lighter and more friable." % 



M. Elie de Beaumont remarks that M. Jobard's coal has the form, 

 colour, aspect, and density of anthracite. 



* The absorption of carbon by, or the crystallization of the volatilized carbon 

 upon, other substances is prettily displayed in the case of straw, matting, or other 

 foreign substances lying on the surface of the materials in the coke- and cinder- 

 ovens. These become impregnated and coated with metallic-like films and masses of 

 crystals ; which action of deposit appears to take place after the doors of the 

 furnace are closed, Avhen there is no escape for the carbon volatilized by the heated 

 mass beneath. — En. Geol. 



+ At this rate quartz, flint, ruby, &c. should possess the hardness of the 

 diamond.— T. L. P. 



t I have been told by the men employed in the South Eastern Railway Com- 

 pany's coke-ovens at Folkestone that the extreme points of the coke-lumps, which 

 are there made for the locomotives on that line, will cut glass like the diam.ond. 

 I have not, however, verified the statement by actual experiment. — En. Geol. 



