FOREIGN COURESPONDENOIO. 
163 
Von Humboldt, " 1 would a.sk why the elementary substances that 
compose one group of cosmical bodies, or one planetary system, may 
not in a great measui'e be identical 1 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 
Musee 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 
Koiivelles 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 mixed 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 ol)server 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 powders. . . . This 
transformed coal is not, however, isomorphous with the black dia- 
mond ; it is lighter and more friable." X 
M. Elie de Beaumont remarks that M. Jobard's coal has the form, 
colour, aspect, and density of anthracite. 
* The absoiiition of carl)on by, or the crystallization of the volatilized carbon 
upon, other substances is prettily disiila^yecl in the case of straw, matting, or other 
foreign s\ibstances lying on the surface of tlie 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 
fimiace are closed, when there is no escape for the carlaon volatilized by the heated 
mass beneath. — Ed. Geol. 
t At this rate quartz, flint, niby, &c. should possess the hardness of the 
diamond.— T. L. P. 
X 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-lumjts, which 
are there made for the locomotives on that line, will cut glass like the diamond. 
I have not, however, verified the statement by actual expermient. — En. Geol. 
