338 Dr George Wilson on the Possible Derivation of 
culate on the possibility of anthracite being converted into 
transparent crystalline carbon. Anthracite itself seems al- 
ways to contain hydrogen, oxygen, and nitrogen, as well as 
sulphur and fixed inorganic matter. Some specimens of the 
mineral, indeed, do not contain more than 70 per cent. of car- 
bon, although the majority contain about 90, and some nearly 
95 per cent. of that substance. It cannot, therefore, be ranked 
along with graphite and the diamond, as a variety of pure 
carbon ; but there seem some very significant reasons for 
thinking that it may be a substance from which the diamond 
is developed. I speak on this point as a chemist, assuming 
that there are no such difficulties of a geological or minera- 
logical kind, opposed to the supposition that anthracite may 
erystallise into the diamond, as forbid the entertainment of 
such a view. So little, indeed, is known concerning the ori- 
ginal matrix, or earliest geological or mineralogical situs of 
the diamond, that we are free, within very wide limits, to 
speculate on the origin of this gem. Little, however, has 
been recently contributed to our hypotheses concerning the 
production of the diamond. Chemists have pretty generally 
abandoned the subject, for a time at least, and have been 
content to draw attention to the supposed fact, that carbon is 
neither fusible nor vaporizable,* and that it crystallises from 
* The late Mr Kenneth Kemp, whose ingenuity was inexhaustible, endea- 
voured to crystallise carbon from its vapour, by producing the voltaic are (or 
so-called electric light) between charcoal-points, within the Torricellian va- 
cuum. It may, perhaps, be questioned whether carbon was truly vaporised in 
this experiment, or only detached in the state of minute particles from the in- 
tensely heated charcoal ; at all events, it did not crystallise, but deposited itself 
as impalpable soot on the sides of the barometer tube. Professor Silliman 
senior, made similar but independent experiments many years ago, and wit- 
nessed, as he believed, the true fusion and volatilisation of carbon, but did not 
obtain it in distinct or transparent crystals. He has lately redirected atten- 
tion to these observations. (American Journal of Science and Arts, November 
1849, p. 413.) 
M. Despretz has recently exposed charcoal to the combined influence of a 
powerful voltaic current, the concentrated rays of the sun and the blow-pipe. 
Small needles of anthracite, exposed to this triple source of intense heat, seemed 
to fuse, and permitted drops to fall from them, which, when received on a pla- 
tina capsule, appeared as minute black globules. (Comptes Rendus, 18th Juin 
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