240 Miscellaneous. 



and its islands ? It is said that nine proofs are sufficient to sub- 

 stantiate a case, and as we have fully that number, I think we may 

 safely credit the theory. The difficulty is perhaps to find the centre 

 of the disturbance. An eye-witness of the earthquake at Algiers 

 supposes the centre of that shock to be in the Atlas Eange ; but as 

 that would be too distant to affect the whole Mediterranean, I think 

 it is more likely to be between the volcanoes of Etna and Vesuvius. 



Yours, etc., 

 The Crescent, Salfoed, L. C. Casabtelli. 



AprinOth, 1867. 



nynisciEXjXjjLnisriBOTJS. 



Remarkable Hard Form of Anthracite. — M. Dumas has 

 called attention, in the Comptes Eendus, to some nodules of 

 anthracite, remarkable for their hardness, which were placed at 

 his disposal by the Count Douhet ; who found them at a dealer's, 

 and secured them for scientific investigation. These nodules have 

 apparently a concretionary structure, and are hard enough to 

 scratch glass, and even harder bodies, with ease. Leaving out 

 the ash, the composition is found to be : — carbon 97-6, hydrogen 

 0-7, oxygen 1-7, which agrees with the composition of anthracite. 

 Its density is 1-66. With the opacity, density, and composition of 

 anthracite, these nodules possess the hardness and take the polish of 

 the diamond. M. Dumas was not the first to notice this interesting 

 form of carbon. Several years ago M. Mene experimented on some 

 anthracite from Creuzot, Dept. Saone-Loire, France. When this 

 coal was raised to a high temperature in a mufile, it was converted 

 into a friable steel-grey mass, in appearance somewhat metallic. 

 When this high temperature was continued about two hours, the 

 fragments in the crucible were nearly always sufficiently hard to 

 scratch glass and steel with the peculiar sound of the diamond. The 

 composition of this substance was found to be : — volatile substances 

 1-0, carbon 96-8, ash 2-2 ; and its density 1-637. At first M. Mene 

 could not procure this hard form of carbon from the anthracites of 

 Valbonnais in . Savoy, and Abercraf in South Wales ; but by con- 

 tinuing the high temperature for four hours he obtained similar results 

 to the previous experiments. Some pieces of coke, prepared from 

 ordinary bituminous coal, mixed with anthracite, with a view to the 

 utilisation of the latter for blast furnaces, presented numerous 

 briUiant points, which scatched glass. The endeavour to apply this 

 carbon in a powdered state to the polishing of metals like steel was 

 unsuccessful, as the powder always scratched the metal. It is to be 

 hoped these important researches may be continued, the " Societe 

 d'Encouragement " having offered a prize for chemical investigations 

 on the production of carbon analogous to the black diamond. — 

 Comptes Bendiis. T. D. 



