6 JDr, Colquhoun on a new Form of Carbon. [July, 



left nothiug but a saline residue of a pure white colour, which 

 dissolved in water without leaving any remainder whatever. 

 This solution, after being mixed with an excess of muriatic acid, 

 was heated moderately for some time in a sand-bath : it was 

 then supersaturated with caustic ammonia, and again digested. 

 But no precipitation whatever resulted fiom the addition of the 

 alkali ; and it followed, therefore, that the solution contained 

 neither oxide of iron nor alumina. The clear liquid was now 

 evaporated to dryness, and the dry residue digested in water. 

 The whole dissolved, except an inconsiderable residue of a 

 whitish-coloured matter, which, after careful washing and desic- 

 cation, amounted to 0*02 gr. This did not seem of consequence 

 enough to merit a particular investigation of its nature, especially 

 as, from the circumstances under which it was obtained, there 

 can be little doubt of its having been silica. Indeed the quan- 

 tity was so very minute, that it would perhaps be hazardous to 

 say that some portion of it at least was not derived from part of 

 the apparatus, or of the reagents employed in the course of the 

 experiment. 



The result of all these experiments seems therefore to be the 

 very important one, that the substance formed outof carburetted 

 hydrogen gas as previously described, in the moment of extrica- 

 tion from an aeriform state, is the genuine basis of the gas, or, in 

 other words, pure, solid, and to all appearance true metallic 

 carbon. And this filamentous conformation will only add one 

 striking variety more to the list, already long, of singularly 

 diversified appearances which that body has already been found 

 to assume in one or other of the kingdoms of nature, in all of 

 which it acts so prominent a part. 



It is not without regret that I find myself quite unable to 

 offer any satisfactory explanation, or even probable conjecture, 

 respecting the peculiar cause which produced this very uncom- 

 mon aggregation of carbon. Its occurrence in the steehfying 

 process was, generally speaking, a rare event, and, in so far as 

 I could judge, irregular and capricious. I remarked, however, 

 that in all the cases in which it was found, it was either half 

 imbedded among a mass of carbonaceous matter, or deposited 

 on the surface of such a mass, which had accumulated above 

 the metal undergoing steelification. It seems, therefore, not 

 improbable, that in all these cases, the apparatus had been 

 traversed by a much larger quantity of carburetted hydrogen gas 

 than was strictly necessary to carry forward the conversion of 

 the iron exposed to it into steel ; and the excess of carbon, in 

 proportion as it was disengaged from its aeriform state from the 

 expansion of the gas by heat, or from whatever other cause, 

 seems to have formed itself, in the act of deposition, into the 

 pure filamentous shape. 



Besides this singularly beautiful carbon formation, which 



