1826.] Dr. Colquhoun on a new Form of Carbon, 3 



and of its penetrating and uniting with the metal, continues to 

 go on, until the iron is saturated, and its conversion into steel is 

 complete. 



Such is the principle of the process, the practical details of 

 which I was occupied for some time in superintending ; and in 

 the various experimental assays of different kinds of manipula- 

 tion, nothing could be more interesting than the diversity of 

 results attending the several separations of the carbon from the 

 gas. In particular, when the steel chest, or vessel containing 

 the iron, was traversed by an excess of carburetted hydrogen 

 gas ; that is, by a quantity from which the heat precipitated 

 carbon in much greater abundance than the iron was capable of 

 absorbing, the deposited particles of carbon, on their transition 

 from an aeriform state, and free as they were from external 

 communication with any foreign body, arranged themselves in 

 singular varieties of form, and texture, and colour. The greater 

 part of these I have met with in several other situations, as I 

 shall by and bye notice, but there was one, and the most 

 remarkable of all, which I have never even heard of as having 

 any where else been found. On opening one day that part 

 of the apparatus where the carbon formation, if any, was to be 

 discovered, there appeared, lying irregularly in various parts of 

 it, a quantity of long capillary threads of carbon, lustrous, and 

 slender, each portion collected into a small bunch, as it were, of 

 parallel lines, and in form extremely similar to a tress of line 

 hair. A single lock of this mineral hair seemed to contain 

 thousands of these thin filaments. There is nothing to which 

 this new form of aggregation of carbon can be better compared 

 than a bunch of fine glass spun hair, or a tuft of one of the most 

 perfect varieties of asbestus. There was nothing peculiar or 

 uncommon about the working of the apparatus, or in the state 

 of any of the materials, in so far as I could discover, to which 

 the formation of so uncommon a product could be even conjee* 

 turally ascribed ; and although in subsequently carrying forward 

 the series of experiments, the same formation occurred, I was 

 never able to trace it to any probable cause. 



In this variety of carbon formation, there obtain many shades 

 of difference, although the basis in every case, as I have esta- 

 blished by careful experiment, is neither more nor less than pure 

 carbon. Thus the hairs in point of length have a range of from 

 an inch, or even less, to eight inches. In thickness, some of 

 them may equal a hair from a horse's mane, while others are as 

 delicate as the filaments of the lightest spider-web. The colour 

 of the whole has been always black, and the lustre invariably 

 bright and metallic. When one tries to bend their two ends 

 together, they prove brittle, and snap short across ; yet when 

 the finger is pressed against the point of one of them, its resist- 

 ance is such that it almost penetrates the skin before giving 



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