ANNALS 



OP 



PHILOSOPHY. 



JULY, 1826. 



Article I. 



Notice of a neiv Form of Carboti supposed to he the pure Metallic 

 Basis of the Substance ; and also of several other interesting 

 A^regations of Carbon^ especially in so far as they elucidate 

 the History of certain Carbonaceous Products found in Coal 

 Gas Manufactories, By Hugh Colquhoun, MD. 



(To the Editors of the Annals of Philosophy.) 

 GENTLEMEN, i»/fl3/ 20, 1 826. 



There is scarcely any substance which acts a more conspi- 

 cuous part in the economy of nature than carbon. In the 

 animal, the vegetable, and the mineral kingdoms, it is equally 

 abundant and useful, nor can any thing be more instructive than 

 to study the infinite variety of purposes which it serves, or more 

 interesting than to observe the wonderful diversity of forms 

 which it puts on. What appearances can be in more perfect 

 contrast to each other than those of soot on the one hand, and 

 of the, diamond on the other? Yet carbon embraces both 

 eisftremes; and by a chain of not very imperfect gradation, it may 

 even be traced in different shapes through intermediate degrees, 

 from the dull, black aspect, and soft texture of soot, up through 

 states of brighter and brighter metallic lustre, and increased 

 compactness, until at last it attains the hardness, and the sparkle, 

 and the crystal of the diamond. It was a discovery which 

 excited great attention at the time when Lavoisier, and after 

 him Mr. S. Tennant, unveiled carbon from beneath this last 

 disguise ; if, indeed, this expression be philosophically admissi- 

 ble, and if it be not impossible to say that any one state of 

 existence is more natural or more proper to the substance than 

 another. For although a form very different from that under 

 which a substance has been commonly known may be popularly 

 termed a disguise, under which it has concealed itself, yet it is 

 not more truly sq than any other of its shapes ; and it is always 

 a decided step in the progress of science, when an entirely new 



New Series, vol. xii, b 



