Dr Petzholdt on the Formation of the Diamond. 323 



organic bodies, makes the following remai'ks :* — " If we sup- 

 pose decay to proceed in a liquid, which contains both carbon 

 and hydrogen, then a compound containing still more carbon 

 must be formed, in a manner similar to the production of the 

 crystalline colourless naphthalin, from a gaseous compound of 

 carbon and hydrogen. And if the compound thus formed were 

 itself to undergo further decay, the final result must be the 

 separation of carbon in a crystalline form. Science can point 

 to no process capable of accounting for the origin and forma- 

 tion of diamonds, except the process of decay. Diamonds 

 cannot be produced by the action of fire, for a high tempera- 

 ture, and the presence of oxygen gas, would call into play 

 their combustibility. But there is the greatest reason to be- 

 lieve that they are formed in the humid way, that is, in a 

 liquid ; and the process of decay is the only cause to which 

 their formation can with probability be ascribed." 



As yet we are ignorant of the nature of the vegetable sub- 

 stance, rich in carburetted hydrogen, by whose decomposition 

 the diamond was formed, and as to what were the particular 

 conditions necessary for the appearance of crystalline carbon. 

 This only we know, however, that the whole process was an 

 extremely slow one, and that it could not in any way be has- 

 tened by an increased temperature, for in that case the carbon 

 could not have crystallized, but must, on the contrary, have 

 been separated in the form of a black powder. 



The conclusion deduced by Newton from certain optical 

 properties of the diamond, viz., that it has been produced 

 from an oily body, is very beautifully confirmed by the newest 

 and most accurate investigations of chemistry, for, according 

 to them, the so-termed oily bodies are proved to be the richest 

 in carburetted hydrogen ; and chemistry, which can alone 

 explain the decompositions of bodies, and their formation from 

 their elements, just requires for the formation of the diamond 

 the decomposition of a substance rich in carburetted hydrogen. 

 There are two different phenomena connected with the above 



* Liehig's Orgaiiische C'hemie in Hirer Anwendung ai'f Agricidtur und Phy- 

 ■)logie, Braunschiveig, 1840, p. 285 ; and Playfair's Translation, p. 143. 



siologie, 



