ConihuJJwn of the Diamond, ioj 



II. 



Experiments on the Combujlion of the Diamond, the Formation of Steel by its Combination with 

 Iron, and the pretended TranfmiJJion of Carbon through the Veffels. By Sir George 

 Stuart Mackenzie, Bart. 



To Mr. NICHOLSON. 



SIR, 



X. HE account which I now fend you, of fome experiments with regard to the proper- 

 ties of the diamond, and the formation of fteel, was read at a meeting of the Royal Society 

 of Edinburgh, on the 3d of February laft. By giving it a place in your valuable Journal, 

 you will much oblige. 



Sir, 



Your obedient fervant, 



Edinb. \Jl. May, 1800. GEORGE S. MACKENZIE. 



The phenomena exhibited by the diamond during combuftion have been defcribed by 

 various authors *, but the temperature at which this combuftion takes place has not as yet 

 been afcertained. I have made feveral experiments on diamonds with a view both to 

 fatisfy myfelf, as to their appearance while burning, and alfo to determine at what degree 

 of Wedgwood's pyrometer they begin to be confumed. My experiments were conducted 

 in the following manner f . 



A diamond was placed on a thin flat piece of baked Cornifh clay, and introduced into a 

 muflle, previoufly heated red hot. It foon acquired the fame rednefs as the muffle, but in, 

 a few moments more, became diftlnguifhed by a bright glow %• It was then removed, and 

 on examination, its tranfparency andluftrc appeared to be afFe£ted. It had a flight milky 

 appearance §, its angles were blunted, and its bulk was alfo confiderablydiminiftied. After 

 being replaced in the muffle, it was confumed flowly, and at laft difappeared entirely. 



The French chcmifts take notice of their having obferved on diamonds after being fub» 

 jefted to a ftrong heat, black fpecks, and a blackilhnefs upon their furfaces. Mitouard 

 fays,, that in one of his experiments, a diamond had become as black as jet. In the many 



• D'Arcet, Rduelle, Cadet, Lavoifier, &c. Journal dePhyfique for 1772,-73,-89. 



•f All the diamonds ufed in thefe experiments were cut and polifhed. 



J This glow is dercribed by D'Arcet and Rouelle as being more or lefs bright, in different diamonds, 

 expofed to heat at the fame time. This difference, I fuppofe, was owing to their being nearer to, or farther 

 from the mouth of the muffle, and confequently differently expofed to the ailion of the air. 



§ " Qui eft d'une tranfparcnce un peu laiteii/i" Journ, de Ph. Vol, I. for 1771, p. 485. 



experiments 



