C 557 3 
XXVII. Some Experiments on the Combustion of the Diamond 
and other carbonaceous Substances, By Sir Humphry Davy, 
LL. D. F. R. S, V. P. R. L 
Read June 23, 1814. 
Since it has been shewn by various accurate experiments, 
that the diamond and common carbonaceous substances con- 
sume nearly the same quantity of oxygene in combustion, and 
produce a gas having the same obvious qualities, a number 
of conjectures have been formed to explain the remarkable 
differences in the sensible qualities of these bodies, by suppos- 
ing some minute difference in their chemical composition; 
these conjectures have been often discussed, it will not be 
necessary therefore to dwell upon them : M. M. Biot and 
Arago, from the high refractive power of the diamond, have 
supposed that it may contain hydrogene ; I ventured to sug- 
gest in my third Bakerian Lecture, from the circumstance of 
its non-conducting power, and from the action of potassium 
upon it, that a minute portion of oxygene may exist in it; 
and in my Account of some new experiments on the fluoric 
Compounds,* I hazarded the idea that it might be the car- 
bonaceous principle combined with some new light and sub- 
tile element of the class of supporters of combustion. M, 
Guyton de Morveau, who conceived he had proved by ex- 
periments made fourteen years ago, that common carbona- 
ceous substances were oxides of diamonds, from his last re- 
searches, conducted in the same manner as those of Messrs, 
• Phil. Trans, for 1814. Part I, p, 72. 
MDCCCXIV. 4, C 
