Some Experiments on the Comhtistmi of the Diamond. 435 



ing two grains, was exposed in the focus in the same manner 

 as the diamond in the first and second experiments, having 

 been previously heated red ; the quantity of oxygen gas employed 

 was 8"5 cubical inches: more than half the plumbago remained 

 unconsumed, and during the combustion some brown ashes were 

 produced. The phaauomena in this experiment were very dif- 

 ferent from those observed In tlie experiuients on the diamond, 

 the gas became clouded during the process, and there was a con- 

 siderable deposition of dew on the interior of the globe. When 

 the original temperature of the globe was restored, and the 

 stop-cock opened, 96-6 grains of mercury entered, and drops 

 of moisture even were observed condensed on the sides of the 

 vessel. 



In the second series of experiments, charcoal formed by the 

 action of sulphuric acid on oil of turpentine, and some produced 

 during the formation of sulphuric ether, from which nitric acid 

 had been distilled, and which afterwards had been strongly ig- 

 nited, and charcoal of oak which had undergone the same pro- 

 cess, were used. 



Three grains of the charcoal from turpentine were employed, 

 2-5 of that from alcohol, and five grains of the charcoal of the 

 oak : in all these instances of combustion the gas became clouded 

 during the combustion, and when the original temperature of 

 the globe was restored, moisture was found condensed in the 

 interior ; much the largest quantity in the experiment on the 

 charcoal of oak, and the least in that on the charcoal procured 

 from oil of turpentine. The charcoal from oak left a residuum 

 of white ashes, which was principally carbonate of lime ; that 

 from oil of turpentine produced no residuum ; that from alcohol, 

 which was formed in a common process of the manufacture of 

 ether, left a minute quantity of ashes, probably owing to the 

 impurity of the sulphuric acid employed. 



The quantity of mercury which entered the apparatus indi- 

 cating the change of vt)lume of the gas, was ir. the experiment 



on the charcoal of oil of turpentine 107"5 grains 



In that on the charcoal of alcohol . 194'5 



In that on the charcoal of oak 5 13-3 



From the results of these different experiments, it appears 

 evident, that the diamond affords no other substance by its com- 

 bustion than pure carbonic acid gas ; and that the process is 

 merely a solution of diamond in oxygen, without any change in 

 the volume of the gas^ for the slight alxsorption in the second 

 experiment is scarcely more than a compensation for the volume 

 occupied by the diamonds consumed. 



It is likewise evident that in the combustion of the different 



kind* of charcoal, water is produced; aaid from the diminution 



E e 2 of 



