and in the Condensation of Vapours. 403 



The following are the details and results of two ex- 

 periments made on the same day (i6th of November, 

 1811) with one of these candles. 



The capacity of the calorimeter for heat was equal to 

 that of 2371 grammes of water. 



SECTION VII. Quantity of Heat developed in the Com- 

 bustion of Charcoal. 



If we could burn under the calorimeter some pieces 

 of wood made into charcoal with the same facility that we 

 burn thin pieces of dry wood, the investigation in ques- 

 tion would not be attended with difficulty ; but the 

 charcoal cannot be burned in this manner. We can 

 light a piece of charcoal very well, and if it be very thin 

 it continues to burn until it is entirely consumed ; but 

 the combustion is so slow, and furnishes so little heat, 

 that it would require several hours to heat the calorim- 

 eter sufficiently to give an appreciable result ; and for 

 this single reason the result could not but be extremely 

 uncertain. 



I have long endeavoured, but without success, to find 



