4 1 8 On the Heat developed in Combustion 



ter; and in order to stop all direct communication of 

 heat between the stove and the calorimeter, the former 

 was masked by plates, and the tube which conducted 

 the vapour to the calorimeter was well covered with 

 flannel. 



The cold water which filled the calorimeter was of a 

 lower temperature than that of the chamber by 6 F., 

 and when the thermometer of the calorimeter announced 

 an augmentation of temperature by 12 F M an end was 

 put to the experiment. 



The water produced by the condensation of the va- 

 pour in the worm was carefully weighed ; and from its 

 quantity, as well as from the heat communicated to the 

 calorimeter, the heat developed by the vapour in its con- 

 densation was determined. 



As a small part of the heat communicated to the 

 calorimeter proceeded from the cooling of the water 

 condensed in the worm, after the vapour had been 

 changed into water, an account was kept of this heat. 

 It was supposed that the water at the moment of con- 

 densation was at the temperature of 212 F., being that 

 of boiling water ; and it was determined, by calculation, 

 what part of the heat communicated to the calorimeter 

 must have been owing to this boiling water. 



In making this calculation, no account was taken of 

 the difference in the capacity of water for heat which 

 depends on its temperature ; this is but imperfectly 

 known, and besides, the correction which would have 

 been the result could not but have been very small. 



The following are the details and results of two ex- 

 periments made on the 2ist of January, 1812. 



