UPON THE 



HEAT DEVELOPED IN COMBUSTION AND IN THE 

 CONDENSATION OF VAPOURS. 



SECTION I. Description of a new Calorimeter. 



\ TTEMPTS have been long ago made to measure 

 JL~\. the heat that is developed in the combustion of 

 inflammable substances ; but the results of the experi- 

 ments have been so contradictory, and the methods 

 employed so little calculated to inspire confidence, that 

 the undertaking is justly considered as very little ad- 

 vanced. 



I had attempted it at three different times within 

 these twenty years, but without success. After havihg 

 made a great number of experiments with the most 

 scrupulous care, with apparatus on which I had long 

 reflected, and afterward caused to be executed by skilful 

 workmen, I had found nothing, however, that appeared 

 to me sufficiently decisive to deserve to be made public. 

 A large apparatus in copper more than twelve feet long, 

 which I had made at Munich fifteen years ago, and 

 another, scarcely less expensive, made at. Paris four years 

 ago, which I have still in my laboratory, attest the de- 

 sire I have long entertained of finding the means of 

 elucidating a question that has always appeared to me 

 of great importance, both with regard to the sciences 

 and to the arts. 



