and in the Condensation of Vapours. 387 

 According to the calculations of M. Lavoisier, we have, 



For 0.7721 lb. of carbon . 55.881 Ibs. of water heated 180. 

 " 0.1208 lb. of hydrogen . 26.780 " " " 



Total . . . 82.661 " " " " 



According to the calculations of Dr. Crawford, it is, 



For 0.7721 lb. of carbon . 44.478 Ibs. of water heated 180. 

 " 0.1208 lb. of hydrogen . 49.528 " " " " 



Total .... 94.006 " 



According to the experiments-, i pound of purified rape 

 oil furnished heat sufficient to raise 93.073 pounds of 

 water 180; and i pound of olive oil enough to heat 

 90.439 pounds. 



From all these comparisons it follows that the estima- 

 tions of Dr. Crawford agree much better than those of 

 M. Lavoisier with the results of my experiments. 



SECTION III. Experiments made with Spirit of Wine, 

 Alcohol^ and Sulphuric Ether. 



As the component parts of these inflammable liquids 

 may be considered as well ascertained by the results of 

 the excellent investigation of M. de Saussure, I under- 

 took to examine them for the second time, in order to 

 discover what quantities of heat are developed in their 

 combustion. I had begun this undertaking five years 

 ago ; but, after having made a considerable number of 

 experiments, I desisted from it on account of the great 

 difficulties that occurred. As soon, however, as I had 

 found means of rendering my apparatus more perfect, I 

 formed the project of recommencing it. 



Before I enter into the particulars of my experiments, 

 I must say a few words respecting the difficulties that 



