and in the Condensation of Vapours. 393 



of combustible matter (carbon and hydrogen) in alcohol. 

 We will see. 



According to the analysis of M. de Saussure, i pound 

 of the alcohol of Lowitz contains 



Carbon 0.4282 Ib. 



Free hydrogen . . . . . . . 0.1018 



Water 0.4700 



Now, according to the calculations of Dr. Crawford, 

 we shall have for the measure of the heat developed in 

 the combustion of 



0.4282 Ib. of carbon . 24.667 Ibs. of water heated 180 F. 

 0.1018 Ib. of hydrogen . 41.738 " " " " 



Total .... 66.405 " " " " 



The experiments gave us . 67.317 " " " " 



It is rare in a research of such delicacy to find the re- 

 sults of experiment agree so perfectly with those of cal- 

 culation. 



SECTION IV. Heat developed in the Combustion of Sul- 

 phuric Ether. 



I have already mentioned the difficulties which I 

 overcame before being able to regulate the combus- 

 tion of this substance in such a way as to render the 

 results of my experiments regular and satisfactory ; but 

 I met with still further difficulties in the course of this 

 delicate inquiry. 



As alcohol is necessarily employed in making sulphuric 

 ether, and as these two liquids may be united in any 

 proportions, it is extremely difficult, if not impossible, 



