in Comhistwn, and in the Condensation of Vapours, 441 



same kind of ether, the following quantities of combusti- 

 ble substances ; viz. 



Carbon 0-5015 lb. 



Free and combustible hvdrogen 1651 



We shall now see if these quantities of combustible sub- 

 stances are sufficient to account for the heat which is mani- 

 fested in our experiments. 



The 0'5013 pound of carbon ought to furnish sufficient 

 heat to raise 2889 pounds of water to 180° of Fahrenheit ; 

 and the 0*1 651 pound of hydrogen sufficient to heat 67'6-l: 

 pounds to the same decree. 



These two masses of water form together 96-53 pounds ; 

 but we shall see that the quantity of heat furnished by the 

 83 parts of ether in the expenments cannot be greater than 

 that which is necessary to heat 70' 3431 pounds of water to 

 160" Fahrenheit. 



As the experiments have been made with the greatest 

 care, and frequently repeated, and always with very uniform 

 results; and as the estimates which we have adopted, 

 with respect to the quantities of heat which are developed 

 in the combustion of hydrogen and in that of carbon, 

 have been confirmed so as to leave little doubt upon this 

 subject : upon investigating the cause of the great difference 

 between the quantity of heat actually developed in the 

 combustion of the 85 parts of sulphuric ether burnt in the 

 experiments which we have examined, and the quantity 

 given by calculation, we are compelled, in my opinion, to 

 admit that there is an error in the analysis of this liquid, 

 and that it does not contain so much free and inflammable 

 combustible matter as M. de Saussure ascribes to it. 



As it seems to me to be murh more probable that an 

 error has been committed in de<ern>ining the quantity of 

 free hydrogen in this substance than in determining the 

 quantity of cafbon, I shall suppose with M. de Saussure 

 that there is really in one pound of sulphuric ether (of the 

 specific gravity of 717) 0-59 of carbon; but instead of 

 estimating the quantity of free hydrogen in this liquid ac- 

 cording to the results of M. de Saussure, I shall adopt the 

 estimate of Mr. Cruickshanks. 



This excellent chemist concluded from his experiments, 

 that in the vapour of sulphuric ether the carbon is to the 

 hydrogen as 3 to 1. 



In the 0-85 pound of sulphuric ether (specific gravity 

 717) which were mixed with the 0*15 pound of alcohol, in 

 order to form one pound of the mixed liquid employed in 

 my experiment^, there werc0*50j5 pound of carbon; and 



dividini!: 



