and in the Condensation of Vapours. 395 



Continuing to make use of the estimates of Crawford, 

 for the quantities of heat developed in the combustion of 

 hydrogen and carbon, we shall see if these estimates are 

 sufficient to account for the heat manifested in these five 

 experiments. 



As the ether employed was a mixture of 15 parts of 

 pure alcohol of Lowitz, and 85 parts of ether of the 

 specific gravity of 717 at the temperature of 16 Reau- 

 mur, and consequently similar to the ether analyzed by 

 M. de Saussure, we shall begin by determining the quan- 

 tity of heat which ought to be developed in the combus- 

 tion of these fifteen parts of alcohol. 



As M. de Saussure has shown that in one pound of 

 Lowitz's alcohol (of the specific gravity of 792). there 

 are 0.4282 pound of carbon and 0.1068 pound of free 

 hydrogen, we ought to find in 0.15 pound of this same 

 liquid 0.06423 pound of carbon, and 0.01527 of free 

 hydrogen. 



According to the estimate of Crawford, 0.06423 pound 

 of carbon ought to furnish a sufficiency of heat in its 

 combustion to raise the temperature of 3.7002 pounds 

 of water 180 F. ; and 0.01527 pound of hydrogen 

 ought to furnish enough to raise 6.2607 pounds of 

 water the same number of degrees ; and these two quan- 

 tities of water, making together 9.9609 pounds, afford 

 a measure of the quantity of heat which must be devel- 

 oped in the combustion of the 15 parts of alcohol, 

 which are found mixed with 85 parts of ether, in order 

 to form the combustible liquid employed under the 

 name of sulphuric ether in my experiments. 



Now, as one pound of this mixed liquid has furnished 

 in its combustion enough of heat to raise 80.304 

 pounds of water 180 F., if we deduct from this mass 



