118 CONTRACTION AND EXPANSION 



has not been ascertained ; but from the foregoing 

 facts, there cannot be a doubt, that it is very low, 

 compared with that of carburetted hydrogen . 



It cannot be maintained that there is less ca- 

 loric in 100 cubic inches of carburetted hydrogen, 

 or olefiant gas, than in an equal volume of hy- 

 drogen. On the contrary, it appears from the 

 results of their combustion, that they contain 

 much more. According to the experiments of 

 Dr. Dalton, caloric enough is evolved during the 

 combustion of 1 Ib. of carburetted hydrogen to 

 melt 85 Ibs. of ice ; while the same weight of 

 olefiant gas afforded heat enough to melt 88 Ibs. 

 of ice. Now, when it is remembered that the 

 volume of hydrogen is 8 times that of carburetted 

 hydrogen, and 14 times that of olefiant gas, weight 

 for weight, it becomes self-evident, that equal 

 volumes of these compound gases contain more 

 caloric than hydrogen. 



The proportions of caloric in equal volumes of 

 alcohol vapour, aethereal vapour, nitrous acid, 

 cyanogen, &c., are still greater than in carbu- 

 retted hydrogen or in olefiant gas. Why then, I 

 repeat, is their elastic force so much less at the 

 same temperature? The obvious answer to this 

 question is, that the larger compound particles of 

 such gaseous bodies exert a stronger affinity for 

 caloric, by which it is drawn into a smaller space, 

 and chemically united, producing definite con- 

 tractions of volume, and consequently an increase 

 of specific gravity. 



