432 On the Determination of the [Due. 



in these experiments our calorimeter contained 895/'5 grains of 

 distilled water. If, to this number we add 62S*56 grains, which-, 

 as we have seen above, represents the quantity of metal in the 

 calorimeter, we have 9586*06 grains of water, which we may 

 consider as containing as much heat as the calorimeter. 



1672'D grains of air, by losing 154*192° of heat, increase the 

 temperature of 9586 06 grains of water 7° : but we find by the 

 rule of proportion that 9586*06 grains, to be heated 7°» require 

 as much heat as 451*18 grains to be heated 154'192°. Hence 

 the specific heats of air and of water are to each other in the 

 ratio of 451*18 to 1672*9, or of 0*2697 to 1. 



By the first method we found the specific heat of air 0*2498, 

 by the second 02813. We see that these three determinations 

 do not differ much from each other. By taking a mean of them, 

 we get 0*2669 for the specific heat of air, that of water being 

 considered as unity. This being determined, it is easy, by 

 means of the first table, to refer the specific heats of all the 

 gases to that of water. Under a pressure of 29*922 inches of 

 mercury, these specific heats are as follows : — 



Water 1*0000 



Air 0-2669 



Hydrogen gas 3*2936 



Carbonic acid 0*2210 



Oxygen 0*2361 



Azote 0-2754 



Oxide of azote 0*2369 



Olefiant gas 0-4207 



Carbonic oxide 0*2884 



Aqueous vapour 0*8470 



Section VII. 



General Considerations. 



We shall terminate this paper by pointing out the general 

 result of the facts which it contains, and by offering some obser- 

 vations on the consequences which may be drawn from them. 



§ I. — Specific Heats of the Gases compared with each other. 



The specific heat of the gases is not the same for every one, 

 whether we attend to their volumes or their weights. The 

 differences, it is true, are not very great in the first point of 

 view. Hence, when very accurate experiments are not made, 

 it is easy to be misled (as some philosophers have been) into the 

 notion that the gases do not differ from each other in this respect. 

 We have not observed any relation between the specific gravity 

 and the specific heats of the gases. The following table is a 

 sufficient proof of this : — 



