iS!3.] Specific Heat of the different Gases. 435 



gives us x = — — . Substituting for a and b their values given 



us bv experiment, namely, 1 and Oyi26, we get x — S/.-J'L . 

 If we subtract from this quantity 19°, the number of degrees 

 above 3'2° tbat the experiments were made, we get 553*9° for 

 the number of degrees of heat contained in ice at the tempera- 

 ture of 32°. This result differs very materially from what we 

 obtained by comparing the specific heats of water and ice ; but 

 it (toes not differ much from G75°, which we should obtain, if, 

 with Dr. Irvine, we considered the specific heat of ice to be 

 08 : but we again repeat that we attach very little importance 

 to this kind of reasoning. 



The difficulty of this sort of experiments has prevented us 

 from determining if the change in the capacity for 1 eat by 

 pressure be the L.ime in all gases. This is exceedingly probable, 

 as the increase of density of each from pressure is the same. 

 Hence the opinion ought' to be admitted till new experiments 

 demonstrate to the contrary. We have no direct proofs of it, 

 however. The very curious experiments of M. de Saissy,* if 

 are exact, may even induce us to entertain doubts on the 

 subject. 



§ IIJ, — Specific Heat of the Gases compared with that of 

 IVaitr, and with different Solids and Liquids. 

 We cannot make experiments to determine the specific heats 

 of the gases without remarking that, when equal volumes are 

 considered, they are very small, compared to the specific heats 

 of liquid and solid bodies. The most careless experiment is 

 sufficient to prove the justice of this assertion, which a more 

 exact examination fully' confirms. Thus, if we compare the 

 specific heat of an equal volume of olefiant gas (which under the 

 same volume has the greatest specific heat) and of water, we find 



that the first is only *tf#*th P arl ot the second - 



If we take the same weight of each, the specific heat of the 

 gases approaches much mure nearly to that of the solid bodies, 

 as may be seen from the result of our experiments, which we 

 here lay before our readers : — 



Specific heat. 



Water l'OOOO 



Air U-2GG9 



Hydrogen 3-2JW6 



Carbonic a. id 0*2210 



Uxygvn 0-2'iGl 



. V. ,-, ;, philosopher of Lyon*, has made experiments, from 



a followi i that when ;■■• » l"«*uie 



toatainoxye , it light, afldTuXygeo itielrgWa out the 



■Hli 



•Z £ 2 



