134 



MOLECULAR MOTION AND ITS ENERGY 



58 



dependence of the specific heat C on temperature. L u s s a n a l 

 found that for a series of gases it varies also with the 

 pressure increasing, in fact, with the pressure. For these 

 gases, therefore, the specific heat c at constant volume 

 cannot be looked upon as invariable ; we shall consequent ly 

 have also to expect that the ratio of the atomic energy G" to 

 the molecular energy E depends on the temperature, and 

 perhaps also on the pressure. 



This expectation is confirmed by some of the numbers 

 given in 55. Wiillner, as was there indicated, has found 

 the following values for the ratio of the specific heats at 

 and 100 : 



For these gases, therefore, there appears a diminution of the 

 ratio as the temperature rises. On the contrary, the value 

 of the ratio of the energy of an atom e to the molecular 

 energy E, as calculated from these numbers, increases as the 

 temperature rises, thus : 



For carbon monoxide, the molecule of which contains 

 only two atoms, the variation is slight ; it is of the same 

 order of magnitude as the deviation from the laws of Boyle 

 and Gay-Lussac. But with the other gases the variation 



1 NIUWO dm. [3] 1894, xxxvi. ; [4] 1895, i. ; 1896, iii. ; 1897, vi. ; 1898, vii. 

 Atti del 1st. Veneto [7] viii. 



