Dynamical Theory of Heat and Light. 



17 



gas, are shown in the following table, and compared with the 

 results of observation for several such gases: 



Gas. 



Values of k — 1. 









According to the 



By 





B.-M. doctrine. 



Observation. 



Air 



f = -2857 



•406 



H, 



5> )> 



•40 



0, 





■41 



cf. 



,, n 



•32 



CO 



'» >» 



•39 



NO 





•39 



CO., 



} = -1607 



•30 



N 9 d 



•i •> 



•331 



NH 3 



I = -1111 



•311 



It is interesting to see how the dynamics of Clausius' 

 theorem is verified by the results of observation shown in the 

 table. The values of & — 1 for all the gases are less than jj, 

 as they must be when there is any appreciable energy of 

 rotation or vibration in the molecule. They are different for 

 different diatomic gases; ranging from *41 for oxygen to 32 

 for chlorine, which is quite as might be expected, when we 

 consider that the laws of force between the two atoms may 

 differ largely for the different kinds of atoms. The values of 

 &— 1 are, on the whole, smaller for the tetratomic and triato- 

 mic than for the diatomic gases, as might be expected from 

 consideration of Clausius' principle. It is probable that the 

 differences of k — 1 for the different diatomic gases are real, 

 although there is considerable uncertainty with regard to the 

 observational results for all or some of the gases other than 

 air. It is certain that the discrepancies from the values, 

 calculated according to the Boltzmann- Maxwell doctrine, are 

 real and great ; and that in each case, diatomic, triatomic, 

 and tetratomic, the doctrine gives a value for £ — 1 much 

 smaller than the truth. 



§ 26. But, in reality, the Boltzmann-Maxwell doctrine errs 

 enormously more than is shown in the preceding table. 

 Spectrum analysis showing vast numbers of lines for each 

 gas makes it certain that the numbers of freedoms of the 

 constituents of each molecule is enormously greater than 

 those which we have been counting, and therefore that unless 

 we attribute vibratile quality to each individual atom, the 

 Phil. Mag. S. 6. Vol. 2. No. 7. July 1901. C 



