752 On Boltzmanrf s Equipartition Hypothesis. 



of fig. Aa. In this case work done in compressing from 

 a to b = change in internal energy + losses. The temperatures 

 at a and b were known with sufficient accuracy. The losses 



Fig. 4a. 



were taken equal to half those represented by the fall of 

 pressure ac. The specific heat could then be obtained by 

 calculation. Clerk, although he makes no mention of it. 

 does tacitly assume that the gas is in its static equilibrium 

 state throughout. 



We can see what would be the effect of a lag behind this 

 equilibrium state. Let 16'3 (fig. 46) be the compression and 







Fig. 46. 





3' n 





s* 





^8^. 771 



1 







«0 





<o 





vs. ^-O^^l^ 



N 





Vv ^^^fclr- 



A 





V»\^ • ~~ 1 



<Q 





1 



PO/. /J ME 



expansion lines of an ideal gas in which there was no lag. 

 The effect of compression is, in the first place to increase 

 the pressure, i. e. to increase the translational energy of the 

 molecules. During expansion the opposite takes place, and 

 the actual expansion line therefore falls below the ideal. 



