263-265] 



Specific Heats 



219 



VALUES OF G p AT C. 



It will be seen that the agreement is good, except in the case of the last 

 two gases. Since, however, G v was only arrived at by using an observed 

 value of C p , the agreement means little more than that various disturbing 

 factors, such as the deviation from Boyle's Law, are of small importance. 

 These deviations are allowed for in calculating the values of C v given in the 

 former table, but are not allowed for by our simple theory. 



Values of 7. 



265. The last table suggests the possibility of calculating the ratio 7 

 (= C p fC v ) from the first and last columns. In the following table 7 is 

 calculated in this way, and is compared with various observed values of 7, 

 determined for the most part directly by methods depending on the velocity 

 of sound or adiabatic expansion, and not on the separate values of C p and G v . 

 The observed values are largely taken from Meyer's Kinetic Theory, p. 125, 

 and Travers' Study of Gases, p. 277. The values ascribed to Lummer and 

 Pringsheim are from a paper in Wied. Annalen, LXIV. p. 555. 



