AND OF THE SECOND LAW 65 



where n= number of gram-molecules (referred to 02=32^) and 



erg 

 #=8.315 (io 7 ) T^- = absolute gas constant [1545 in F.P.S. system] 



Here the first of Eqs. (22), represents the combined laws of BOYLE, 

 GAY-LUSSAC, and AVOGADRO. We get besides from the equating 

 of (20) and (21), the additional relations, 



, . . . (23) 



CTS. 



where mechanical equivalent A =4.i9(io 5 ) ^ C.G.S. system. 

 From this follows 



c v =3.o, c p = 5, and ;r = T (24) 



C 9 3 



as is known for monatomic gases. 



Furthermore, we find for the mean kinetic energy L of a 

 molecule 



L =Jf=2 kT - 



We also have 



n w wt. of a molecule 



<D=-^= = ; = c ; r = const, for all gases. (26) 



N m molecular wt. of a molecule 



With the help of the specific heats and the characteristic equation 

 of the gas, the whole thermodynamic behavior of the gas is disclosed. 

 All this has resulted from the indentification of the mechanical and 

 thermodynamic expressions for entropy and is an indication of 

 the fruitfulness of the method pursued. PLANCK also shows that 

 this method leads to the finding of results heretofore unknown. 



