G10 Prof. 0. W. Richardson on Distribution of the 



balances the force due to the gradient of the pressure. This 

 establishes electrical equilibrium without establishing thermal 

 equilibrium, which is what is required. Under this suppo- 

 sition the condition for equilibrium is 



1 5T ~ ST' 

 and one obtains for the specific heat of electricity, 



a _ i fcKU+pV) Y fr I 



a ~ ml " 3T V ST J 



~~ Ne I 3 3T V ST J l ; 



When x is small this reduces to 



3 R 

 a = 2~e ; 



and when w is large, corresponding to very low temperatures, 



JNe 



(23) 



Formula (23) has also been obtained, in a rather different 

 way, by Keesom *. 



3. Tliermoelectromotive Force. 

 By the principle of the conservation of energy, the thermo- 

 electromotive force F of a circuit of two metals denoted by 

 the suffixes 1 and 2, with junctions at the temperatures 1\ 

 and T , must satisfy the equation 



F = 



+ (^2- 



o-JdT. 



Substituting the values of P and cr already found, this 

 becomes 



F 



1 f Tl 



y ~dp 

 BT 



dT- 



£ 



Vdp 



Wnen x is small this reduces to 



F = ?(T 1 -T )lo g (g) i =f(T 1 -T )lo g g) ; 

 and when x is large 



* Loc. cit. p. 26. 



(24) 



• (25) 



• (26) 



