﻿736 Photo-electric Constant and Atomic Heat. 



The physical interpretation of this relation is difficult at 

 present. It would seem, however, that 



(1) Both phenomena are due to the ci ultimate discon- 



tinuity " o£ energy as postulated in the quantum 

 theory ; 



(2) When a limited number of quanta are absorbed by a 



molecule, the various properties of: the molecule are 

 not necessarily affected to the same extent — as 

 some quanta may function in one way, some in 

 another ; 



(3) For anv particular metal, the proportion that affects 



the atomic heat is related to the proportion that 

 affects the photo-electric constant : and if the 

 nature of the metal is changed, this relation is one 

 of inverse proportion. 



The work of Xernst and Debye * shows that the atomic 

 heat at constant volume is a more reliable physical constant 

 than the atomic heat at constant pressure (the quantity 

 usuallv measured). The atomic heats at constant volume all 

 tend asvmptotically to the same limiting high-temperature 

 value, 5'95; whereas the atomic heats at constant pressure 

 approach values which are different for different elements. 

 The magnitude of the difference between the values of the two 

 atomic heats is dependent on the amount of work required 

 to compress the heated solid block to the volume it occupied 

 when unheated ; that is to lessen the amplitude of swing of 

 the minute vibrating systems. 



Consequently, the results given in this paper suggest that 

 the divergences of the values of the photo-electric constant 

 from the value of one quantum, 6'6 x 10 ~ 27 , are due to the 

 work done in changing the amplitude of swing of the newly- 

 charo-ed atoms left within the metal. 



My thanks are due to Mr. I. 0. Masson for kindly 

 correcting the proofs. 



The University, Melbourne. 



* Xernst and Lindemann, Zeitsch. f, Elektrochemie, 1911, p. 817 ; 

 Debye, Ann. der FJnjsik, 1912, p. 789. 



