164 



hv 



3c'L - 

 Time between two successive emissions =J e 



Stt'-v- 



Larmor'" in an expansion and generalization of ideas implied in Planck's 

 theory divides a system which is a seat of energy into clementarj' receptacles 

 of energy called "cells." The "element of disturbance" possessing the ele- 

 ment of energy under consideration is as likely in its travels to occupy any 

 one of these cells as any other. Instead of the relation f = hv,,, which Planck 

 obtains, Larmor finds that the ratio of the energy-element to the extent of 

 hi.s standard cell is an absolute physical cjuantity. Larmor claims that his 

 theory evades an atomic constitution of energy although this seems to be 

 open to argument. Planck believes that his constant h provides for Larmor's 

 "elements of disturbance." Larmor's radiation formula reduces to that of 

 Planck. 



Jeans" has worked out a rather complete and satisfactorj^ electron theory 

 of metals, but wIkmi api)lied to radiation his results, exjjressed in terms of a 

 single universal constant, are in condict with expcM'iment. Planck considers 

 that Jeans' formula recjuires a second universal constant which he identifies 

 with /(, the "wirkungs-ciuantum," Jeans' formula being a special case where 

 h = 0. 



Lot us now turn to some of the experimental facts which can be accounted 

 for on the basis of the Cjuantum hypothesis. The agreement with the experi- 

 mental facts of radiation has already been mentioned. 



The ex})erimentaliy determined specific heats of crystalline substances, 

 especially at low temperatures, do not agree with the older theories, but 

 Einstein'-' by ajjplying t lie ciuantum hypothesis to this case has dcfhiccd 1 lie 



^ \—\ 



eT [tJ 



formulae = 3R ^ , where R is the gas const.ant, [i- a positive con- 



.e-r J 



stant, and v and T as before, are the vibration frcfiuency and the absolute 

 temperature. Nernst and Magnus have found that this formuiais only ap- 

 pro.ximate and have added a term bT'. «'\ This formula agrees wit h the results 



'»Roy. Soc. Proc, Ser. A, 83, pp. 82-9.5, 1000. 

 "Phil. Mag., 17, pp. 77.3-794, 1909; ibid 18, pp. 209-226, 100). 

 >'.\n.n. (lor Physik, 22, 1, pp. 180-190, 1906. 



"Journ. de Phys., 9, pp. 721-749, 1010, Zeits-lir. Klo •trocliom., 17, pp. 20.5-275, 1911: .\nn. der 

 Physik, 30, 2, pp. .39.5-439, 1911. 



