Continuity 39 



ineffective is certain, else all the energy 

 would be dissipated or transferred from 

 matter into the ether ; and the reasonable- 

 ness of their radiative inefficiency is 

 not far to seek, when we consider the 

 comparatively leisurely character of 

 molecular movements, at speeds com- 

 parable with the velocity of sound. 

 Admittedly, however, the effective 

 rigidity of molecules must be complete, 

 otherwise the sharing of energy must 

 ultimately occur. They do not seem 

 able to be set vibrating by anything less 

 than a certain minimum stimulus; and 

 that is the basis for the theory of quanta. 

 Quantitative applications of Planck's 

 theory, to elucidate the otherwise shaky 

 stability of the astronomically consti- 

 tuted atom, have been made; and the 

 agreement between results so calculated 

 and those observed, including a deter- 

 mination of series of spectrum lines, is 

 very remarkable. One of the latest con- 

 tributions to this subject is a paper by 

 Dr. Bohr in the Philosophical Maga- 

 zine for July, 1913. 



