64 THE ROYAL SOCIETY OF CANADA 



systems (matter in the solid or liquid state such as dust-particles, 

 water droplets, etc.) 



Further, the experimental verification of Rayleigh's Law to a 

 high degree of accuracy is interesting in that its final expression is a 

 result of classical dynamics and continuous absorption and re-emission 

 of energy; from this point. of view it seems to the writer that the hypo- 

 thesis of emission by "quanta" cannot be universally applied to radia- 

 ting molecular systems. 



In this connection it is interesting to notice that in the recent 

 theory of specific heats as proposed by Debye, Born 1 and Kàrmàn, 2 

 and now generally recognized as an adequate interpretation of ex- 

 perimental results, the interpretation of Planck's constant h has been 

 transferred from association with the individual atom to the process 

 whereby energy is interchanged between molecular systems vibrating 

 under those intramolecular forces and constraints which in their 

 integrated form determine the elastic properties of the solid state. 

 Similarly in view of the above-mentioned verification of Rayleigh's 

 Law it is difficult to see how Planck's "quantum" can be associated 

 with the individual molecule, at any rate for that system of vibrations 

 which enter into the forced oscillations with consequent re-emission 

 of radiant energy thus constituting the phenomenon of molecular 

 scattering. In the opinion of the writer one might with advantage 

 seek for the interpretation of Planck's h in the problem of "black- 

 body" radiation in the fact that the radiating units probably perform 

 vibrations under the intramolecular forces and constraints which de- 

 termine the solid state, while at the same time the reaction of the total 

 aggregate of radiating systems must profoundly modify the character 

 of the radiation from the original sources before it emerges from the 

 interior of the solid into free space for experimental examination. 



Louis V. King. 

 McGill University, June 6, 1914. 



1 Debye, Ann. der Phys. (4), 39, p. 789 (1912). 



2 Born and Kàrmàn, Phys. Zeitschr. 14, p. 15; also, p. 65 (1913). 



