THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



I. Liglit Absorption and Fluorescence- — VI. Atomic and 

 Molecular Energy Quanta. By E. C. C. Baly, Grant 

 Professor of Inorganic Chemistry in the University of 

 Liverpool *. 



IN the present paper it is proposed to consider the quan- 

 titative relationships between the various frequencies 

 exhibited by a substance in the light o£ the energy quantum 

 iheory. These relationships have been detailed in various 

 papers "\, and they would seem to offer a very definite oppor- 

 tunity for the application of this theory. Many attempts 

 have been made to apply the quantum theory, but it must be 

 confessed that the results have not always proved to be very 

 convincing. There is no doubt that any attempts to make use 

 of this theory can only be justified if the results obtained are 

 exact. Confidence in the theory cannot be fostered if the 

 arguments lead to exact deductions from which the obser- 

 vations differ in a marked degree. For example, the Bjerrum 

 theory of molecular rotational frequencies J is a casein point, 

 since this leads to the conclusion that a given substance will 

 exhibit a series of frequencies in the infra-red, the series 



* Communicated by the Author. 



t Phil. Map-, xxvii. p. 632 (1914), xxix. p. 223, xxx. p. 510 (1915) ; 

 Paly and Tryhorn, Phil. Mag-, xxxi. p. 417 (1910); Baly and Garrett, 

 Phil. Mag. xxxi. p. 512 (1916) ; Garrett, Phil. Mag. xxxi. p. 505 

 (1916). 



% Nernst, Festschrift, p. 90 (1912). 



Phil. Mag. Ser. 6. Yol. 40. No. 235. July 1920. B 



