T H K 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 





[SIXTH SERIES.] 







MA Y 1913. 



LXVII. The .Dispersion of Metals. By Lynde P. Wheeler, 

 Assist. Prof, of Physics, Sheffield Scientific School of Yale 

 University *. 



THE increase in our experimental knowledge of the dis- 

 persion of metals which has occurred in the past ten 

 years, invites a more complete discussion than it thus far 

 seems to have called forth of those relations between th« 

 optical and other physical constants of metals which theory 

 demands. The most detailed investigation of these relations 

 which has been made up to the present time appears to be 

 that of Nicholson t« In his paper he uses the equations of 

 the theory to calculate (in the manner first pointed out by 

 Schuster) the ratio of the number of free electrons to the 

 number of molecules in unit volume, and also to the calcu- 

 lation of the value of the so-called dielectric constants of the 

 metals. He discusses, however, only the classical measure^ 

 ments of Drude, and hence the consideration of dispersion 

 was practically excluded. In fact, nowhere, to the author's 

 knowledge, has there appeared an adequate discussion of the 

 more modern measurements of Minor %, Bernoulli §, Tool ||, 

 Ingersoll^f, and Tate**, in the light of the demands of the 

 ^electron theory. 



* Communicated bv the Author. 



t Nicholson, Phil. Mag. [6] xxi. p. 24-5 (1911). 



% Minor, Ann. d. Phys. x. p. 581 (1903). 



§ Bernoulli, Ann. d. Phys. xxix. p. 585 (1909). 



11 Tool, Phys. Rev. xxxi". p. 1 (1910). 



•ff Ingersoll, "Astroph. Journ. xxxii. p. 265 (191C), 



** Tate, Phys. Rev. xxxiii. p. 321 (1912). 



Phil. Mag, 8. 6. Vol. 25. No. 149. May 1913. 2 Z 



