330 



TABLES 379, 380. 



TABLE 379. -Magneto- Optic Rotation. 

 Gases. 



See also Siertsema, Ziting. Kon. Akad. Watt., Amsterdam, 7, 1899; 8, 1900. 



Du Bois shows that in the case of substances like iron, nickel, and cobalt which have a variable 

 magnetic susceptibility the expression in Verdet's equation, which is constant for substances of con- 

 stant susceptibility, requires to be divided by the susceptibility to obtain a constant. For this 

 expression he proposes the name " Kundt's constant." These experiments of Kundt and Du 

 Bois show that it is not the difference of magnetic potential between the two ends of the medium, 

 but the product of the length of the medium and the induction per unit area, which controls the 

 amount of rotation of the beam. 



TABLE 380. Verdet's and Kundt's Constants. 



The 



following short table is cjuoted from Du Bois' paper. The quantities are stated in c. g. s. 

 measure (radians) being used in the expression of " Verdet's constant " and " Kundt's co 



measure, circular 

 Kundt's constant." 



SMITHSONIAN TABLES. 



