THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[FIFTH SERIES.] 



APRIL 1891, 



XXXIV. On Kerr's Magneto-optic Phenomenon in the case 

 of Equatorial Magnetization of Iron. By R. Sissingh*. 



1. "IT^ERRt found in the rears 1877 and 1878 that, on 

 JQl the reflexion from magnetized iron of light 

 polarized in a plane parallel or perpendicular to the plane 

 of incidence, there arises in the reflected ray, in addition 

 to the component furnished by the metallic reflexion, another 

 component polarized in a plane at right angles to this one. 

 An exact explanation of this phenomenon requires the deter- 

 mination of the amplitude and phase of the magneto-optic 

 component and its relation to the angle of incidence. This 

 determination, in the case of iron magnetized parallel to the 

 plane of incidence and to the reflecting surface, is the object 

 of the present investigation, in which the results obtained are 

 compared with the theory of H. A. Lorentzf. This theory 

 permits of a more simple explanation of the phenomenon § . 



2. Method of Observation. — If the polarizer is perpendicular 

 or parallel to the plane of incidence, and the analyser in a 

 plane perpendicular to the polarizer, the reflected light after 



* Translated from Wied. Ann. vol. xlii. p. 115 (1891), by James L. 

 Howard. 



t J. Kerr, Phil. Mag. (o) vol. iii. p. 321, 1877 ; (5) vol. v. p. 161 

 (1878). 



X H. A. Lorentz, Verslagen en Meeded. der Acad. Amsterdam, Reeks 2, 

 Deel xix. (1883) ; Bcibldtter, viii. p. 8*39 (1881). 



§ For this explanation the reader may be referred to my original 

 paper in the Verhandelingen der Akad. von Wetemchappen (Amsterdam), 

 Deel xxviii. 



Phil. Mag. S. 5. Vol. 31. No. 191. April 1891. Y 



