( IV i. 



THE 



LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[SIXTH SERIES.] 



NOVEMBER 1918, 



XLI. The Dispersal of Light by a Dielectric Cylinder. 

 By Lord Rayleigh, O.M., F.B.S.* 



I^HE problem of the incidence of plane electric waves on 

 an insulating dielectric cylinder was treated by me as 

 long ago as 1881 1- Further investigations upon the same 

 subject have been published by Seitz f and by Ignatowski § 

 who corrects some of Seitz's results. Neither of these 

 authors appears to have been acquainted with my much 

 earlier work. The purpose of the present paper is little 

 more than numerical calculations from the expressions 

 formerly given, but in order to make them intelligible it 

 will be well to quote what was then said. The notation is 

 for the most part Maxwell's. 



" We will now return to the two-dimension problem with 

 the view of determining the disturbance resulting from the 

 impact of plane waves upon a cylindrical obstacle whose 

 axis is parallel to the plane of the waves. There are, 

 as in the problem of reflection from plane surfaces, two 

 principal cases — (1) when the electric displacements are 

 parallel to the axis of the cylinder taken as axis of z, 

 (2) w r hen the electric displacements are perpendicular to 

 this direction." 



* Communicated by the Author. 



t Phil. Mag. vol. xii. p. 81 (1881) ; Sci. Papers, vol. i. p. 533. 

 X Ann. d. Physik, xvi. p. 746 (1905) ; xix, p. 554 (1906). 

 § Ann. d. Physik, xviii. p. 495 (1905). 



Phil. Mag. S. 6. Vol. 36. No. 215. Nov. 1918. 



2 C 



