THE 

 LONDON, EDINBURGH and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[FOURTH SERIES.] 

 AUGUST 1853. 



X. On the Reflexion of Polarized Light from the surface of 

 Transparent Bodies. By the Rev. Samuel Haughton*. 



IN the year 1837, Mr. George Green of Cambridge published 

 in the Transactions of the Cambridge Philosophical Society f, 

 a paper on the u Laws of Reflexion and Refraction of Light at 

 the common surface of two Non- crystallized Media," in which 

 he obtained formulae for the intensity of reflected polarized light 

 which appeared to explain the peculiarities of polarized light 

 reflected from the surface of transparent bodies endowed with a 

 high refractive index, as observed by Brewster, Airy, and other 

 observers. 



Formulae intended to answer the same purpose were deduced 

 from theory, and published by M. Cauchy in 1839 : these for- 

 mulae are not the same as those obtained by Mr. Green. 



The principle from which Mr. Green deduced his formulae is 

 the following : — that in general there must be in an elastic 

 medium both normal and transverse vibrations; and that although 

 we are obliged to assume in physical optics that the velocity of 

 propagation of the former is infinitely greater than that of the 

 latter, yet the evanescent normal waves which are produced at 

 the bounding surface of two transparent bodies will produce an 

 effect upon the transverse waves by changing their phase. 



In order to apply this principle, and calculate the change of 

 phase, Mr. Green uses the method of the Mecanique Analytique 

 of Lagrange ; and in applying it to the problem of reflexion, adds 

 an hypothesis obtained from the analogy of gases, which hypo- 

 thesis reduces the conditions at the limits obtained by following 

 Lagrange's method to other conditions, which are identical with 

 those used by M. Cauchy, and obtained by him from what he 

 calls the ( principle of continuity of movement/ 



* Communicated by the Author. 

 t Vol. vii. part 1. 

 Phil. Mag. S. 4. Vol. 6. No. 37. Aug. 1853. G 



