IS 14.] ' Memoir on New Optical Phenomena. 8S 



circumstances, in order to render the explanation more clear. The 

 action of metallic surfaces being very feeble relative to the polari- 

 zation of the direct ray, we may neglect their influence. 



This phenomenon may be ultimately reduced to this : when a 

 ray of light falls upon a glass forming with it an angle of 35° 25', 

 all the light uhich it reflects is polarized in one sense. The light 

 which passes through the glass is composed, 1. Of a quantity of 

 light polarized in the opposite sense to that which has been reflected, 

 and proportional to that quantity. 2, Of another portion not 

 modified, and which preserves the characters of direct light. These 

 polarized rays have exactly all the properties of those which have 

 been modified by doubly refracting crystals. Hence what 1 have 

 said elsewhere of the one may be applied to the other. 



The following are the general results which may l)e drawn from 

 the experiments of which I have given an account, and which 

 ought to be added to those which I have already published on this 

 subject. 



Whenever we produce, by any means whatever, a polarized ray, 

 we necessarily obtain a second ray polarized in a direction diametri- 

 cally opposite; and these rays follow different routes. Light cannot 

 receive this modification in one direction without a proportional part 

 of it receiving it in an opposite direction. 



The curious observation which M. Arrago has lately stated to the 

 Class would seem alone, at first view, to constitute an exception to 

 this general rule. He has remarked, that the coloured rings, l)y 

 transmission, presented the phenomena of polarization ; and in this 

 case the most distinct zones apj^ear polarized in the same direction 

 as the reflected light : but if we reflect upn the cause of this 

 phenomenon, we shall perceive that it is not an exception to the 

 general rule. 



All bodies, both opaque and diaphanous, polarize light under all 

 angles, tliough for each of them this phenomenon is at a maximum 

 at a particular angle. VVc may therefore say, in gener.'d, tliat all 

 light, which has experienced the action of a body by reflection or 

 refraction, contains polarized rays, whose poles arc determinate 

 relative to the plane of reflection or refraction. This light has 

 properties and characters which the light has not that comes to us 

 directly fioin luminous bodies. 



I subjected to the same trials the coloured zones formed by the 

 dispersion of light when it passes very near opnijue bodies : but I 

 have not hiiheito made a single remark worth reporting to the 

 Class. 



1 sliaU add to these observations the result of some researches 

 which i formerly aruioiuKcd on the s;ime subject. 1 hnve deter- 

 nnricd witii res[)cct to many sul)stances the angle of reflection at 

 which the incident light is most comidetely polarized; and 1 have 

 ascertained iliat this angle neither follows the order of the refractive 

 powers, nor that of the dispersive forces. It is a property of bodies, 



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