234 On Polarization of Light by Refraction. 



But these two quantities are exactly equal, and hence we obtain 

 the important general law, that, — At the first surface of all bodies, 

 and at all angles of incidence, the quantity of light polarized by re- 

 fraction is equal to the quantity polarized by reflection. I have said 

 *of all bodies,' because the law is equally applicable to the surfaces 

 of crystallized and metallic bodies, though the action of their first 

 surface is masked or modified by other causes. 



It is obvious from the formula that there must be some angle of in- 

 cidence where R=l — R, that is, where the reflected is equal to the 

 transmitted light. When this takes place, we have sin^ cp = cos^ 9', 

 that is, 



The reflected is equal to the transmitted light, when the inclination 

 of the planes of polarization of the reflected pencil to the plane of 

 reflection, is the complement of the inclination of the planes of po- 

 larization of the refracted pencil to the same plane; — or if we refer 

 the inclination of the planes to the two rectangular planes into which 

 the planes of polarization are brought, — The reflected will be equal 

 to the transmitted light when the inclination of the planes of polari- 

 zation of the reflected pencil to the plane of reflection, is equal to 

 the inclination of the plane of polarization of the refracted pencil to 

 a plane perpendicular to the plane of reflection. 



In order to show the connection between the phaenomena of the 

 reflected and those of the transmitted light, I have given the follow- 

 ing Table, which shows the inclination of the planes of polarization 

 of the reflected and the refracted pencil, and the quantities of light 

 reflected, transmitted, and polarized, at all angles of incidence upon 

 glass, m being equal to 1.525, and the incident lights 1000. 



