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. ait 
-Ttis obvious front the formula that there must be some angle of in- 
cidence where R=1—R, that is, where the reflected is equal to the 
» transmitted light. When this takes place, we have sin? g=cos® ¢/, 
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 10 
the inclination of the plane of polarization of the refracted pencil to 
a plane perpendicular to the plane of reflection. : a 
In order to show the connection between the phenomena 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 
Teflected, transmitted, and polarized, at all angles of incidence upon 
glass, m being equal to 1.525, and the incident light=1000. 
os 
