392 Sir David Brewster on the Compensations of Polarized Light. 



At 83°, when this takes place, the totally reflected light mn is polarized, as 

 shown at ef. Fig. 9, in a plane at right angles to that of reflexion. But as the 

 angle of incidence diminishes, the polarization diminishes, till at an angle of 

 68° it becomes common light, the polarization produced by total reflexion at the 

 second surface exactly compensating, as at cd, that produced by refraction at the 

 first. 



At angles less than 68°, the totally reflected light is partially polarized in the 

 plane of reflexion, the polarization increasing till the scattered light disappears. 



The polarization of the light that afterwards suffers total reflexion, is pro- 

 duced by its refraction at the first surface ab, Fig. 1 of the rhomb, and the phe- 

 nomena above described arise from the opposite action of the reflecting surface 

 CD ; at one angle producing an inferior degree of polarization, at another com- 

 pensating it, and at another overbalancing it. 



St. Leonard's College, St. Andrew's, 

 April 24th, 1841. 



