STUDY OF ORES AND METALS. 



435 



The intensity contributed by the component of the wave D (azimuth 

 8) in the plane of incidence is accordingly 



The total intensity for the components of all waves D (non-polar 

 ized light) in the plane of incidence is 



Jo 



IT 12 



cos^ e-de. 



Similarly the total intensity for the components of all waves D 

 (non-polarized light) normal to the plane of incidence is 





7r/2 



E^C2^ I swU-de. 



The ratio of the two intensities is 



Ip C\ (sin i-cos i + sin r-cos rY 



Is Co 



sin^ (i + r) 



— = cos* {i — r). (46) 



The same expression can be derived more directly from equation 

 ( 16) if we consider the waves to pass through the system in reverse 

 direction which is permissible. A series of values computed by 

 means of this equation is listed in Table 8 and shown by the curve 

 of Fig. 9. 



TABLE 8. 



Let a plane-polarized light beam be incident at the angle i on a plane 

 parallel glass plate of refractive index 1.515; let the plane of polarization in- 

 clude angle of 45° with the plane of incidence. The ratios of the inten- 

 sities of the two components, parallel and normal to the plane of incidence, 

 of the beams emerging from the plate under these conditions are given in this 

 fable. 



In this figure the curve drawn by Koenigsberger and furnished with 

 his apparatus is reproduced as the dotted curve. (Refractive index 



