STUDY OF ORES AND METALS. 



The ratio of the ampHtudes (equation 27) becomes 



Rs (ni — i)(w2 + i) Es 



Rp («i + i)(w2 — i) Ep' 



419 



(32) 



Fig. 2. The curves in this figure indicate the change in the percentage 

 intensity ratio (ordinates) of the two components of normally reflected light 

 with change in the least refractive index »i (abscissae) and in the birefrin- 

 gence (Ho — "1) (curves) of a crystal plate. 



The fact that this is a real quantity proves that there is no phase 

 difference between the two components ; the phenomena observed on 

 such plates are due therefore entirely to a difference in the ampli- 

 tudes of the reflected wave components. The reflected light is plane- 



