STUDY OF ORES AND METALS. 



417 



This IS a complex quantity and indicates that a phase difference 

 exists between the two components (parallel and normal to plane of 

 mcidence) of the reflected light; the reflected light is in general 

 elliptically polarized. In case the azimuth of the plane polarized inci- 

 dent light e coincides with either e^ or e^, the reflected light is plane- 

 polarized. The azimuths for which the reflected light is plane-polar- 

 ized occur at intervals of 90°. 



The intensity ratio of the components of the reflected light is 

 found by division of (21) by (25) 



Irs 



Irp 



[(ni - 1)2 -t- nr'Ki^][(n2 -f i)^ -f Ui'Ki'] Is 



[(ni + 1)2 + Wi2ki2][(W2 - l)2 + n.^Ki"] Ip' 



The phase difference for Ep = Es or tan €=i is A^ — A^ or 



2W2K2(«l^— I+Wi^/Ci^) — 2niKi(n2^ — I + ^2^2^) 



71- (28) 



tan (Ai — A2) 



(W]2— I + n-^K^){n2^ — 1 + n^yK'f) -f ^niKxriiKi 



(29) 



Transparent Media. 



In order to realize clearly the effects of absorption phenomena it 

 is essential to ascertain first the behavior of non-absorbing media, 

 then to pass to the more complex problem of absorbing bodies. 



Isotropic Substances. — For non-absorbing bodies k = o; in this 

 case equation (22) reduces to the ordinary Fresnel expression for 

 the intensity of rays reflected from an isotropic plate 



Ir 



Tr f n — i\ 



TABLE 2. 



(30) 



In this table are listed the relative intensities of light reflected at vertical 

 incidence from polished surfaces of substances of given refractive indices. 

 Thus a plate of refractive index 2.1 reflects 0.1259 of the incident light. 



PROC. AMER. PHIL. SOC, VOL. LVIII, AA, JaN. 21, 192O. 



