Fred J. Bates 



which can be true only when K^=i. Consequently (V) can only 

 be made to hold, and still maintain the condition (III), by chang- 

 ing the angles between the directions of vibration and the normal, 

 that is, O^ takes the position OH' . 



Hence (I) for light of any amplitude becomes 



(^isin [aizh:8a])'--t-(^2Ein [a2±:8a])2-j |-(^„_isin [a„_i±:Sa])- 



+ (.4„sin [a„±8a])-'= 



(^isin [a„4:8a])-*+(^2sin[a„_i+8a])2H |-(.-^„_isin [aaTSa])^ 



+ (.4«[sinai-8a])'^ (VI) 



il" 11 W 



Fig. L 



Let us now consider a specific example and solve for 8a. As the 

 source of light take the wave-lengths from 566 /a/a to 580/ift cut 

 from the solar spectrum. (ai+a„) (fig. i), which is the angle be- 



256 



