2 L. B. Tuckerman 



I wish here to express my indebtedness to Mr. A. Q. Tool for 

 his aid in revising the manuscript and in experimentally verify- 

 ing many results. 



GEXERAL THEOREM 



i. The Inductive Theorem 



First Form. A plane wave of monochromatic, elliptically po- 

 larized light propagated away from the observer falls normally 

 upon a series of plane parallel, doubly refracting plates. In each 

 plate the planes of polarization of the ordinary and extraordinary 

 vibrations are chosen as axes of reference, and the positive di- 

 rection in each such that a positive rotation of 90 ° turns the -)- 

 ordinary direction into the -j- extraordinary direction. Each 



plate is designated by a subscript (1,2 k,k-\-i /;), 



and the constants of the light emerging from it, referred to 

 the same axes, by the same subscript. The angle between the 



Fie. 1 



ordinary axes or principal azimuths of two plates is designated 

 by the subscripts in parentheses, as the angle (k,k4-i), and is 

 assumed positive when a positive rotation through the angle 

 (k.k+i) will bring the axes of the first plate into coincidence 

 with those of the second (fig. 1). The light as it emerges from 

 the k th plate is assumed to be defined by the equations : 



158 



