12 



L. B. Tuckerman 



After passing through three plates : 

 First Form 



Qi=+-Q„ + COS 2 (O, I ) COS2(l,2) .... COS2(2,3) 



— COS2(0, i) sill 2 ( I, 2) COS2 7r7V 2 sin2(2,3) 



— sin 2 (0,1 ) cos2 7TiV, sin2(i,2) cos2(2,3) 



— Sin2(0,l) COS2ttA / ' ] C0S2( 1,2 ) COS 27rA r , sill2 (2,3) 



-f-sin2(o,i) sui27rA^ sin 2 ^A^ sin 2 (2, 3) 



K„ +sin 2(0,1) cos 2 (1,2) cos 2(2,3) 



— sin 2(0, 1) sin2( 1, 2 ) cos27rA 2 sin2(2,3) ( 



-|- COS 2(0, I) COS27rA ;r 1 sin2(l,2) COS2(2,3) 



-f-cos 2(0,1) cos 2 tv A\ cos 2 ( 1,2) cos 2 7r N 2 sin 2 (2,3) 

 — cos2(o, 1 ) sin2 7rA r , sin 27ryV 2 sin 2(2,3 ) 



+ sin2 7rA A j sin2( 1, 2) ...... cos 2(2, 3) 



-|- sin27rA r I cos 2 ( 1,2) cos2 7rA^, sin 2 ( 2,3 ) 



-4- COS2 7TA 7 , sin 2 7rA^ sin 2 (2, 3) 



4. Interpretation of Results 



If the major and minor axes of the original ellipse are taken 

 as axes of reference, the following relations are obtained : 



Q o = I A(O\-£\)=y 2 / (i-e i )=P u 



K =0 E cos<£ =0 E cos— =0 



2 



7T 2€ 



S=0 E sin<£=7>sin— =P— p-V 

 00 000 2 °i-j-<r o 



1 ~\-^ i n 



(16) 



E 

 where e, the ellipticity of the light, is the ratio — . The values of 



P, Q, K and S referred to any axes may be obtained by giving A 7 ", 



168 



