from the Boundaries of Diffracting Apertures. 

 Table I. 



119 



0-00 

 0-20 

 0-40 

 0-60 

 0-80 

 090 

 0-92 

 0-94 

 0-96 

 0-98 

 0-99* 

 100 

 1-01 



- -162 



- -219 



- -119 

 + -255 

 4- -819 

 +1-139 

 + 1-417 

 + 1-662 

 +1-405 

 + -815 

 + -396 

 + -073 



- -524 



(X const, factor). 



262 



478 



142 



650 



6711 



12902 



20076 



27613 



19754 



6649 



1571 



53 



2746 



1-02 



1-04 

 1-06 

 108 

 1-10 

 1-20 

 1-40 

 1-60 

 1-80 

 2-00 

 2-40 

 2-60 



i/E 



-l 

 -l 

 -l 

 -i 

 -l 



+ 

 + 

 + 

 + 



527 

 701 

 549 

 269 

 047 

 359 

 058 

 254 

 358 

 101 

 054 



( X const, factor). 



7905 



23307 



28911 



23909 



16096 



10964 



1294 



34 



645 



1281 



102 



29 



the boundary itself (BB in the figure) from a large value 

 on either side of it. This feature depends on the inner 

 radius R T of the annulus being small and the outer radius R 2 

 being very large, and is entirely confirmed by observations 

 under these conditions. 



Fig. 1. 



If the radii Rx and R 2 of the annulus in the focal 

 plane do not differ much, or if they are both large, the 

 brightness falls off to zero on the boundary, but not very 

 suddenly. A large number of well-defined fringes also 

 appear on either side of the boundary in the former case 

 (see, for instance, PL III. fig. 13). This will be shown 

 from the following calculations based on the data obtained 



