sin (R 5 P) . Jif^L^. - G2/C1 sino^ 

 C1/G2 X PR .. 



but ^il^\ ^^"^ °h ° ^"^^ ^2"^ 



by Snell's law: fR S P) = a^ 



(E-6) 



(E-7) 



Contou 



■^2 







^ 



..^ 







^^__ 



S 





Contour 1 



NJ^wz""' 



="*». 



^ 



2 





\ 





tangent to 

 ^ id -contour 



mid - contour 

 [sino^) X PR 

















\ 



R 





FIGURE E-l 



Application 



of 



Snell's 



Low 



to 



template 



construction 



The template constructed on these prir.ciples is illustrated in 

 Figure 12 of the text. The point labelled "turning point'' corresponds 

 to R, and the line labelled "orthogonal" corresponds to the incoming 

 orthogonal, 



II. Diffraction 



A. Vfaves pas si ng a sini?:le breal'cwater . - The general ecuation for pro- 

 gressive irrotational wavesof small amplitude may be written: 



AikG 

 g 



cosh (kd) . pikCt . F(x,y) 



(E-8) 



where L = the wave length 

 ^ L 



E-2 



