Contour \ 



20 fm — — 



Template 

 "orthogonal" line^ 



tangent to 

 nr^id - contour \ 



{%. 



; VAOT") 



^0 





60 



\^ 



incoming 

 orthogonal 



\ /Ci ^- — 



point 



13 a 



Contour 

 20fm — 



tangent to 

 mid-contour\ 



Template 

 "orthogonal"iine 



(1.107) 



KHS 



IP' 



t\.0A5l 



incoming 

 orthogonal 



Note: The template has been turned about R until the value 9r =1.045 

 intersects the tangent to the mid-contour. The template orthogonal 

 line lies in the direction of the turned orthogonal. This direction is to 

 be laid off at some point "b" on the incoming orthogonal which is equi- 

 distant from the two contours along the incoming and outgoing orthogonals. 



13b 



USE OF THE REFRACTION TEMPLATE 



FIGURE 13 

 23 



