136 Prof. W. B. Morton and Miss Harvey: Application of 



The discontinuity in Y(6j3) when 6 passes the value /3 

 gives the transit at infinity from one side of the jet to the 

 other. 



The equation for y is of the same type, the function being 

 replaced by 



7r.F((9%) = sin%{log(l-cos((9 + %))-log (cos fl-cos^, 0< Xi 



and =sin %{ log (l — cos (0 + %)) 



— log (C0S%-C0S 0)\-7TCOSX, #>%• 



Fig. 6. 



6o 



i-K> 



Nomogram for x. 



If, now,#we cover a plane with curves of the family 

 #=cos%, y = F(#%) for different values of 6, we shall be 

 able to read off the values of x and y respectively at points 



