606 



THE BELL SYSTEM TECHNICAL JOURNAL, MAY 1954 



It is possible to translate such solution curves into ^ — a curves in a 

 direct graphical manner if a mesh of constant ^ lines is drawn in the 

 first quadrant. From (30) these are given by 



\x - {p + a{\ - /3')]Xi - /?' = 0, 



or 



Xi^ 



1 - 



^ + 



V 



= 1 



^\ 



Xi 



1 - )82_ 



The contour, /3 = 6, is just the contour x = \ — l)' displaced along the 

 <r-axis by an amount, — p/(l — h^). The contours of constant jS all pass 

 through the point o- = o-q , X = cro + p and are shown in Fig. 7. Their 



i.2 



0.5 0.6 0.7 08 0.9 1.0 I.I 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 



K 



Fig. 7 — Contours of constant iS^ = X for j> = 0.5. 



\ — a\ 



