436 



BELL SYSTEM TECHNICAL JOURNAL 



'c 



3 

 O 



V--'- 



1» 





I. 



i2 ^o 



'I* 



I ^,_ 





£ 2» 



,/'■ 



/ 



.c/5 



o 



c 

 .9 



03 

 O 

 O 



nJ 



.S 

 O 



■^ 



i3 



c 



o 



be 



