KENNELLY AND PIERCE. 



TELEPHONE RECEIVERS. 



137 



Figure 11. Circular graph for experimental bipolar receiver, with one 

 volt at terminals. Diameter 10.9 ohms. Depression angle (2/3) 26.5°. 

 «o = 6465?; a = 20?. 



Figure 12. Circular graphs collected to one and the same scale. The 

 largest circle and the smallest circle are graphs with experimental receivers. 

 Two Ught circles near together are graphs with bipolar Bell receiver. Broken 

 circle is graph with watch-case.- 



