238 



PROCEEDINGS OP THE AMERICAN ACADEMY 



Experiments were also made with the same apparatus in which the 

 strength of the field magnet of the telephone was kept constant by 

 maintaining a constant current in its coils, while the line current was 

 varied. In the first series of these the diaphragm was separated from 

 the end of the core by a distance of ^V inch. The results are 

 given in Table III., and Series VIII., IX., XL, XIII., and XIV. 

 are graphically illustrated by the curves of Figure 3. 



TABLE III. 



Series VIII. 

 Magnetizing Currrent = 135 milliamperes. 



Line Current. 

 3.15 

 2.76 

 2.05 



Excursion. 

 33 

 27 

 14 



Series IX. 

 Magnetizing Current = 160 milliamperes. 

 Line Current. Excursion. Line Current. 



3.46 73 2.29 



2.98 56 1.72 



2.74 46 



Excursion. 

 32 

 23 



