KENNELLY AND PIERCE. 



TELEPHONE RECEIVERS. 



133 



ing, that the effect of the reaction of the motion of the diaphram in 

 modifying the electrical properties of the telephone receiver is of im- 

 portance in experiments on sound, where an electrically driven tuning 

 fork or telephone is used as the source of sound, because the power 

 consumed in producing the sound may change with the change of the 



TABLE X. 

 Values of Power. Watch-case Receiver at 0.3 Volt. 



stationary sound-wave system in the room. In our experiments, the 

 sound emitted from the test telephone was reflected from the various 

 walls of the room and formed a stationary system with nodes and 

 loops at various parts of the room. As an assistant walked about the 

 room while the measurements were being made, it was found that the 

 bridge, previously balanced, was thrown successively in and out of 

 balance as the reflection and absorption of the assistant's clothing 



