104 PROCEEDINGS OP THE AMERICAN ACADEMY 



The figures obtained with the long line to New York are very 

 instructive, as they give some knowledge of the loss of current which 

 is sustained in long distance telephony. When tlie transmitter was 

 at the Institute, near to the dynamometer, the full current produced 

 by the former passed through the latter instrument, while, when the 

 transmitter in New York was the one used, it is clear that only what 

 was left after all leakage, etc. passed through the measuring instru- 

 ment. Assuming the sounds as produced at the two stations to be of 

 approximately the same pitch and loudness, it appears that only about 

 one one-hundredth of the original current produced at the transmitting 

 station is finally utilized at the receiving station. It further appears 

 from these figures that about 13 per cent of the current produced at 

 the transmitting station was utilized in ordinary telephonic transmission 

 over the local lines from 95 Milk Street to the Laboratory. 



Rogers Laboratory of Physics, 



June, 1888. 



