OF ARTS AND SCIENCES. 253 



(3.) 



(1-) 



(2.) 



(3.) 



Magneto Transmitter. 



Some experiments were also made upon a Dolbear electrostatic re- 

 ceiver in circuit with a Hunning transmitter and high resistance induc- 

 tion coil. The currents produced when speech was readily transmitted 

 and reproduced by the Dolbear receiver were too slight to be measured 

 by the dynamometer, although amply sufficient to reproduce speech in 

 a magneto receiver interposed in the circuit. 



At first sight some of the results given in the preceding tables are 

 quite unexpected. Thus in some cases the magneto transmitter gives 

 a current as great as the Blake carbon transmitter, or even greater, 

 although as used in actual practice the latter is far louder. Tin's proba- 

 bly comes from the fact that with the magneto transmitter the lijis were 

 habitually placed close to the mouthpiece of the instrument, so that, 

 even if the same actual strength of voice were used, the effect on the 

 diaphragm of the magneto would be greater than on the diaphragm of 



