VIBRATIONS IN TONE GENERATOR 
85 
multiplied by the current for the corresponding frequency give the 
amplitude. After these constants were once obtained it was only 
necessary to measure the current through the receiver in order to 
know its amplitude for any given frequency. 
To rnake the comparison between the amplitude of the receiver 
and the tone generator the arrangement shown in figure 11 was 
used. R is the receiver, T is a tube leaving the resonating cham- 
ber C and terminating just above the receiver diaphragm, D is a 
Rayleigh disc mounted at an opening in the opposite end of the 
chamber from which the tube leaves. In this comparison it was 
assumed that if the diaphragm of the receiver thus arranged and 
vibrating with a given frequency and amplitude gave a certain de- 
