14 



KENNELLY AND KUROKAWA. 



ment is ^ 1.83Y 55 ?6. The angle /3°, according to theory, is the angle 

 which the locus of damped impedance makes with the vertical or X 

 axis, in the neighborhood of the resonant frequency. The frequency 

 of apparent resonance is /„ = 930.6 ~ at 20°C. The quadrantal fre- 

 quencies are/i = 912 oo and/o = 953 ^^^ ; so that A = 4l7r = 128.8 and 

 the sharpness of resonance Ao = ^tt/^/A = 45.4. 



^ The next step is to connect the receiver to its acoustic load. In the 

 case of Figure 2, the load is the cylindrical column of air in the tube 

 TT. The resistance and inductance of^the telephone are now meas- 



20 ~i* Is ti 3S~ 



LENGTH OF MR COLUMN 



Figure 7. Curves of Apparent Resistance and Reactance of Receiver 

 when attached to Air Column of successivelj' varied Length. 



ured at successive positions of the piston P, holding the frequency /, 

 and alternating-current strength, constant. The values of receiver 

 resistance and inductance so measured, are found to fluctuate period- 

 ically as the length L of the air column in the acoustic load changes. 

 Figure 7 gives a pair of wavy curves in one test, at/ = 921 co and I = 

 1.575 milliamperes rms. in the receiver. 



8 Bibliography 16, page 527. 



