PHASE DIFFERENCE OF CONDENSERS 
315 
for which perfect resonance will be secured. All values of the 
total current will be larger than for sine wave conditions and 
for a given value of the coil current 0 L, the radius of the arc 
d will he increased resulting in a greater value of the phase 
angle -e-. 
In the ordinary laboratory experiment this is not a serious 
matter unless the harmonics are very prominent. In our own 
laboratory this difficulty is avoided by the introduction of con- 
siderable inductance in series with the parallel circuit. 
The above method of measuring the phase difference of con- 
densers is not proposed as a standard or accurate method. It 
is, however, of some theoretical interest and has proven to he 
of great practical value in a laboratory where students are 
studying the alternating current circuit with the use of the 
commercial paper condenser. 
Physical Laboratory, 
State University of Iowa. 
