Pujpin — Resonance Analysis of Alternating Currents. 481 



Another somewhat more difficult but very instructive way 

 of proving the persistence of the harmonics is represented in 

 fig. 7. In circuit with the primary of the large machine and 

 transformer described above are two equal air-core transformers, 

 a o and a' b'. By means of a double switch either one of the 

 two can be made a part of the resonator circuit, c df. A 

 number of condensers, D, in series, are connected across pri- 

 mary circuit as indicated. The two air-core transformers, a b 

 and a' b', will be equivalent when the resonator voltmeter e 

 gives the same indications, no matter which one of the two 

 transformers be connected to the resonator. This balanced 

 arrangement having been obtained, the balance will be dis- 

 turbed as soon as the condenser D is plugged in, and it will be 



disturbed in a great variety of ways, according to the capacity 

 plugged in. But when the transformer B is of closed mag- 

 netic circuit type, then the resonator indications remain prac- 

 tically the same as long as the resonator is switched on the 

 air-core transformer a' b', no matter what capacity is plugged 

 in the condenser D. When the resonator is switched on the 

 air-core transformer, a b, then its indications will be different 

 for every particular capacity in D. In fact the circuit A, a, b, 



