474 _Pupi?i — Resonance Analysis of Alternating Currents. 



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The curves in fig. 5 were plotted from this table by taking 

 the readings of the first column for the abscissse and the cor- 

 responding readings of the second and third columns for ordi- 

 nates. The upper curve corresponds to the fundamental and 

 the lower curve to the harmonic. The two curves are two 

 straight lines parallel to each other, which means that the fun- 

 damental and the harmonic increase at the same rate from 

 nearly one third excitation tofidl excitation of the alternator. 

 This result was not expected, but its correctness was verified 

 beyond all reasonable doubt. 



The same series of experiments was extended to lower exci- 

 tations of the alternator, but, since I had no low reading alter- 

 nating current voltmeter, the excitation was measured by 

 measuring the exciting field current. This current was 10 

 amperes at full excitation and the series of experiments ex- 

 tended down to 1*5 amperes, hence to nearly one seventh of 



