PIERCE. — OSCILLATIONS OP A HERTZ OSCILLATOR. 335 



total length of the oscillator, for oscillators of length between 8 and 

 30 meters. 



This result is 4.5 per cent higher than Abraham's theoretical value 

 computed by the formulas 



X = 2/(1 + 5.6 e 2 ) 

 c _ 1_ 



The results obtained in the present experiments are in approximate 

 agreement with two measurements given by Drude and with a series of 

 measurements obtained by Conrat, both using oscillators of length 

 between 2 and 6 meters. 



Jefferson Physical Laboratory, 

 Cambridge, Mass., 



December, 1909. 



