[ 331 ] 



XXX T. The Variation of Potential along a Wire transmitting 

 Electric Waves. By C. A. Chant, University of Toronto, 

 Toronto, Canada'*. 



[Plate VII.] 



I. Introductory. 



HERTZ f was the first to explore a wire along which 

 electric undulations were passing. His oscillator con- 

 sisted of two sheet-brass plates 40 cms. square, connected by 

 a copper wire 60 cms. haig, in the middle of which was a 

 spark-gap. Opposite and parallel to one plate was placed 

 another of equal size, from which was led off a copper wire, 

 the first metre of which was curved and the rest of it straight. 

 As a detector he used his circular resonator, 70 cms. in 

 diameter. The nodes were well marked in two wires, the 

 length of the straight portions of which were 5" 5 m. and 

 8 in. respectively. The half-wave-length was determined 

 to be 2'S m. 



These experiments were repeated and extended by Sarasin 

 and de la Rivet, who some what increased the effect by using 

 two wires led off from two plates placed opposite the oscil- 

 lator plates, the resonator being held between them. These 

 experiments showed very clearly that the apparent wave- 

 length measured along the wire was dependent purely on the 

 size of the resonator, the wave-length being equal to eight 

 times the diameter of the resonator. 



Somewhat similar results were obtained by Waitz§, who 

 used a circular resonator to which were attached two wires, 

 one joined near each terminal knob, and led off either 

 parallel to each other or in opposite directions. In the 

 former case, by sliding along a bridge laid across the wires, 

 the sparks between the resonator knobs passed through 

 maximum and minimum intensities ; in the latter case, by 

 hanging capacities on the wires and sliding them along, the 

 sparks varied similarly. He worked with plate oscillators of 

 two sizes, as w r ell as cylindrical and spherical ones. He 

 found that his minima depended entirely on the dimensions 

 of his circular resonator. 



The conclusion naturally drawn by Sarasin and de la Rive 

 and Waitz from their experiments was that the oscillator 



* Communicated by Prof. Trowbridge. 



t IT. Hertz, Wied. Ann. xxxiv. p. 551 (1888); 'Electric Waves." 

 p. 106. 



X E. Sarssin and L. de la Rive, Archives ties Sciences Physiques et 

 Naturelles, Geneve, t. xxiii. p. 113 (1890). 



§ K. Waitz, Wied. Ann. xli. p. 435 (1800). 



