TH E 



AMERICAN JOURNAL OF SCIENCE 



[FOURTH SERIES.] 



Art. I. — An Experimental Investigation into the " Shin "- 

 effect in Electrical Oscillators ; by C. A. Chant. 



1. Introductory and Theoretical. 



The first explicit reference to the fact that, when a con- 

 ductor is subjected to a periodic electromotive force, the 

 current is not uniformly distributed over a cross-section of the 

 conductor, is to be found in Art. 690 of Maxwell's Electricity 

 and Magnetism. Upon obtaining the equation connecting the 

 impressed electromotive force with the effective electromotive 

 force and the inductive electromotive force he introduces terms 

 which " express the correction of this value [of the inductive 

 electromotive force] arising from the fact that the current is 

 not of uniform strength at different distances from the axis of 

 the wire. The actual system of currents has a greater degree 

 of freedom than the hypothetical system in which the current 

 is constrained to be of uniform strength throughout the sec- 

 tion. Hence the electromotive force required to produce a 

 rapid change in the strength of the current is somewhat less 

 than it would be on this hypothesis." 



It is quite certain, however, that Maxwell did not foresee 

 the great interest and importance which the subject was des- 

 tined soon to develop. 



In a series of papers written between 1884 and 1887 Heavi- 

 side* dealt with the entire question of the propagation of 

 electric currents into conductors and of magnetization into 

 cores when produced by a periodic electromotive force. He 

 was one of the first to insist that the action should be con- 

 sidered as entering the conductor from the surrounding dielec- 



* Electrical Papers, vol. i, pp. 353, 429 ; vol. ii, p. 168. 



Am. Jour. Scl— Fourth Series, Yol. XIII, No. 73. — January, 1902. 

 1 



