﻿IMDEXED. 



THE Y ^^ 



LONDON, EDINBURGH, anb DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[SIXTH SERIES.] 



NOVEMBER 1906. 



XLIX. Experiments on the Propagation of Longitudinal 

 Waves of Magnetic Flux along Iron Wires and Rods. By 

 Thomas R. Lyle, M.A., Sc.D., Professor of Natural 

 Philosophy in the University of Melbourne, and J. M. 

 Baldwin, M.A., B.Sc* 



1. ri^HE following experiments were undertaken in order 

 JL to investigate the changes in the Fourier character- 

 istics of waves of magnetic flux as they travel along iron 

 wires and rods. In all cases these flux- waves were started 

 at the middle points of the rods or wires by sending alter- 

 nating currents through short coaxial solenoids placed there. 

 The subject has already been attacked in different ways 

 by several experimenters, and from the difference in phase 

 of the flux oscillations at two points a so-called " velocity of 

 magnetization " has been obtained from the formula, 



_2ttI 

 t, -0T' 



where i?=the " velocity of magnetization," 

 T = the period of the oscillations, 

 </> = the difference in phase at two points I centi- 

 metres apart. 



Oberbeck f worked with rods and bundles of wires, in some 

 cases 40 cm., in others 1 metre long, and by means of a 



* Communicated by the Physical Society : read January 26, 1906. 

 t A. Oberbeck, Wied. Ann. vol. xxii. p. 73 (1884). 



Phil. Mag. S. 6. Vol. 12. No. 71. Nov. 1906. 2 F 



