﻿Waves of Magnetic Flux along Iron Wires. 465 



induction wave precludes the possibility of a satisfactory 

 solution on the basis of our present knowledge. 



16. It was thought, however, that apartial explanation of some 

 of the phenomena observed might be obtained if the initial flux 

 was made up of elementary magnetic lines very heterogeneous 

 as regards their phases. As these passed along the specimen 

 there would be a retardation of the phase of each line due to 

 " velocity " as well as a change of the phase of the resultant 

 flux at any section due to groups of lines in special phases 

 leaking out at special distances from the origin. If this were 

 so, the phases of the lines at different distances from the axis 

 of the rod or bundle should be different, as at any section 

 those lines about to leak out would be near its circumference. 

 To test this the wires of specimen D were divided into three 

 groups. The first group of 28 wires was taped to form a 

 circular cylinder, and round it was wound a search-coil of 

 50 turns insulated. Over this central cylindrical bundle the 

 •second group of 45 wires was uniformly distributed and taped 

 so that the whole formed a circular cylinder coaxial with the 

 first. An insulated search-coil of 50 tarns was wound round 

 the middle of the compound bundle formed. The remaining 

 group of 110 wires was now added and taped so as to be 

 coaxial with the others, and a third search-coil of 50 turns 

 was wound round the middle of the whole. 



The bulging caused by the search-coils was not very great. 

 The magnetizing coil was wound on a bobbin, and could be 

 placed at any distance on the specimen from the search-coils. 

 Bv means of a switch the search-coils could be connected in 

 different ways, so that when continued to the wave-tracer the 

 latter determined for us the flux-waves through the central 

 bundle or through either of the surrounding tubular bundles 

 of wires for different distances from the magnetizing coil. 



The result of this investigation was to show that while at 

 the centre of the magnetizing coil the flux-density and phase 

 varied over the section — the phase of the first harmonic for 

 the outer layer being 4*56 degrees ahead of that for the central 

 portion and the amplitude varying from 07 lines per wire for 

 the outside portion to 58*5 lines per wire for the central, — 

 yet for distances greater than 15 cms. from the magnetizing 

 coil there was no appreciable difference in the phases of the 

 first harmonics, wave-forms, or densities of the fluxes through 

 the three different portions of the compound bundle. Hence 

 no such explanation as that imagined at the beginning of this 

 paragraph can be tenable. 



17. It was also thought that if we determined in amplitude 

 and phase the magnetizing force required to produce the 



Pfiil. Mag. S. 6. Vol. 12. No. 71. Nov. 1906. 2 H 



