﻿4:66 Prof. Lyle and Mr. Baldwin on Propagation of 



different resultant fluxes at different sections of the specimen 

 in any one series of the transmission experiments, we might 

 obtain some information that would help to explain the 

 phenomena. 



This was done for specimen A and for a cylindrical bundle 

 made up of 46 of the iron wires from specimen D. 



The specimen was inserted in a long solenoid and by means 

 of the wave-tracer, using it as described in a former paper * 

 by one of us, the amplitudes and phases of the magnetizing 

 forces required to produce uniform oscillating fluxes of dif- 

 ferent amplitudes and phases were obtained and the results 

 plotted. From these curves and the results given in this 

 paper on specimen A, and similar results obtained from the 

 narrow bundle, we were able to obtain the amplitude and 

 phase of the resultant magnetizing force that acted at each 

 section of the specimens in the transmission experiments. 

 When these characteristics of the magnetizing force were 

 plotted against corresponding distances along the specimen 

 from the magnetizing solenoid, the curves obtained were less 

 instructive than those for the characteristics of the flux at 

 different distances which have been given in this paper. 



18. To sum up : — When waves of magnetic flux that have 

 been started by alternating currents in a short solenoid placed 

 at the centre of a long iron rod, or bundle of iron wires, are 

 transmitted along the rod or bundle, we find that — 



(1) The retardation of phase of the first harmonic of the 

 flux at any point distant x from the centre, behind the first 

 harmonic of the initial flux, first increases with x, attains a 

 maximum and then diminishes, and keeps diminishing until 

 the flux is dissipated if the specimen is sufficiently long for 

 this to be effected. 



(2) The leakage coefficient X x of the amp. f x of the first 



1 r] -p 



harmonic, which we define by the equation \ x — — -j-jy first 



increases with a?, attains a maximum, and then diminishes 

 and keeps diminishing until the flux is dissipated. 



(3) The distances from the magnetizing solenoid at which 

 the phase retardation and the leakage coefficient become 

 maxima are equal (or very nearly so), and the point at which 

 these maxima occur we call the critical point of the specimen, 

 and its distance from the magnetizing solenoid the critical 

 distance, for the particular initial flux and frequency used. 



(4) Previous investigators of this subject, using less sensi- 

 tive methods, were only able to obtain observations within the 



* T. R. Lyle, " Variation of Magnetic Hysteresis with Frequency," 

 Phil. Mag. vol. ix. p. 102 (1905). 



