﻿436 Prof. Lyle and Mr. Baldwin on Propagation of 



completely, not only current and E.M.F. waves, but also flux- 

 waves over a wide range of amplitudes. 



For instance, by its means can be accurately determined 

 flux-waves whose amplitudes range from very large values 

 down to a fraction of a single magnetic line ; and by sub- 

 jecting its readings to harmonic analysis we have been able 

 to obtain the Fourier characteristics of the resultant flux 

 oscillations at all points along rods of iron or steel, \ in. in 

 diam. and 10 feet long, which have been magnetized by an 

 alternating current circulating in a short solenoid placed at 

 their middle points, when the amplitude of the flux-density 

 at the centre was as low as 10,000. 



3. The experiments, of which the results will be given 

 below, were made on 



A. A long rod of Lowmoor iron J in. in diameter. 



B. A long rod of silver steel \ in. in diameter. 



C. A long iron wire \ in. in diameter. 



D. A bundle of 185 charcoal iron wires, each *079 cm. in 



diameter, 370 cm. long, tightly taped together so as 



to form a circular cylinder. 

 d x . A bundle of 46 of the wires from D. 

 d 2 . A bundle of 12 of the wires from D. 



In each case at the middle point of the rod or bundle 

 a short coaxial solenoid was placed, and through it an 

 alternating current obtained from a rotary converter supplied 

 with direct current from storage-cells was sent. 



The magnetizing-current wave and the resultant flux-waves, 

 crossing the sections of the bar or bundle at different points 

 along its length, were quantitatively determined by the wave- 

 tracer using the galvanometer method * described in the 

 paper already quoted. The wave forms so obtained were 

 subjected to harmonic analysis, the results of which are given 

 in the Tables below. Some of the more interesting of the 

 results of the investigation are also exhibited by means of 

 curves. 



The arrangement of the apparatus, the method of experi- 

 ment, and the reduction of the observations were the same 

 in all essential features as that fully described in a former 

 paper f by one of us. Instead of the fixed secondary coil o£ 

 5 or 10 turns wound on the iron rings used in the experi- 

 ments just quoted, three small search-coils were used. One 

 of these, wound close to the rod or bundle, was fixed at the 



* T. R. Lyle, "Wave-Tracer and Analyser," Phil. Mag. vol. vi. p. 549 

 (1903). 



t T. R. Lvle, "Variation of Magnetic Hysteresis with Frequency,' 

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



