iribhyOLl 



J. 



T II H 

 LONDON, EDINBURaH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[SIXTH SERIES.] 



JS^OV EMBER 1903. 



LXIX. Preliminary Account of a Wave-J racer am 

 By Prof. Thomas R. Lyle *. 

 [Plates XXIL & XXIII.] 



A RESEARCH was lately undertaken by me in order to 

 determine directly the magnetic properties o£ iron 

 when subjected to alternating mngnetizing forces, and to 

 investigate its behaviour under the actual working conditions 

 to which it is exposed in alternate-current working. 



For this purpose it was necessary to obtain simultaneous 

 values of magnetizing force and induction at any instant, 

 for any wave-form of exciting current ; and I have succeeded 

 in doing so by means of a w ave-tracer and analyser which I 

 think v\ ill be of sufficient interest to electricians to merit a 

 preliminary description. Some examples of the work it can 

 do will be given in the present paper ; and I hope to publish 

 at as early a date as great pressure of teaching-work will 

 allow a detailed account of the research for which it was 

 originally devised. 



Xot only, however, does my wave-tracer and analyser 

 determine accurately by means of a steady galvanometer- 

 reading instantaneous values of an oscillating E.M.F., current, 

 or magnetic flux at any point of their wave-form ; and hence 

 by a number of readings, or by photography, the wave-forms 

 themselves of these quantities, but it also analyses these wave- 

 forms, obtaining what I call their components. By the /ith 

 component of a periodic function I mean the periodic function 



* Communicated by the Author. 

 Phil Mag. S. 6. Vol. 6. No. ^o. Nov. 1903. 2 



