JOURNAL OF THE COLLEGE OP SCIENCE, IMPERIAL UNIVERSITY, 

 TOKYO, JAPAN. 



VOL. XVI, ARTICLE 10. 



Note on the Vibration of Ferromagnetic Wires 

 placed in a Varying Magnetizing Field. 



By 



K. Honda, Rigahuslii, 



and 

 S. Shimizu, Bigakushi. 



1. It is well known that ferromagnetic bodies emit an audible 

 sound at the moment of making and breaking the magnetizing 

 current. Page'^ first heard the sound in the magnet, when an electric 

 current passed through a copper spiral placed between tlie poles of a 

 horse-shoe magnet. The sound was more intense at the break than 

 at the make. A Similar phenomenon was also observed by 

 Delezenne"-*. Marrian^^ placed an iron or steel wire in a coil, and 

 by making and breaking the magnetizing current, he heard a sound 

 due to the longitudinal fundamental vibration of the wire. Matteucci^^ 

 examined the effect of tension and found that the pitch of the sound 

 was independent of the tension, but that the intensity was decidedly 

 increased. The investi si-ation with iron bars of different leng-ths led 



1) Page, Pogg. Ann. 43, 411, 1838 ; Wiedemann's Electricität III, 838. 



2) Delezenne, Bibl. univ. ser. nouv. Iß, 406, 1838. 



3) Marrian, Phil. Mag. 25. 382, 1844. 



4) Matteucci, Archives 5, 389, 1845. 



