JOURNAL OF THE COLLEGE OF SCIENCE, IMPERIAL UNIVERSITY, 

 TOKYO, JAPAN. 



VOL. XVI, ARTICLE 13. 



Change of the Modulus of Rigidity in Ferro- 

 magnetic Substances by Magnetization. 



By 



K. Honda, RigakusJii, S. Shimizii, Rigakiishi, 

 and 

 S. Kusakabe, RigakushL 



1. We have already seen that the change of elasticity hy 

 magnetization i« not so small as has generally been admitted. The 

 present experiment deals with the change of rigidity by magnetiza- 

 tion. The investigation is especially important, inasmuch as the 

 change of rigidity by miignetization is reciprocally related to that of 

 magnetization by torsion. 



In the course of his experiments on the mutual relations between 

 torsion and magnetism, G. Wiedemann'^ observed that the torsion 

 of an iron wire was diminished by magnetization. This shows an 

 increase of rigidity. C. Inirus"-' hung two identical iron wires in the 

 same vertical line, separated by a rigid piece of brass, wiiich carried 

 the index mirror ; to the lower end of the wire, a weight was 

 attached. The wire was twisted and then either the upjDcr or the 

 lower end of the system fastened. If both ends were twisted equally 



1) Wiedemann's Electricität III, 796. 



2) Barus, Amer. Jour; 34, 175, 1887 ; Phy. Eev. XIII, 257, I'JOl. 



