JOURNAL OP THE COLLEGE OP SCIENCE. IMPERIAL UNIVEESITY, 



TOKYO, JAPAN. 



VOL. XVI, ARTICLE 14. 



The Wiedemann Effect in Ferromagnetic 

 Substances. 



By 



K. Honda, Rigakushi aiid S. Shimizu, Bigakushi. 



With Plates I-III. 



The Wiedenuinn etfect in iron and nickel is so well known that 

 it is superÜiious to enter into the details of the phenomenon. The 

 experiments by Gr. Wiedemann,'^ C. G. Knott," ^ Professor Nagaoka 

 and one of our members'^^ show that so long as the longitudinal field is 

 not strong, the direction of twist in iron coincides with that of a 

 circular field, if this direction is right-handedly related to that of the 

 longitudinal field ; they also show that in nickel the direction of 

 twist is opposite to that of iron. In strong field, however, the direc- 

 tion of twist in iron is reversed, so that iron and nickel are twisted 

 in the same direction. The direction of twist is reversed, when one 

 of the circular and longitudinal fields changes its direction. AYiede- 

 mann effect in nickel steels of diff'erent percentages was recently 

 studied by Professor Nagaoka and one of our members, and it was 

 found that the direction of twist was the same as that of iron. The 

 effect of tension on the Wiedemann eff'ect in iron and nickel was 



1) G. Wiedemann, Pogj?. Ann. 103, 571, 1858 ; 106, ll'>l, 1859 ; Electricitiit III, 797. 



2) Knott, Trans. Roy. Soc. Edinb.. 32 (1), 193, 1882/8.3 ; 35 (2), 377, 1889 ; 33 (2), d85, 1891. 



3) Nagaoka and Honda, Jour of Coll. of Sei.. XIII, 263, 1900. 



