336 



H. XAGAOKA. 



in a manner slightly (lifteront from that of Professor Ewing. The 

 wire was suddenly twisted in the magnetizing field, and the quantity 

 of the current thereby produced was measured by means of a ballistic 

 galvanometer. In this way, I found that the direction of the transient 

 current in nickel is opposite to that in iron. Nothing corresponding 

 to the peculiar reversal of polarity was, however, observed. In addi- 

 tion to this, I found that the current in both iron and nickel reaches a 

 maximum for a certain moderate strength of the magnetizing field. 

 In iron, under a constant longitudinal field, there was also a definite 

 angle of twist which gave a maximum current, but in nickel the 

 current always increased with the increase of twist. The fact that 

 the current in nickel is opposite to that in iron has also been inde- 

 pendently discovered by Herr L. Zehnder.* The above experiments 

 of mine are published in Philosophical Magazine for January 1890. 

 Resuming the investigation more recently, I examined the transient 

 current in iron, steel, and nickel, either by twisting the wire suddenly, 

 ok by reversing the direction of the magnetizing force after the wire 

 had been twisted. Also wires of different diameters were examined. 



Fig. 1. 



Fig. 2. 



NZ3- 



-^=>— , 



Wiedemann's Annale», Bd. 38. p. GS, 1889. 



