Effect of Twist on the Magnetization of Nickel 



and Iron. 



By 

 H. Nagaoka, Rigakushi, 



of tho 

 Imperial University. 



Plate XXVII. 



The present paper is n continuation of one published some- 

 time ago under the title 'Combined effects of torsion and longitude 

 nal stress on the magnetization of nickel.'* The results there de- 

 scribed were only for a single specimen of nickel, and moreover the 

 range of twist to which the wire under examination was subjected 

 was always the same, namely, ± 4?5 per cm. length of the twisted 

 wire. The main facts established in thai paper were as follows : — 



When the nickel wire is twisted in a constant magnetizing field, 

 the magnetization curve obtained during torsion and detorsion under- 

 goes a gradual transformation as the amount of longitudinal stress 

 acting on the wire is increased. Inder low tensions, the -magnetiza- 

 tion increases on twisting", and decreases on untwisting;. The nature of 

 the hysteresis is such that the ascending branch of the curve is always 

 above the descending branch, and the curve is quite symmetrical on 

 both sides of zero twisting. On increasing the longitudinal stress, 

 the magnetization curse becomes gradually deformed, while at the 

 same time, there is great decrease of magnetization. Eventually when 

 the loading reaches a certain value, one end of the wire acquires 



* See this Tournai Vol. TT. pg. 2S3. 



