EFFECT OF ÖTUlvSS ON MACJNETIZATIOX. 37 



(c) Change uf nuKjnelizat'wii hij tw'id under différent 



tensions : (of, r)/^_ y. 



In very low liekly, tlie iiKignetizatiuii coii.siderably increases 

 with twist ; in liiglicr fields, it first increases, but afterward 

 begins to decrease with the twist, and in still higlier fields, 

 the magnetization decreases nearly uniformly with the twist, 

 as shown in Figs. oO, 132, 34, oG, 38 and ol>. The change 

 of magnetization rapidly increases with the percentage content 

 of nickel. 



As for the cyclic effect (Figs. 31, 33, 3Ô, 37, 38 and 40), 

 it coincides fairly with the initial, excejtt in w^eak fields. In 

 28. 74^^ Ni. and 70.329^ Ni., the increase of magnetization is only 

 observable in very weak fields, and the magnetization generally 

 decreases with twist. In Ö0.72<jo Ni, the magnetization first 

 increases with the twist, attains u maximum, and then decreases. 

 As the tension is increased, the change becomes gradually less. 



Curves {o/,., II),, r (Figs. 41, 42, 43, 44, 45, 40 and 47 in full 

 lines) obtained from (oT,, 7)jfy, rise and fall steeply in a very low 

 field, cut the axis of i/, become negative, and after passing through 

 rather conspicuous negative maxima, slope away gradually toward 

 the axis, with the increasing field. ol is numerically greater 

 for a greater twist. In 50.72o^ Ni., however, rî/ for a small twist 

 is always positive, tending to zero, as the field increases. 



Curves (o/,, ll)-,r for cyclic effect shown in the same figures 

 are similar to the above curves, and become coincident with them 

 above a moderate field. The increase of magnetization with small 

 twists becomes less as the tension increases; and for 28. 74^^ Ni. 

 and 70.32^^ Ni., it almost vanishes at a high tesnion. 



