EFFPXT OF STRESS (»\ I\I ACXETIZATIOX. 4') 



Tlu' t'lVcct (»t ,i;iviiii;- ;i iiiaxiniiiin twist at once dues not 

 inatc'iially diller tVom tliat o\' a graded twisting. 



{d) Magnelizalion under constant twist combined with ten- 

 sions : (/, //)t,,. 



The efiect of a constant twist on magnetization is compara- 

 tively great, especially in higli fields. In 28. 74^^ Ni., the magne- 

 tization is slightly increased by a small twist, hut above a 

 moderate twist, it decreases. In 50.72^^ Ni., the increase of magne- 

 tization by a small twist is not appreciable, but the magnetization 

 always decreases wntli greater twist. The magnetization of 70.o2^^ 

 Ni., is also decreased by twisting, exce}>t in weak fields in which 

 a slight increase is observed. In all cases, the change of magne- 

 tization decreases with increasing tension. 



In 28.74 0^ Ni., curves (o7, H\,r (Fig. 41 in dotted lines) 

 deduced from (7, If)-.,, show a somewhat different aspect from 

 those deduced from {ol, t)^,^ especially for a small twist. For a 

 small value of twist, ol is always positive and have a faint 

 maximum ; for a greater twist, it is first negative and afterward 

 positive ; and for a still greater twist, it is always negative, and 

 except in weak fields, it takes a course parallel to the corre- 

 sponding curve obtained from the last experiment, but the former 

 lies somewhat below the latter. 



In '"yO.l'Ir^ô Ni., curves {ol, H)-, ,■ (Figs. 42 and 4;> in dotted 

 lines) deduced from (/, 7/jt, y have a quite ditîërent aspect, i.e., 

 nl is always negative. It rapidly decreases in weak fields, and 

 after passing through a negative maximum, slopes away very 

 slowly toward the axis of H \vith increasing field. Tension leduces 

 the decrease of magnetization. 



In 70.:>2^ Ni., curves (/)/. ll)-.,-,- (Figs. 44, 40, AiS and 47 

 in dotted lines) deduced from (/, //):, ;,. take a course similar to 



