8 



ART. U.— K. HONDA AND S. SHIMIZÜ: 



Twist hl/ rurij'uui the ciirulur fidd. In Figs. 7 and S, we notice 

 that under a constant longitudinal Hold, the angle of twist at first 

 increases at a constant rate, l)iit later at a gradually diminishing rate. 

 As the longitudinal field is increased, the curves approximate to right 

 lines, a result which is tu he expected from Kirchhoff's theory of 

 magnetostriction. For according to the theory, if the circular field is 

 small compared with the longitudinal field, the amount of twist for a 

 given longitudinal field is proportional to the longitudinal current. 

 The amount of twist is greater in \b% nickel steel than in o5% 

 nickel steel. 



From Figs 7 and 8, we can obtain the twist under a given longi- 

 tudinal current by gradually increasing the longitudin.al field ; the 

 result so obtained, if it is compared with Figs. 1 and 2, shows that 

 the twist produced by the interaction of the circular and longitudinal 

 fields is independent of the order of applying them. 



Some observed angles of twist are exhibited in the ft:)llowing 

 tables : — 



45% nickel steel. 



