14 



AKT. 14.— K. HONDA AND S. SHIMIZU; 



cation of the circular field followed by tliat of tlie longitudinal one 

 is far greater than tlie twist obtained when the order of application 

 is reversed. 



The oreneral feature of the twist for cobalt is similar to that 



o 



in nickcL In cast cobalt (Fig. 15), the twist is increased first slowly 

 and then rai)idly, as the circular field is increased. AVith the increase 

 of the longitudinal field, the twist reaches a maximum and then 

 gradually diminishes. If the longitudinal field be strong enough, 

 the twist occurs at first in the opposite direction and then in the 

 ordinary. In annealed cobalt (Fig. 16), the twist is very small and 

 the rate of increase is nearly constant. Here also the twist obtained 

 by first applying the circular field and then the longitudinal is several 

 times greater than the twist when the carder of application is reversed. 

 Some observed angles of twist in iron, nickel, and cobalt bars 

 are «Jfiven in the fdlowincr tables. Here the current (J is o^iven in 

 amperes per square centimeter. 



Iron bar. 



