see 



H. NAGAOKA. 



With varying twists in a constant field of '20 C. G. S. units, 

 Curves I., IL, III. in Fig. VIII. were obtained with three specimens of 

 steel wires of different gauge. Their diameters were 1.26 mm., 1.50 

 mm., and 1.82 mm. respectively. The readings are as follows: — 



In these three curves, we notice the same characteristics as have 

 been already noticed in similar experiments with iron. There is a 

 certain angle of twist for which the transient current is a maximum. 

 This angle of twist varies with the thickness of the wire, and is smaller 

 for the thick than for the thin wire. Thus the currents in iron and 

 steel are in every respect similar, except in the amount of the transient 

 current developed and the position of the maximum current. 



When soft iron or nickel wire is twisted it immediately acquires 

 a large permanent set. and would in no case return to the initial 

 position of no torsion. In steel, the limit of elasticity is very great 

 compared with soft iron or nickel. Whenever the steel wire is 

 twisted and afterwards released, the wire almost always returns to its 

 former position although the amount of twist is considerable. The 



