334 



H. NAGAOKA. 



Different experiments were tried with wires oï various thicknesses, 

 and with different amounts of twist. lS(3me of the results are shown 

 plotted in Figs. (5) and (6). In all of these the untwisting by mag- 

 netization becomes greater l)y ]oa(hng. When the permanent twist is 

 small, the curve representing change of torsion reaches a maximum 

 quite aln-uptly. The course of the curve immediately after passing the 

 maximum is quite steep for some time, but after the magnetizing force 

 attains a certain value, the return twist l)ecomes very small. More- 

 over, there is hysteresis on the gradual removal (3f the magnetizing 

 force. An inspection of the figures will be of more service than mere 

 verbal description. 



With large twists, the features of the curve of torsion do not 



greatly differ from those obtained with the unloaded wire. The chief 



change wrought by the loading is that after the maximum untwisting 



has been passed, the curve goes down more steeply than in the case 



when there is no load. This evidently suggests the possibility that 



the curve for the loaded wire will cut the line of ntj untwisting in 



mao-netizinof fields smaller tlian those needed to effect the same for un- 

 es o 



loaded wires. And this I f(3und to be the case, as shown by the readings 

 on the following page, which were made on a wire of 0.17 mm. 

 diameter under a load of 342 grm. Aveight. 



The former readings are shown plotted in curve (2) Fig. 4, and 

 the first part of the latter in (4) Fig. 6, and the readings in strong 

 fields in curve (3) Fig. 4. The comparison of these two curves with 

 (1) sliows that with the loaded wire the initial position is reached at 

 smaller mao-netizintr fields than with the iud(xaded wire. Moreover, 

 there is hysteresis when the permanent twist is moderate, but priming 

 when the twist becomes large. 



Finally the effect of transverse magnetization on the permanent 

 twist was investig-ated. The \v\re beinir treated as before described, 



