228 Mr. K. Tsuruta on some Effects of 



soft iron when twisted and untwisted within a moderate 

 range and, what is not to be omitted, under a moderate 

 amount of longitudinal tension. However, 1 then came 

 across a curious circumstance as I went on to widen the 

 range of twist. Immediately after the curve of fig. 3 a 



Fig. 8. 



had been obtained with the same wire and within the same 

 range as the previous, the readings plotted in fig. 3 b were 

 taken for the range of + 47r, of course with the process of 

 drilling the wire interposed. It will be observed that with 

 all the other features the same in both cases, the direct 

 branches in the latter are below the back branches, while in 

 the former their relative positions are reversed. 



As this was discovered in the particular piece of wire 

 within the range of twist +2ir and + 47T, it seemed to me 

 worthy of being repeatedly examined even with that par- 

 ticular piece ; and I made many series of observations on it. 

 It may be cited that I tried to get a number of curves for 

 different ranges one after another, and each preceded by 

 the process of drilling. Thus the following four sets : — 



(1) ±10. % fig. 4a; (2) +8.^, fig, 4 b ; (3) + 6.^, 



2-7T 



fig- 4 c ; (4) +4 . — , fig. 4td. The general features of all 

 the curves are similar, and the hysteresis phenomenon is 



