542 K. Honda, S. Shimizu, and S. Kusakabe on Change of 



and the rigidity, and the observed change of twist due to 

 magnetization, gives the ratio of the change (SK) to the 

 rigidity (K) itself. 



H 20. 60. 100. 200. 400. 600. 800. 



^Xl0 3 ..0-19 0-58 0-76 0- 



1-10 1-18 1-22 



These numbers are also plotted against magnetizing force 

 in fig. 4 ; the course of the curve resembles that of mag- 

 netization, having one inflexion point and approaching to an 

 asymptotic value as the field is increased. 



-4 



lO* 2 









Fig. 4. 



















































K 







$ 



7^ 

















/ 



/ 







(1)//= 



/436> 



/0* 









/ 









(3) - - 

 (4)- = 



27.^5 



x/O 6 

















(5)- = 



(6)- = 



J5..95 



x/0 6 

 */0 6 







IWOL 



cftflM 



ST££. 





















' So> 



ST££ 



cw — 



L 







=-=5 



H 







- - 







COB> 



VlT 







2C 



O 



4< 



10 



6( 



)0 



8( 



)0 

























That there is untwisting by magnetization forms a re- 

 ciprocal relation to the well-known fact that the magnetization 

 of iron decreases by twisting. 



The above results for soft iron agree in quality with those 

 of previous experimenters, and the amount of the change 

 nearly coincides with some of Barus's results. In the ex- 

 periment of Day the change of rigidity was a little smaller 

 than in the present case, and greatly affected by the amount 

 of twisting couple, in contradiction to our results. Stevens's 

 experiment gave much greater change of rigidity. 



