6 ART. 13.-K. HONDA. S. SHIMIZÜ AND S. KUSAKABE : 



tioii of tlu' jHillcy, W'is veritinl in tlu' iollowinn; w;iy. Tlu' fmo 

 copper uii-e was fixed 1o the uxial line of the pulley and the 

 depression or elevation of the axis itself due to magnetization of the 

 ferroma.unetie rod was observed liy means of a rotating cylinder 

 carrying a mirror. A minute deflection amounting to only a fraction 

 of a millimeter was noticed, whereas the deflection was several centi- 

 meters when the copper wire was fixed to a point on the circum- 

 ference of the pulley. Hence the actual depression or elevation of the 

 axis, if any, was negligibly small. 



The samples to be tested were the same as those used in the 

 former experiment, except in the case of the nickel rod. 



In the present experiment, the length of each rod was reduced to 

 22 cm, and the diameter of the cobalt bar also to 1.082 cm. The 

 nickel rod, used in the former experiment was turned into a square 

 rod from a plate, and the mechanical process, which tlie sj:>ecimen 

 underwent, hardened it in magnetic quality. Moreover the nickel 

 was not sufficiently thick for the torsion experiment, so that another 

 nickel bar, tlie diameter of which was 1.117 cm, was substituted for it. 

 The new specimen was turned into a cylindrical form from a thick 

 bar, and was magnetically much softer. 



Our a})paratus was not suited for the absolute measurement of the 

 modulus of rigidity and therefore its determination was, in the usual 

 manner, carried on with Professor Nagaoka's apparatus above referred 

 to. The results were : 



4. Soft iron. The rigidity of soft iron is always increased by 

 mao-netization, as will be seen fi-om the following table and Fig. 1. 



n 7 C~) CD 



