4:62 K. Honda, S. Shimizu, and S. Kusakabe on Change of 



due to magnetization was within the limit of experimental 

 errors. The disturbance of the results due to magnetic 

 elongation or contraction in the longitudinal direction was 

 eliminated by means of the rotating cylinder which served as 

 one of the fulcrums. 



The bar bent slightly downwards if loaded ; hence when it 

 was magnetized it would strive to make itself straight. This 

 may cause an apparent increase of elasticity ; but it was con- 

 firmed by direct experiments that the effect was negligibly 

 small, because the reading obtained by inclining two coils with 

 respect to the bar to a degree greater than the actual case 

 was almost the same as in the case when the coils rested in a 

 coaxial line. 



Since the bar was considerably shorter than the whole 

 length of the coils, it lay nearly in a uniform field except at 

 the middle. The effect of the air-gap between the coils was 

 also studied, varying its width by 1 or 2 cms. ; however, 

 such a change had no sensible effect on our results. 



3. The dimensions of the specimens used in our experiments 

 and their moduli of elasticitv were as follows : — 



Metals : 



Soft Iron. 



Steel. 



Wolfram 

 Steel. 



Nickel. 



Cobalt. 



Length 



6400 cm. 



64-00 cm. 



64-U0cm. 



24-20 cm. 



27-30 cm. 



Breadth 



903 



0-920 



948 



0-510 



Eadius 



i Thickness ... 



0-901 



0-913 



0-953 



0-511 



= 0-680 



Elasticity ... 



2-02 xlO 12 



2-01 x 10 12 



2-05 xlO 12 



1-96 xlO 12 



1-79 XlO 12 



The present arrangement was not suitable for the absolute 

 measurement of the modulus of elasticity, since the yielding- 

 effect of several parts of the arrangement disturbs the result. 

 Hence the modulus of elasticity was determined by the ordinary 

 method of flexure with two reflecting mirrors. 



The intensity of magnetization of the specimens was deter- 

 mined by the magnetometric method. The results are given 

 in fig. 2. Ordinates represent the intensity of magnetization,, 

 and abscissae the effective field. 



The magnetic change of length was found to have an 

 intimate relation to the change of elasticity, so that it was 

 measured for each specimen. To each end of the bar a brass 

 rod of the same thickness and 15 cms. long was soldered. 

 The bar was then vertically suspended coaxial with the mag- 

 netizing coil by means of a screw adjustment. From its 

 lower end a weight of 1 or \ kilogram was hung by a 



