CHANGE OF ELASTIC CONSTANTS OF FERROMAGNETICS. 



61 



of 7.(i4"xlO~^ per cm. of the specimen. The specimens tested in 

 the present experiment ^Yere those used in the previous experi- 

 ment above quoted, and had the following dimensions : 



Metals Diameter Length Rigidity 



Soft iron 0.1 KSG cm. 20.43 cm. 7.i)2 x 10^' 



Nickel Lllf) 21.42 7.41x10^^ 



On the other hand, the determination of the change of rigid- 

 ity by the ordinary method of first apj^lyiug the couple and then 

 the magnetizing field was always made, and the results obtained 

 by the two different methods were compared. The magnetizing 

 coil was the same as that used in the last experiment, so that the 

 heating effect due to the magnetizing current was negligibly small. 

 In using the present arrangement, all necessary precautions 

 were taken, which were referred to in the paper above quoted. 

 The results are given in the following: — 



Nickel. 



Figs. 67 and 68. 



TABLE XXXVIII. 



