44 Messrs. K. Honda and T. Terada on the Change of 



As may be seen from fig. 1, nickel contracts by magneti- 

 zation in a way similar to that given by many earlier 

 experimenters; in weak fields the contraction rapidly in- 

 creases with the increasing field, but gradually tends to an 

 asymptotic value, as the field attains a higher value. The 

 increased tension decreases the amount of contraction fol- 

 low fields, while for higher fields it increases the contraction. 

 Thus there exists a certain field in which the effect of the 

 additional tension is null. This neutral point for two suc- 

 cessive tensions shifts toward the higher field, as the tension 

 increases. In their general course, the curves are quite 

 similar to those already obtained by Mr. S. Shimizu and- 

 one of us*. 



The change of elasticity of nickel is given in the table 

 below and in PI. I. fig. 2. 



Table II. 

 AT = +713 gr./mm. 2 



* = 10°-0 C. 



T=1540 

 H. 



gr./inra. 3 



T=3021 



gr./nnn. 2 



T=4498 



gr./mm. 2 



* E XlO*. 

 En 



If. 



^XlO 2 . 



H. 



^ E X10'. 



4-5 



- 005 



9-3 



- 0-54 



110 



-0-4.0 



10-4 



- 1-59 



195 



- 1-67 



25-0 



-1-24 



25-0 



- 8-41 



344 



- 3-98 



510 



-331 



31 -3 



-1215 



49-9 



- 841 



70-3 



-611 



377 



- 14-40 ' 



643 



— 12 -22 



99 



-9-90 



503 



- 710 



71-1 



-1106 



106-3 



-8-18 



71-5 



- 3- JO 



90-9 



- (VI 9 



129-4 



-543 



118 2 



- 0-42 



131-8 



- 2-43 



191-9 



- 3 21 



196-7 



+ 0-98 



210 



- 101 







287 



+ 2-20 



288 



- 0-61 



277 



-172 



40G 



4- 2-19 



397 



4- 0-27 



390 



i 



-0-83 



In the above table AT denotes the weight applied or 

 removed for studying the elongation of the specimen. 



The coefficient of elasticity first decreases as the field 

 increases, attains a minimum value, whence it begins to 

 increase, at first rather abruptly and then gradually. The 

 effect of tension is to drive the field corresponding to the 

 minimum elasticity towards the higher field, and also to 



* K. Honda & S. Shimizu, Journ. Sc. Coll. vol. xvi. Art. 9 (19C2). 



