Effect of Stress on Magnetization. 107 



The theoretical relations to be tested were, however, 

 deduced on the supposition that the magnetization is 

 independent o£ the order o£ magnetizing and straining, so 

 that in comparing the theory and the experiment, too much 

 weight is not to be placed on the above correspondence. 



The values of ~tj, -^yt and ^-q- were deduced from 

 0-tL oH uH 



our previous experiment, while the corresponding values for 

 S7p> S7f 25 an( i s~r were obtained from the present experiment. 



ai ei- ol> ^j r'd 2 !-] 



In the following tables, ^m and ^™ are the values of 

 these differential coefficients obtained from curves (SI, T)h ; 

 while ^p and ^^ are the values of the coefficients 



from curves (I, H) T . =s ^yj is the value obtained from 

 ±/ Lo-tLJ H 



1 p^T^ ~i 



the results of the elongation method ; while ™ ^-= 



is that obtained from the tension effect on magnetic elonga- 



1 p"^ "" 1 



tion. - sr^r is the value of the coefficient obtained from 

 the result of the oscillation method, and - ^p- that 



obtained from Barus's method ; while - spr an d - ^y 



are the values obtained from curves (SI, t) h and (I, H) T re- 

 spectively. To find the values of these differential coefficients, 

 corresponding curves were carefully drawn on section papers ; 

 a fine straight line drawn on a thin glass plate was brought 

 into contact with the curve at the required point and the 

 trigonometrical tangent of the inclination of this straight line 

 was evaluated. Some of the calculated results are given 

 below : — 



