CHIXGE OF ELASTICITY BY MAGNETIZATION. 



15 



From the last table, we see that the increase of elasticity under a 

 constant field generally becomes less as the load is increased, except 

 in weak fields, in which we notice a maximum as in the case of the 

 elons'îition method. The ratio of -rr for wolfram steel is several times 

 greater than that by the method of elongation. The principal cause of 

 the discrepancy may probably be due to the fact thtit the wolfram 

 steel used in the present experiment was magnetically much softer 

 than the specimen used in the former experiment, for the latter was 

 hardened by stretching. It is a well established fact that a 

 hardened iron or steel wire sutlers comparatively small magnetic 

 elongfation and that the eftect of tension on the elongation is also 

 very small. Hence it is to be expected that the result of the method 

 of elonsfation comes out to be much smaller than that given by the 

 present experiment. 



6. Steel. Steel shows a comparatively small increase of elasticity; 

 the results of observation are given in the following table and 

 graphically drawn in F ig. 5. 



