the Magnetization of Nickel. 135 



Table I. (continued). 



Twist applied. 



Twist. Magnetometer- 



Q reading. 



560 



+ 45 635 



+ 90 740 



+ 135 744 



+ 180 740 



+ 135 657 



+ 90 493 



+ 45 370 



310 



The wire, on being freed from the torsion-apparatus, was 

 found to have taken a permanent set of about 35° ; being left 

 free to take this position, the magnetometer-reading was 500. 

 Once more brought to zero of the torsion-scale, the mag- 

 netometer-reading was 315. It is to be noted that a similar 

 remark as to the permanent set applies in all similar cases 

 during the experiments detailed below. The wire we used 

 w^ould not bear 180° twist in either direction without per- 

 manent set. 



To alter the magnetism of the wire without applying a 

 magnetizing-coil, a small but powerful steel magnet was 

 applied to the wire, as in the old method of magnetization by 

 " simple touch." The true south pole of the magnet was 

 placed against the wire, and the magnet was passed from the 

 highest point downward several times ; thus reversing the 

 effect due to terrestrial magnetism. 



Magnetometer-reading .... 215 



The magnet was now passed from the lowest end to the top 

 of the wire, the southern pole being still the one in contact 

 with the ware. The effect was to increase very much the 

 effect due to terrestrial magnetism. 



Magnetometer-reading .... 805 



Twist was now applied to act upon the residual magnetism 

 which had been acquired during the operations just described. 

 The following is the result : — 



