130 



Scientific Proceedings, Royal Dublin Society. 



When this hard nickel wire was tested in transverse magnetic fields of 

 strength 250 units and of frequencies 25, 50, 100, and 200 per second respec- 

 tively, it was found that the damping of the torsional oscillations was increased 

 as compared with the effect of no field or of a direct field of 800 units ; but 

 when the frequency of the applied field was increased, the damping was 

 decreased. 



300 



g 



200 



IOO 



Fig. 1. — Number of Vibrations. 



A few of the values — enough to enable the curve to be drawn if required — 

 are given in Table IV, and also in column marked D.C., for the sake of 

 comparison, some of the values obtained when no field or a direct field of 

 800 units was round the wire. 



