Brown — The Subsidence of Torsional Oscillations. 



129 



the, same when no field, and when a direct transverse magnetic field of 

 800 units was round the wire, the values being those given in column 2 of the 

 Table. 



Table III. 

 Rigidity == 810 x 10 6 grammes per sq. cm. 



From the values in Table III, by comparing columns 2 and 4 it will be 

 seen that the application of an alternating transverse magnetic field of 

 800 units and frequency 50 per second decreases the amplitude of the 70th 

 oscillation by about 30 per cent., as compared with 22 per cent, when the 

 wire was soft (Table I). From a comparison of Tables I and III it will be 

 seen that when a direct magnetic field of 800 units was acting on the wire, a 

 change in the rigidity from 708 x 10 6 to 810 x 10 6 grammes per sq. cm. 

 showed in the amplitude of the 70th oscillation an increase of 160 per cent., 

 but in the case of an alternating field of the same strength and frequency 

 50 per second, the amplitude of the 70th oscillation was increased 100 per 

 cent. 



The results for the soft wire and for the hard wire for no field (O) and for 

 an alternating field of 800 units (A. C.) are shown in the form of curves in 

 figure 1 (p. 130), where the two tipper curves refer to the hard wire and the 

 two lower curves to the wire in the soft state. 



