Bkown — The Subsidence of Torsional Oscillations. 



127 



the letter H represents the strength of the magnetic field applied in each 

 case, and the letter n refers to the frequency of the alternating field. 



Table I. 

 Eigidity == 708 x 10 6 grammes per sq. cm. 



From Table 1 by comparing the values in columns 2, 3, and 6, it will be 

 seen that with a soft nickel wire, both the direct and alternating magnetic 

 fields increase the damping of torsional oscillation, that is, the amplitude of 

 the 70th oscillation is decreased by about 14 per cent, by the application of 

 a direct transverse magnetic field of strength 800 units, and by about 

 22 per cent, by applying an alternating transverse magnetic field of the same 

 strength, and of frequency 50 per second. The values — not given in the Table 

 —obtained with direct transverse fields of lower strength than 800 units, 

 showed that the change in the damping of the torsional oscillations began to 

 be noticeable when a field of about 300 units was applied, and it gradually 

 increased till the values given in column 3 were attained. In the previous 

 work, when the wire was three times longer £225 cms.), and with the same 

 oscillating load on, there was no difference in the damping of the oscillations 

 for no field, and for a field of 200 units. 1 



In order to find the effect of transverse magnetic fields of different 

 frequencies on a soft nickel wire, arrangements were made as before to 



Loc. cit., p. 99. 



x2 



