Scientific Proceedings, Royal Dublin Society. 



Table VI. 

 Eigidity == 760 x 10 s grammes per sq. cm. 



From the values in Tables II to VI it will be seen that as the simple rigidity 

 of the wire decreases, the damping or subsidence of the torsional oscillations 

 increases, roughly as a straight line law, and that increasing the frequency of 

 the alternating magnetic field to five times has very little effect on the damp- 

 ing of the oscillations, in each state of hardness. When the wire is fairly hard, 

 as in Tables II, III, and IV, the damping is slightly less when the frequency 

 of the magnetic field is increased ; whereas when the wire is slightly softer, as 

 in Tables V and VI, the damping is slightly increased for increased frequency. 

 The turning-point seems to lie between the values of the rigidity, 780 and 

 770 x 10 6 grammes per sq. cm., as will be seen from the following table, in 

 which are collected the amplitudes of the 70th vibration when the wire was 

 in different states of hardness, and for both direct and alternating magnetic 

 fields at the different frequencies ; the amplitude of the starting vibration 

 being at the distance marked 300 on the scale in each case. 



Table VII. 



