134 



Scientific Proceedings, Royal Dublin Society. 



Table VII. 

 Eigidity = 780 x 10 6 grammes per sq. cm. 



From Table VII it will be seen that the application of transverse 

 magnetic fields, both direct and alternating, have a pronounced effect on the 

 damping of the torsional oscillations when the iron wire is of comparatively 

 short length. 



The amplitude of the 70th oscillation is decreased by about 36 per cent, 

 by the application 'of a direct field of strength 800 units, as is seen from 

 columns 2 and 3 ; from columns 4 and 6 for an increase of the alternating 

 field of four times, the amplitude is decreased also about 36 per cent. ; and 

 from columns 2 and 6 it is decreased 47 per cent, by the application of an 

 alternating field of 800 units. 



The results obtained, with no field (0), for a field of 800 units direct (d.c), 

 and with alternating (a.c), are shown in the form of curves in fig. 2 

 (p. 135). 



The results obtained with the short wire when alternating magnetic fields 

 of strength of 250 units at the four different frequencies were employed are 

 given in Table VIII, and also, for comparison, the values when there was no 

 field on the wire. 





