132 



Scientific Proceedings, Royal Dublin Society. 



on the scale-pan end of the silk string was 2670 grammes, that is, the same 

 as was used with the corresponding length of the nickel wire. 



The more important of the results obtained in the subsidence of torsional 

 oscillations are given in Table V; the values — not given in the Table — obtained 

 with transverse magnetic fields of lower strength than 200 units, both direct 

 and alternating, were proportionately lower than those in the Table. 



Table V. 

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



From the Table it will be seen, from inspection of columns 2 and 3, that 

 the application of a direct transverse magnetic field of 200 units has slightly 

 increased the damping of the torsional oscillations, and from columns 2 and 4 

 that an alternating field has decreased the amplitude of the 70th oscillation 

 by over 11 per cent., that is, by about the same amount as was obtained for a 

 soft nickel wire when tested under the same conditions. 



The iron wire was tested in alternating transverse magnetic fields of 

 strength 65 units, and of frequencies 25, 50, 100, and 200 per second respec- 

 tively, and some of the values obtained are given in Table VI ; and for 

 comparison the values obtained with no field are also given. 



