104 



Scientific Proceedings^ Royal Dublin Society. 



approximate values we were able to obtain with alternating transverse fields 

 it is evident that their action is the reverse of that for alternating longitu- 

 dinal fields, where the changes in the rigidity were greater than for direct 

 longitudinal fields, whereas the changes for alternating transverse fields are 

 less than for direct transverse fields. 



20 



Amperes. 



30 



Fig 



2.— UppCT Curve D. C. Field. Load 2 x 10= grni./cm«. 



Lower Curve A. C. Field (re = oO). Load 4 x 10^ grm./cm'' 



In conclusion, it may be said : — 



1. The initial increase in the rigidity of nickel is less for alternating than 

 for direct longitudinal magnetic fields, whilst the subsequent decrease is 

 greater for alternating longitudinal fields than for direct fields. 



2. The higher the frequency of the longitudinal magnetic field used the 

 greater the decrease in the rigidity. 



3. The changes in the rigidity of nickel wire with transverse magnetic fields 

 are the reverse of those due to longitudinal fields, both direct and alternating. 



4. The greater the load on the wire, when subjected to transverse 

 magnetic fields, the smaller the change in the rigidity for fields between zero 

 and 960 units, 



