1904.] Magnetic Field on Torsional Oscillations, etc. 287 



the amplitudes at a given stage in the course of the subsidence with 

 various fields, and the amplitudes at the same stage in the subsidence 

 with zero field. The stage chosen was in each case the instant after 

 the completion of the fortieth vibration after the attainment of the 

 initial amplitude indicated on the curve. The abscissae are galvano- 



meter deflections and are proportional to the fields : each unit of 

 deflection means a field of 15*54 C.G.S. units. 



Curve I shows the effects of the various fields on the wire as it was 

 received from the makers. The wire was then hardened by being- 

 drawn down as described; and it was then found that no effect of 

 magnetisation on subsidence was perceptible. 



The nickel wire was next annealed by heating it to a bright red heat 



