1904.] Magnetic Field on Torsional Oscillations, etc. 289 



a collocation of molecules much more easily affected by a magnetic 

 field. 



Effect of Permanent and Temporary Strain in Nickel Wire. — This is 

 illustrated on fig. 3, which is constructed on the same principle as 

 figs. 1 and 2. Curve I describes the behaviour of the wire in its 

 original state. After this curve had been obtained for the different 

 fields, a weight (that of a large vibrator) of 11,202 grammes was hung 



on the wire and left for two days. At the end of that time curve II 

 was obtained, showing that the permanent strain had increased the 

 differences of amplitude remaining after the forty oscillations. The 

 weight was left on for another 2 days, and curve III was observed. 

 Two repetitions of the process gave curves IV and V, which practically 

 coincide with III, and are not drawn. 



It is remarkable that permanent strain should have in nickel 

 practically the same effect as annealing in increasing the effect of field 



