BETWEEN LONGITUDINAL AND CIRCULAK MAGNETIZATIONS. 297 



The transverse field fit whicli the change of magnetization 

 attains a maximum value decreases slowly as the longitudinal 

 field is increased ; and the point at which the change of mag- 

 netization vanishes recedes rapidly towards the origin as the 

 longitudinal field is increased. 



For weak longitudinal fields, the change of magnetization 

 is lincarlv related to the streno;th of circular field, if it is not verv 

 weak. In strong transverse fields, the decrease of magnetization 

 reaches a maximum and then again diminishes as the longi- 

 tudinal field is increased. 



If the axial current he broken gradually or suddenly, the 

 intensity of magnetization always increases to a value greater 

 than the initial. In weak fields, the increase is very great, 

 amounting sometimes to double its initial value. 



Fig. 7 shows that the value of oJ/1 is comparatively large 

 in weak fields, but decreases rapidly as the longitudinal field is 

 increased. Hence tlie rate of increase of magnetization increases 

 as the longitudinal field decreases, till it reaches a certain value, 

 beyond which the rate again diminishes. 



Figs. 4 and 8 show the curves of longitudinal mag- 

 netization when difterent circular fields are in action. Here 

 the magnetization in low fields is increased when the transverse 

 field is weak. In strong fields, it decreases for all transverse 

 fields. 



The hysteresis curves shown in Figs. 2 and T) are similar in 

 appearance with that of torsion,'' but as will be seen hereafter, 

 it arises from an entirely different cause. The symmetry of the 



1) Phil. Trans. 1878; Reprint of Papers, Vol. 11. P. 380. 



