212 Prof. J. A. Ewing on the Molecular 



stage (b) brings the molecules into the general direction 

 shown in fig. 5, or rather that is the direction they assume 



Fig. 4. 



when «£) is removed, and the residual magnetism contributed 

 by the group is then the sum of their moments resolved 

 along «£). When <£) is acting, the components along ^ are 

 slightly greater, for the molecules are then (stably) deflected 

 through a small angle towards the line of *£). 



Let «£) be further increased — we now have the third stage 

 (c) (fig. 3), which consists in the closer approach to satura- 

 tion that is caused by the molecules being more nearly pulled 

 into exact line with <£) (fig. 6). Whether there will be insta- 

 bility during the deflexion of them from the lines of fig. 5 

 will depend on the closeness of the poles, and on the inclina- 

 tion of the lines of fig. 5 to the direction of § (see below). 

 In some groups saturation will be complete with a finite value 

 of § ; in others, it will only be closely approximated to. In 

 magnetizing any actual specimen of iron, we have, of course, 

 to deal with a multitude of groups the lines to which lie at 

 very various inclinations to »§. If we remove the force .0 at 

 a point in stage c, we find very little, if any, more residual 

 magnetism than was found at the end of stage b. The 



