404 



ON MAGNETS. 



2 I/ L 2 V] 



il' 5*) ' 



\ / J 



For X > D, 



Lastly, for X = oo, 



Fig. 91 represents the course of the phenomenon for particular 

 values: M = iooo, L = 3, D = 5. The magnetising forces are taken 



as abscissae ; the ordinates of the curve OAB represent the temporary 

 magnetism, and that of the curve O'A' the residual magnetism, The 

 former consists at first of a rectilinear portion corresponding to the 

 values of X comprised between and 3 ; it then rises suddenly, and 

 rapidly approaches its asymptote. The curve of residual magnetism 



