In the Motion of the Magnetic Field. 319 



(13) 





and therefore 



i- .-. H . ,1 <»> 



or 



— e 



6 v 



(15) 



Formula (1*5) now contains both cases of magnetization: that 

 of magnetic and that of paramagnetic bodies. In reality, when 

 the coefficient X is sufficiently large and v sufficiently small, 

 k assumes positive values and we enter the sphere of para- 

 magnetism. 



From the equations (13) we obtain besides this 



J=_^Iand^ i/J 2 =i-P; 



v z 2 v 



whence it is evident that — given a comparatively large value 

 to \ and small value to v — the velocity of magnetic motion of 

 matter and its energy under the same magnetization I are 

 comparatively greater. We conclude from this, that the 

 absorption of energy by motion of matter in paramagnetic 

 bodies is comparatively greater than in diamagnetic ones, as 

 has been already pointed out, and that in consequence thereof 

 appears that anomalous propagation of the magnetic induction- 

 tubes which is observed in paramagnetic bodies. Besides 

 that, as we already decided to regard the phenomenon of 

 diamagnetism as the reflexion of lines of induction at the sur- 

 faces of particles of matter, we must now consider paramag- 

 netism to be also the reflexion of the induction lines, but 

 taking place without change of sign. Thus we find here the 

 same phenomenon of double-signed reflexion with and with- 

 out change of sign as we also see in other branches of physics, 

 as for instance in the reflexion of waves of light and sound at 

 the surfaces separating media of different nature. 



In the case of a crystalline substance the magnetic energy 

 of unit of volume is expressed by a formula which is analogous 

 to formula (10), but the vectors I, J, H are replaced here by 

 their components (A, B, C), (L, M, N), and (a, ]3, <y) re- 

 spectively. By applying to it Lagrange's equations we get a 

 system of equations : 



