324 JB. Rosing on the Participation of Matter 



Here the coefficient tc is expressed by the above formula ^15) 



^(2 + *)-- 



6 V 



and oF is defined by equation (24). 



This system of equations represents the ^general conditions 

 of static magnetization on the supposition of the existence of 

 magnetic pressure and magnetic deformations. We will pro- 

 ceed to examine these formulae. 

 Formula 



r tt x f 8F 



vj J 



shows that the process of magnetization is composed of two 

 processes, one, expressed by term #H, is a process which can 

 be completely reversible and which represents, as we have 

 already had occasion to see, a simple reflexion of induction- 

 lines from matter ; the other process is expressed by the 

 term 



\C8¥ 



and arises in consequence of absorption of energy by the mag- 

 netic deformations. The value of this term wholly depends 

 on the free energy F of deformations. It is in the nature of 

 these deformations that the explanation of all the complex and 

 intricate phenomena which appear in the magnetization of 

 iron must be sought. 



It is evident from equation (25), that in a paramagnetic 

 substance — given I and H positive — the vector J has the oppo- 

 site sign to the coefficient \ } and k having a positive value, the 



product — k— y is greater than nil. On the other hand, 



when I and H are increased, and consequently J too, the de- 

 formations likewise increase, and with them F. Therefore 

 the integral 



\ C8F 



"VjT 



taken from the beginning of magnetization I = J = H = 0isa 

 positive quantity. 



Thus, owing to the absorption of energy in a paramagnetic 

 substance, magnetization increases. 



To show this still more clearly, we will put the equations 



