Theory of Electromagnetic Action. 455 



shown in equations (13) for a particular case) the inductions 

 through the molecular circuits remain constant. Hence in a 

 magnetizable body these inductions must be the same in the 

 unmagnetized state of the body as in its magnetized state ; 

 and this seems to show that the magnetization consists in the 

 turning round, into facing on the whole in the same direction, 

 different lines or chains of regularly arranged molecular mag- 

 nets, or molecular circuits, as opposed to an alignment of a 

 number of circuits previously perfectly mixed up in their 

 arrangement. For if each of these chains have its compo- 

 nent molecules all facing the same way, and the different 

 chains be so arranged that the body has no magnetic moment 

 in mass, the constant induction of large amount through each 

 circuit can be accounted for ; and this appears to me to be 

 the more natural explanation. A body which had its mole- 

 cular circuits perfectly mixed up as to direction could not, it 

 seems to me, be magnetized at all, except in so far as to pro- 

 duce an induction through each of the circuits equal and 

 opposite to the integral of the magnetizing force over that 

 circuit, unless indeed the coefficients of self-induction are in 

 all cases so large as to give a considerable induction through 

 each circuit due to its own current alone. If the latter were 

 the case, the result of causing all the molecular circuits to face 

 one way would be to produce an induction, in the same direc- 

 tion, over every part of a section of the body across the 

 direction of the magnetizing force ; if it were not the case, 

 the induction across such a section would be everywhere 

 small, in consequence of the fact that the surrounding circuits 

 before the alignment contribute on the whole nothing to the 

 induction through a particular circuit, which induction must 

 afterwards still have the same small value. 



Thus, if the current in each circuit does not by itself pro- 

 duce an induction in itself considerable, a moderate magne- 

 tizing force, applied to a body composed of molecules perfectly 

 mixed as to the directions of their axes, ought to produce 

 diamagnetic quality, in consequence of the creation of the 

 magnetic induction required to keep the total induction 

 through each circuit at its former value. 



Of course diamagnetic quality is most simply accounted for 

 by supposing the molecules immovable. The only effect of 

 placing the body in a magnetic field would then be to produce 

 induced currents corresponding to diamagnetization. 



