WITH MAGNETISM AND ELECTRICITY. 173 



the magnetic moment produced by the magnetizing force in each 

 molecule regarded singly m, there results for each particle an 

 additional magnetizing force, due to the action of the other, by 

 which the magnetic moment m is augmented. This new mag- 

 netizing force, resulting from the reciprocal action of the par- 



tides, is expressed according to known laws by —^, where r de- 

 notes the distance between the particles. The total magnetizing 



(2m\ 

 X + —3- j produces, therefore, in the particle under con- 



1+ ^iF-^)'ni' When, on the 



contrary, two bismuth particles are situated in a line parallel to 

 the direction of the magnetizing force X, calling the diamagnetic 

 moment corresponding to this force of magnetization —fi (the 

 negative sign signifies that for similarly directed magnetizing 

 forces the diamagnetic moment is opposed to the magnetic one), 

 then for each particle there results, from the action of the other, 



2/L6 



a new force ^, where r denotes the distance between the 



particles ; consequently to the total force of magnetization 

 ( X — -^ j corresponds the diminished diamagnetic moment 



— (l— ^^^j//,. Hence the antithesis, that the magnetism of 



the two iron particles in the line of magnetization is increased by 

 their reciprocal action ; but that, on the contrary, the diamag- 

 netism of the two bismuth particles lying in this direction is dimi- 

 nished by their reciprocal action. 



The result is the reverse when the iron and bismuth particles 

 lie in a line perpendicular to the direction of the magnetizing 

 force ; here the magnetism of the particles of iron is weakened 

 by their reciprocal action ; the diamagnetism of the bismuth 

 particles, on the contrary, is strengthened through the same 

 cause. We find, in fact, the weakened magnetism of the iron 

 particle 



