410 Prof. Weber on the Theory of Diamagnetism. 



in the line of magnetization by their reciprocal action is "a direct 

 consequence of diainagnetic polarity." M. Weber (I believe) 

 founds this proposition on the following considerations : — Let a 

 series of bismuth particles lie in the axial line between the mag- 

 netic poles N and S : the 'polarity excited in these particles by 

 the direct action of the poles will be that shown in the figure, 

 bein.a; the reverse of that of 



iron particles under the same 

 circumstances. But as the end ~\^ 

 n of the right-hand particle 

 tends to excite a maaiuetism 



iiOs nQs 



like its own in the end s' of the left-hand particle, and vice versa, 

 this action is opposed to that of the magnet, and hence the mag- 

 netism of such a row of particles is enfeebled by their reciprocal 

 action. 



Now it appears to me that there is more assumed in this in- 

 genious argument than experiment at present can bear out. 

 There are no experimental grounds for the assumption, that what 

 we call the north pole of a bismuth particle exerts upon a second 

 bismuth particle precisely the same action that the north pole of 

 an iron particle would exert. Magnetized iron repels bismuth ; 

 but whatever the/«c/ may be, the conclusion is scarcely warranted, 

 that therefore magnetized bismuth will repel bismuth. Supposing 

 it were asserted that magnetized iron attracts iron and repels 

 bismuth, while magnetized bismuth attracts bismuth and repels 

 iron, would there be anything essentially impossible, self-contra- 

 dictory, or absurd involved in the assertion ? I think not. And 

 yet if even the possible correctness of such an assertion be granted, 

 the proposition above referred to becomes untenable. It will 

 be observed that it is against a conclusion rather than a fact that 

 I contend. With regard to the fact, I should be sorry to express 

 a positive opinion ; for this is a subject on which I am at present 

 seeking instruction, which may lead me either to M. Weber's 

 view or the opposite. Be that as it may, the result cannot ma- 

 terially affect the respect I entertain for evei-y opinion emana- 

 ting from my distinguished correspondent on this and all other 

 scientific subjects. 



J. T. 



