Bodies are repelled from the Poles of a Magnet. 275 



mutually neutralized each other, on account of their confused 

 grouping. The act of magnetization he supposed to consist in 

 setting these molecular currents parallel to each other ; and 

 starting from this principle, he reduced all the phaenomena of 

 magnetism to the mutual action of electric currents. 



If we reflect upon the experiments recorded in the foregoing 

 pages from first to last; on the inversion of magneciystallic 

 phsenomena by the substitution of a magnetic constituent for a 

 diamagnetic ; on the analogy of the effects produced in magnetic 

 and diamagnetic bodies by compression ; on the antithesis of the 

 rotating actions described near the commencement ; on the in- 

 dubitable fact that diamagnetic bodies, like magnetic ones, owe 

 their phsenomena to an induced condition into which they are 

 thrown by the influencing magnet, and the intensity of which is 

 a function of the magnetic strength ; on the circumstance that 

 this excitation, like that of soft iron, is of a dual character; on 

 the numerous additional experiments which have been recorded, 

 all tending to show the perfect antithesis between the two classes 

 of bodies ; — we can hardly fail to be convinced that Mr. Faraday^s 

 first hypothesis of diamagnetic action is the true one — that dia- 

 magnetic bodies operated on by magnetic forces possess a polarity 

 " the same in kind as, but the reverse in direction of that acquired 

 by magnetic bodies." But if this be the case, how are we to 

 conceive of the physical mechanism of this polarity ? According to 

 Coulomb's and Poisson's theory, the act of magnetization con- 

 sists in the decomposition of a neutral magnetic fluid ; the north 

 pole of a magnet, for example, possesses an attraction for the 

 south fluid of a piece of soft iron submitted to its influence, 

 draws the said fluid towards it, and with it the material particles 

 with which the fluid is associated. To account for diamagnetic 

 phajnomena this theory seems to fail altogether : according to it, 

 indeed, the oft-used phrase, ' a north pole exciting a north pole, 

 and a south pole a south pole,' involves a contradiction. For if 

 the north fluid be supposed to be attracted towards the influencing 

 north pole, it is absurd to suppose that its presence there could 

 produce repulsion. The theory of Ampere is equally at a loss to 

 cxj)lain diamagnetic action ; for if we suppose the particles of 

 bismuth surrounded by molecular currents, then according to all 

 that is known of electro-dynamic laws, these currents would set 

 themselves parallel to, and in the same direction as those of the 

 magnet, and hence attraction, and not repulsion, would be the 

 result. The fact, however, of this not being the case proves that 

 these molecular currents arc not the mechanism by which dia- 

 luagtietic induction is effected. The consciousness of this, I 

 doubt not, drove M. Weber to the assumption that the phieno- 

 iiiciia of diamagnetism are jjroduced by molecular currents, not 



