Prof. Faraday on some Points of Magnetic Philosophy. Ill 



powerful magnets), if we represent bismuth by a magnet, re- 

 versely polar, as bismuth is supposed to be, we obtain induced 

 magneto-electric currents, not like those of bismuth, but the 

 contrary; and if we turn the representative magnet round, so 

 as to give it the position in which it yields currents like those 

 of the bismuth, then its polarity contradicts, or is the reverse 

 of the assumed polarity of the bismuth. 



3359. Now until the polarity or direction of the magnetic 

 force which determines the course of the induced magneto-elec- 

 tric currents produced in every moving conductor, is distin- 

 guished and separated from the polarity or direction which 

 causes movement amongst bodies subjected to the same force, 

 how can these phsenomena be accounted for by the supposition 

 that the bismuth sphere is in the same polar condition as the 

 reversed globe magnet ? The reversed magnet is, in fact, the 

 contrary to bismuth and to iron ; — then bismuth and iron must 

 be the same. The direct magnet is the same as the bismuth, in 

 that polarity which induces a current ; — then the magnet and the 

 bismuth are the same. How easily all these effects present 

 themselves in a consistent form, if read by the principle of re- 

 presentative lines of force. The reversed globe magnet at a 

 distance from the dominant, shows, in revolving, the effect of 

 the lines of force within it (3116.); as the magnet is ap- 

 proached, its external sphondyloid of power is compressed in- 

 wards (3238. fig. 15), and at last the magnet is self-contained ; 

 then showing the equalization of its own powers, and as yet the 

 absence from within it of any of the powers of the chief magnet ; 

 so that it gives no induced currents, though in a place where 

 bismuth and iron would give them freely. Within that di- 

 stance the effect of the superior and overpowering force of the 

 great magnet appears (3358.), which, though it can take 

 partial possession of the little magnet, still, when removed, 

 suffers the force of the latter to develope itself again, and present 

 the same series of phsemonena as before. 



33G0. Van Rces admits, I believe, that the moving wire 

 shows truly the presence, direction, and nature of the magnetic 

 force or forces ; and it is very important to know that the set- 

 ting of a magnetic needle, or crystal of bismuth, and the produc- 

 tion of a current of electricity in a moving conductor, are like 

 correlative and consequent effects of the magnetic force ; the 

 power of producing one or the other effect being rigidly the same. 

 Philosophers should either agree or differ distinctly on this point ; 

 so that if they differ, they may point out clearly the physical 

 separation of the phenomena; which, if established, must lead 

 to new and important discoveries. The polarity direction which 

 the moving conductor makes manifest, whether that conductor 



