426 Dr. Faraday on the Physical Character of 



words quantity and intensity (2866. 2868. 2870.). I would, 

 however, rather not attempt to limit or define these or such like 

 terms now, however much they may be wanted, but wait until 

 what is at present little more than suggestion, may have been 

 canvassed, and if true in itself, may have received assurance 

 from the opinions or testimony of others. 



3294. The association of magnet with magnet, and all the 

 effects then produced (3218.), are in harmony, as far as I can 

 perceive, with the idea of a physical line of maguetic force. If 

 the magnets are all free to move, they set to each other, and then 

 tend to approach ; the great result being, that the lines from all 

 the sources tend to coalesce, to pass through the best conductors, 

 and to contract in length. When there are several magnets in 

 presence and in restrained conditions, the lines of force, which 

 they present by filings, are most varied and beautiful (3238.); 

 but all arc easily read and understood by the principles I have 

 set forth. As the power is definite in amount, its removability 

 from place to place, according to the changing disposition of the 

 magnets, or the introduction of better or worse conductors into 

 the surrounding media, becomes a perfectly simple result. 



3295. As magnets may be looked upon as the habitations of 

 bundles of lines of force, they probably show us the tendencies 

 of the physical lines of force as they also occur in the space 

 around ; just as electric currents, when conducted by solid wires, 

 or when passing, as the Leyden or the voltaic spark, through 

 air or a vacuum, are alike in these essential relations. In that 

 case, the repulsion of magnets when placed side by side, indi- 

 cates the lateral tendency of separation of lines of magnetic force 

 (3267.). The effect, however, must be considered in relation to 

 the simultaneous gathering up of the terrestrial lines of force in 

 the surrounding space upon each magnet, and also the tendency 

 of each magnet to secure its own independent external medium. 

 The effect coincides with, and passes into that of the lateral re- 

 pulsion of balls of iron in a previously equal magnetic field (2814.); 

 which again, by a consideration of the action in two directions, 

 i. e. parallel to and across the magnetic axis, links the pheno- 

 mena of separation with those of attraction. 



3296. When speaking of magnets, in illustration of the ques- 

 tion under consideration, I mean magnets perfect in their kind, 

 *'. e. such as are very hard and hold their charge, so that there 

 shall be neither internal reaction of discharge or development 

 (3224.), nor any external change, except what may depend upon 

 such absolute and permanent loss of exciting power as is conse- 

 quent upon an over-ruling change of the external relations. 

 Heterogeneous magnets, which might allow of irregular varia- 

 tions of power, are out of present consideration. 



