Voltaic Induction. 33 



also well known that when the metal in which the induction takes place, 

 is made to move to and from the magnet, opposite voltaic currents, 

 result; the cause of which, admitting the hypothesis, will be appa- 

 rent. For it is obvious that the magnetic forces N«r, I\V, Nz" do 

 not act in parallel lines, but diverge from the point N, of the mag- 

 net ; and whether we attribute this want of parallelism, to a repul- 

 sion among themselves, to an attraction towards the opposite poles 

 of the instrument, or, which is most probable, to the curvature that 

 characterizes their action as they issue from the polar surface, and 

 which is exhibited more intelligibly by the electro-dynamic cylinder, 

 still it will follow that the particles, placed between them, must be 

 more influenced by those forces intercepted than by those upon the 

 opposite sides, and from which they are receding. Accordingly, the 

 outer forces N«r, No;' 7 will effect induction during the motion towards 

 the magnet and the inner ones during the retreat. The difference 

 between the four movements will be apparent from an inspection of 

 the figure. All particles in their motion downwards will have a simi- 

 larity of magnetic rotation, which also will happen when they are 

 moved upwards ; but the direction in the last case will be the reverse 

 of the former. When, however, we suppose the motion to be to or 

 from the magnet, counter currents will arise on opposite sides of the 

 magnetic axis S N, all the particles, above it, acquiring one kind of 

 rotation, and all those below it, the opposite. 



Viewed in relation to single particles, the difference of induction, 

 here supposed to result from motion, upon opposite sides, may ap- 

 pear to be very inconsiderable : but it must be remembered that the 

 portions of matter, simultaneously influenced, are infinitely numerous 

 and are exposed, almost in the same instant of time, to an infinity of 

 forces acting in uniformity with each other. The disproportion is, 

 perhaps, not much greater, (for infinity limits both.) than that which 

 exists between an atom and the universe. But it is freely admitted 

 that all this reasoning should have no weight attached to it, unless 

 fully supported by experiment ; I shall, therefore, proceed to deter- 

 mine the direction of the voltaic currents corresponding with these 

 circles of magnetic rotation and show that the hypothetical deduction 

 is in full accordance with their actual existence. This point being 

 satisfactorily established, the conclusion urges itself irresistibly, that 

 all voltaic currents, arising from the influence of a magnet or elec- 

 tro-dynamic cylinder, are caused by the ordinary process of magnet- 

 ic induction, remotely and immediately by the order of rotation. 



Vol. XXVI— No. 1.5 



