Franklin, Dufay and Ampere. 465 



surfaces of the magnet, is equivalent externally to one vortex, 

 since in either case every electric particle on that surface 

 will so move as to describe tangents to a circle drawn about 

 the axis of the magnet. When the electrical vortices of the 

 pole of one magnet conflict in their direction with those of 

 another, as when similar magnetic poles are approximated, 

 repulsion ensues ; but if the vortices are coincident in direction, 

 as when dissimilar poles are near, attraction takes place. When 

 a current through a galvanized wire* concurs in direction 

 with the magnetic vortices, as above described, attraction 

 ensues; repulsion resulting when it does not so concur. 

 Hence the magnet, if moveable, will strive to assume a posi- 

 tion in which its electrical currents will not conflict with those 

 of the wire on one side more than on the other : also the wire, 

 if moveable, will tend so to arrange itself as to produce the 

 same result, which can arrive only when the needle is at right 

 angles to the wire, and its sides consequently equidistant 

 therefrom. 



13. Electric currents will produce magnetic vortices, and, 

 reciprocally, magnetic vortices will produce electric currents. 

 Hence the magnetism imparted to iron by galvanized spirals, 

 anil the Faradian currents produced by magnetized iron 

 within spirals not galvanized. 



14. Ampere's theory has, in a high degree, the usual fault 

 of substituting one mystery for another; but, on the other 

 iiand, it has, in an equally high extent, the only merit to which 

 any theory can make an indisputable claim : I mean, that of 

 associating facts so as to make them more easy to comprehend 

 and to remember, enabling us by analogy to foresee results, 

 and thus affording a clue in our investigations. Evidently, 

 the author of this theory was guided by it, in his highly in- 

 teresting and instructive contrivances ; and Professor Henry 

 ascribes his success in improving the electro-magnet, to the 

 theoretic clue which he had received from Ampere. 



15. Nevertheless, the postulates on which this Amperian 

 hypothesis is founded, appear to me unreasonable. They 

 require us to concede that about every atom of a permanent 

 magnet a process is going on, analogous to that generally 

 admitted to exist in a galvanic circuit, where two fluids pass 

 each other in a conimon channel by a series of decompositions 

 and recompositions (7). In the galvanic circuit this process 

 is sustained by chemical reaction ; but without any co-endu- 

 ring cause, how is it to be sustained permanently in a magnet? 

 Is it reasonable to assume that the heterogeneous constiiiienls 



• I consider a wire as galvanized wlicn it is made the medium of the 

 dihchurge from a galvanic battery. 



Phil. Mc/fr. S. 3. Vol. 32. No. 217. June 184S. 2 H 



