Researches in Magnetic Electricity. 367 



are not secondary, but tertiary phenomena ; the secondary pro- 

 duction, being the development or neutraUzation of magnetic 

 forces. And, as Mr. Sturgeon has very ably set forth in his beau- 

 tiful theory of electro-magnetic lines, in the present state of our 

 knowledge, it is indispensable to the explication of the reciprocal 

 action of magnetism and electricity, to suppose the existence of a 

 secondary intervening medium, whether the coiled conductors act 

 with or without the co-operation of ferruginous bodies. One sin- 

 gular fact which I noticed, nearly two years since, remains to be 

 reconciled with the postulates, that a direct shock cannot be ap- 

 preciated from an elementary current, and that secondaries are 

 strictly consequences remote from primitives. When two, three 

 or four pairs of plates, or any number below twelve, arranged as a 

 compound series, are connected with coiled conductors, with or 

 without soft iron enclosed, the sparks and deflagrations, are far 

 more brilliant on breaking the circuit, than with the same plates 

 used as a simple or elementary battery. This fact is readily ac- 

 counted for. The battery current itself is capable of passing 

 through perceptible space, with appreciable duration, and as the 

 secondary current, (which is the natural electricity of the wire, 

 set in motion by magnetic forces,) returns to its equibrium through 

 the medium of the battery plates and its liquid, the two currents 

 must here move in conjunction, and enhance the combustion of 

 the metals used. I have strictly examined the power of the pure 

 secondary developed in this way, and find it never to exceed the 

 secondary from the same pairs arranged as an elementary series. 

 In fact, the secondary begins to diminish, just when the magne- 

 tizing power of the compound battery begins to diminish, which 

 is well known to occur, as the series extends. The properties of 

 small and large compound batteries, have moreover been exam- 

 ined while the currents have been passing through circuits from 

 twenty feet to half a mile, without any observable characteristic 

 changes. But to return to the action of the compound electro- 

 magnet. The superior value of these magnets, whether made of 

 flat plates, or fine wire, may be traced to several causes. First, 

 the homogeneous texture of the iron from which wires or flat 

 plates are made, is favorable to the extensive development of 

 magnetism. Secondly, the same quality favors its neutralization, 

 when the exciting cause is withdrawn. Thirdly, the sum of the 

 actions of so many highly charged magnets, and lastly, the mu- 



