xvi 



port of his theory much more decidedly than it is by myself. I intend to 

 enclose a copy of it to you, and only want the means of sending it. 



" I find all the usual attractions and repulsions of the magnetic needle by 

 the conjunctive wire are deceptions, the motions being not attractions or 

 repulsions, nor the result of any attractive or repulsive forces, but the 

 result of a force in the wire, «which, instead of bringing the pole of the needle 

 nearer to or further from the wire, endeavours to make it move round it 

 in a never-ending circle and motion whilst the battery remains in action. I 

 have succeeded not only in showing the existence of this motion theoreti- 

 cally, but experimentally, and have been able to make the wire revolve 

 round a magnetic pole, or a magnetic pole round the wire, at pleasure. 

 The law of revolution, and to which all the other motions of the needle and 

 wire are reducible, is simple and beautiful. Conceive a portion of connect- 

 ing wire north and south, the north end being attached to the positive pole 

 of a battery, the south to the negative ; a north magnetic pole would then 

 pass round it continually in the apparent direction of the sun from east to 

 west above, and from west to east below. Reverse the connexions with the 

 batterv, and the motion of the pole is reversed. Or if the south pole is 

 made to revolve, the motions will be in the opposite directions, as with the 

 north pole. 



« If the wire be made to revolve round the pole, the motions are according 

 to those mentioned. For the apparatus I used there were but two plates, 

 and the direction of the motions was of course the reverse of those with a 

 battery of several pair of plates, and which are given above. Now I have 

 been able experimentally to trace this motion into its various forms, as ex- 

 hibited by Ampere's helices, &c, and in all cases to show that dissimilar 

 poles repel as well as attract, and that similar poles attract as well as repel, 

 and to make, I think, the analogy between the helice and common bar- 

 magnet far stronger than before ; but yet I am by no means decided that 

 there are currents of electricity in the common magnet. I have no doubt 

 that electricity puts the circles of the helice into the same state as those 

 circles are in that may be conceived in the bar-magnet ; but I am not cer- 

 tain that this state is directly dependent on the electricity, or that it can- 

 not be produced by other agencies, and therefore, until the presence of elec- 

 trical currents be proved in the magnet by other than magnetical effects, I 

 shall remain in doubts about Ampere's theory." 



Oct. 8th he writes to J. Stodart, Esq. : — 



" I hear every day more and more of those sounds, which, though only 

 whispers to me, are, I suspect, spoken aloud amongst scientific men, and 

 which, as they in part affect my honour and honesty, I am anxious to do 

 away with, or at least to prove erroneous in those parts which are disho- 

 nourable to me, You know perfectly well what distress the very unex- 

 pected reception of my paper on Magnetism in public has caused me, and 

 you will not therefore be surprised at my anxiety to get out of it, though 

 1 give trouble to you and others of my friends in doing so. If I under- 



