78 Faraday on new Ekctro-Magnetical Motions, 



and a little loop of platinum passed round the magnet and wire, 

 to prevent them from separating too far. Revolution again 

 took place on making the connexion, but more slowly as the 

 distance increased. 



The direction in which the wire moved was according to the 

 way in which the connexions were made, and to the magnetic pole 

 brought into action. When the upper part of the wire was con- 

 nected with the zinc, and the lower with the copper plate, the 

 motion round the north and south poles of a magnet were as 

 in fig. 4 and 5, looking from above ; when the connexions were 

 reversed, the motions were in the opposite direction. 



On bringing the magnetic pole from the centre of motion to 

 the side of the wire, there was neither attraction nor repulsion ; 

 but the wire endeavoured to pass off in a circle, still having the 

 pole for its centre, and that either to the one side or the other, 

 according to the above law. 



When the pole was on the outside the wire, the wire 

 moved in a direction directly contrary to that taken when the 

 pole was in the inside ; but it did not move far, the endeavour 

 was still to go round the pole as a centre, and it only moved till 

 that power and the power which retained it in a circle about its 

 own axis were equipoised. 



The next object was to make the magnet revolve round the 

 wire. This was done by so loading one pole of the small mag- 

 net with platinum that the magnet would float upright in a basin 

 of mercury, with the other pole above its surface ; then con- 

 necting the mercury with one plate, and bringing a wire from 

 the other perpendicularly into it in another part near the float- 

 ing magnet : the upper pole immediately began to revolve round 

 the wire, whilst the lower pole being removed away caused no 

 interference or counteracting effect. 



The motions were again according to the pole and the con- 

 nexions. When the upper part of the wire was in contact with 

 the zinc plate, and the lower with the copper, the direction of 

 the curve described by the north and south poles were as in 

 fig. 6 and 7. When the connexions were reversed, the motions 

 were in the opposite directions. 



