86 Faraday on Ntw Electro-Magmtkal Motions, 



concentric currents of electricity in them, arranged round the axis 

 of the magnet. In support of this theory, he first formed the spiral 

 or helix wire, in which currents could be made to pass nearly 

 perpendicular to, and round the axis of a cylinder. The ends of 

 such helices were found, when connected with the voltaic appa- 

 ratus to be in opposite magnetic states, and to present the appear- 

 ance of poles. Whilst pursuing the mutual action of poles and 

 wires, and tracing out the circular movements, it seemed to me 

 that much information respecting the competency of this theory 

 might be gained from an attempt to trace the action of the 

 helix, and compare it Avith that of the magnet more rigor- 

 ously than had yet been done ; and to form artificial electro- 

 magnets, and analyze natural ones. In doing this, I think I 

 have so far succeeded as to trace the action of an electro- 

 magnetic pole, either in attracting or repelling, to the circulating 

 motion before described. 



If three inches of connecting wire be taken, and a magnetic 

 pole be allowed to circulate round the middle of it, describing a 

 circle of a little less than one inch in diameter, it will be moved 

 with equal force in all parts of the circle, fig. 14; bend then 

 the wire into a circle, leaving that part round which the pole 

 revolves perpendicularly, undisturbed, as seen by the dotted 

 lines, and make it a condition that the pole be restrained from 

 moving out of the circle by a radius. It will immediately be 

 evident that the wire now acts very differently on the pole in the 

 different parts of the circle it describes. Every part of it will 

 be active at the same time on the pole, to make it move through 

 the centre of the wire ring, whilst as it passes away from that 

 position the powers diverge from it, and it is either removed 

 from their action or submitted to opposing ones, until on its 

 arriving at the opposite part of the circle it is urged by a very 

 small portion indeed of those which moved it before. As it 

 continues to go round, its motion is accelerated, the forces 

 rapidly gather together on it, until it again reaches the centre of 

 the wire ring where they are at their highest, and afterwards 

 diminish as before. Thus the pole is perpetually urged in a 

 circle, but with powers constantly changing. If the wire ring 



