﻿300 Mr. C. W. Vincent on the Relations of 



half an inch in length sufficed to give an amount of electricity 

 energetic enough to modify materially the forces exerted by the 

 magnets in their mutual relations, though not sufficient to ab- 

 solutely neutralize for the time their respective polarity. 



The experiment was then reversed : an electrified glass tube 

 was presented to the north end of the test-needle in such a man- 

 ner that it was drawn across the magnetic meridian ; and whilst 

 so held a small bar-magnet, held horizontally and parallel to the 

 tube, was gradually brought near. Under these circumstances 

 the needle, when the bar-magnet was close enough, could be 

 brought to a state of equilibrium between the two, attracted and 

 repelled by neither, but quite easily affected by an electrified 

 body, another magnet, or a piece of soft iron being approached 

 to it. The same state of equilibrium was obtained by presenting 

 to either pole of the needle the pole of the magnet of the same 

 name — in the one case placing it in juxtaposition with the tube, 

 in the other opposite to it. 



When the test-needle is electrified either positively or nega- 

 tively, it is attracted by neutral conductors ; but if conductors 

 round about it be at something like equal distances, its direction 

 is then assimilated to the magnetic north and south. 



The magnetic needle, in an apparently neutral state between 

 the opposing magnet and electrified body, was examined and 

 found to have the opposite static electricity to that acting induc- 

 tively on it ; so that it would appear capable of holding the two 

 forces at the same time. 



The foregoing experiments appear to the writer to demonstrate 

 that : 



If the one or the other or both poles of a magnet are subject 

 to the inductive influence of another magnet, the effect of bring- 

 ing static electricity into the magnetic field, whether it be in the 

 positive or negative state of separation, is to weaken their mutual 

 inductive power. 



A piece of soft iron wire suspended by the middle behaved in 

 the magnetic field as if it were a magnet when acted on by the 

 opposing forces, the mutual reaction being very clearly seen 

 when the magnetic or electric force was in preponderance or 

 closer approximation ; and if the two were made to unite in di- 

 rection, the iron was capable of being drawn to either the elec- 

 trifier or the magnet from a greater distance than it could have 

 by either per se. A strongly electrified glass tube placed at 

 right angles to the poles of the horseshoe-magnet before men- 

 tioned, whilst the soft iron was suspended in front, charged the 

 end of the iron nearest to itself with positive, the further end 

 with negative electricity; and the electric attraction for a neutral 

 mass P added to the magnetic attraction, enabled the magnet to 



