Bodies are repelled from the Poles of a Magnet. 



259 



Action of Magnet and Current combined. — In examining this 

 subject, eight experiments were made with each particular bar ; 

 it will be remembered that fig. 6 gives a general view of the 

 arrangement. 



1. Four experiments were made in which the magnet was 

 excited first, and after the suspended bar had taken up its posi- 

 tion of equilibrium, the deflection produced by the passage of a 

 current through the surrounding helix was observed. 



2. Four experiments were made in which the helix was excited 

 first, and when the bar within it had taken up its position of 

 equilibrium, the magnetism was developed and the consequent 

 deflection observed. 



Normal Paramagnetic Bar. — In experimenting with the soft 

 iron it was necessary to place it at some distance from the mag- 

 net, otherwise the attraction of the entire mass by one or the 

 other pole would completely mask the action sought. Fig. 7 

 represents the disposition of things in these experiments : N and 



Fisr. 7. 



S indicate the north and south poles of the magnet ; ah is the 

 bar of iron ; the helix within which the bar was suspended is 

 shown in outline around it ; the arrow shows the direction of 

 the current in the upper half oi the helix; its direction in the 

 under portion would, of course, be the reverse. 



On exciting the magnet, the bar of soft iron set itself parallel 

 to the line joining the poles, as shown by the unbroken line 

 in fig. 7. 



When the direction of the current in the helix was that indi- 

 cated by the arrow, the bar was deflected towards the position 

 dotted in the figure. 



Interrupting the current in the helix, and permitting the 

 magnet to remain excited, the bar returned to its former j)osition: 

 the current was now sent through the helix in the direction of 



