260 Prof. Tyndall on the Nature of the Force by which 



the arrow, fig. 8 ; the consequent deflection was towards the 

 dotted position. 



Fig. 8. 



t±: 



Both the current which excited the magnet and that which 

 passed through the helix were now interrupted, and the polarity 

 of the magnet was reversed. On sending a current through the 

 helix in the direction of the arrow, the deflection of the bar was 

 from the position of the defined line to that of the dotted one, fig. 9. 



L , • 



Interrupting the current through the helix, and permittuig 

 the bar to come to rest under the influence of the magnet 

 alone, a current was sent through the helix in a direction op- 

 posed to its former one : the deflection produced was that shown 

 in fig. 10. 



The position of equilibrium finally assumed bythe bar depends, 

 of course, upon the ratio of the forces acting upon it : in these 

 experiments, the bar, in its final position, enclosed an angle of 

 about 50 degrees ^\ith the axial line. 



