210 ON MAGNETISM. 



current as in Figure 66 will deflect the red end towards 



Fig. 66. 



the reader's eye. That in Figure 67 will deflect it from 



Fig. 67, 



the reader's eye. The magnetic attraction is always 

 normal to the direction of the current; a singular circum- 

 stance, we believe, in physical action. The direction 

 may be remembered from the following fanciful rule. 

 Conceive an insect to travel along the wire, in the 

 direction of the graphite current, with his face 

 always turned (upwards or downwards, or horizontally, 

 as the case may be) to view the red end of the 

 needle. Then the galvanic power deflects that red 

 end towards his left hand. 



