194 



ON MAGNETISM. 



suspension will overcome it, and will turn the magnet 

 further from the magnetic meridian, till the balance 

 is restored. It is plain here that, by noting the 

 position of the magnet, we have the means of ascer- 

 taining the direction and magnitude of the changes 

 which terrestrial directive force undergoes. 



It is indifferent whether the rotating apparatus 

 (or ' torsion circle ') be connected with the fixed beam, 

 so as to act on the two upper points of attachment, 

 or with the magnet, so as to act on the two lower 

 points of attachment. It is also indifferent whether, 

 in the former case, the two lower points are in the 

 longitudinal direction of the magnet: in the three 

 diagrams to which we shall now refer, we shall sup- 

 pose that they are in an inclined position. 



Figure 56 is a side view of the magnet in an 



Pig. 56. Fig. 57. 



L-L 



