330 MAGNETS AND CURRENTS 



The magnetic power of a magnet, while not confined to 

 the magnet itself, does not extend indefinitely into the sur- 

 rounding region ; the influence is strong near the magnet, 

 but at a distance becomes so weak as to be inappreciable. 

 The region around a magnet through which its magnetic 



FlG. 224. Iron filings scattered over a magnet arrange themselves in definite lines. 



force is felt is called the field of force, or simply the magnetic 

 field, and the definite lines in which the filings arrange them- 

 selves are called lines of force. 



The magnetic power of a magnet is not limited to the 

 magnet, but extends to a considerable distance in all direc- 

 tions. 



307. The Influence of Magnets upon Each Other. If while 

 our suspended magnetic needle is at rest in its characteristic 

 north-and-south direction another magnet is brought near, 

 the suspended magnet is turned ; that is, motion is produced 

 (Fig. 225). If the north pole of the free magnet is brought 

 toward the south pole of the suspended magnet, the latter 

 moves in such a way that the two poles N and 5" are as close 

 together as possible. If the north pole of the free magnet 



