INFLUENCE OF MAGNETS UPON EACH OTHER 227 



FIG. 97. Iron filings scattered over a magnet arrange themselves in definite lines. 



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

 selves are called lines of force. 



The influence of magnets upon each other. If a magnet 

 is brought near a magnetic needle, the needle turns ; that is, mo- 

 tion is produced (Fig. 98). 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 TV and S are 

 as close together as possible. 

 If the north pole of the free 

 magnet is brought toward the 

 north pole of the suspended 

 magnet, the latter moves in 

 such a way that the two poles 

 N and N are as far apart as 

 possible. In every case that 

 can be tested, it is found that 

 i a north pole repels a north pole, and a south pole repels a 

 j south pole ; but that a north and a south pole always attract 

 I each other. 



FIG. 98. A south pole attracts a 

 north pole. 



CLARK INTRO. TO SC- 



