too 



MAGNETISM. 



netic needle, and is the essential part of the mariner's 

 compass. 



240. ATTRACTION OF MAGNETS FOR EACH 



How do the . 



poles of mag- OTHER. The law of attraction between 

 'each^tter? magnets is, that unlike poles attract, and 

 like poles repel. The north pole of one 

 magnet, therefore, attracts, and is attracted by the south 

 pole of another. 



241. WHY THE MAGNETIC NEEDLE POINTS 

 In^gneriT nee- N RT H. In accordance with the law stated 

 die point in the last paragraph, the tendency of the 



noTth ? 



magnetic needle to point north, may be ac- 

 counted for by supposing the south pole of an enor- 

 mous magnet, to exist somewhere near the north pole 

 of the earth. If we call the end of the needle which 

 points north its north pole, it is evident that the sup- 

 posed pole at the north must be a south pole. For the 

 same reason, xve might suppose the north pole of an 

 enormous magnet to exist near the south pole of the 

 earth. Connecting these poles, we should accordingly 

 have an immense magnet running through the earth 

 from north to south. This supposition will account 

 for many of the phenomena of magnetism ; but it is 

 not supposed to be the true one. Another theory is 

 presented in a subsequent paragraph. 



242. INDUCED MAGNETISM. When a 



Sio;To/~ P iece f * ron is brought near to a magnet, 

 magnetism, in the iron receives magnetism, by induction, 



soft iron. ., . . ., ., 



and becomes itself, temporarily, a magnet. 

 If approached to the south pole, its adjacent end ac- 



