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GENERAL SCIENCE 



AN ARTIFICIAL MAGNET 

 After being dipped in iron filings. 



A BAR MAGNET 

 MADE or STEEL 



it. The strings of filings at one end all point to the 

 same part of the magnet. The parts to which the filings 



point are the poles of the 

 magnet. The magnetic force 

 is greatest at the poles and 

 decreases to zero toward the 

 middle of the magnet. The 

 middle, where there is no attraction, is called the equator, 

 and the line joining the two poles is called the axis of 

 the magnet. In a horseshoe magnet the equator is at 

 the curved part, the poles at the two ends, and the axis 

 is a straight line joining the two poles. When a magnet 

 is suspended so that it can swing 

 freely, the end pointing north is called 

 the north-seeking pole, or simply the 

 north pole, and is marked N on the 

 magnet; the other end is called the 

 south seeking, or south pole, and is indicated by S. 

 A compass is a magnetized steel bar balanced on a 

 pointed support so that it can swing freely without much 

 friction. It is shaped so that one can tell easily in what 

 direction it points, that is, tell in what direction the axis 

 stands. When a compass needle is free to 

 turn, it will stand with its axis parallel to 

 the magnetic meridian. The compass box 

 has the directions and degrees marked so 

 that it is easy to tell the different directions. 

 163. Magnetic Attraction and Repulsion. 

 - There is no visible difference in the way 

 the two ends of a bar magnet attract iron 

 filings. But there is a difference in the 

 two poles, which can be seen by presenting them suc- 

 cessively to the same end of a magnetic needle. One 



A HORSESHOE 

 MAGNET 



