418 WELLS'S NATURAL PHILOSOPHY. 



needles, they will adhere to the extremities of. the magnet, as is representee! 

 in Fig. 347, 



Can a magnet Wheu a natuial magnet is brought near to, 

 iTpTopirte? °^ ^^ contact with a piece of soft iron or steel, 

 it communicates its attractive jiroperties, and 

 renders the iron a magnet. In doing so, it loses none of 

 its original attractive influence, 



What are arti- Bars of iron or steel which by contact with 

 ficiai magnets? natural magiicts, or by other methods, have 

 acquired magnetic properties, are termed artificial magnets. 



For all practical purposes, artificial magnets are used in preference to nat- 

 ural magnets, and can be made more powerful. 



The attractive force of mag-nets has received 



Pefine the , r. -i.*- -r-i i i i 



iiipaningoftho thc namcoi Magnetic ±i orce, and that de- 

 terms masrnetic (^ • ^ • ^ f 

 force and' mag- partmcnt of scienco which treats oi magnets 



and their properties is denominated Mag- 

 netism. 



This designation must not be confounded with Animal ifagnetism, a term 

 ■which has been adopted to designate a certain influence which one person 

 may exercise over another by means of the will. 



whjit are the '^^^* ^ attractive power of the magnet is 

 poiesofamag. not diffiiscd uuiformly over every part of its 

 surface, but resides principally at opposite 

 points or extremities of its surface. These points are 

 termed poles. 



Between the regions of greatest attraction, a point may 

 be found where the attractive influence wholly disappears. 



When a bar magnet is rolled in iron fiUngs, the filings attach themselves 

 to the magnet in the manner represented in Fig. 3i8, and in this way clearly 

 indicate the location of the magnetic lorce. 



Fig, 348. 



In a steel magnet, the actual poles, or points of greatest magnetic intensity, 

 •re not exactly at the ends, but at a distance of about one tenth of an inch 

 from each extremity. 



