404. MAGNETISM. 



be rendered magnetical, the north pole will be de- 

 pressed, and the south pole elevated above the 

 horizon : this property is called the inclination or 

 dip of the needle. 



Cavallo gives the following method of illustrating 

 this: take a globular magnet, or, what is more 

 easily procured, an oblong one, and place it hori- 

 zontally upon a table ; then take another small 

 oblong magnet, and suspend it by means of a 

 thread tied to its middle, or centre of gravity, so 

 that it will remain in an horizontal position, when 

 not disturbed by the vicinity of iron, or other 

 magnets. Now bring this small magnet held by 

 the thread, just over the middle of the large 

 magnet, and within two or three inches of it ; the 

 former will turn its south pole towards the north 

 pole of the large magnet, and its north pole to- 

 wards the south pole of the large one. 



It will be also noticed, that the small magnet, 

 whilst kept just over the middle of the large one, 

 will remain parallel to it; for since the poles of the 

 small magnet are equally distant from the contrary 

 poles of the large magnet, they are equally at- 

 tracted ; but if the small magnet be brought a 

 little nearer to one end than to the other of the 

 large magnet, then one of its poles, namely, that 

 which is nearest to the contrary pole of the large 

 magnet, will be inclined downwards, and, of 

 course, the other pole will be elevated above the 

 horizon. This inclination, it is evident, must in- 

 crease according as the small magnet is placed 

 nearer to one of the poles of the large one, be- 

 cause the attraction of the nearest pole will have 

 more power upon it. If the small magnet be 

 brought just opposite to one of the poles of the 

 large one, it will turn the contrary pole towards 



