134 ON MAGNETISM. 



dragged the red magnetism of the affected magnet to 

 one end and there left it fixed : here it seems that it 

 draws the red magnetism of the iron bar (or a portion 

 of it) to one end, but cannot leave it fixed there : that 

 in the instance of iron, as distinguished from steel, the 

 separate kinds of magnetism take the earliest oppor- 

 tunity of returning to their original seats and producing 

 neutral magnetism in every part. 



Fig 50 We a ^ so see ^ ne reason wnv a horse-shoe 



magnet so energetically attracts a piece of 

 iron touching both its poles, as in Figure 

 50. Each pole of the horse-shoe converts 

 the corresponding part of the iron into a 

 pole of opposite quality, and the existence 

 of each impressed pole at one end of the 

 iron seems to have a tendency to intensify 

 the opposite pole at the other end, and thus the 

 iron is in the state of a powerful magnet attracted 

 by another powerful magnet, and the attraction (pro- 

 portional to the product of the powers) is very 

 energetic. 



59. Rapid diminution, with increase of distance, of 

 the attraction between a magnet and soft iron. 



The magnetic power of the permanent magnetism 

 in one pole of the magnet varies, as has been demon- 

 strated, inversely as the square of the distance of the 

 magnetic body on which it acts. It appears reasonable 

 to suppose that its influence in inducing magnetism 



