140 



ON MAGNETISM. 



Fig. 51. 



O 

 O 

 O 

 O 

 O 

 O 

 O 

 O 

 O 

 O 



the second line to represent the 

 state of their magnetisms as affect- 

 ed by the induction of the great 

 masses of blue and red magnetism 

 external to them. (The effect of 

 one of these masses alone is pre- 

 cisely similar in kind to that of 

 the two masses.) Then, in analogy 

 with everything that we have seen of 

 magnetization of steel magnets and 

 of iron bars, we may conceive the 

 blue magnetism of each circle to be 

 drawn towards the external red mass, 

 and the red magnetism of each circle 

 to be drawn towards the external 

 blue mass, as shewn in the figure. 

 The effect of this will be that, 

 through all the intermediate parts 

 of the series, the blue and red alternate in such a 

 way that we cannot perceive any clear tendency 

 in them to produce magnetic effect on an external 

 body: but there is certainly a red pole at one end 

 and certainly a blue pole at the other. When we 

 conceive a system of parallel lines of the same kind 

 passing through a mass of iron, we find that the whole 

 exterior surface which is turned towards the great red 

 mass is clothed with blue magnetism, and that the 

 whole which is turned towards the great blue mass is 

 clothed with red magnetism : and the mass resembles 

 to some extent a steel magnet. 



