66 FRAGMENTS Ol SCIENCE 



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repels, the north pole of the needle. The half proves to 

 be as perfect a magnet as the whole. You may break 

 this half and go on till further breaking becomes impos- 

 sible through the very smallness of the fragments; the 

 smallest fragment is found endowed with two poles, and 

 is, therefore, a perfect magnet. But you cannot stop 

 here: you imagine where you cannot experiment; and 

 reach the conclusion entertained by all scientific men, 

 that the magnet which you see and feel is an assem- 

 blage of molecular magnets which you cannot see and 

 feel, but which, as before stated, must be intellectually 

 discerned. 



Magnetism then is a polar force; and experience hints 

 that a force of this kind may exert a certain structural 

 power. It is known, for example, that iron filings 

 strewn round a magnet arrange themselves in definite 

 lines, called, by some, " magnetic curves," and, by oth- 

 ers, "lines of magnetic force." Over two magnets now 

 before me is spread a sheet of paper. Scattering iron 

 filings over the paper, polar force comes into play, and 

 every particle of the iron responds to that force. We 

 have a kind of architectural effort if I may use the 

 term exerted on the part of the iron filings. Here 

 then is a fact of experience which, as you will see 

 immediately, furnishes further material for the mind to 

 operate upon, rendering it possible to attain intellectual 

 clearness and repose, while speculating upon apparently 

 remote phenomena. 



The magnetic force has here acted upon particles visi- 

 ble to the eye. But, as already stated, there are numer- 

 ous processes in nature which entirely elude the eye of 

 the body, and must be figured by the eye of the mind. 



