352 FRAGMENTS OF SCIENCE. 



suffices to show that you have not a magnet with a 

 single pole that each half possesses two poles with a 

 neutral point between them. And if you again break 

 the half into two other halves, you will find that each 

 quarter of the original strip exhibits precisely the 

 same magnetic distribution as the whole strip. You 

 may continue the breaking process: no matter how 

 small your fragment may be, it still possesses two oppo- 

 site poles and a neutral point between them. Well, 

 your hand ceases to break where breaking becomes a 

 mechanical impossibility; but does the mind stop 

 there? No: you follow the breaking process in idea 

 when you can no longer realise it in fact; your thoughts 

 wander amid the very atoms of your steel, and you 

 conclude that each atom is a magnet, and that the 

 force exerted by the strip of steel is the mere summa- 

 tion, or resultant, of the forces of its ultimate particles. 

 Here, then, is an exhibition of power which we can 

 call forth at pleasure or cause to disappear. We mag- 

 netise our strip of steel by drawing it along the pole of 

 a magnet; we can demagnetise it, or reverse its mag- 

 netism, by properly drawing it along the same pole in 

 the opposite direction. What, then, is the real nature 

 of this wondrous change? What is it that takes place 

 among the atoms of the steel when the substance is 

 magnetised? The question leads us beyond the region 

 of sense, and into that of imagination. This faculty, 

 indeed, is the divining-rod of the man of science. 

 Not, however, an imagination which catches its crea- 

 tions from the air, but one informed and inspired by 

 facts; capable of seizing firmly on a physical image 

 as a principle, of discerning its consequences, and of 

 devising means whereby these forecasts of thought 

 may be brought to an experimental test. If such a 

 principle be adequate to account for all the phenomena 



