368 FRAGMENTS OF SCIENCE 



sure of this, and do not take the statement on my 

 authority. 



Now, take a second darning-needle like the first, and 

 magnetize it in precisely the same manner: freely sus- 

 pended it also will turn its eye to the north and its point 

 to the south. Your next step is to examine the action of 

 the two needles, which you have thus magnetized, upon 

 each other. 



Take one of them in your hand, and leave the other 

 suspended; bring the eye- end of the former near the eye- 

 end of the latter; the suspended needle retreats: it is re- 

 pelled. Make the same experiment with the two points; 

 you obtain the same result, the suspended needle is re- 

 pelled. Kow cause the dissimilar ends to act on each 

 other — ^you have attraction — point attracts eye, and eye 

 attracts point Prove the reciprocity of this action by 

 removing the suspended needle, and putting the other in 

 its place. You obtain the same result. The attraction, 

 then, is mutual, and the repulsion is mutual. You have 

 thus demonstrated in the clearest manner the fundamental 

 law of magnetism, that like poles repel, and that unlike 

 poles attract, each other. You may say that this is all 

 easily understood without doing; but do it, and your 

 knowledge will not be confined to what I have uttered 

 here. 



I have eaid that one end of your bar-magnet has a 

 mark upon it; lay several silk fibres together, so as to get 

 sufficient strength, or employ a thin silk ribbon, and form 

 a ioop large enough to hold your magnet. Suspend it; it 

 turns its marked end toward the north. This marked end 

 is that which in England is called the north pole. If a 

 common smith has made your magnet, it will be conven- 



