362 FRAGMENTS OF SCIENCE. 



simple attraction observed in the first instance is now re- 

 placed by a dual force. Repeat the experiment till you 

 have thoroughly observed the ends which attract and those 

 which repel each other. 



"Withdraw the magnet entirely from the vicinity of your 

 needle, and leave the latter freely suspended by its fibre. 

 Shelter it as well as you can from currents of air, and if 

 you have iron buttons on your coat or a steel penknife in 

 your pocket, beware of their action. If you work at night, 

 beware of iron candlesticks, or of brass ones with iron rods 

 inside. Freed from such disturbances, the needle takes up 

 a certain determinate position. It sets its length nearly 

 north and south. Draw it aside from this position and let 

 it go. After several oscillations it will again come to it. 

 If you have obtained your magnet from a philosophical-in- 

 strument maker, you will see a mark on one of its ends. 

 Supposing, then, that you drew your needle along the end 

 thus marked, and that the eye-end of your needle was the 

 last to quit the magnet, you will find that the eye turns to 

 the south, the point of the needle turning toward the north. 

 Make sure of this, and do not take this 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 point to the north and its eye 

 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 sus- 

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

 of the latter ; the suspended needle retreats : it is repelled. 

 Make the same experiment with the two points, you obtain 

 the same result, the suspended needle is repelled. Now 

 cause the dissimilar ends to act on each other — you have 

 attraction — point attracts eye and eye attracts point. Prove 



