188 MAGNETS. 



temporary magnet will be opposite to those of the perma- 

 nent magnet. The molecules of the iron seem to be 

 polarized by the force of the magnet when brought within 

 the limited range of that force. The combined fluid is 

 separated in each molecule, because the fluid acting at the 

 pole of the magnet attracts its opposite and repels its like, 

 and this separating influence is greater than the mutual 

 attraction of the two fluids thus torn asunder. The iron 

 is said to be magnetized by induction. If the distance 

 between the iron and the magnet be diminished, the 

 inductive influence is thereby increased. Actual contact 

 is not necessary, but when the iron and the magnet 

 touch, this inductive force is the greatest. This force, 

 like other forms of attraction, varies inversely as the 

 square of the distance ( 100 [2]). 



312. Illustrations of Magnetic Induction. (a.) When 

 a piece of soft iron, as a nail or ring, is brought near the end of a 

 magnet, the molecules of 

 the iron are polarized (i. e., 

 their magnetic fluids are 

 separated), and the iron be- 

 comes a magnet for this 

 reason. When the ring 

 touches the magnet it will 

 be supported. Bring a 

 second ring near the first 

 ring. The action of the 

 first ring, which is a mag- 

 net now, polarizes the p I( , 

 Second ring and thus ren- 

 ders it a magnet also. Let it touch the first ring magnet and it 

 will be supported. In this way quite a number of rings (Fig. 124) 

 may be supported, each ring in turn being thus magnetized by its 

 predecessor. Of course, the attractive and repulsive forces are con- 

 tinually weakening from the first to the last ring. Now support 



