IO4 POLARIZATION I HOW SUSTAINED. 



CHAPTER XIII. 



THE CONTINUOUS CIRCULATION OF ELECTRIC CURRENTS 

 ABOUT MAGNETS AND MOLECULES SUSTAINS THEIR 

 POLARIZATION. 



TT may seem incredible that electric currents, 

 whereby molecular and magnetic forces are 

 sustained, can circulate continually about molecules 

 and magnets ; but this fact is verified experimen- 

 tally, and the direction of the circulation may be 

 reversed several thousand times in a minute, with 

 a corresponding reversal of their poles. By 

 placing a common steel y^^^XXX^OOOTv 

 sewing-needle within a ~T r [)(JOO(/0000)^ 

 spiral coil of wire, as in /^^^^^ ^/ 

 Fig. 2 7, the slightest trans- Fig , 27 . 



mission of electric action through the coil puts in 

 motion a corresponding circulation of currents 

 about the steel needle, and renders it permanently 

 magnetic. That particular end of the needle, 

 about which the circuit of the current is in the 

 direction shown at s, being similar to that of the 

 hands of a watch about a dial-plate, is found to 

 manifest the peculiar properties of the south pole 

 of a magnet. Where the current comes out at 



