114 ARTIFICIAL CURRENT-CHANGER. 



. 



EFFECT OF CHANGING THE DIRECTION OF ELECTRIC 

 CURRENTS. 



By artificially changing the directions of electric 

 currents transmitted through the approximated 

 sides of bodies serving as electrodes, their recip- 

 rocal movements toward, or from each other, are 

 producible at pleasure. This is effected by the 

 use of a " Current-changer," as in 

 Fig. 33. Two elastic steel springs, 

 w w, are severally connected with 

 Fig ' 33> the two poles of a battery circuit, 



for transmitting the current first to one half of a 

 semi-cylindrical clasp s, and then to the other half 

 successively, by the turning of the spindle A, shown 

 by a cross-section. The two clasps, s s, are insu- 

 lated by varnished silk from the spindle, and are 

 severally connected with the two ends of a con- 

 ducting-wire by which the direction of the battery 

 circuit is to be reversed. This device is used as an 

 automatic current-changer ; and, by its timely rever- 

 sals from an attractive to a repellent electric force, 

 a freely movable coil of conducting wire is made to 

 revolve several thousand turns in a minute. 



The instantaneous change of direction of cir- 

 culating electric currents about bodies and mole- 

 cules, and consequent instantaneous changes from 

 reciprocal attraction to reciprocal repulsion, is 

 shown by the blow of a hammer on a bar of iron, 

 as indicated in Fig. 34. 



