140 EULOGY ON AMPERE. 



sented to you a uiucli more general fact tbaii tliat of the i)bysici.st of 

 Copenhagen. 



In that short interval of time he had conjectured that two connecting 

 wires, two wires traversed by electrical currents, would act on each 

 other; he had devised extremely ingenious arrangements to make these 

 wires movable without the necessity of detaching the extremities of 

 each from the respective i^oles of their batteries. He had embodied 

 these conceptions in instruments capable of acting; he had, in fact, 

 reduced his wonderful idea to a decisive experiment. I do not know 

 whether the vast held of physics ever exhibited so beautiful a dis- 

 covery conceived and consummated with so much rapidity. 



This brilliant discovery of Ampere may be summed up in these words: 

 Two ])arallel connecting wires attract each other when the electricity 

 traverses them in the same direction ; on the contrary, they repel each 

 other when the electric currents move in opposite directions. 



The connecting wires of two batteries similarly i)laced, of two bat- 

 teries whose copper and zinc poles respectively coriespoud always, 

 then attract each other. There is in the same way always repulsion be- 

 tween the connecting wires of two batteries when the zinc pole of one 

 is opposite the copper pole of the other. 



It is not a necessary condition of these singular attractions and re- 

 pulsions that the wires in operation should belong to two different bat- 

 teries. By bending and rebending a single connecting wire such an 

 arrangement may be made that two of its portions, opposite to each 

 other, may be traversed by the electrical current either in the same or 

 in opposite directions. The phenomena, then, are absolutely identical 

 with those which result from currents proceeding from two distinct 

 sources. 



The phenomena of CErsted, from their origin, had been called, very 

 appropriately, electro-magnetic. To those of Ampere, in which the 

 magnet plays no distinct part, the more general name of electrodyna- 

 mics has been applied. 



The experiments of the French savant did not escape at first those 

 criticisms which envy reserves for all things possessing novelty, im- 

 portance, and a future. Men were unwilling to see in the attractions 

 and repulsions of these currents anything more than a hardly appre- 

 ciable modificatiou of the ordinary electrical attractions and repulsions 

 known since the time of Dufay. On this point the replies of our friend 

 were prompt and decisive. 



Bodies similarly electrified repel each other ; similar currents attract 

 each other. Bodies in an opposite condition of electricity attract each 

 other; unlike currents repel each other. 



Two bodies similarly electrified repel each other from the moment of 

 contact ; two wires traversed by similar currents remain together like 

 two magnets, if brought into contact. 



!N^o subterfuge in the world could resist this close argumentation. 



