140 EULOGY ON AMPERE. 



sented to you ;i iiiueli more general fact tlian that of the physicist of 

 (Jopeiihagen. 



lu 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 exti^emely ingenious arrangements to make these 

 wires movable without the necessity of detacliing the extremities of 

 each from the respective poles of their batteries. lie 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 lield of ])hysics ever exhibited so beautiful a dis- 

 covery conceived and consummated with so much rapidit3\ 



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

 Two parallel connecting wires attract each other when the electricity 

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

 otlier when the electric currents move in opposite directions. 



Tiie connecting wires of two batteries similarly i)laccd, of two bat- 

 teries whose copper and zinc poles respectively correspond 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 o])posite the c()])per 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 i)henomena of (Ersted, 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 electro-dyna- 

 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 modification of the ordinary electrical attractions an<l repulsions 

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

 were prompt and decisive. 



Bodies similarly electrified re])el each other; similar currents attract 

 each other. Bodies in an opjtosite 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. 



No subterfuge in the world could resist this close argumentation. 



