EULOGY ON AMPERE. 145 



with reference to the action of a magnet on a connecting wire, and still 

 more silent, were it x^ossible, as to the action that two of those wires ex- 

 ercise upon each other. 



If, on the contrary, we take, with Ampere, the action of two cur- 

 rents for the primordial fact, the three classes of phenomena will depend 

 on one principle, one single clause. The ingenious conception of our 

 associate possesses thus two of the most salient characteristics of a 

 true laws of nature, simplicity and fertility. 



In all the magnetic experiments attempted before the discovery of 

 CErsted the earth had acted like a large loadstone. It was to be presumed, 

 then, like a magnet, it would act on electrical currents. Experiments, 

 however, had not justified the conjecture. Calling to his aid the electro- 

 dynamic theory and the talent for inventing apparatus, so brilliantly 

 displayed by him, Ampere had the honor of filling the inexplicable 

 hiatus. 



For several weeks native and foreign physicists crowded the humble 

 study in the street Fossee-Saint- Victor to witness with amazement a con- 

 necting wire of platina take a definite direction through the action of 

 the terrestrial globe. 



What would Newton, Halley, Dufay, ^pinus, Franklin, and Cou- 

 lomb have said if it had been announced to them that a day would 

 come when, in default of a magnetic needle, navigators would ho able 

 to guide their vess'4s by observing electrical currents, electrified wires? 



The action of the earth on a conducting wire is identical in all the cir- 

 cumstances presented by it, with that which w^ould proceed from an as- 

 semblage of currents, having its seat in the depths of the earth, south 

 of Europe, and whose movements would be like the diurnal revolutions 

 of the globe from west to east. Let it not be said, then, that, the laws 

 of magnetic action being the same in the two theories, it is a matter of 

 indifference which to adopt. 



Suppose the theory of Ampere true, and the earth, as a whole, inev- 

 itably a vast voltaic pile, creating currents moving in the direction of 

 the diurnal revolution ; and the memoir in which is found this magnifi- 

 cent result will take rank, without disadvantage, with the immortal 

 works which have made of our globe a simple planet, an ellipsoid fiat 

 tened at the poles, a body formerly incandescent in all its parts ; incan- 

 descent still down in its depths, but retaining on its siuface no appre- 

 ciable trace of this original heat. 



It has been asserted that the beautiful conceptions of Ampere, of 

 which I have just given a detailed analysis, were coldly received ; it has 

 been said that the French geometers and physicists showed themselves 

 little inclined either to recognize or study them ; that the academy, with 

 the exception of one single member, swaj'ed by its prejudices, refused 

 for a long time to yield itself to unexceptionable proof. 



These charges reached the public through an eloquent and eminently 



honorable organ. I cannot, therefore, pass them by without notice. 

 10 s 



