loG EULOGY ON AMrEKE. 



2. Demo )i,slra lions of a )i.cw theory, from icliich can he d educed all the 

 laws of refraction, ordinari/ and extraordinary ; read at the academy 

 Mareli27, 1815. 



o. A memoir on the determination of the curved surfaces of luminous 

 waves in a medium whose elasticity differs in three dim.ensions ; read at the 

 Academy of Sciences Aug-u.st 20, 1828. 



ampere's RESEAliCHES IN THE SCIENCE OF ELECTS0-DYNA3IICS. 



Amougst the works of our friend there is one which excels all the oth- 

 ers ; it constitutes, in itself, a beautiful science, audits name, "Electro- 

 dynamics," will ever be inseparably linked with that of Ampere. Instead 

 of presenting to your thoughts twenty different subjects in succession, 

 l)ermit me to concentrate them for a time on the vast and teeming con- 

 ception of our friend, happy if I succeed in disengaging it from any 

 appearance of obscurity and ambiguity it may have presented up to 

 this time, and thus show the elevated rank which will entitle it, 

 with the most beautiful discoveries of the age, to the gratitude of pos- 

 terity. While so many of the ancient and modern sciences were making 

 rapid and momentous progress, the science of magnetism had remained 

 almost stationary. We have known that, for centuries at least, barsot 

 iron, and more especially of steel, freel}' sui)ported, turn towaid the 

 north. This curious property has given us the two Americas, Austra- 

 lia, the numerous archepelagoes, and the hundreds of isolated islands of 

 Oceanica, &c.; it is to it this, in cloudy and foggy weather, the mariuer, 

 l^lowiugthe mighty oceans, has recourse, to guide and direct his ship; 

 no truth in physics has had results so colossal. ^Nevertheless, until the 

 present time, nothing had been discovered regarding the nature of the 

 peculiar modification undergone by a bar of neutral steel during the 

 mysteriq^is — I bad almost said, cabalistic — operations which translorra 

 it into a- nagnct. 



The whole pheuomena of magnetism, the diuiiuntion, the destruction, 

 the inversion of the polarity of the needle of the compass, occasioned 

 sometimes on ships by violent discharges of lightning, seemed to estab- 

 lish some intimate connection between magnetism and electricity. Nev- 

 ertheless, the labors, orZ hoc, undertaken at the request of several acad- 

 emies in order to develop and strengthen this analogy, led to so few 

 decisive results that we read, in a programme by Ampere himself, printed 

 in 1802 : 



"The professor will demonstrate that the electrical and magnetic phe- 

 nomena are owing to two different fluids, which act independently of 

 each other." 



Sciences had reached this point Mhen, in 1819, the Danish })h3 sicist, 

 CErsted, announced to the learned world a fact, wonderful in itself, but 

 more so especially from the consequences deduced from it ; a fact the 

 memory of which Avill be transmitted from age to age, as long as science is 



