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2. Demonstrations of a new theory, from which con be deduced all the laws of refraction, 
ordinary and extraordinary, read at the academy March 27, 1815. 
3. A memoir on the determination of the curved surfaces of luminous waves in a medium whose 
elasticity differs in three dimensions, read at the Academy of Sciences August 26, 1828. 


Amongst the works of our friend there is one which excels all the others; it constitutes, in 
itself, a beautiful science, and its name, " Electro-dynamics," will ever be inseparably linked with 
that of Ampère. Instead of presenting to your thoughts twenty different subjects in succession, 
permit me to concentrate them for a time on the vast and teeming conception 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 posterity. 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, bars of iron, and more especially of steel, 
freely supported, turn toward the north. This curious property has given us the two Americas, 
Australia, the numerous archipelagoes, and the hundreds of isolated islands of Oceania, &c.; it is 
to it this, in cloudy and foggy weather, the mariner, plowing the 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 mysterious – I had almost said, cabalistic – 
operations which transform it into a magnet. 
The whole phenomena of magnetism, the diminution, the destruction, the inversion of the polarity of 
the needle of the compass, occasioned sometimes on ships by violent discharges of lightning, seemed 
to establish some intimate connection between magnetism and electricity. Nevertheless, the labors, 
ad hoc, undertaken at the request of several academies in order to develop and strengthen 
this analogy, led to so few decisive results that we read, in a programme by Ampère himself, 
printed in 1802: 

“The professor will demonstrate that the electrical and magnetic phenomena are owing to two 
different fluids, which act independently of each other.” 
Sciences had reached this point when, in 1819, the Danish physicist, Oersted 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 will be transmitted from acre to age, as long as science is 
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