156 THE AGE OF ELECTRICITY. 



an experimeutal demonstration of the laws of the propagation of elec- 

 tricity through slightly conductive bodies and to verify the correctness 

 of the formulae that Ohm had merely indicated as being mathemat- 

 ically analogous to Fourier's theory on the propagation of heat. With 

 similar means he disclosed the relations existing between the theorems 

 of static electricity and the propagation of currents. His investiga- 

 tions of thermoelectric i)henomena and the properties of crystals are 

 stamped with the same mark of perfection ; the methf»ds adopted by 

 him still stand among the most elegant and correct. The one fault with 

 his investigations was perhaps that they were too early and could not 

 be well understood; they were subsequently thrown in the shade by 

 more brilliant discovery, and it was only when nearing the close of his 

 career that Gaugain enjoyed the well-deserved satisfaction of being 

 api)reciated according to his merits. 



Augustin Fresnel was born at Brogiie. He is not therefore a citizen 

 of the Department of Calvados, but he is one of yours as a Low Nor- 

 man, and a memorable circumstance of his life binds him to you by 

 even closer ties. At the beginning of the "Hundred days" he was 

 suspended from his office of engineer for expressing too openly his 

 partiality to the restoration, and came to enjoy his enforced leisure in 

 the small village of Mathieu, the elder Ivouelle's home. He undertook 

 at that place his labors on optics which were to make him famous. 

 l>ut for that fortunate disgrace, Fresnel would, we fear, never have 

 found time to give himself up to scientific investigation, by reason of 

 his extremely delicate health, and to give full scope to his genius. 

 From that time, and during a period of twelve years, his papers follow 

 one another with prodigious fecuiulity, as though he had a presentiment 

 that his days were numbered. He shattered forever the hypothesis of 

 emission by showing that all the phenomena of interference and diffrac- 

 tion are the necessary consequence of the doctrine of undulations; and 

 he followed up the expansion of that theory in all its details by setting 

 down tiie rules of reilection, refraction, double refraction, etc. 



Whenever he found that mathematical analysis or the accepted 

 notions on the mechanical structure of the mediums did notattbrd him 

 adequate resources, he boldly skii)ped the arduous passages over which 

 he had no time to tarry and guessiBd the rest. After eighty years his 

 work remains intact, confirmed more and more by subsequent investiga- 

 tions. His i)apers still constitute the most fruitful reading for physi- 

 cists. They afford a better comprehension of his mind, and offer a vast 

 number of disseminated prolific notions which had at first escaped 

 notice, and which others after him tiiought they had discovered. New- 

 ton alone, according to an English savant, is greater than he. 



A bust of Fresnel stands on his grave at the Pere-Lachaise ceme- 

 tery. Some years ago the Societe de Physique set about to search 

 for any memento of this national celebrity. An abandoned grave, hid- 

 den from view by wild vegetation, was discovered with great difficulty. 



