204 GREAT MEN OF SCIENCE 



powerful inventive genius, tireless industry, strict love of 

 truth, and technical mastery.' 



Fresnel came from Normandy; his father was an architect.^ 

 He made poor progress at school; he learned slowly and with 

 great difficulty. Nevertheless, when he was able to go to the 

 technical high school in Paris, at the age of sixteen and a 

 half, he began to make rapid progress, especially in the 

 mathematical sciences. At about the age of twenty, he had 

 completed his education in road and water engineering, and 

 he then entered State service in this capacity. This re- 

 mained his chief occupation throughout life. The year 1815 

 brought a short interruption, as Napoleon returned from 

 Elba, and Fresnel was most anxious to join the troops which 

 were to oppose his entry into Paris, in spite of the fact that 

 Fresnel was little adapted to bodily exertion. He was taken 

 a prisoner half dead, but was treated with great gentleness. 



At this time he began his optical studies, to which he was 

 led by reports from the Academy in Paris, and these studies 

 occupied his thoughts when engaged on the lonely occupa- 

 tion of supei"vising roadmaking. He read at that time of 

 'polarised light' and complains in letters that he cannot guess 

 what it is. When he was referred to books (such as Hauy's 

 Physics) he soon was so far advanced as to be able to under- 

 take his own investigation with the aid of simple apparatus in 

 his leisure hours, and. in the same year, 181 5, he presented to 

 the Paris Academy his first and valuable paper on the dif- 

 fraction of light. From this time to the year 1826, appeared 

 the great series of his profound optical researches, which are 

 not only astonishing even to-day, but have actually retained 

 their full value as regards their innumerable results. The 

 cost of his necessary experimental equipment was met by his 

 entering the Commission for lighthouses, and obtaining the 

 position of an examiner in the technical school; but these were 



^ Compare CEuvres Completes de A. Fresnel, Paris, 1870. 3 vols. 



