264 FRESNEL. 



covered, important applications rise up, as if by enchant- 

 ment, out of experiments which, until then, would seem 

 likely to remain for ever among the number of abstract 

 speculations. A fact which no direct utility had as yet 

 recommended to the attention of the public becomes, per- 

 haps, the step on which a man of genius supports himself 

 to climb up to those primary truths which change the 

 whole face of science, whether for creation of some eco- 

 nomical moving power, which all manufacturing arts will 

 henceforth adopt, and of which not the least merit is that 

 of delivering thousands of operatives from overwhelming 

 toils which assimilated them with the brutes, ruined their 

 health, and brought them to a premature death. If to 

 fortify these reflections examples may be thought neces- 

 sary, I should feel no other embarrassment than that of 

 too wide a choice. But here there is no necessity to 

 enter on such details ; for to all the theoretical researches 

 already mentioned, Fresnel has added an important labour, 

 having an immediate practical application, which will cer- 

 tainly place his name among those of the benefactors of 

 the human race. This work, every one. knows, had for 

 its object the improvement of light-houses. I will pro- 

 ceed to trace the outline of its progress, and shall thus 

 have finished the sketch which I proposed to offer you of 

 the brilliant scientific career of our late colleague. 



Persons unacquainted with nautical matters are usually 

 seized with a sort of fear when the vessel which carries 

 them, at a distance from continents or islands, has no 

 other witness of its progress than the stars and the waves. 

 A view of any coast the most barren, the most rocky, the 

 most inhospitable, dissipates, as if. by enchantment, those 

 undefined fears which their absolutely isolated position 

 had inspired, while, to the experienced navigator, it is 



