474 HISTORY OF OPTICS. 



an explanation of refraction on the principles of 

 the undulatory theory ; alleging, as the reason for 

 doing so, that the theory was still little known. 

 And in succeeding years there appeared in the same 

 work, his theory of reflection. His memoir on 

 this subject (Memoire sur la Loi des Modifications 

 que la Reflexion imprime a la Lumiere Polarisee,) 

 was read to the Academy of Sciences in 1823. 

 But the original paper was mislaid, and, for a time, 

 supposed to be lost; it has since been recovered 

 among the papers of M. Fourier, and printed in 

 the eleventh volume of the Memoirs of the Aca- 

 demy 6 . Some of the speculations to which he 

 refers, as communicated to the Academy, have never 

 yet appeared 7 . 



Still Fresnel's labours were, from the first, duly 

 appreciated by some of the most eminent of his 

 countrymen. His Memoir on Diffraction was, as 

 we have seen, crowned in 1819: and, in 1822, a 

 Report upon his Memoir on Double Refraction 

 was drawn up by a commission, consisting of MM. 

 Ampere, Fourier, and Arago. In this report 8 Fres- 

 nel's theory is spoken of as confirmed by the most 

 delicate tests. The reporters add, respecting his 

 "theoretical ideas on the particular kind of undu- 

 lations which, according to him, constitute light," 

 that "it would be impossible for them to pronounce 

 at present a decided judgment," but that "they 



8 Lloyd. Report on Optics, p. 363. (Fourth Rep. of Brit. Ass.) 

 * Ib. p. 316, note. 8 Ann. Chim. torn. xx. p. 343. 



