140 



made the subject of elaborate investigation by other writers. 

 That celebrated analyst, conceiving (though without suffi- 

 cient reason, as will presently appeal') that he had fully ex- 

 plained the known laws of the propagation of rectilinear yihra- 

 tionsby the hypothesis that the luminiferous ether, in media 

 transmitting such vibrations, consists of separate molecules 

 symmetrically ?LYYa.r\gedi with respect to each of three rectangu- 

 lar planes, and acting on each other by forces which are some 

 function of the distance, was led very naturally to imagine 

 that he would find the laws of circular and elliptic vibrations, 

 in other media, to be included in the more general hypothesis 

 of an unsymmetrical arrangement. Accordingly, in a letter 

 read to the French Academy on the 22nd of February, 1836, 

 a letter to which he attached so much importance that he 

 desired it might not only be published in the Proceedings, 

 but also " deposited in the Archives" of that body (see the 

 Comptes renchis des Seances de V Academie des Sciences, tom. 

 ii.p. 182), he gave a precise statement of his more extended 

 views, informing the Academy that he had submitted his new 

 theory to calculation, and that, among other remarkable re- 

 sults, he had obtained (with a slight variation or correction) 

 the laws of circular polarization, discovered by Arago, Biot, 

 and Fresnel. Referring to his Memoir on Dispersion, pub- 

 lished at Prague, under the title of Nouveaux Exercices de 

 Mathematiques, he observes, that the I'esults therein con- 

 tained may be generalised, by "ceasing to neglect" in the 

 equations of motion [the equations marked (24) in § 2 of 

 that memoir], certain terms which vanish in the case of a 

 symmetrical distribution of the ether. He then goes on to 

 say— 



" Nos formules ainsi generalisees representent les phe- 

 nomenes de I'absorption de lalumiere ou de certains rayons, 

 produite par les verres colores, la tourmaline, &c., le phe- 

 nomene de la polarisation cii-culaire produite par le cristal 

 de roche, I'huile de terebenthine, &c. {Voir les experiences 



