14 1 



hypothesis, and had even gone so far as to reject along with it 

 the whole of M.Cauchy's views about the mechanism of light. 

 For though, in my paper, I have said notliing of any mecha- 

 nical investigations, yet, as a matter of course, before it was 

 read to the Academy, I made every effort to connect my 

 equations in some way with mechanical principles; and it 

 was because I had failed in doing so to my own satisfaction, 

 that I chose to publish the equations without comment,* as 

 bare geometrical assumptions, and contented myself with 

 stating orally to the Academy, as I did some months after to 

 the Physical Section of the British Association in Bristol 

 (see Transactions of the Sections, p. 18), that a mechanical 

 account of the phenomena still remained a desidercdian which 

 no attempts of mine had been able to supply. I am not sure 

 that on the first occasion I stated the precise nature of these 

 attempts, though I incline to think I did ; but I have a dis- 

 tinct recollection of having done so on the second occasion, 

 in reply to questions that were asked me by some Members 

 of the Association. -j- Now, my first attempt to explain those 

 equations, which was made almost as soon as 1 discovered 

 them, actually turned upon the very idea which about the 

 same time found entrance into the mind of M. Cauchy — 

 I mean the idea of an unsymmetrical arrangement of the 

 ether. For as it was generally believed, at that period, 



» The circunislances here related will account for what Mr. Whewell {History of 

 the Inductive Sciences, vol. ii. p. 449) calls the " obscure and oracular form" in 

 which those equations were published. Having, at that time, no good explanation 

 of them to give, I thought it better to attempt none. But in thegeneral view which 

 I have since taken (see p. 103 of this volume), they do not offer any peculiar diffi- 

 culty. 



f At the period of this meeting, M. Cauchy's letter on Elliptic Polarization 

 had been published for some months ; but I was not then aware of its existence. 

 Indeed the letter appears not to have attracted any general notice ; for the theory 

 which it contains was afterwards advanced in England as a new one, and M. 

 Cauchy has been lately obliged to assert his prior claim to it, through the medium 

 of Professor Powell. — See iiotei, pp. 1 U, H'J. 



