141. 



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 nothing 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 desideratum 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.f Now, ray 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 circumslances 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 the general 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 

 ol'Professor Powell. — See notes, pp. Ill, 149. 



