[ 42 J 



VII. On certain recent Investigations in the Theory of Light, 

 By Professor Stokes. 



To the Editors vf the Philosophical Magazine and Journal. 



Gentlemen, 



IN the recently published Part of the Philosophical Transac- 

 tions occurs a paper by my friend the Rev. Joseph Power, 

 entitled "Theory of the Reciprocal Action between the Solar 

 Rays and the different Media by which they are reflected, 

 refracted, or absorbed; in the course of which various optical laws 

 and phsenomcna are elucidated and explained,^' for a copy of 

 which I am indebted to the kindness of the author. The results 

 arrived at in this paper are of a remarkably novel and therefore 

 attractive character, but the investigations appear to me to lie open 

 to the gravest objections. I am at present engaged in discussing 

 the matter privately with Mr. Power, and I am unwilling to 

 trouble the public and fill your pages with the details of the con- 

 troversy. If, as I hope and expect, Mr. Power and I come ulti- 

 mately to agree, our views can be laid before the public with 

 much more brevity. My only object in mentioning the subject 

 at present is to show that the question has been taken up. 

 I am. Gentlemen, 



Your faithful Servant, 

 Pembroke College, Cambridge, G. G. Stokes. 



June 20, 1854. 



VIII. On the Mathematical Theory of Electricity in Equilibrium, 

 By William Thomson, B.A., Fellow of St. Peter^s College. 



[Extracted from the "Cambridge and Dublin Mathematical Journal," 

 Nov. 1845. Notes and additions of the present date, March 1854, are 

 enclosed in brackets.] 



I. On the Elementary Laws of Statical Electricity^. 



1. nnHE elementary laws which regulate the distribution of 

 A electricity on conducting bodies have been determined 

 by means of direct experiments, by Coulomb, and in the form 

 he has given them, which is independent of any hypothesis f, 

 they have long been considered as rigorously established. The 

 problem of the distribution of electricity in equilibrium on a 

 conductor of any form was thus brought within the province of 

 mathematical analysis; but the solution, even in the simplest 

 cases, presented so much difficulty that Coulomb, after having 



* This paper is a translation by the author (with considerable additions) 

 of one which appeared in Liouville's Journal de Mathhiatique, vol. x. 

 p. 209. 



t See the first Note at the end of this paper. 



