V. On the Nature of the Molecular Forces which regulate the Constitu- 

 tion of the Luminiferous Ether. By S. Earnshaw, M.A. of St. John's 

 College, Cambridge. 



[Read March 18, 1839.] 



There are already before the world by various authors several 

 Memoirs, which, collaterally or incidentally, embrace the subject of the 

 present communication. There is observable in them, however, much 

 disagreement of results, which seems chiefly to arise from the extreme 

 length and complexity of the investigations by which those results are 

 obtained ; to avoid which, as much as possible, their authors are compelled 

 to adopt means of simplification, which we cannot always be certain a 

 priori are sufficiently approximative. In the following pages the subject 

 will be found to be treated in a manner perfectly new and direct, and, 

 it is hoped also, satisfactory, inasmuch as the analytical operations employed 

 are brief and simple, involving no principles of a difficult or doubtful 

 character. 



The authors to which I have just alluded have generally adopted, as 

 a most extensive means of simplification, symmetrical arrangements of 

 the particles of the ethereal medium. This may be necessary and even 

 allowable in some cases : but as it has never been shewn that such 

 arrangements actually do exist in Nature, nor even that they can exist 

 in Nature, I have been careful to confine myself to the investigation of 

 properties which are independent of arrangement, or rather, which do 

 not involve the hypothesis of a peculiar arrangement. 

 Vol. VII. Part I. N 



