98 Mr EARNSHAW, ON THE NATURE 



I may also remark that the investigations which follow are in other 

 respects of a very general character. For, in this attempt to discover 

 the laws of molecular action of the ether, amongst the experimental 

 properties, assumed as the basis of analytical investigation, are, I believe, 

 none which are peculiar to the luminiferous ether. I think it probable, 

 that most terrestrial bodies possess in a greater or less degree of per- 

 fection the properties here assumed : and consequently, the title of this 

 paper might have been made more comprehensive. It might, perhaps, not 

 improperly be, " An Investigation of the Nature of the Molecular Forces, 

 which regulate the Internal Constitution of Bodies. " This might, however, 

 be disputed, and therefore in the investigations I have referred only to 

 the luminiferous ether. Nevertheless, that the reader may more easily 

 judge what degree of claim the following pages have to that general 

 character which is here ascribed to them, I shall, in as few words as 

 possible, introduce a statement of the experimental assumptions, and the 

 results respectively derived from them. 



I. It is assumed that the ether consists of detached particles; each 

 of which is in a position of equilibrium, and when slightly disturbed 

 is capable of vibrating in any direction. (Many solid as well as aerial 

 bodies transmit sound, which is generally supposed to imply the exist- 

 ence of the same properties in them as are here assumed to be true of 

 the ether.) 



The most curious and perhaps least expected result of this assumption 

 is, that the molecular forces which regulate the vibrations of the ether do 

 not vary according to Newton's law of universal gravitation : and it is not 

 a little remarkable, that a force, whether attractive or repulsive, varying 

 according to this law, is the only one which cannot possibly actuate the 

 particles of a vibrating medium. 



II. It is next assumed, that the motion of a vibrating particle is 

 more affected by the influence of the particles which are near to it than 

 of those which are more remote. (This is certainly true of many other 

 substances besides the ether.) The result which is sought to be derived 

 from this assumption is, that the molecular forces which regulate the vibra- 



