170 Sir Oliver Lodge on a Possible 



latter would by no means be a mere framework of reference 

 axes and, as such, illegitimately privileged. For in referring 

 a class of phenomena to the sether here advocated we would 

 ultimately refer them to assignable physical things, namely 

 those most massive gigantic bodies which, so to speak, have 

 the strongest grip upon that medium. It is, among other 

 things, this latter -remark that I hope to make particularly 

 clear at an early opportunity. 



London, 

 December 22, 1919. 



XVI. Xote on a Possible Structure for the Ether. 

 By Sir Oliver Lodge*. 



DR. SILBERSTEIN'S communication gives me an 

 opportunity for calling attention to a paper of mine on 

 many points in connexion with the ether which mast surely 

 be of interest even to those who are contemplating the 

 abandonment of that medium. In that paper an estimate is 

 made of etheriai density, and an attempt to measure experi- 

 mentally its lower limit is described ; there are also comments 

 of interest from Sir Joseph Larmor and Sir J. J. Thomson. 

 The paper is in the Phil. Mag. ser. 6, vol. xiii. pp. 188-5(jb', 

 and is of date April 11)07 ; though among other things it 

 relates experiments conducted in and about 1893. 



The transmission of transverse vibrations like light shows 

 that the ether cannot be a mere structureless fluid ; and if it 

 is to be treated dynamically, which at first is surely a legiti- 

 mate attempt, it must have properties akin to what we call, 

 in matter, Rigidity and Inertia. Its inertia must be something 

 fundamental, which underlies and accounts for the inertia we 

 perceive in matter, possibly in a way having some analogy 

 with a motion of a solid through a perfect fluid. For when 

 an electric charge is moved, a magnetic field in the shape of 

 an ether vortex-rin^ is generated (with an energy of circula- 

 tion per unit volume equal to fju(eu sin By/Sirr*), and this 

 confers upon the charge its observed momentum if the 

 medium has the requisite density (see Phil. Mag., April 

 1907, vol. xiii. p. 492). The rigidity may be explicable 

 hydrodynamically by a vortex circulation — a turbulent 

 motion having a circulatory velocity of the same order as 

 that of the waves which the medium is able to transmit. 



In Lord Kelvin's laminar vortex arrangement the velocity 



* Communicated by the Author. 



