APP. M.] LARMOR'S THEORY 229 



singularity (beknottedness) of dimension large compared 

 with the negative, it would be but a feeble agent in the 

 transformation of energy, and thus could readily escape 

 detection. Cf. Jfther and Matter, 122. But the 

 absolute structure of an electron is probably very unlike 

 the distributions of electric charge on spheres and ellip- 

 soids that have hitherto been taken to represent it. 



The theory of a simple molecule appeared for the first 

 time in Phil. Trans., 13th August, 1894, pp. 806-818; 

 inertia purely electric, on p. 807 ; estimate of size and 

 dimensions, and electrodynamics of orbital motions, on 

 p. 814; Hall effect, etc., on p. 815. There does not 

 appear to be anything in Lorentz's papers, either of 1892 

 or 1895, to correspond to the ideas there introduced. 



With reference to a theory of the Zeeman effect : . the 

 simplest type of illustrative system, amenable to calcu- 

 lation, would be a statical one, in which the electrons 

 would all vibrate round positions of stable equilibrium. 

 But this requires extraneous supporting force, if they are 

 in empty space. A definite subdivision of the periods 

 has been worked out for J. J. Thomson's statical illustra- 

 tion, in which this innate instability of a statical system 

 of negative electrons (Earnshaw's theorem) is obviated 

 by supposing them inside a region of continuous positive 

 electrification, which may be taken to represent the posi- 

 tive electron. If the volume density of this is small, the 

 resulting stability will be but slight, and a small displace- 

 ment will upset the system, and lead to its break-up ; 

 which is unlikely, perhaps unreasonable. 



But here, as before, it is only isotropic configurations, 

 in the same sense as in the hydrokinetics of solids in 

 fluids, namely, those with which an associated quadratic 

 function must be wholly isotropic, including the configura- 

 tions of the regular solids, that split the lines definitely 



