106 Electronic Energy and Relativity. 



inertia of the Lorentz electron is wholly electromagnetic 

 may be insecure — at least if equation (1) be made funda- 

 mental. 



In certain respects, the perfect conversion that Abraham's 

 equation of motion predicates (and that our test does not 

 disallow) may be said to introduce the limit-case (m l = 0). 

 The consequent perpetual balance of the forces replacing 

 (P, 11), not uniquely at the terminal velocity but through ail 

 stages of approach to it, was at its date novel *. Nevertheless 

 the main issue is not decided there, because we deal with 

 excess only beyond an initial value. A nucleus of mass 

 for an electron is not yet barred until some inherent contra- 

 diction due to it has been clearly located, 



The disguise of mechanical energy as electromagnetic is- 

 favoured through equations (13, 11). The effective deduc- 

 tion of (ra /4) that appears in the developments for both 

 electrons can be reconciled numerically with a composite 

 rest-massf. Any "weight-mass" is presumably external to 

 that conversion of energy in the electronic problem, which 

 the scale-factor must seek to cover. A preliminary inclusion 

 of associated mass must be made inoperative in the rectified 

 estimate of electromagnetic activity. The elastic con- 

 formity of one set of equations to varied physical suppositions 

 is strongly marked in all these phases, and in other combi- 

 nations left unmentioned that correct algebra permits. Such 

 uncertainties must continue until new evidence decides them. 

 One pertinent inquiry will concern itself with the quantity 

 (7(1-)), whose integral powers figure so prominently. Is 

 this series naturally commensurate with intervals that the 

 physics determines ? 



University of California. 



* Abraham, loc. cit. p. 129, eq. VI. ; p. 144, eq. (95 a). Also, on 

 grounds of formal resemblance, it was sometimes misunderstood to^ 

 be nothing else than d'Alembert*s idea, 



t The additional " potential energy " required by Abraham's argument 

 agrees in magnitude, within the velocity-range <0, c), with what the- 

 particular scheme of equations (27, 28, 29) would set aside as " pseudo- 

 conversion.*' Compare Abraham, loc. cit. pp. 189-95. Also the sug- 

 gestion added to equation (12) above. 



