586 Dr. A. C. Creliore on an Atomic Model 



present. It will be recognized, however, that such specula- 

 tion* is quite a different thing from the random speculation 

 of many. 



The first important problem is to determine the form that 

 an electrical charge, E, will assume when left to itself. The 

 so-called Lorentz solid electron is usually pictured as a sphere 

 when not in translational motion. For this electron the usual 

 results give the electromagnetic f energy as 



W = 3E 2 /5a£, (69) 



and the mass % 



-MS- ■ ■ • ■ ■ ^ 



The state of: internal motion of the charge is neglected in 

 these results, each element of charge remaining stationary 

 with respect to the others. This condition may be seen to 

 be one of equilibrium, but the equilibrium is unstable. If 

 the sphere be set in rotation, forces due to its motion are 

 brought into existence which must automatically adjust 

 themselves by finding a condition of motion that will balance 

 all forces. By eliminating W/5ak from (69) and (70) we 

 obtain a value for W in terms of mass and the velocity of 

 light as follows : — 



W^imc 2 (71) 



Einstein and others have considered that mc 2 rather than 

 ??u ,2 /2, or any other fraction of it, represents the total energy 

 associated with a mass of matter. Regarding these above 

 formulae as applying to the nuclear charge, say of the 

 hydrogen atom, it is evident that the total energy expressed 

 by (71) should be mc 2 and not jmc 2 . It appears that the 

 extra one-quarter mc 2 is due to the normal state of internal 

 motion of the nucleus. If the electromagnetic theory de- 

 mands a state of motion for equilibrium, then the electrical 

 charge at rest becomes a pure fiction, having no existence 

 anywhere. 



Electromagnetic theory assumes that there exists a pres- 

 sure over the entire surface of the electron to keep its 

 elements from expanding the charge, and the difference in 

 pressure § for the solid Lorentz electron from centre to 

 surface is given by the formula, 



P = 3E 2 /87m 4 £. ....... (72) 



* Heaviside, ' Electrical Papers/ vol. i. p. 333. 

 t Schott, ' Electromagnetic Radiation/ eq. (381). 

 X Loc. cit. eqs. (379), (380). 

 § Loc. cit. art. 257. 



