Energy of the Lorentz Electron: 



497 



direction X. (The figure is drawn lor (1 — / 8 2 )i = i, and J of 

 the total rlux lies between successive lines.) The velocity " 

 with which the energy travels is given by 



r 1 / 2/3 *\ n *o \ 



2/3sin^0 Y| 



• • (7) 



u is the velocity relative to the moving nucleus. When /3 

 is small, u=v practically, ami the ellipses hecome circles. 



> x 



Thus at small velocities the energy of the field, viewed from 

 the nucleus, goes round in circular paths with a uniform 

 velocity equal to that of the lor ward motion of the system. 

 The actual velocity in space (or relative to the observer) is 

 the resultant of u and v ; this is 2v in the equatorial plane 

 and diminishes gradually to zero as the axis is approached. 

 It is the same as if the (completed) ellipses rolled forward 

 on tiie axis without changing their shape as the nucleus 

 advanced. 



( 'onsideration of what happens in the space occupied By 

 the nucleus presents the pure electromagnetic theory of the 



