capable of Storing an Electrion. 697 



between CM, and CN (the latter being slightly less than the 

 radius of the atom), there is repulsion from the centre, rising 

 to a maximum of enormously great amount at some distance 

 CK between CM and ON", and coining to zero at the distance 

 CN. Between CN, and CA the radius of the atom, the force 

 becomes again attractive, and continues so, varying inversely 

 as the square of the distance for all the distances of the 

 electrion from the centre of the atom, greater than CA. The 

 curve shown in the diagram may for brevity be called the 

 work-curve. It shows by the ordinate PL the work, positive 

 or negative, required to move an electrion from an infinite 

 distance to any point P within or without the atom ; which I 

 denote by w. Thus if we denote CP by r, we have 



*=£ «' 



where F denotes the force (positive when attractive, negative 

 when repulsive) of the atom on an electrion in the position P. 

 Hence this force is indicated in the diagram by the tangent 

 of the inclination of the curve at any point L, to the line of 

 centres, CA. 



§ 3. For all points outside the atom we have 



*-? 00, 



where a denotes the excess of the vitreous over the resinou s 

 electricity permanently belonging to the atom ; and e denotes; 

 according to the general usage of scientific writers on radio- 

 activity, the quantity of resinous electricity in any one 

 electrion. Thus for the equation of the curve outside the 

 atom, we have 



w =- ~ ( 3 )- 



By this we see that our curve outside the atom consists of 

 portions of two rectangular hyperbolas. 



The maximum ordinate through M, and the minimum 

 ordinates through C and N, show that the point M is a posi- 

 tion of unstable equilibrium, and that the points C and 1ST are 

 positions of stable equilibrium ; for a single electrion placed 

 within the atom. The point I on the curve, being a point of 

 inflexion in the branch sloping downwards to the right, 

 indicates that K is a position in which the atom experiences a 

 maximum of repulsive force. Considering a spherical surface 



Phil. Mag. S. 6. Vol. 10. No. 60. Dec. 1905. 3 B 



