696 



Lord Kelvin : Plan of an Atoi 



electricity consists of equal atoms. I assume, and I believe 

 there is general agreement in this assumption, that each of 

 these atoms of resinous electricity, which I am calling elec- 

 tions, has, besides its ordinarily defined property of electric 

 attraction or repulsion, a property o£ somehow acting upon 

 ether, and in virtue of this action having quasi-inertia. The 

 nature of this action I believe to be attraction and consequent 

 enormous condensation of ether around the centre of the 

 electrion. (Baltimore Lectures, Lecture XX. §§ 238, 239.) 



§ 2. My present assumption is Boscovichianism pure and 

 simple. It merely declares that there is, between a single 

 electrion and a single atom of ponderable matter void of 

 electrions, a definite force in the line of their centres varying 

 according to the distance ; which for distances greater than 

 the radius of the atom is attraction according to the inverse 

 square of distance between the electrion and the centre of the 

 atom. It leaves us absolutely free to assume any law of force 

 whatever that suits our purpose, when the electrion is within 

 the atom. To give capacity to the atom for storing enormous 

 electric energy by placing a single electrion at its centre, or 

 at a very small distance from its centre, I assume, as indicated 

 in the accompanying diagram, fig. 1, that the force on the 



Fig-. 1. — Work-curve. 



On the right side of the diagram, slope up to right implies attraction ; 

 slope down implies repulsion. 



electrion at distances less than a certain distance CM from 

 the centre is towards the centre ; and that at all distances 



