﻿316 Dr. A. 0. Crehore on the 



From these premises alone certain important conclusions, 

 which are in harmony with experimental observations, 

 follow almost axiomatically. In neutral atoms, as electrons 

 are added forming increasingly heavier elements, and as the 

 positive electricity increases in volume by a fixed amount 

 tor each electron, retaining an approximately spherical shape, 

 it results that the diameter of the rings lying in a plane 

 must increase at a greater rate than the diameter of the 

 corresponding positive electricity, since the latter increases 

 nearly as the cube root of the number of electrons and the 

 former at a greater rate, somewhere between the first power 

 and the square root of the same number. There must, then, 

 come a time when, as electrons are added, the diameter of 

 the outside ring equals that of the positive electricity. No 

 more electrons than this can be accommodated within the 

 positive electricity, and there is, therefore, a superior limit 

 to atomic weights. As nearly as can be estimated, this 

 point is reached for that number of electrons which corre- 

 sponds to the element uranium, the heaviest of the elements, 

 and it is not surprising that there are no heavier atoms 

 found. In these heavier atoms the outside ring is most 

 unstable, and comparatively slight forces may drive an 

 electron outside of the positive electricity, where the law of 

 force suddenly changes allowing it to escape. It seems 

 natural on this view to expect to find self-radioactive 

 elements at the latter end of the periodic table, and in fact 

 we come to uranium, thorium, radium, radium emanation, 

 etc., all self-radioactive elements. The degree of radio- 

 activity should not follow precisely this order, as will be 

 evident when the irregularities introduced by the equilibrium 

 positions are taken into account. 



Scattering of the Alpha Particles. 



The scattering of the alpha particles may be explained by 

 this form of atom as well as by the central nucleus atom. 

 A study of the electric and magnetic fields surrounding a 

 single atom of this kind shows that it is possible for an alpha 

 particle to pass straight through the atomic field without de- 

 viation or to be reflected at any possible angle. The deviation 

 depends upon the relative directions of the axes of rotation of 

 the atom and of the approaching atom, and upon the direction 

 of the line of approach. The forces may be either attractive 

 or repulsive according to circumstances. While no quanti- 

 tative proof is here given of the precise law of scattering, it 

 must be conceded that the known laws of scattering supply 



