﻿1066 Mr. R. Hargreaves on Atomic Systems 



no need for a cement as difficult to explain as the atom 

 itself ; an orbital motion is provided, and the materials 

 could not be fewer. The question how far these structures, 

 regarded as representations of the atom, meet the demands 

 from the various branches of Physics and Chemistry is 

 therefore a fundamental one, to which it is desirable to 

 obtain an answer as complete as possible. 



§ 1. The characteristic feature of the scheme is a structure 

 or configuration consisting o£ two concentric rings, one of 

 positive the other of negative electrons in like number. 

 The charges are disposed at regular intervals on the circum- 

 ferences of their respective circles, while in angular position 

 elements of one type lie half-way between those of opposite 

 type (fig. 1). For this configuration we are seeking, not a 



Fig. 1. 



Arrangement of positive and negative electrons in concentric circles 



for w=4. 



position of equilibrium but one of steady motion for each 

 element in its own circle. The symmetry of the structure 

 ensures a purely central force on each element; the main- 

 tenance of the symmetry demands a common angular 

 velocity, which requires an adjustment of the radii. The 

 condition to be fulfilled is 



m^aPa^ : m 2 co 2 a 2 = ¥ 1 : F 2 , (i.) 



m being mass, a radius, F attraction to centre, with the sub- 

 scripts 1 and 2 attached respectively to positive and negative 



