MORE ABOUT ELECTRONS 79 



posed of isolated elements in motion, but never in 

 contact. The atoms, of which each molecule is 

 formed, themselves contain thousands of elements, 

 which describe, round one or more centres, curves 

 as regular as those of celestial bodies." 



Lord Kelvin supposed a radio-active atom might 

 be composed of " concentric layers of positive and 

 negative electricity, disposed in such a way that 

 its external action is nil, and that nevertheless the 

 force emanated from the centre may be repellent 

 for certain values when the electron is within it." 



Sir Oliver Lodge says ; " The electron has been 

 shown to possess in kind, though not in degree, the 

 fundamental properties of the original atom of 

 which it had formed a part ; and it becomes a 

 reasonable hypothesis to surmise that the whole of 

 the atom may be built up of positive and negative 

 electrons interleaved together, and of nothing else, 

 an active or charged ion having one electron in 

 excess or defect, but the neutral atom having an 

 exact number of pairs." 



The atomic sidereal systems are more or less 

 stable ; the larger systems, such as radium, thorium, 

 polonium, which contain thousands of corpuscles, 

 are naturally less stable than the smaller systems 

 with fewer corpuscles. Radium, indeed, has been 

 aptly compared by Sir Oliver Lodge to a contract- 

 ing nebula. " Roughly," he says, " the process 



