ATOMIC DISINTEGRATION. 171 



This, too, breaks down but this time with a perfect con- 

 flagration of decomposition in which the alpha particles, the 

 stray corpuscles, or beta-rays, and the gamma-rays all ap- 

 pear together. 



We may, therefore, define a ladio-active substance as one 

 whose atom consists of a complex group of corpuscles the 

 configuration of which depends for its maintenance upon a 

 certain velocity of movement of the corpuscles comprising 

 it and beneath which velocity the corpuscles rearrange 

 themselves with the evolution of an amount of energy which 

 breaks down the atom. 



Our theory of an atom is that it is a sphere of positive 

 electrification enclosing a number of negatively electrified 

 corpuscles the negative electricity of the corpuscles exactly 

 balancing the positive electricity of the enclosing sphere. 

 On this theory we have been able to explain all the mysteries 

 of matter, which it has been the function of preceding chap- 

 ters to describe, in terms of what we already know. 



We have been able to show, also, that these mysteries of 

 matter inevitably result from the acceptance of the theory. 



