682 The Evolution of Matter 



changes are interposed between two radio-active transformations 

 which can be followed, show that spontaneous transmutation is 

 possible without measureable radio-activity. And, indeed, any theory 

 of disintegration, such as Thomson's corpuscular hypothesis, would 

 suggest that atomic rearrangements are of much more general occur- 

 rence than would be apparent to one who could observe them only 

 by the effect of the projectiles, which, in special cases, owing to some 

 peculiarity of atomic configuration, happened to be shot out with 

 the enormous velocity needed to ionize the surrounding gas. No 

 evidence for such ray-less changes in ordinary elements is yet known, 

 perhaps none may ever be obtained ; but the possibility should not 

 be forgotten. 



In the strict sense of the word, the process of atomic disintegra- 

 tion revealed to us by the new science of radio-activity can hardly 

 be called evolution. In each case radio-active change involves the 

 breaking up of a heavier, more complex atom into lighter and 

 simpler fragments. Are we to regard this process as characteristic 

 of the tendencies in accord with which the universe has reached its 

 present state, and is passing to its unknown future? Or have we 

 chanced upon an eddy in a backwater, opposed to the main stream of 

 advance ? In the chaos from which the present universe developed, I 

 was matter composed of large highly complex atoms, which have 

 formed the simpler elements by radio-active or ray-less disintegra- 

 tion ? Or did the primaeval substance consist of isolated electrons, 

 which have slowly come together to form the elements, and yet have 

 left here and there an anomaly such as that illustrated by the 

 unstable family of uranium and radium, or by some such course are 

 returning to their state of primaeval simplicity? 



