PRESIDENTIAL ADDRESS. V 



sense, we are now aware that the atoms of some elements 

 are unstable, and that after a certain "life" the atom of 

 the radioactive element suddenly explodes. For a single 

 atom the rotation of the rings of electrons in their orbits 

 &nd the eccentricity of the orbits are apparently such that 

 at a certain moment the whole position is no longer stable, 

 and the atom decomposes into one or more different atoms 

 quite suddenly. 



From one element we can thus in an instant get one or 

 two other elements. The suddenness of the change makes 

 us dislike to use the word evolution here, but at any rate, 

 one species of matter does produce in this case either one 

 new species or two new species. Granted that some might 

 care to call this evolution, still, it applies to only a few of 

 the elements as far as is known. It is true that change 

 might occur in some of the other elements at so slow a 

 rate as not to be detectable by any available means. 

 Granted again that this is a possibility, we know that 

 when an element changes, it is always (in our experience 

 on the earth's surface) to an element or elements of equal 

 or lower atomic weight. If every element has arisen by 

 evolution, then we are led back ultimately to a parent of 

 high atomic weight. Uranium is the element of highest 

 known atomic weight. The question therefore arises as 

 to where the uranium atom comes from. If it comes from 

 the atom of some other element, there must at any rate 

 have been one or more primary elements which disinteg- 

 rated into the atoms of uranium and other elements. How 

 do these primary elements arise? At this stage of the 

 enquiry we are baffled. Some elements have arisen from 

 other elements, but no means have yet been discovered 

 of creating an atom of any kind of matter from electrons 

 and a positively charged nucleus. The formation of the 

 atoms, more particularly those of highest atomic weight is 

 still a mystery. 



