PRESIDENTIAL ADDRESS. 23 



sucli plants as may be grown by water culture. On the 

 other hand one would look for possible transmutation rather 

 in the more complex creations of the animal world, say in 

 man, where it would be extremely difficult to prove trans- 

 mutation. The changes which one may be allowed to 

 imagine as a faint possibility, are say, (a) carbon from 

 oxygen, or (b) a meta-sulphur of atomic weight 31 from 

 phosphorus (atomic weight 31). 



The interest in finding that such a change could take 

 place would be not only on account of the transmutation 

 per se, but on account of the large amount of energy 

 which would be set free. 



In the case of starvation of a human being, it may be 

 noticed that if oxygen atoms to the extent of one-hundredth 

 of a gram changed into carbon atoms by loss of a-particles, 

 the amount of energy liberated would probably be equal 

 to considerably more than the energy given by an ordinary 

 day's consumption of food. 



The Future of the Earth. 

 While the beginning of both matter and life remains 

 undiscovered, speculation may be made as to the future of 

 the earth. The old idea of a gradually cooling earth, on 

 which life would gradually become extinct, with a dissipa- 

 tion of energy and (to some extent also) dissipation of 

 matter is not the only one now before us. 



It has been suggested (15) that the temperature of. the 

 inner core of the earth may be increasing owing to the heat 

 liberated in radioactive changes. This heat is retained as 

 the outer surface shell of the earth is a very poor conductor 

 of heat. If, therefore, the crust some day should succumb 

 to the increased pressure within, the whole of the matter 

 of the earth would probably become (again ?) a globe of 

 glowing gas. This is surely the Discontinuity of Nature 

 par excellence, and all the evolution of the atoms, the 



