PREFACE 



THE present volume is intended for the general 

 reader, interested in modern science, who finds few 

 clews to recent advances in his memories of the formal 

 instruction of school or college days. 



During the last twenty years physical research has 

 penetrated the mysteries of the chemical elements and 

 has demonstrated that their atoms are granular in 

 structure and electrical in nature. Transmutation 

 - the dream of the alchemists is to-day recognized 

 as a natural process in the case of radioactive sub- 

 stances. An element common to all matter has been 

 found in the electron which has been isolated and 

 studied. It is a reality of modern science and in 

 terms of it scientists are rapidly explaining the phe- 

 nomena of all physical science, the essential unity of 

 which its discovery has emphasized. 



The existence of electrons and their determining 

 effect in the composition of the chemical elements are 

 easily demonstrable facts, compared to which the in- 

 destructibility of matter is a speculative assertion and 

 the independence of mass and speed an exploded theory. 

 Nevertheless our education is so constrained by 

 established curricula and text-books adapted thereto, 

 that a knowledge of these facts is usually acquired 

 only by college students who elect the more advanced 

 courses. Even in the subject of electricity most of 



vii 



