Summary 35 



tion of the component electrons and protons. One 

 kind of element may in certain cases give rise to 

 another. A transmutation of elements does sometimes 

 occur. There has been a unification of the different 

 kinds of matter. 



10. Similarly, there has been a startling unifica- 

 tion of energies. Thus light, electricity, and mag- 

 netism come into a series, and Einstein has shown 

 how gravitation may be brought into line with the 

 rest. The energies have been unified and matter tends 

 to be swallowed up by electricity. 



11. The story of the fashioning of the earth has 

 been well worked out, mostly in terms of processes at 

 present operative. 



12. A succession of events made the hot earth a 

 possible home for living creatures. Taken together, 

 these events may be philosophically spoken of as a 

 "preparation" for life, but that is not a scientific con- 

 cept. The cooling was followed by the establishment 

 of an atmosphere and a hydrosphere. The importance 

 of water and its circulation is fundamental. The 

 surface of the young earth must have shown an 

 abundant presence of carbon, hydrogen, and oxy- 

 gen in combination, and these, along with nitrogen in 

 the air, are the requisites for the physical basis of 

 life. These carbon compounds readily tend to form 

 colloids, which are characteristically necessary for 

 the make-up and continuance of living creatures as 

 we know them. The making of the soil with its maze 

 of capillary spaces and air-ducts was another "prepa- 

 ration"; it may have been a cradle for incipient or- 



