lo PHYSICAL SCIENCE 



Planck's theory that radiation can leave an atom 

 only in definite units or quanta — a theory which, 

 as we shall see, explains bright line spectra, but 

 seems to be inexplicable on the principles of 

 classical mechanics. 



Finally, we pass to the bearing of all this 

 new knowledge on cosmical problems. Physics 

 is rapidly annexing the domain of astronomy, 

 as it has already invaded the realms of chemistry 

 and biology. By the aid of the spectroscope we 

 examine the chemical nature of the sun and stars, 

 we measure the rates of their motions and re- 

 volutions, and obtain data from which we may 

 speculate about their origin, development, and 

 decay. And the principle of relativity teaches 

 that time and space are relative to ourselves, 

 and their mysteries not unconnected with the 

 mystery of the human mind. From the internal 

 structure of the atom to the majestic progress 

 of the suns, the investigations of Physical Science 

 are surely and continuously gaining new know- 

 ledge for mankind. 



We scatter the mists that enclose us. 



Till the seas are ours and the lands, 

 Till the quivering aether knows us, 



And carries our quick commands. 

 From the blaze of the sun's bright glory 



We sift each ray of light. 

 We steal from the stars their story 



Across the dark spaces of night. 



But beyond the bright search-lights of science. 



Out of sight of the windows of sense, 

 Old riddles still bid us defiance, 



Old questions of Why and of Whence. 

 There fail all sure means of trial, 



There end all the pathways we've trod, 

 Where man, by belief or denial. 



Is weaving the purpose of God. 



