THE FINITE UNIVERSE 



it seems to be finite, and if it is finite it can be 

 measured and weighed. Moreover, the disclosures 

 of the telescope are only three centuries old, those 

 of the spectroscope and camera but half a century. 

 Set this in imagination against five or ten thou- 

 sand years of invention, investigation, and dis- 

 covery like to that of the last three or four gener- 

 ations, and who shall set bounds to what man 

 may know then? 



For one thing, it is coming slowly into view that 

 space is not nearly so empty as used to be im- 

 agined. If the wave theory of light is true, and it 

 seems well founded, then space is filled with a 

 substance as tangible and no doubt as tractable 

 as the waters of the sea. Again, gravitation is 

 the weakest of known forces. Compared with 

 the energy we must conceive as binding together 

 the molecules, or in action when a pinch of salt 

 is dissolved in a glass of water, gravity is al- 

 most inconceivably feeble. These colossal electri- 

 cal and molecular forces, whose very existence 

 has but recently been revealed, we may one day 

 utilize and control. If, as Professor Dolbear pict- 

 uresquely remarks, we could some way get a 

 "kick" on the ether, space navigation would be 

 easy. It does not seem impossible that we shall 

 be able to do this within another hundred or two 

 hundred years. There is the gleam of such a 



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