Problems of Astronomy 



continually increasing telescopic power brings 

 into view, are not situated at greater and greater 

 distances, but that we actually see the boundary 

 of our universe. This indication lends a peculiar 

 interest to various questions arising out of the 

 motions of the stars. Quite possibly the prob- 

 lem of these motions will be the great one of the 

 future astronomer. Even now it suggests 

 thoughts and questions of the most far-reaching 

 character. 



I have seldom felt a more delicious sense of 

 repose than when crossing the ocean during the 

 summer months I sought a place where I could 

 lie alone on the deck, look up at the constellations 

 with Lyra near the zenith, and, while listening 

 to the clank of the engine, try to calculate the 

 hundreds of millions of years which would be 

 required by our ship to reach the star a Lyne if 

 she could continue her course in that direction 

 without ever stopping. It is a striking example 

 of how easily we may fail to realize our knowl- 

 edge when I say that I have thought many a 

 time how deliciously one might pass those hun- 

 dred millions of years in a journey to the star 

 a Lyrae, without its occurring to me that we are 

 actually making that very journey at a speed 

 compared with which the speed of a steamship 

 is slow indeed. Through every year, every hour, 

 every minute, of human history from the first 

 appearance of man on the earth, from the era of 

 the builders of the pyramids, through the times 

 of Caesar and Hannibal, through the period of 

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