Problems of Astronomy 



and the apparent motion is, therefore, smaller. 

 Accurate observations upon such stars have been 

 commenced only recently, so that we have not 

 yet had time to determine the amount of the 

 motion. But the indication seems to be that 

 it will prove quite a measurable quantity, and 

 that before the twentieth century has elapsed 

 it will be determined for very much smaller stars 

 than those which have heretofore been studied. 

 A photographic chart of the whole heavens is 

 now being constructed by an association of ob- 

 servatories in some of the leading countries of 

 the world. I cannot say all the leading coun- 

 tries, because then we should have to exclude our 

 own, which, unhappily, has taken no part in this 

 work. At the end of the twentieth century 

 we may expect that the work will be repeated. 

 Then, by comparing the charts, we shall see the 

 effect of the solar motion and, perhaps, get new 

 light upon the problem in question. 



Closely connected with the problem of the 

 extent of the universe, is another which appears, 

 for us, to be insoluble because it brings us face to 

 face with infinity itself. We are familiar enough 

 with eternity, or, let us say, the millions or hun- 

 dreds of millions of years which the geologists 

 tell us must have passed while the crust of the 

 earth was assuming its present form, our moun- 

 tains being built, our rocks consolidated and suc- 

 cessive orders of animals coming and going. 

 Hundreds of millions of years is, indeed, a long 

 time, and yet, when we contemplate the changes 

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