88 THE PROBLEMS OF ASTRONOMY. 



yet had time to determine the amount of the motion. But the indica- 

 tion 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 observatories in some of the leading countries of 

 the world. I can not say all the leading countries, 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 infiuity itself. We are familiar enough with eternity, or, 

 let us say, the millions or hundreds of millions of years which geolo- 

 gists tell us must have passed while the crust of the earth was assuming 

 its present form, our mountains being built, our rocks consolidated, 

 and successive orders of animals coming and going. Hundreds of 

 millions of years is indeed a long time, and yet, when we contemplate 

 the changes supposed to have taken place during that time, we do not 

 look out on eternity itself, which is veiled from our sight, as it were, by 

 the unending succession of changes that mark the progress of time. 

 But in the motions of the stars we are brought face to face with eternity 

 and infinity, covered by no veil whatever. It would be bold to speak 

 dogmatically on a subject where the springs of being are so far hidden 

 from mortal eyes as in the depths of the universe. But, without 

 declaring its positive certainty, it must be said that the conclusion 

 seems unavoidable that a number of stars are moving with a speed 

 such that the attraction of all the bodies of the universe could never 

 stop them. One such case is that of Arcturus, the bright reddish star 

 familiar to mankind since the days of Job, and visible near the zenith 

 on the clear evenings of May and June. Yet another case is that of a 

 star known in astronomical nomenclature as 1830 Groombridge, which 

 exceeds all others in its angular proper motion as seen from the earth. 

 We should naturally suppose that it seems to move so fast because it 

 is near us. But the best measurements of its parallax seem to show 

 that it can scarcely be less than two million times the distance of the 

 earth from the sun, while it may be much greater. Accepting this 

 result, its velocity can not be much less than 200 miles per second, and 

 may be much more. With this speed it would make the circuit of our 

 globe in two minutes, and had it gone round and round in our latitudes 

 we should have seen it flypast us a number of times since I commenced 

 this discourse. It would make the journey from the earth to the sun 

 in five days. If it is now near the center of our system it would prob- 

 ably reach its confines in a million of years. So far as our knowledge 



