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SYDNEY CHAPMAN^ B.A., D.SC.^ F.R.A.S., ON 



is found that the number of faint stars would increase far more 

 rapidly than they do in fact. From these two arguments, that 

 such a distribution of stars would appear to be infinitely bright, 

 and the actual excess of the rate of increase in the number of 

 stars as calculated over that which is observed, it is clear either 

 that the stars must be distributed so as to become less numerous 

 as we proceed outwards from the sun, or else they must become 

 intrinsically I'ainter. There is also a third possible explanation, 

 that the light may be absorbed before it reaches us. Without 

 ruling out this latter possibility of there being in space a certain 

 amount of absorption of the light of the stars, it appears that 

 the stars do get less numerous as we proceed outwards from the 

 sun, at any rate in most directions. As the size of telescopes 

 is increased or the time of exposure of photographs is 

 lengthened, more and more faint stars are detected, but it is 

 probable that a point has now already been reached at which a 

 large proportion of the faintest stars revealed are not stars 

 fainter by reason of their greater distance, but are stars 

 intrinsically fainter than those previously detected and that they 

 are mingled amongst them. We are thus led to a conception of 

 the universe as being of limited extent, containing a great 

 number of stars in the form of a huge oblate spheroid, encircled 

 by that great stellar band which we term the Milky W^ay. 

 This great stellar system is finite, and if we were to travel 

 outwards from the sun, beyond a certain distance, the number 

 of stars would be found to thin out, and finally we should come 

 to a region where there were few stars or none at all. 



The stars then are gathered together in a single great system, 

 and much is already known about it. It is a system 

 characterized in its motions (for the stars are moving), 

 its composition (for that is largely known), and in its structure, 

 by unity and order, not less than by its almost unending 

 variety. All these combine to make the stellar universe the 

 most magniticent object of contemplation in the whole range of 

 material things. 



The stars may be regarded from another point of view, 

 from which, perhaps, they appear to lose that inipressiveness 

 which these large numbers give to them. Yet this is only at 

 first sight, as will speedily appear. When we pass from the 

 total number of the stars to the total amount of liglit which 

 tliey give us, we pass from quantities that are impressive l)y 

 their extreme vastness to quantities that are almost insignificant, 

 for though the stars are so numerous, yet all their vast numbers 

 combined together yield to us very little light indeed. Yet, if 



