258 IN STARRY REALMS. 



times the diameter of the others ; therefore, the relative 

 quantities of these spaces are to be obtained by multiplying 

 1,000 by 1,000 and by 1,000 again. Thus we finally 

 learn that the amplitude of our vision is augmented ta 

 one thousand million times its original extent by the 

 use of our greatest telescopes. It need, therefore, be no 

 matter for surprise that the number of stars visible through 

 our great telescopes or recorded on the sensitive films of 

 photographic plates should number scores of millions. In 

 fact, it would sometimes seem surprising that the number 

 of telescopic stars is not even greater than it actually 

 appears to be. If we are able to explore one thousand 

 million times as much space we might expect that the 

 number of objects disclosed would be also increased about 

 a thousand million fold, but this is certainly not the case. 

 The truth seems to be that our sun is but one star of a 

 mighty cluster of stars ; we happen to lie near the middle 

 of the cluster, and the rest of the stars belonging to it 

 form what we know as the Milky Way. There are, of 

 course, other clusters scattered through the heavens, some 

 of them, perhaps, as great as that body of stars which forms 

 the Milky Way. Owing to our residence in this cluster 

 we see the neighbouring suns in multitudes, .and thus we 

 receive the impression that the solar system lies in an 

 exceptionally rich part of the universe in as far as the 

 distribution of stars is concerned. 



On the outskirts of the universe lie those faintest and 

 dimmest of objects which we can just perceive through our 

 greatest telescopes. We know that many of the stars 

 around us would still remain visible in great instruments, 

 even though they were removed a thousand times as far 



