CHAP. XV.] THE GENERAL DISTRIBUTION 01* STARS. 125 



resultant of two superimposed galaxies. The general view till 

 recently was that the Milky Way is not a great circle, because it was 

 thought the sun was not situated in its plane. The whole mass of 

 stars was likened to a millstone split along one edge, which was Sir 

 William Herschel's first idea. But the recent work, chiefly of Gould 

 in Argentina, has shown that it practically is a great circle. However 

 that may be, in one part of the heavens this wonderful Milky Way 

 appears as a single, very irregular, stream, and in another part it 

 appears to be duplicated. 



This galaxy of stars is full of wonderful majesty and complexity. 

 We find in it indications of delicate markings going out into space, 

 apparently coming back strengthened ; of streams in all directions ; of 

 clusters clinging to those streams, and so on. In other parts it is 

 curdled, which is the only term which I can use to express my mean- 

 ing. In one region we may find it absolutely free from any important 

 stars ; in another we may find it mixed with obvious nebula ; and in 

 another we may find it mixed not only with obvious nebula, but with 

 a great number of bright-line stars involved not only in the Milky 

 Way, but in the nebula itself. 



We have now, fortunately for science, priceless photographs of 

 these different regions which give us an idea of the enormous number 

 of stars in some parts, and of the streams of nebulous matter which 

 are seen in the Milky Way from region to region. Here we find a 

 regular river of nebulous matter rushing among thousands of stars, 

 elsewhere the galaxy seems to tie itself in knots. There is an indivi- 

 duality in almost every part of it, which we can study on our photo- 

 graphic plates ; practically there are no two parts alike. Other 

 photographs bring before us the curdled appearance which is visible in 

 different regions, and finally the connection of the infinite number of 

 stars with obvious nebulous matter. In this way, then, we are enabled 

 to form an idea of the general conditioning of things as we approach 

 the Milky Way. 



The next important point is that the enormous increase of stars in 

 the Milky Way is not limited to the plane itself, but that there is 

 really a gradual increase from the poles of the Milky Way, where we 

 find the smallest number of stars. It is not very easy to bring together 

 all the information, for the reason that different observers give different 

 measures ; they take different units for the space they have determined 

 to be occupied by stars from the pole towards the galactic plane ; and 

 also the number of stars in the northern hemisphere is not the same 

 as the number in the southern hemisphere. But roughly speaking we 

 may say, if we represent the number of stars at the galactic pole by 

 four, the number of stars in the galactic plane will be about fifty-four. 



