THE EVER-WIDENING WORLD OF STARS. 49 



nebulae are arranged in two distinct hut irregular 

 clusters, separated by a well-marked zone almost en 

 tirely free from nebulae. And this zone coincides 

 almost exactly with the Milky Way. 



What are we to understand by so special an arrange 

 ment as this ? A modern astronomer says it clearly 

 proves that the nebulae do not belong to the star- 

 world ; but I can see no escape from an exactly oppo 

 site view. A simple illustration will serve to exhibit 

 the nature of the case. Suppose a person found a 

 space of ground on which gravel was arranged in the 

 form of a ring, and that rough stones were thickly 

 spread over the whole space except the gravel ring, 

 would he conclude that there was no association be 

 tween the arrangement of the gravel and the arrange 

 ment of the stones, because few stones were to be 

 found on or near the gravel ? Would he not rather 

 find in this peculiarity distinct evidence that there 

 was some association ? He would, we think, argue 

 that the gravel had been collected into one place and 

 the stones into another, in pursuance of some one par 

 ticular scheme. The corresponding conclusion in the 

 case of the stars and nebulae would clearly be that the 

 stars had been drawn together in one direction and the 

 nebulae in another, out of a common world of cosmical 

 matter.. In other words we should look on the nebulae 

 as members of the same system or scheme that the 

 stars belong to. 



And here it may be asked how the conclusion thus 

 deduced from the arrangement of stars and nebulae can 



B 



