STAR-GROUPING, STAR-DRIFT, AND STAR-MIST. 141 



streams which He on the same side of the galaxy tend 

 towards the two Magellanic clouds. 



Most intimate signs of association between lucid stars 

 and the galaxy can be recognized (L) in the part extending 

 from Cygnus to Aquila ; (ii.) in the part from Perseus to 

 Monoceros ; (iii.) over the ship Argo ; and (iv.) near Crux 

 and the feet of Centaurus. 



Before proceeding to the subject of Star-drift, three 

 broad facts may be stated. They are, I believe, now 

 recognized for the first time, and seem decisive of the 

 existence of special laws of distribution among the stars : 



First, the rich southern region, though covering but a 

 sixth part of the heavens, contains one-third of all the lucid 

 stars, leaving only two-thirds for the remaining five-sixths of 

 the heavens. 



Secondly, if the two rich regions and the Milky Way be 

 considered as one part of the heavens, the rest as another, 

 then the former part is three times as richly strewn with lucid 

 stars as the second. 



Thirdly, the southern hemisphere contains one thousand 

 more lucid stars than the northern, a fact which cannot but 

 be regarded as most striking when it is remembered that the 

 total number of stars visible to ordinary eyesight in both 

 hemispheres falls short of 6000. 



Two or three years ago, the idea suggested itself to me 

 that if the proper motions of the stars were examined, they 

 would be found to convey clear information respecting the 

 existence of variety of structure, and special laws of distri- 

 bution within the sidereal system. 



In the first place, the mere amount of a star's apparent 

 motion must be regarded as affording a means of estimating 

 the star's distance. The nearer a moving object is, the 

 faster it will seem to move, and vice versd. Of course in 

 individual instances little reliance can be placed on this 

 indication ; but by taking the average proper motions of a 

 set of stars, a trustworthy measure may be obtained of their 

 average distance, as compared with the average distance of 

 another set 



