STELLAR DISTRIBUTION. 221 



slightly richer in stars visible to the naked eye 

 than other parts of the heavens, while the bright 

 areas are between 60 and 100 per cent richer 

 than the dark areas." The Dutch astronomer, 

 Charles Easton, finds a connection between the 

 distribution of ninth -magnitude stars and the 

 luminous and obscure spots in the Galaxy. 



It was noticed by Gould, from observations 

 made at Cordova, that " a belt or stream of 

 bright stars appears to girdle the heavens 

 very nearly in a great circle which intersects 

 the Milky Way." According to Gould, the 

 belt includes Orion, Canis Major, Argo, Crux, 

 Centaurus, Lupus, and Scorpio in the southern 

 hemisphere, and Taurus, Perseus, Cassiopeia, 

 Cepheus, Cygnus, and Lyra in the northern. 

 This was interpreted by Celoria as indicating 

 the existence of two galactic rings, but Gould 

 considered the zone of bright stars to form with 

 the Sun a subordinate cluster of about five 

 hundred stars within the Galaxy. 



Perhaps the most elaborate investigations on 

 the structure of the Universe have been those 

 of Kapteyn, commenced in 1891. In that year 

 he demonstrated that stars are bluer and 

 more easily photographed in the Galaxy than 

 elsewhere, a discovery independently made by 

 Gill at the Cape, and Pickering at Har- 



