CLUSTERS OF STARS. 189 



again find in the comparison of these zones, an absolute pre- 

 ponderance 69 on the side of the more beautiful southern 

 heavens. 



When in 1843 I requested Captain Schwinck (of the 

 Engineers) to communicate to me the distribution according 

 to right ascension of the 12148 stars (from the 1st to the 7th 

 inclusive), which, at Bessel's suggestion, he had noted in his 

 Mappa, ccelestis, he found in four groups 



Right Ascension 50 to 140 3147 stars. 



140 230 2627 



230 320 3523 



320 50 2851 



These groups correspond with the more exact results of the 

 Etudes stellaires, according to which the maxima of stars 

 of the 1st to the 9th magnitude occur in the right ascension 

 6h. 40m. and 18h. 40m., and the minima in the right ascen- 

 sion of Ih. 30m. and 13h. 30m. 70 



It is essential that, in reference to the conjectural structure 

 of the universe and to the position or depth of these strata 

 of conglomerate matter, we should distinguish among the 

 countless number of stars with which the heavens are 

 studded, those which are scattered sporadically, and those 

 which occur in separate, independent, and crowded groups. 

 The latter are the so-called stellar clusters or swarms, which 

 frequently contain thousands of telescopic stars in recogniz- 

 able relations to each other, and which appear to the unaided 

 eye as round nebula3, shining like comets. These are, the 



w Op. cit. 9 795, 796 ; Struve, Etudes cFAstr. stell. pp. 66, 

 73, (and note 75). 



70 Struve, p. 59. Schwinck finds in his maps, R. A. 90, 

 2858 stars ; R. A. 90 180, 3011 stars ; R. A. 180 - 270, 

 2688 stars ; R. A. 270 - 360. 3591 stars ; sum total, 12148, 

 stars to the 7th magnitude. 



