OF THE COSMOS. CLUSTERS OF STARS. 119 



When,, in the year 1 843, I asked Captain Schwink to be 

 so kind as to communicate to me the distribution, in right 

 ascension, of the 12148 stars (1st to 7th magnitude inclu- 

 sive), which, at Bessel's instance, he had entered in his 

 " Mappa ccelestis," he found, in four groups- 

 Eight ascension, 50- 140; 3147 stars 

 140- 230 j 2627 " 

 230-320; 3523 " 

 " 320- 50; 2851 " 



These groups agree with the still more exact results of the 

 " Etudes stellaires " according to which, the maxima of stars 

 from the 1st to the 9th magnitude fall in the right ascen- 

 sions of 6h. 40m. and 18h. 40m., and the minima in those 

 of Hi. 30m. and 13h. 30m. ( 236 ) 



In reference to conjectures respecting the structure of 

 the Universe, and the position or depth of the sidereal 

 strata, it is essential to distinguish, among the countless 

 multitude of stars, those which are scattered sporadically, 

 from those which we find crowded in detached independent 

 groups. The latter are the " clusters of stars" which have 

 been spoken of : they often contain many thousands of 

 telescopic stars in recognisable relation to each other, 

 and are seen by the naked eye as round or oval nebulse, 

 appearing like comets. These are the "nebulous stars" 

 of Eratosthenes ( 23 ?) and Ptolemy ; the " nebulosa3" of the 

 Alphonsine Tables of 1252, and those of Galileo, which (as 

 it is said in the Nuncius sidereus) sicut areolse sparsirn per 

 sethera subfulgent. 



