NUMBER OF THE FIXED STABS. 143 



The number of stars distinctly visible to the naked eye 

 (amounting in the horizon of Berlin to 4022, and in that of 



confidence. Bessel has enumerated about 61000 different 

 stars from the 1st to the 9th inclusive, in his collective 

 zones between 15 and + 45, after deducting such stars 

 as have been repeatedly observed, together with those 

 of the 9' 10 magnitude; whence we may conclude, after 

 taking into account such as have probably been overlooked, 

 that this portion of the heavens contains about 101500 

 stars of the above-named magnitudes. My zones between 

 + 45 and + 80, contain about 22000 stars, (Durchmus-* 

 terung des nbrdl. Himmels, s. xxv.) which would leave 

 about 19000, after deducting 3000 for those belonging to. 

 the 9*10 magnitude. My zones are somewhat richer than 

 Bessel's, and I do not think we can fairly assume a larger 

 number than 2850, for the stars actually existing between 

 their limits ( + 45 and + 80) ; whence we should obtain 

 130000 stars to the 9th magnitude inclusive, between 15 

 and + 80. This space is, however, only 0-62181 of the 

 whole heavens, and we therefore obtain 209000 stars for the 

 entire number, supposing an equal distribution to obtain 

 throughout the whole firmament ; these numbers again closely 

 approximate to Struve's estimate, and indeed, not impro- 

 bably exceed it to a considerable extent, since Struve 

 reckoned stars of the 9 -10 magnitude among those of 

 the 9th. The numbers which, according to my view, may 

 be assumed for the whole firmament, are therefore as follows : 

 1st mag., 20; 2nd, 65; 3rd, 190 ; 4th, 425 ; 5th, 1100; 6th, 

 3200; 7th, 13000; 8th, 40000; 9th, 142000; and 20000<> 

 for the entire number of stars from the 1st to the 9th magni- 

 tude inclusive. 



If you would contend that Lalande (Hist, celeste, p. iv.) has 

 given the number of stars observed by himself with the naked 

 eye at 6000, I would simply remark that this estimate con- 

 tains very many that have been repeatedly observed, and 

 that after deducting these, we obtain only about 3800 stars 

 for the portion of the heavens between 26 30' and + 90 

 observed by Lalande. As this space is 0*72310 of the whole 

 heavens, we should again have for this zone 5255 stars visible 



