60 KANT'S UNIVERSAL NATURAL HISTORY 



distances from the centre the time which such a star 

 would require to revolve once round the sun would be 

 more than a million and a half years ; and this would only 

 produce a displacement of its position by one degree in four 

 thousand years. Now, as there are perhaps very few fixed 

 stars so near the sun as Huygens has conjectured Sirius 

 to be, as the distance of the rest of the heavenly host 

 perhaps immensely exceeds that of Sirius, and would there- 

 fore require incomparably longer time for such a periodic 

 revolution; and, moreover, as it is very probable that the 

 movement of the suns of the starry heavens goes round 

 a common centre, whose distance is incomparably great, 

 so that the progression of the stars may therefore be 

 exceedingly slow, it may be inferred with probability from 

 this, that all the time that has passed since men began 

 to make observations on the heavens is perhaps not yet 

 sufficient to make perceptible the alteration which has 

 been produced in their positions. We need not, however, 

 give up the hope yet of discovering even this alteration, 

 in the course of time. Subtle and careful observers, and 

 a comparison of observations taken at a great distance 

 from each other, will be required for it. These observa- 

 tions must be directed especially to the stars of the 

 Milky Way, 1 which is the main plane of all motion. Mr 

 Bradley has observed almost imperceptible displacements 

 of the stars. The ancients have noticed stars in certain 

 places of the heavens, and we see new ones in others. 

 Who knows but that these are just the former, which 

 have only changed their place? The excellence of our 



1 Likewise to those clusters of stars, of which there are many found 

 together in a small space, as, for example, the Pleiades, which per- 

 haps make up a small system by themselves in the greater system. 



