Declination q/' some of the ■principal Fixed Stars. 177 



be found north of its predicted place, it will always be a star 

 north of the zenith, and the quantity of its motion extremely 

 small. There may l)e observed a much greater tendency to 

 southern motion in some jiarts of the heavens than in opposite 

 or distant parts as to right ascension, and in much the greater 

 portion ot the heavens the southern motion seems to prevail. 

 A southern star, as Sirins, situated in tliat part of the heavens 

 most favourable for southern motion, will be foimd more to 

 the south of its predicted place than Aniares, situated in the 

 part least favourable for southern motioji, though it is itself 

 more southward. 



Several stars have moved more from their predicted places 

 than other neighbouring stars: when this happens, the motion 

 is always southward ; I have yet met with no exception to this 

 rule; not a single star can be found having an extra tendency 

 to northern motion ; and indeed the northern motion in any 

 star is so very small, that it would never have excited atten- 

 tion. 



A very great deviadon will be found in three very bright 

 stars, Capella, Procyon, and Sirins : the proper motion of each 

 of these is southward; it therefore follows that these proper 

 motions are accelerated. The proper motion of Arcturus is 

 very great, and likewise southward. It is situated in that part 

 of the heavens where the southern tendency is least discerni- 

 ble, and is nearly quiescent; its proper motion in polar di- 

 stance may therefore be considered as uniform, 'i'here is a 

 circumstance that deserves notice, though it raay be merely 

 accidental : the stars in the Greenwich catalogue, whose pro- 

 per motions are south, nearly equal in number those tliat are 

 north, yet tlie quantity of southern proper motion exceeds the 

 northern in the pro})ortion of four to one. 



I shall at present offer no conjecture on the cause of these 

 deviations, but endeavour, by continued observations, more 

 accurately to ascertain the law which they follow. Should the 

 weather prove favourable tor observation, I hope before the 

 Society sejiarate for the summer, to be able to give greater 

 accuracy to the numbers here subjoined. Indeed I should 

 not have made so early a connnunication on the subject, but 

 as the Clreenwich observations of 1820 are about to be pub- 

 lished, they might without tliis explanation have appeared 

 erroneous; for I find that during that year the instrument was 

 lather defective from general unsteadiness, than from any pcr- 

 cej)tible deviation of the telescope. It was not till after the 

 month of February 1821, that the instrument got completely 

 out of repair. It must however be admitted, that the obser- 

 vations of tiiat year ought not to be employed in (lie tleter- 



V'ol. (i2. No. JOS. ASVyi/. 182;). Z miiiatioii 



