OF THE COSMOS. PARALLAX OF STARS. 189 



Maclear in 1839, at 0"-9128. ( 311 ) This would make it the 

 nearest of all the fixed Stars whose parallaxes have yet been 

 measured, and three times nearer than 61 Cygni. 



The parallax of a Lyrse, has long been the subject of 

 Struve's observations. The earlier observations (1836) gave 

 ( 312 ) between 0"-07 and 0"-I8 ; later ones gave /7 -2613, and 

 a distance of 771400 semi-diameters of the Earth's orbit, 

 with a light passage of 1 2 years ; ( 313 ) but Peters has found 

 the distance of this bright Star still greater, since he gives 

 its parallax at only 0"'103. This result contrasts with 

 another Star of the first magnitude (a Centauri), and with a 

 Star of the sixth magnitude (61 Cygni). 



The parallax of Polaris was determined by Peters, by 

 many comparisons made in the years 1818 1838, at 

 O y< 106, and the more satisfactorily as the same comparisons 

 give the aberration 20'H55. ( 314 ) 



The parallax of Arcturus is, according to Peters, /x *127 

 (Rumker's earlier observations with the Hamburgh Meridian 

 Circle had given it much larger). The parallax of another 

 star of the 1st magnitude, Capella, is still less, being, 

 according to Peters, 0"'046. 



The Star 1830 of Groombridge's Catalogue, which, ac- 

 cording to Argelander, has shown the greatest proper 

 motion of any star yet observed, has a parallax of /7> 226, 

 as inferred from 48 very exactly observed Zenith distances 

 by Peters in 1842 and 1843. Paye had believed it to be 

 5 times greater, viz., 1"'08, or more considerable than the 

 parallax of a Centauri. ( 3l5 ) 



The following table contains the parallaxes of the nine 

 stars which deserve the greatest amount of confidence, with 

 the names of the observers, and the probable errors of the 

 determinations. 



