192 COSMOS. 



1832, and by those of Maclear in 1839.^ According to this 

 statement, it is the nearest of all the fixed stars that have 

 yet been measured, being three times nearer than 61 Cygni. 



The parallax of a Lyree has long been the object of 

 Struve's observations. The earlier observations (1836) 

 gavef between 0"-07 and 0"-18 ; later ones gave 0"-2613, 

 and a distance of 771,400 mean distances of the earth, with 

 a ])eriod of twelve years for the transmission of its light. | 

 But l^eters found the distance of this brilliant star to be 

 much greater, since he gives only 0"*103 as the parallax. 

 This result contrasts with another star of the first magni- 

 tude (a Centauri), and one of the sixth (61 Cygni). 



The parallax of the Polar Star has been fixed by Peters, 

 at 0"'106, after many comparisons of observations made be- 

 tween the years 1818 and 1838 ; and this is the more sat- 

 isfactory, as the same comparisons give the aberration at 

 20"-45o.§ 



The parallax of Arcturus, according to Peters, is 0"'127. 

 R-iimker's earlier observations with the Hamburg meridian 

 circle had made it considerably larger. The parallax of an- 

 other star of the first magnitude, Capella, is still less, being, 

 according to Peters, 0"'046. 



The star No. 1830 in Groombridge's Catalogue, which, 

 according to Argelander, showed the largest proper motion 

 of all the stars that hitherto have been observed in the firm- 

 ament, has a parallax of 0"-226, according to 48 zenith 

 distances which were taken with much accuracy by Peters 

 during the years 1842 and 1843. Faye had believed it to 

 be five times greater, 1""08, and therefore greater than the 

 parallax of a Centauri. || 



* Sir John Herscliel, Outlines, p. 54-5 and 5.51. Madler {Astr.,?,. 425) 

 gives in the case of a Centauri the parallax 0"-9213 instead of 0"-9128. 



t Struve StelL compos. Meiis. Microm., p. clxix.-clxxii. Aiiy makes 

 the pai'allax of a Lyrse, which Peters had previously reduced to 0"-\, 

 still low^er; indeed, too small to be measurable by our present instru- 

 ments. {Mem. of the Royal Astr. Soc, vol. x., p. 270.) 



^ Stnive, On the Micrometrical Admeasurements by the Great Refract- 

 or at Dorpat (Oct., 1839), in Schum., Astr. Nachr., No. 396, s. 178. 



$ Peters, in Stnive, Astr. StelL, p. 100. II Id., p. 101. 



