192 COSMOS. 



1832, and by those of Maclear in 1839>' According to this 

 Btatement, it is the nearest of all the fixed stars that havo 

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



The parallax of a Lyras has long been the object of 

 Struve's observations. The earlier observations (1836) 

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

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

 a period of twelve years for the transmission of its light. | 

 But Peters 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 i)y 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"-455.§ 



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

 Riimker's earlier observations with the Hamburg meridian 

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

 other star of the first magnitude, CapcUa, is still less, bemg, 

 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, l"-08, and therefore greater than the 

 parallax of a Centauri. |1 



* Sir John Herschel, Outlines, p. 545 and 551. Madler {Astr., s. 425j 

 gives ill the case of a Centauri the paj-ajlax 0"-9213 instead of 0"-9128. 



t Striive Btell. compos. Mms. Microm., p. clxix.-clxxii. Airy makes 

 the paralkx of a Lyra?, which Peters had previously reduced to 0"-l, 

 fitill lower; indeed, too small to be measurable by our present instru- 

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



\ Stnive, On the Micrametrical Admeasurements by tJie Great Refract 

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



i Peters, in Struve, Astr. StelL, p. 100. II Id., p. 101. 



