OUTLINES OF NATURAL PHILOSOPHY. 



Dissertatio de cfanuisjixarum aberrationibus. Ro- 

 nwe, 1742. LA LANDE, Astron* 2857. 



. 



- , . , TT . , 



229. When two stars appear very near to one 



another, or when their distance subtends a very 

 small angle, the variations in that angle, at op- 

 posite seasons of the year, may serve to deter- 

 mine the parallax of the fixed stars. 



1 



This method of ascertaining the distance of the fixed 

 stars, seems to have been first thought of by GALI- 

 LEO, Syst. Cos. Diak 3. Pr HERSCHEL has also 

 recommended it ; and the double stars which he 

 has discovered, as well as the Lamp Micrometer 

 which he has invented, give hopes that it may 

 prove successful. 



230. From the consideration of the quantity 

 of the light of the fixed stars, compared with 

 the quantity of the light of the Sim, it has been 

 concluded, that the parallax of a star of the se- 

 cond magnitude, is not more than f of a se- 

 cond ; and of a star of the sixth magnitude, not 

 more than TO- or T V of that quantity. 



The very ingenious paper in which these conclusions 

 are dedbced, is by the Reverend Mr MITCHELL. 

 Phil Trins. vol. Ivii. p. 234, &c. 



) : >qq 



281. The 



