208 OUTLINES OF NATURAL PHILOSOPHY. 



The effect on the declination, therefore, does not in- 

 volve the declination itself, and is the same for all 

 stars having the same right ascension. 



The inequalities here considered, do not 

 affect the position of the stars relatively to one 

 another, nor to the plane or pole of the eclip- 

 tic ; they affect thgir position only relatively to 

 the plane of the equator, or to the position of 

 the Earth's axis. 



It was from this general fact> combined with the re- 

 lation observed between these inequalities, and the 

 motion of the moon's nodes, that BRADLEY was led 

 to the construction given above. In separating 

 between the inequalities belonging to the nutation, 

 and those depending on the aberration, (which ob- 

 servation always presented as combined together), 

 he has displayed great acuteness and sagacity* 



See WOODHOUSE, Astron. chap. 17. 



SECT. 



