PHYSICAL ASTRONOMY. 



The sign , when applied to the node, or the aphe- 

 lion, implies that the motion is retrograde. 



6.- The motions of the node and of the apogee, given 

 in Astronomical Tables, are different from the 

 above, as the annual procession of the equinoxes 

 is included. Thus the annual motion of the 

 nodeis 8".98 + 50".25 = + 4-1 ".2 7, in respect 

 of the equinoxes, though it is only 8".98 in re- 

 spect of the fixed stars. 



269. In like manner, the place of Venus in 

 her orbit is not sensibly disturbed, but the or- 

 bit itself is subject to change. 



270. In the orbit of the Earth, the apsides 

 move forward annually at the rate of 11".807719 

 in respect of the fixed stars ; and the eccentri- 

 city diminishes, so that the secular variation of 

 the greatest equation of the centre is 17".66. 

 VOL. II. S a. Of 



