VOL. XLV.] PHILOSOPHICAL TRANSACTIONS. 435 



nual precession, to every 5th degree of the place of the moon's ascending node, 

 in the following tables ; just as they result from the hypothesis, as at first laid 

 down ; it appearing, from what has already been remarked, that these will be 

 sufficiently exact for practice in all cases. 



The Equation of the Equinoct. Points. The Equation of the Obliquity of the Ecliptic. 



\ s 8 Sig. O I II Subst. y s g Sig. O I II Add. 



from r Sig. VI VII Vm Add. *^^°'" 1^ Sig. VI VII VIII Subst. 



1 1 



0" 0."0 l."3 19."6 30" 0" 0."0 7."8 4."5 30» 



5 2.0 13.0 20.5 25 5 90 7.4 3.8 25 



10 3.9 14.5 21.2 20 10 8.9 6.9 3.1 20 



15 5 8 16.0 21.8 15 15 8.7 6.4 2.3 15 



20 7.7 173 22.2 10 20 8.5 5.8 1.6 10 



25 9-6 18.5 22.5 5 25 8.2 5.2 0.8 5 



30 11.3 19.6 22.6 30 7.8 4.5 0.0 



Subst. Sig. V IV III > s 8 Add. Sig. V IV III ) s 8 



- from T " from T 



Add. Sig. XI X IX Subst. Sig. XI X IX 



) * 8 The Annual Precession of the Equinoctial Points, 



from r Sig. 01 II III IV V 



0° 58".0 57".0 54".2 50".3 46'".5 43".7 So" 



Sir Isaac Newton, in determining the quantity of the annual precession from 

 the theory of gravity, on supposition that the equatorial is to the polar diameter 

 of the earth as 230 is to 229, finds the sun's action sufficient to produce a pre- 

 cession of 9"4- only ; and, collecting fi-om the tides the proportion between the 

 sun's force and the moon's, to be as 1 to 4-l, he settles the mean precession, 

 resulting from their joint actions, at 50". But since the difference between the 

 polar and equatorial diameter is found, by the late observations of the gentlemen 

 of the Academy of Sciences, to be greater than what Sir Isaac had computed it 

 to be; the precession, arising from the sun's action, must likewise be greater 

 than what he has stated it at, nearly in the same proportion. From whence it 

 will follow, that the moon's force must bear a less proportion to the sun's than 

 4.4- to 1 ; and perhaps the phenomena, which I have now been giving an account 

 of, will supply the best data for settling this matter. 



3k 2 



