C 37 ] 
Sir Ifaac Newton, in determining the Quantity 
of the annual Prcceftion from the Theory of Gra- 
vity, upon Suppofition that the Equatorial is to the 
Polar Diameter of the Earth as 230 is to 229, finds 
the Sun’s Action fufficient to produce a Precdfion 
of 9"! only; and, collecting from the Tides the 
Proportion between the Sun’s Force and the Moons 
to be as 1 to 4I, he fettles the mean Precelllon, rc- 
fulting from their joint Actions, at 50". But llnce 
the Difference between the Polar and Equatorial 
Diameter is found, by the late Obfervations of the Gen- 
tlemen of the Academy of Sciences, to be greater than 
whatSir Ifaac had computed ittobe; the Preccffion, 
arifing from the Sun’s Action, muff likewife be greater 
than what he has ftated it ar, nearly in the fame Propoi* 
tion. From whence it will follow, that the Moons 
Force mufl bear a lefs Proportion to the Sun’s than 
4-i to 1 5 and perhaps the ‘Phenomena, which I have 
now been giving an Account of, will fupply the 
be ft ‘Data for fettling this Matter. 
As I apprehend, th:t the Obfervations already fee 
down will be judged fufficient, to prove in general 
the Truth of the Hypothecs before advanced 5 I (hall 
not trouble your Lordfhip with the Recital of more, 
that I made of Stars lying at greater Diftances from 
the Zenith j thofe not being fo proper, for the Rea- 
fon before -mention’d, to eftablifh the Point that I had 
chiefly in View. But as it may perhaps be of fotne Ule 
to future Aftronomers, to know what were the mean 
Differences of Declination, at a given Time, between 
fome Stars, that lie nearly oppofite to one another^ 
in Right Afcenfion, and not far from either of the 
Colures ; I fnall fet down the Refult of the Compa- 
rifon of a few, that differ fo little in Declination, 
that 
