[ 392 ] 
thereby be known. And the formula differ in no- 
thing from thofe of the motion of the nodes of the 
earth’s equator, and of the alteration of the obliquity 
of the earth’s axe to the plane of the ecliptic, but in 
this j that the adtion of the fun on the ring to make 
it turn, is exerted entirely thereon whereas in the 
problem of the preceftlon this force mu ft neceffarily 
be diftributed throughout the whole mafs of the earth, 
on account of the adherence of the ring to the globe 
of the earth. 
DIVISION of the WORK. 
This memoir is divided into four fedtions. 
The i ft fedtion treats of the motion of the pole of 
the terreftrial equator caufed by the fun. 
The 2d fedtion treats of the motion of the pole of 
the terreftrial equator caufed by the moon. 
The 3d fedtion treats of the motion of the pole of 
a ring, or of the orbit of a moon, caufed by the fun. 
The 4th fedtion contains the application of the for- 
mula found in the other fedtions. 
SECT. I. 
Of the motion of the pole of the terrejlrial 
equator caufed hy the aSlioit of the fun . 
Problem I. 
Article 1. To find the moment, which refults from the 
attraction of each particle of the earth towards the 
fun, in the inverfe ratio op the fquare of the dijlance , 
to make the earth's axis turn upon its centre C. 
Let E F E F £, fg. 1. if 1. be the fedtion of the 
earth by the plane of the circle of the fun’s declina- 
tion ; 
