[ 426 ] 
viding, therefore, each circular arc by its radius, we 
fhall have the quantity of the angle : And 
The angle of the preceffion, during the time of a 
femi-revolution of l l l l x of the pole of the lunar 
orbit, will be to the angle of the nutation, in the 
fame time, 
As f 7T x ( i 
to 2 x, or as x 
Schol 1UM. 
24. Whatever has been faid as to the moon and 
the fun, may be equally applicable to all the other 
planets ; but as the effedt of the adtion of the reft of 
the planets upon the earth is not fenfible, we fhall 
not take it into confideration. 
S E C T. III. 
Of the motion of the foie of a ring , caufed by 
the aSlion of the fun: or of the motion of 
the pole of the moon s orbit . 
25. We have feen, in slrt. 9. that if, inftead of 
the terreftrial fpheroid, we were to fuppofe a fimple 
ring placed at the circumference of the equator, the 
motion of the pole of fuch ring would be found by 
the fame formula as that for the motion of the pole of 
the earthy fuppofing only, in tha tformule, — 1 — = k 
1 1 2 a 
• . • t . ■ 1 1 
• i : v* vy, : n i’a 
By 
