[ 4°2 ] 
Problem III. 
5. Having given, the moment wherewith the earth 
turns about the axe Qfif of the circle of the fun's 
declination , To find the motion of the pole P, or , 
which is the fame , of the point E in the plane of the 
circle of the fun's declination. 
By Prob. I. the moment wherewith the earth turns 
2 S 
about the axe C by the a&ion of the fun, is ~ 
s 
x a 7r v u * tt aS - 
By Prob. II. the moment wherewith the earth 
turns about the fame axe C 6), the velocity of the 
point P, or of the point £, being is (1 — 2a) x ^ p 
x ^ T a 
- g 
We fhall have then a yr v u x ^ = (1 — 2a) 
, 2, S aa v u 
x tt h x fV 4 ; whence we get ^ = — And 
this is the motion of the pole P, or of the point £, 
about the centre C. Which was to be found. 
COROLLAR Y. 
6. In like manner, the moment wherewith the 
crown E £fE' gfE turns about the axe being 
given, the motion of the point E may be known. 
For, 
By the Coroll, of Prob. I. the moment of this 
crown, turning about the axe CJ^by the adtion of the 
r . 2 , $ 
fun, is ~-—r x a tt 1/ w x a*. 
s 
By 
