[ 5°5 3 
XXXII. On the Precejfton of the Equinoxes produced by 
the Sun's Attraction. By the Rev. Mr. Ifaac Milner, 
M. A. and Fellow of Queen’s College, Cambridge ; 
communicated by the Rev. Dr. Shepherd, F. R. S. 
Read June 24, 1779. 
TF the aCtions of the Sun and Moon upon the different 
parts of the earth were equal; or if the earth itfelf 
were perfectly fpherical, and of an uniform denfity from 
the center to the furface; in either cafe the attractions of 
thofe remote bodies would have no effeCt on the pofition 
of the terreftrial equator, and the equinoctial points 
1 
would conftantly be the fame in the heavens. But it was 
impoffible to give the earth a rotatory motion round an 
axis without giving at the fame time a centrifugal force 
to its parts. This force is greateft at the equator, and is 
in a contrary direction to that of gravity; on either fide 
of the equator the force is lefs; and, moreover, only 
part of its effects is oppofed to that of gravity. It is ufual 
in determining the figure of the earth to confider the 
whole mafs as in a ftate of fluidity, and the different co- 
lumns as fuftaining one another at the center. If the 
earth. 
