324 On the Precession of the Equinozes. 
dent, that whatever be the size of the ring, equal portions 
it are on each side of the Ecliptick ; that is, the centre 
of attraction passes through the centre of the matter of the 
Earth and its ring ; so that all the effect, which the attrac- 
tion of the Sun can have, in consequence of the ring, ari- 
ses merely from the different distances of A and O equal 
to the diameter of the Earth ; and such an effect as this, if 
it is any sensible effect, it can have only at the solstices ; 
for, at the Equinoxes, the portions of the ring on each side 
of the Ecliptick are at equal distances from the Sun; and of 
course, from the solstices to the Equinoxes the effect, if 
any must be constantly diminishing. But while the Moon, 
by reason of the angle of its orbit, is at a distance from the 
plane of the Ecliptick on one side, there is nothing on the 
other side to balance it, or to prevent it from being has- 
tened, by attraction, tothe plane. In fig. 2, pl. 3, let LP bea 
portion of the moon’s orbit, M the moon, and S E the 
plane of the Ecliptick. It is evident, that when the Moon 
is at L, there is nothing at P to balance it. 
Again, suppose the orbit of the moon was a ring of moons, 
or any material substance, the case would be different from 
that of the Equatorial ring, because the greater difference 
in the distances of the different parts of the ring would 
more materially affect the ratios of gravitation. 
The precession of the Equinoxes, if caused by the Equa- 
torial ring, must arise, either from a diminution of the an- 
gle of the Equator with the Ecliptick, or from a change in 
the direction of the line of the Equatorial odes. j 
ormer, we have no evidence, that there 1s 
such a regular diminution of the angle ; but on the contra- 
to see any method in which a regular and successive varia- 
tion of the line’of the nodes should be effected. In rela- 
tion to the moon, we can see no rational method of ac- 
Counting for the entire revolution of its nodes, except the 
eccentricity of its orbit. If the Earth was in the centre of 
the moon’s orbit, there would still be a motion of the nodes 
backward and porwr butno revolution. Thecentre of the 
~qnatorial ring is the centre of revolution and att : 
and we know not how a revolution of the Equatorial Nodes 
