'the spectator of all time and
all existence,' to borrow once more his own grand expression, or viewed,
in the language of Spinoza, 'sub specie aeternitatis,' they were still
at rest, but appeared to move in order to teach men the periods of time.
Although absolutely in motion, they are relatively at rest; or we
may conceive of them as resting, while the space in which they are
contained, or the whole anima mundi, revolves.

The universe revolves around a centre once in twenty-four hours, but the
orbits of the fixed stars take a different direction from those of the
planets. The outer and the inner sphere cross one another and meet again
at a point opposite to that of their first contact; the first moving in
a circle from left to right along the side of a parallelogram which is
supposed to be inscribed in it, the second also moving in a circle along
the diagonal of the same parallelogram from right to left; or, in other
words, the first describing the path of the equator, the second, the
path of the ecliptic. The motion of the second is controlled by the
first, and hence the oblique line in which the planets are supposed to
move becomes a spiral. The motion of the same is said to be undivided,
whereas the inner motion is split into seven unequal orbits--the
intervals between them being in the ratio of two and three, three of
either:--the Sun, moving in the opposite direction to Mercury and
Venus, but with equal swiftness; the remaining four, Moon, Saturn, Mars,
Jupiter, with unequal swiftness to the former three and to one another.
Thus arises the following progression:--Moon 1, Sun 2, Venus 3, Mercury
4, Mars 8, Jupiter 9, Saturn 27. This series of numbers is the compound
of the two Pythagorean ratios, having the same intervals, though not in
the same order, as the mixture which was originally divided in forming
the soul of the world.

Plato was struck by the phenomenon of Mercury, Venus, and the Sun
appearing to overtake and be overtaken by one another. The true reason
of this, namely, that they lie within the circle of the earth's orbit,
was unknown to him, and the reason which he gives--that the two former
move in an opposite direction to the latter--is far from explaining the
appearance of them in the heavens. All the planets, including the sun,
are carried round in the daily motion of the circle of the fixed stars,
and they have a second or oblique motion which gives the explanation
of the different lengths of th