1/6.4 8 Satellites, and three rings.
Uranus. 1/10.9 4 Satellites.

Thus taking as our standard of comparison the Earth with its one moon,
we see that Mercury, in which the centrifugal force is relatively less,
has no moon. Mars, in which it is relatively much greater, has two
moons. Jupiter, in which it is far greater, has four moons. Uranus, in
which it is greater still, has certainly four, and more if Herschel was
right. Saturn, in which it is the greatest, being nearly one-sixth of
gravity, has, including his rings, eleven attendants. The only instance
in which there is nonconformity with observation, is that of Venus. Here
it appears that the centrifugal force is relatively greater than in the
Earth; and, according to the hypothesis, Venus ought to have a
satellite. Respecting this anomaly several remarks are to be made.
Without putting any faith in the alleged discovery of a satellite of
Venus (repeated at intervals by five different observers), it may yet be
contended that as the satellites of Mars eluded observation up to 1877,
a satellite of Venus may have eluded observation up to the present time.
Merely naming this as possible, but not probable, a consideration of
more weight is that the period of rotation of Venus is but indefinitely
fixed, and that a small diminution in the estimated angular velocity of
her equator would bring the result into congruity with the hypothesis.
Further, it may be remarked that not exact, but only general, congruity
is to be expected; since the process of condensation of each planet from
nebulous matter can scarcely be expected to have gone on with absolute
uniformity: the angular velocities of the superposed strata of nebulous
matter probably differed from one another in degrees unlike in each
case; and such differences would affect the satellite-forming tendency.
But without making much of these possible explanations of the
discrepancy, the correspondence between inference and fact which we find
in so many planets, may be held to afford strong support to the Nebular
Hypothesis.

Certain more special peculiarities of the satellites must be mentioned
as suggestive. One of them is the relation between the period of
revolution and that of rotation. No discoverable purpose is served by
making the Moon go round its axis in the same time that it goes round
the Earth: for our convenience, a more rapid axial motion would have
been equally good; and for any possible inhabita