uences. Nay, more,
the formation of planets, the formation of satellites and of asteroids,
is accounted for. We see why the outer planets and satellites are larger
than the interior ones; why the larger planets rotate rapidly, and the
small ones slowly; why of the satellites the outer planets have more,
the inner fewer. We are furnished with indications of the time of
revolution of the planets in their orbits, and of the satellites in
theirs; we perceive the mode of formation of Saturn's rings. We find an
explanation of the physical condition of the sun, and the transitions of
condition through which the earth and moon have passed, as indicated by
their geology.

But two exceptions to the above peculiarities have been noted; they are
in the cases of Uranus and Neptune.

The existence of such a nebulous mass once admitted, all the rest
follows as a matter of necessity. Is there not, however, a most serious
objection in the way? Is not this to exclude Almighty God from the
worlds he has made?

First, we must be satisfied whether there is any solid evidence for
admitting the existence of such a nebulous mass.

The nebular hypothesis rests primarily on the telescopic discovery made
by Herschel I., that there are scattered here and there in the heavens
pale, gleaming patches of light, a few of which are large enough to be
visible to the naked eye. Of these, many may be resolved by a sufficient
telescopic power into a congeries of stars, but some, such as the great
nebula in Orion, have resisted the best instruments hitherto made.

It was asserted by those who were indisposed to accept the nebular
hypothesis, that the non-resolution was due to imperfection in the
telescopes used. In these instruments two distinct functions may be
observed: their light-gathering power depends on the diameter of their
object mirror or lens, their defining power depends on the exquisite
correctness of their optical surfaces. Grand instruments may possess
the former quality in perfection by reason of their size, but the latter
very imperfectly, either through want of original configuration, or
distortion arising from flexure through their own weight. But, unless an
instrument be perfect in this respect, as well as adequate in the other,
it may fail to decompose a nebula into discrete points.

Fortunately, however, other means for the settlement of this question
are available. In 1846, it was discovered by the author of this book
that the s