manded by
the theory, which he emphatically disclaims, from the presidential chair
of the British Association for the Advancement of Science.

"If it is to be regarded as demonstrated truth, or as receiving the
smallest support from any observed numerical relations which actually
hold good among the elements of the primary orbits, I beg leave to
demur. Assuredly it receives no support from the observation of the
effects of sidereal aggregation as exemplified in the formation of
globular and elliptic clusters, supposing them to have resulted from
such aggregation. For we see this cause working out in thousands of
instances, to have resulted, _not_ in the formation of a single large
central body, surrounded by a few smaller attendants disposed in one
plane around it, but in systems of infinitely greater complexity,
consisting of multitudes of nearly equal luminaries, grouped together in
a solid elliptic or globular form. So far then as any conclusions from
our observations of nebulae can go, the result of agglomerative
tendencies _may_ indeed be the formation of families of stars of a
general and very striking character, but we see nothing to lead us to
presume its further result to be the surrounding of those stars with
planetary adherents."[206]

_This theory is contradicted by the peculiarities of our solar system._
The orbits of the comets being inclined at all angles to the sun's
equator, are often out of the plane of his rotation, and so in the way
of the theory. The moons of Uranus revolve in a direction contrary to
all the other bodies, and fly right into the face of the theory.
According to the nebular theory, the outer planets, first cast off from
the sun, ought to be lighter than those nearer him, as these had longer
pressing near the middle of the mass; and the sun himself, having been
pressed by the weight of all the rest of the system, should be the
densest body of the whole. And the author of _The Vestiges of Creation_,
in expounding the theory, manufactures a set of facts to suit it, and
tells his readers that the planets exhibit a progressive diminution in
density from the one nearest the sun to that which is most distant. Our
solar system could not have lasted thirty years had that been the case.
The Earth, Venus, and Mars, are nearly of the same density. Uranus is
more dense than Saturn, which is nearer the sun. Neptune is more dense
than either. The sun, which ought to be the heaviest of all, accordin