Vestiges of the Natural History of Creation | Page 4

of revolution
are to each other in the same proportion as the cubes of their mean
distances,--a most surprising result, for the discovery of which the
world was indebted to the illustrious Kepler. Sir John Herschel truly
observes--"When we contemplate the constituents of the planetary
system from the point of view which this relation affords us, it is no

longer mere analogy which strikes us, no longer a general resemblance
among them, as individuals independent of each other, and circulating
about the sun, each according to its own peculiar nature, and connected
with it by its own peculiar tie. The resemblance is now perceived to be
a true FAMILY LIKENESS; they are bound up in one
chain--interwoven in one web of mutual relation and harmonious
agreement, subjected to one pervading influence which extends from
the centre to the farthest limits of that great system, of which all of
them, the Earth included, must henceforth be regarded as members."
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Connecting what has been observed of the series of nebulous stars with
this wonderful relationship seen to exist among the constituents of our
system, and further taking advantage of the light afforded by the
ascertained laws of matter, modern astronomers have suggested the
following hypothesis of the formation of that system.
Of nebulous matter in its original state we know too little to enable us
to suggest how nuclei should be established in it. But, supposing that,
from a peculiarity in its constitution, nuclei are formed, we know very
well how, by virtue of the law of gravitation, the process of an
aggregation of the neighbouring matter to those nuclei should proceed,
until masses more or less solid should become detached from the rest.
It is a well-known law in physics that, when fluid matter collects
towards or meets in a centre, it establishes a rotatory motion. See minor
results of this law in the whirlwind and the whirlpool--nay, on so
humble a scale as the water sinking through the aperture of a funnel. It
thus becomes certain that when we arrive at the stage of a nebulous star,
we have a rotation on an axis commenced.
Now, mechanical philosophy informs us that, the instant a mass begins
to rotate, there is generated a tendency to fling off its outer portions--in
other words, the law of centrifugal force begins to operate. There are,
then, two forces acting in opposition to each other, the one attracting
TO, the other throwing FROM, the centre. While these remain exactly
counterpoised, the mass necessarily continues entire; but the least
excess of the centrifugal over the attractive force would be attended

with the effect of separating the mass and its outer parts. These outer
parts would, then, be left as a ring round the central body, which ring
would continue to revolve with the velocity possessed by the central
mass at the moment of separation, but not necessarily participating in
any changes afterwards undergone by that body. This is a process
which might be repeated as soon as a new excess arose in the
centrifugal over the attractive forces working in the parent mass. It
might, indeed, continue to be repeated, until the mass attained the
ultimate limits of the condensation which its constitution imposed upon
it. From what cause might arise the periodical occurrence of an excess
of the centrifugal force? If we suppose the agglomeration of a nebulous
mass to be a process attended by refrigeration or cooling, which many
facts render likely, we can easily understand why the outer parts,
hardening under this process, might, by virtue of the greater solidity
thence acquired, begin to present some resistance to the attractive force.
As the solidification proceeded, this resistance would become greater,
though there would still be a tendency to adhere. Meanwhile, the
condensation of the central mass would be going on, tending to produce
a separation from what may now be termed the SOLIDIFYING
CRUST. During the contention between the attractions of these two
bodies, or parts of one body, there would probably be a ring of
attenuation between the mass and its crust. At length, when the central
mass had reached a certain stage in its advance towards solidification, a
separation would take place, and the crust would become a detached
ring. It is clear, of course, that some law presiding over the refrigeration
of heated gaseous bodies would determine the stages at which rings
were thus formed and detached. We do not know any such law, but
what we have seen assures us it is one observing and reducible to
mathematical formulae.
If these rings consisted of matter nearly uniform throughout, they
would probably continue each in its original form; but there are many
chances against their being uniform in constitution. The unavoidable
effects of irregularity in their constitution would be to cause