That the present order of things had a beginning, is taught by every
analogy around us, and as we have the glaring fact forced upon us, that
our globe has experienced a far higher temperature on its surface than
obtains at present, and moreover, as it is demonstrated beyond a cavil,
that the interior is now of far higher temperature than is due to solar
radiation, we are justified in concluding, not only that the condition
of the interior of our globe is that of fusion, but that its original
temperature was far higher than at present; so that the inference is
allowable that there has been a time when the whole globe was _perhaps_
in this state. But why should we stop here? There are three states of
matter, the solid, the fluid, and the gaseous; and with this passing
glance at the question, we will jump at once to the theory of La
Place,--that not only our own globe, but the whole solar system, has
been once in the nebulous state.
In justice to himself, the author ought to remark, that he had reasoned
his way up to this starting point, before even the name of La Place had
reached his ears. He makes the remark in order to disclaim any desire to
appropriate that which belongs to another; as he may innocently speak of
things hereafter, the idea of which has occurred to others. It is not
his intention here to say a word _pro_ or _con_ on the nebular
hypothesis; it is sufficient to allude to the facts, that the direction
of rotation and of revolution is the same for all the planets and
satellites of our system; and that the planes on which these motions are
performed, are nearly coincident. That this concordance is due to one
common cause, no one acquainted with the theory of probabilities will
pretend to deny.