thusiastic admirers. It might have seemed, indeed, to have something
like a basis of fact to rest upon, had the conception of the elder
Herschell been verified, when he announced the existence of a nebulous
fluid, capable of being distinguished, by certain well-defined marks,
from unresolved clusters of stars; but even then it presupposed so many
postulates, which could in no way be established by experimental or
historical evidence, that it could scarcely be regarded in any other
light than as an ingenious speculation or a splendid conjecture. For,
let it be considered, first of all, that the theory proceeds on the
assumption of the existence and wide diffusion of a nebulous fluid of
whose reality there is no actual proof; secondly, that it necessarily
requires, also, the supposed existence of certain favorable conditions;
and, thirdly, the operation of certain invariable laws; and it will be
manifest at once that it is purely hypothetical throughout, and that it
includes a variety of topics which never have been, and never can be
made the subjects of experimental verification. For it postulates, in
the words of an acute writer, "the establishment of nuclei in the body
of the elemental mass, as well as the action of heat on its substance,
and then seeks to explain the concentration of the nebulous particles
into these nuclei by the force of gravitation, the rotation of the
bodies so produced by the confluence of the nebulous fluid, the
separation of a portion of the outer surface of these revolving masses
in the form of rings, the disruption of these rings, and the subsequent
recomposition of their fragments into separate spheres, answering to the
planets and satellites of our system."[32] But even were the existence
of a nebulous fluid admitted, we have no access to know what was its
internal structure; we cannot determine whether it was uniform and
homogeneous throughout, or whether it contained nuclei which might
become centres of aggregation; we have no means of estimating the
intensity of the heat which belonged to it, or of calculating the
process by which it was dispersed, so as to occasion the condensation of
successive portions of the mass. No eye ever saw the separation of any
part of it in the form of a ring, or the disruption of that ring, or the
subsequent recomposition of its fragments into a solid sphere. And even
had all this been matter, not of mere conjecture, but of actual
observation, it would still h