relationship to become strictly philosophical, the
conception of the Aether as advanced in this work must be accepted. For
with the present conception of a frictionless Aether, such a hypothesis
is altogether untenable, because it supposes something that is contrary
to all experience and observation.

On the basis of a condensing frictionless Aether into any kind of solid
body, be it nebula, meteor, sun or star, we have to suppose that it is
possible for a medium (the Aether, which is outside the Law of
Gravitation according to the present theory) to be condensed into a
body, that is, a nebula or meteor which is subject to the Law of
Gravitation; and the question arises, at what point in the history of
its condensation does this frictionless Aether pass out of the condition
of having no weight, to the condition when it has weight; or, in other
words, from the condition when it is outside the Law of Gravitation, to
the condition when it comes under the Law of Gravitation?

No satisfactory solution can possibly be offered to such a problem.
Therefore one of two results must follow, either that the Aether is not
frictionless, but possesses weight; or, that the condensation of the
Aether is not possible. With the theory of Aether presented in this
work, the whole question receives a simple and philosophical solution.
As Aether is matter, it is therefore atomic; and being atomic, it is
subject to the Law of Gravitation; and therefore, possessing mass and
weight, it can readily pass into other forms of matter, and with such a
conception Lord Kelvin's hypothesis becomes not only possible but
probable. So that it is exceedingly probable that nebulae are nothing
more nor less than condensed Aether, the same as comets were suggested
to be condensed Aether. It may be asserted that such a hypothesis lacks
that experimental evidence which is so necessary for its establishment,
but I hope to show in the last chapter that Faraday has given the world
that very experimental evidence which will place this hypothesis upon a
firm and solid foundation, and enable it to pass out of the region of
the hypothetical into the region of fact and experiment.

According to our hypothesis, therefore, nebulae are simply condensations
of the electro-magnetic Aether that exists in interstellar space, and
the various spectra of the different nebulae indicate the stage of
development to which the process has arrived. Where the spectra are
bright, and c