contrary to all
experience, while the latter is opposed to that simplicity of conception
by which we only postulate one medium, the Aether, to fill all space.

Thus we are led to the conclusion, that the gaseous matter, be it
hydrogen or nitrogen, must have some relation to the electro-magnetic
Aether that is so universal in its extent. Already this relationship has
been dealt with by one who has done more for the development of
aetherial physics than any other scientist. Lord Kelvin, in his paper
"On the Clustering of Gravitational Matter in any part of the
Universe,"[43] has solved this relationship, though in so doing he has
had to depart somewhat from the idea of an incompressible Aether. In
that paper he writes as follows: "If we consider Aether to be matter, we
postulate that it has rigidity enough for the vibrations of light, but
we have no right to say that it is absolutely incompressible. We must
admit that sufficiently great pressure could condense the Aether in a
given space, allowing the Aether in the surrounding space to come in
towards the ideal shrinking surface." In another part of the paper,
dealing with the same question, he writes: "In regions where the density
was greater than in neighbouring regions, the density would become
greater still; in places of less density, the density would become less,
and large regions would quickly become void or nearly void of atoms.
These large void regions would extend so as to completely surround
regions of greater density." He then points out, that as soon as this
density becomes something like the density of the atmosphere, then
collisions would take place between the particles, and continues: "Each
collision would give rise to a train of waves in the Aether. These waves
would carry away energy, spreading it out through the void Aether of
infinite space. The loss of energy thus taken away from the atoms would
reduce large condensing clusters to the conditions of a gas in
equilibrium under the influence of its own gravity, rotating like our
sun or moving at moderate speed as in spiral nebulae. Gravitational
condensation would at first produce rise of temperature, followed later
by cooling, ultimately freezing, giving solid bodies, collision between
which would produce meteoric stones such as we see them."

Here then we have a definitive relationship between Aether and nebulae
given to us from one of the keenest intellects of the present time, but
in order for that