ankine, _Phil. Mag._, 1851. His theory is known as the
"Hypothesis of Molecular Vortices."

He assumed that "each atom of matter consists of a nucleus or central
point, enveloped by an elastic atmosphere, which is retained in its
position by attractive forces, and that the elasticity due to heat
arises from the centrifugal force of those atmospheres revolving or
oscillating about their nuclei or centres."

Now in this assumption we find that he admits that each atom has an
atmosphere, such atmosphere evidently being an aetherial one, and in
that case the hypothesis would agree with the statement in Art. 46, that
every atom possesses an aetherial atmosphere. He further points out that
the atmosphere is retained in its position by attractive forces. This is
also in harmony with the hypothesis given in Art. 45, which proves that
Aether is gravitative, and therefore the atmosphere of the atom would be
held in its position by the attractive force of Gravitation, as
suggested by Young in his Fourth Hypothesis.

Further, he goes on to show that the elasticity of the atomic atmosphere
is proportionate to its density, which is also in conformity with the
statement made in Art. 47, and is also in accordance with Boyle's Law.
Then he goes on to prove that the quantity of heat in a body is measured
by the molecular revolutions of the vortices.

He does not clearly define the exact character of those molecular
vortices, but I take it to mean that each atmosphere is in a state of
revolution around its atomic centre, in the same way that the atmosphere
of a planet is in a state of revolution around its central body.

Such an assumption is entirely in harmony with experience, as there is
an analogy for its assumption from the planetary system; and if an atom
is a world in miniature, as I believe it to be, then the atmosphere of
the atom ought to revolve around its central nucleus in the same way
that the atmosphere of a planet revolves around its nucleus or central
body.

He then deals with temperature, and with the pressure of gases caused by
heat, showing the relation of elasticity and pressure to temperature in
a table of results given in the _Phil. Mag._ for 1851. I must refer the
reader to the paper itself for fuller details. Thus from one of the
greatest thinkers of modern times we have further testimony to the
hypothesis that Aether is matter and is therefore gravitative, and
because of its gravitating tendency, it forms a