of
repulsion. Why then do not the mutually repellent members of the group
part company? The reason of this stability is that _two_ forces, the one
attractive and the other repulsive, are in operation between every two
atoms, and the position of every atom is determined by the equilibration
of these two forces. The points at which attraction and repulsion are
equal to each other is the atom's position of equilibrium. When the
atoms approach too near each other, repulsion predominates and drives
them apart; when they recede to too great a distance, attraction
predominates and draws them together." If, therefore, there are TWO
forces at work in the atomic world, viz. attraction and repulsion, then
the question arises, Can that repulsive power be increased in any way,
and if so, by what means? Such repulsive motion, as experiment and
experience teach us, can be increased, and such increase may be derived
from the absorption of heat which gives rise to increased atomic motion,
and so to increased aetherial motion away from the atom, by which the
repulsive action of one atom upon another is increased. Thus an atom's
repulsive power may be increased by heat; the greater the heat absorbed,
the greater the repulsive power that any atom or body exerts upon a
neighbouring atom or body. We can therefore understand how it is, that a
body when changed from a solid to a liquid condition occupies a larger
space in the latter condition than in the former; or why a body when
changed from a liquid to a gaseous condition occupies a still larger
volume in the latter than in its previous condition. The expansion in
both cases is essentially the result of the increased repulsive motion
that has been imparted to its atoms or molecules by the increased heat,
and this increased repulsive power has overcome the attractive power of
the atoms or molecules, with the result that they have been driven
further and further apart, until, in the gaseous state, the atoms may
be very far apart indeed. Wherever, therefore, we have heat of any kind,
there we have a repulsive motion, such motion being proportionate to the
heat radiated, that is, the aetherial waves propagated by the body. If,
therefore, in the atomic world we find a repulsive motion, which is due
to the vibratory motions of the Aether generated by heat, the question
now confronts us, as to whether in the solar system, and indeed all
through the universe, there is not the same repulsive motion fr