ideration to
account for such phenomena as the refraction and reflection of light,
but, as we have seen in Art. 46, such a property as density is
inconceivable in connection with a medium which is neither atomic and
possesses no mass. On the assumption, however, of an atomic and
gravitative Aether, the difficulty is at once solved, and the density of
the Aether, and different degrees of density are at once placed upon a
logical and philosophical basis. So that in relation to the elasticity
and density of the Aether upon which the transmission and reflection of
wave motion depend, an atomic and gravitative Aether establishes and
confirms the undulatory theory.

There is also another aspect of the subject that is worthy of notice. I
refer to the effect of an atomic and gravitative Aether upon Newton's
corpuscular theory of light. Newton's corpuscular theory failed in not
being able to account for the relative velocity of light in rare and
denser media, and if by an atomic Aether in conjunction with the
undulatory theory, the phenomenon can be accounted for, as I believe it
can, then our aetherial vortex atoms are analogous to Newton's
corpuscles. This distinction will, however, have to be made, viz. that
Newton supposed his luminous corpuscles to be emitted by the luminous
body, whereas in the conception of our aetherial atoms, we conceive them
to be stationary relatively in space, and only subject to those
vibrations and oscillations that give rise to the aetherial waves
recognized in the undulatory theory.

It would indeed be a consummation to be desired, if, by an atomic
Aether, it can be proved that Newton's Corpuscular Theory was made to
harmonize with the Undulatory Theory, and that it can be I am profoundly
convinced. Professor Preston is also of this view, for in his _Theory of
Light_, writing on this subject, he says, page 19: "In conclusion, we
may state that we believe an ingenious exponent of the emission theory,
by suitably framing his fundamental postulates, might fairly meet all
the objections that have been raised against it."

We will now apply the hypothesis of an atomic and gravitating Aether to
Huyghens' principle of wave propagation, and see if this atomicity in
any way destroys that principle, or whether it simplifies and confirms
it.

Let us briefly review our conception of the Aether before making the
application. In the first place, because Aether is gravitative, we
learned from Art. 45 that