ies to grasp
them, except that it can grasp the B but not the A; it is, in fact,
only the unreal that can apprehend the unreal, and the real the real.

The above simile may help some of my readers to understand how the
phenomena of Nature, though having no real existence apart from our
senses, have the appearance of reality to us, because both we and the
whole Phenomenal Universe are the unreal of our analogy, namely, the
reflection or shadow of the Real on the physical plane. If we run
against a stone wall, which is also part, with us, of the shadow, we
hurt ourselves and acknowledge its existence, but to the Real it would
not be an obstruction at all, it is not there. We know that this wall
is not really solid, it is made up of Atoms revolving round each other
but never touching, but the man in the street would give as the reason
why it hurt, that it was dense, or what is called hard; if the wall
were made of hay, or cotton wool, or of sunbeams, we should not suffer
by running against it; in fact, the denser anything becomes, the more
it shows its character of being real to our senses. If we take this as
the true explanation for the Physical Universe, we are met with
something quite beyond our powers of comprehension, when we try to
form a conception of the all-pervading Ether; unless we may look upon
it as actually a _presentation_ of the Reality itself. If we wave our
hand, we can feel the obstruction of the air, but we cannot feel the
Ether. We think our earth very solid, and we know it is rushing round
the sun at the enormous rate of 60,000 miles per hour, but it finds no
obstruction in the Ether, there is no retardation of its velocity; and
yet the study of Radio-Activity has quite lately shown us that that
Ether is not only as dense as iron, or a hundred or a thousand times
denser, but millions of times denser than that metal; and yet it
permeates all matter like a sieve. In Sir Oliver Lodge's words, "the
Ether is so dense that matter by comparison is like a gossamer or a
filmy imperceptible mist." We can, therefore, by again using our
"Ghost" analogy, understand why matter cannot obstruct the Ether, or
vice versa; there is no perceivable friction between them, unless, as
I shall presently suggest, we may find something akin to obstruction
by Matter, not to Ether itself, but to its pressure, in the phenomenon
of Gravitation.

The evidence we are gradually winning from Radio-Activity seems to be
leading us to t