that it
arose from these same volcanoes which had illuminated the northern sky
when I was ashore, and followed me still with their glare. I had been
carried into this darkness, through some vast opening which now lay
behind me, disclosing the red volcano glow, and this it was that
caused that roundness and resemblance to the moon. I saw that I was
still moving on away from that light as before, and that its changing
position was due to the turning of the boat as the water drifted it
along, now stern foremost, now sidewise, and again bow foremost. From
this it seemed plainly evident that the waters had borne me into some
vast cavern of unknown extent, which went under the mountains--a
subterranean channel, whose issue I could not conjecture. Was this the
beginning of that course which should ultimately become a plunge deep
down into some unutterable abyss? or might I ever hope to emerge again
into the light of day--perhaps in some other ocean--some land of ice
and frost and eternal night? But the old theory of the flow of water
through the earth had taken hold of me and could not be shaken off. I
knew some scientific men held the opinion that the earth's interior is
a mass of molten rock and pent-up fire, and that the earth itself had
once been a burning orb, which had cooled down at the surface; yet,
after all, this was only a theory, and there were other theories which
were totally different. As a boy I had read wild works of fiction
about lands in the interior of the earth, with a sun at the centre,
which gave them the light of a perpetual day. These, I knew, were only
the creations of fiction; yet, after all, it seemed possible that the
earth might contain vast hollow spaces in its interior--realms of
eternal darkness, caverns in comparison with which the hugest caves on
the surface were but the tiniest cells. I was now being borne on to
these. In that case there might be no sudden plunge, after all. The
stream might run on for many thousand miles through this terrific
cavern gloom, in accordance with natural laws; and I might thus live,
and drift on in this darkness, until I should die a lingering death of
horror and despair.

There was no possible way of forming any estimate as to speed. All was
dark, and even the glow behind was fading away; nor could I make any
conjecture whatever as to the size of the channel. At the opening it
had been contracted and narrow; but here it might have expanded itself
to miles, an