t, to lay in a supply of food that would be
sufficient for many days in case we escaped, and second, to allow our
eyes to accustom themselves better to the darkness.

Already we were able to see with a fair amount of clearness; we could
easily distinguish the forms of those who came to bring us food and
water when they were fifteen or twenty feet away. But the cavern in
which we were confined must have been a large one, for we were unable
to see a wall in any direction, and we did not venture to explore for
fear our captors would be moved to bind us.

But Harry became so insistent that I finally consented to a scouting
expedition. Caution seemed useless; if the darkness had eyes that
beheld us, doubly so. We strapped our ponchos, heavy with their food,
to our backs, and set out at random across the cavern.

We went slowly, straining our eyes ahead and from side to side. It was
folly, of course, in the darkness--like trying to beat a gambler at his
own game. But we moved on as noiselessly as possible.

Suddenly a wall loomed up before us not ten feet away. I gave a tug at
Harry's arm, and he nodded. We approached the wall, then turned to the
right and proceeded parallel with it, watching for a break that would
mean the way to freedom.

I noticed a dark line that extended along the base of the wall,
reaching up its side to a height of about two feet and seemingly
melting away into the ground. At first I took it for a separate strata
of rock, darker than that above. But there was a strange brokenness
about its appearance that made me consider it more carefully.

It appeared to be composed of curious knots and protuberances. I
stopped short, and, advancing a step or two toward the wall, gazed
intently. Then I saw that the dark line was not a part of the wall at
all; and then--well, then I laughed aloud in spite of myself. The
thing was too ludicrous.

For that "dark line" along the bottom of the wall was a row of
squatting Incas! There they sat, silent, motionless; even when my
laugh rang out through the cavern they gave not the slightest sign that
they either heard or saw. Yet it was certain that they had watched our
every move.

There was nothing for it but retreat. With our knives we might have
fought our way through; but we were unarmed, and we had felt one or two
proofs of their strength.

Harry took it with more philosophy than I had expected. As for me, I
had not yet finished my laugh. We