e sort of script," said Challenger.

"Looks like a guinea puzzle competition," remarked Lord John, craning
his neck to have a look at it. Then suddenly he stretched out his hand
and seized the puzzle.

"By George!" he cried, "I believe I've got it. The boy guessed right
the very first time. See here! How many marks are on that paper?
Eighteen. Well, if you come to think of it there are eighteen cave
openings on the hill-side above us."

"He pointed up to the caves when he gave it to me," said I.

"Well, that settles it. This is a chart of the caves. What! Eighteen
of them all in a row, some short, some deep, some branching, same as we
saw them. It's a map, and here's a cross on it. What's the cross for?
It is placed to mark one that is much deeper than the others."

"One that goes through," I cried.

"I believe our young friend has read the riddle," said Challenger. "If
the cave does not go through I do not understand why this person, who
has every reason to mean us well, should have drawn our attention to
it. But if it does go through and comes out at the corresponding point
on the other side, we should not have more than a hundred feet to
descend."

"A hundred feet!" grumbled Summerlee.

"Well, our rope is still more than a hundred feet long," I cried.
"Surely we could get down."

"How about the Indians in the cave?" Summerlee objected.

"There are no Indians in any of the caves above our heads," said I.
"They are all used as barns and store-houses. Why should we not go up
now at once and spy out the land?"

There is a dry bituminous wood upon the plateau--a species of
araucaria, according to our botanist--which is always used by the
Indians for torches. Each of us picked up a faggot of this, and we
made our way up weed-covered steps to the particular cave which was
marked in the drawing. It was, as I had said, empty, save for a great
number of enormous bats, which flapped round our heads as we advanced
into it. As we had no desire to draw the attention of the Indians to
our proceedings, we stumbled along in the dark until we had gone round
several curves and penetrated a considerable distance into the cavern.
Then, at last, we lit our torches. It was a beautiful dry tunnel with
smooth gray walls covered with native symbols, a curved roof which
arched over our heads, and white glistening sand beneath our feet. We
hurried eagerly along it until, with a deep groan of bitter
disappointment,