, unless, indeed,"--and his
eyes glistened as a thought darted into his mind,--"unless, indeed, he
should find a lake where he left a dry cave. Good! I'll try it."

With his hands in his pockets, the captain stood a few moments and
thought, and then he went to work. From the useless little vessel which,
had belonged to the Rackbirds he gathered some bits of old rope, and
having cut these into short pieces, he proceeded to pick them into what
sailors call oakum.

Early the next morning, his two canvas bags filled with this, he started
for the caves. When he reached the top of the mound, and was just about
to hold his lantern so as to take a final glance into its interior, he
suddenly turned away his head and shut his eyes.

"No," he said. "If I do that, it is ten to one I'll jump inside, and what
might happen next nobody knows."

He put the lantern aside, lifted the great lid into its place, and
then, with a hammer and a little chisel which he had brought with him
from the tools which had been used for the building of the pier, he
packed the crevices about the lid with oakum. With a mariner's skill he
worked, and when his job was finished, it would have been difficult for
a drop of water to have found its way into the dome, no matter if it
rose high above it.

It was like leaving behind a kingdom and a throne, the command of armies
and vast navies, the domination of power, of human happenings; but he
came away.

When he reached the portion of the cave near the great gap which opened
to the sky opposite the entrance to the outer caves, the captain walked
across the dry floor to the place where was situated the outlet through
which the waters of the lake had poured out into the Rackbirds' valley.

The machine which controlled this outlet was situated under the
overhanging ledge of the cave, and was in darkness, so that the captain
was obliged to use his lantern. He soon found the great lever which he
had clutched when he had swum to the rescue of Ralph, and which had gone
down with him and so opened the valve and permitted egress of the water,
and which now lay with its ten feet or more of length horizontally near
the ground. Near by was the great pipe, with its circular blackness
leading into the depths below.

"That stream outside," said the captain, "must run in here somewhere,
although I cannot see nor hear it, and it must be stopped off by this
valve or another one connected with it, so that if I can get this