r. Fellow that
guesses big rock goes," said Chick-chick.

"Right!" said Matt.

"An' Brick guesses left," said Chick-chick for Glen. "Matt gets the
try."

Matt waited for no counsel.

"I know just about where the opening lies," he said, stepping on the
pile of masonry. "I'll dive clear through the passage."

With a quick spring he disappeared beneath the turbid water.

The boys waited an anxious minute, swinging their lanterns far out over
the current. Suddenly Glen thrust the lantern he held into Apple's hand
and made a quick jump into the swirl of waters. He was up in a moment
with a heavy burden.

"It's Matt!" he cried. "I saw his hand sticking out of the water and
jumped for it. He's hurt himself."

The boys were down by his side in a moment, Apple holding a lantern high
above his head.

"We must get him up on one of those ledges," said Glen. "He's breathing,
but he isn't conscious."

It would have been a hard task under ordinary circumstances, but in
their excitement the three scouts made light work of it. One ledge
shelved down toward the water making their ascent easier, and from there
they managed to lift the injured boy still higher, well out of reach of
the water.

Blood was pouring persistently from a wound in the scalp, but with his
knowledge of "first aid" Apple was able to stop this quickly by making
pressure. They had no bandage material of any description but they took
turns in making pressure with their fingers until the blood seemed
inclined no longer to flow and the wound showed a tendency to be covered
by a firm clot. Matt came to himself for a few minutes, spoke a few
half-conscious words and then drifted off again into quiet; but this
time it seemed more like the quiet of sleep so they made no effort to
disturb him.

"He must have hit his head against something pretty sharp when he
dived," said Glen. "I'll go more carefully and just swim gently along
the side where the opening ought to be and reach out with my hands for
it."

But while they were attending Matt the water had made a very appreciable
rise. It would scarcely be possible to feel along the edges now. The
water was too high.

"I'll have to swim under water, fellows," said Glen.

"Don't ye do it, Brick," advised Chick-chick. "You don't want to chance
Apple and me having to make another rescue, with Matt on our hands
already."

"You won't have to make any rescue. I'll swim easily and feel well in
front of me."

"I d