itiated. But he paid no attention to anything but the stream of yellow
coins that were settling down over his feet, and neglected the fact that
now he could ascend.

Gold! With the word ringing through his brain Mart leaned over
cautiously, so as not to lose his balance, and stirred the heap of coins
with his fingers. He wanted to take some of them up, but had no pockets.
Going to his knees, he began to stuff the coins wildly under his belt,
under the broad straps of his shoes, even forcing some beneath the
weights of his chest.

While he was doing this, he suddenly felt tug after tug on his
line--frenzied pulls that woke him from his gold-fever instantly. What
was wrong? He answered with one "all right" signal, but still the tugs
continued, at both lifeline and air line. Concluding that he had best
ascend, in any case, he cautiously emerged from the opening until he
once more stood outside the wreck.

He put out his hand toward the kris, meaning to take it up with him;
then his heart seemed to stop beating and he stood frozen with horror.
What was that dim, vague shape sweeping past, up above?

Mart stood gazing upward, unable to move as the realization of his
terrible position flashed on his mind. The long, tapering shadow told
its message only too clearly. The Pirate Shark had returned--and he was
trapped! Now he understood the meaning of those frantic tugs. Bob had
seen the shadow and had tried to warn him. Too late!

With a groan of agony, Mart drew back into the opening. He remembered
what old Jerry had said--that so long as a man had his back to
something, kept on his feet, and had a weapon, he was all right.
Therefore, he must not try to go up, for then the shark could grab him
with ease.

Cold sweat stood out on his forehead. What was it Jerry and the others
had said about the Pirate Shark always nipping the air hose first? Poor
Mart trembled as he still stared up, in hope that the shark might have
flitted past and would not return. Again came Bob's frantic tugs, and on
a sudden Mart felt calmness flood into his brain, and he reached for his
air hose.

"By golly, I've got a fighting chance and that's all!" he muttered, then
his lips clenched.

He pulled the air hose twice, then twice again, with the signal for more
air. He repeated it, for he knew now what he must do. To attempt going
up was impossible; the shark would cut his line, and then come down to
finish him. Therefore he must get all the air p