ed at the end, and was bumping against his legs. It was a rope.

"Good old Bob!" he thought, as a momentary wave of coherence restored
his brain to itself for an instant. "I've got to fasten it--don't
believe I can hold on very long!"

However, the trailing end of his own life line was still attached to his
belt. Hauling it in, he managed to get the two lines knotted, then gave
the four pulls to "haul up!" He perceived the line tighten immediately,
when a terrible gasping for air seized him and shook him; he tore at his
diving suit with his hands, a spasm of agony making him reckless whether
he let in the water or not. But fortunately the rubber-cloth was stout.

His frantic efforts had exhausted what little oxygen was left to him. He
knew faintly that the wreck had seemed to drop away from him, that he
was swinging up through the water--and just as the water seemed to be
growing lighter, everything went black before his eyes, there was a rush
of stars, and he knew no more.

Up above on the landing, Bob was pulling away desperately, with fear in
his heart. At one side lay the figure of Jerry, still in diving dress
but with helmet removed. The old quartermaster lay very still and white,
but Bob had no chance to work over him. When Mart's line had parted and
that terrible shadow had appeared down below, Bob had almost given up.
Then he had leaped into energy, for he knew that now Mart's life
depended on him alone.

He had swiftly cut away Jerry's back-weight and attached it to a line,
which he lowered, swinging it back and forth in the hope that Mart would
see it. The under-water battle had lasted only for two or three minutes,
although it had seemed an age to poor Mart, and now Bob was hauling up
with all his energy. He had seen the dim shadow shoot off, leaving a
great trail of blood, and he knew that Mart must be hard pressed for
air; as he pulled, he prayed that the shark would not return until his
friend was safe.

With a sob of relief, he caught the flicker of the copper helmet in the
water, and finally got the limp form to the surface. Pulling Mart in was
a hard matter, but it was finally accomplished, and Bob fell on the
helmet and unscrewed it with trembling hands. Mart's bloody face and
ghastly pallor struck him with cold fear, but he went to work at once to
drive air into the contracted lungs, hoping against hope.

How long he worked over the unconscious figure he never knew. He shouted
again and again f