tematic search."

In a short time every conceivable nook and corner had been explored.
Though it seemed absurd that the wrench should be lost, yet a fearful
conviction began to settle down over the startled ones that it would
not be found in time.

Even the breathing air of the "Pollard's" interior could not be renewed
without the wrench. Though each strove to conceal his feelings from
the others, grim horror soon had them all in its grip.

CHAPTER XVIII

THE LAST GASP OF DESPAIR

"I can't realize it yet, or believe it. It can't be true," shuddered
David Pollard.

"We surely did," asserted Captain Jack.

"Could you swear that you have seen the wrench since we sailed?" asked
Jacob Farnum, white-faced but cool.

"I--I can't quite say as to that," replied Benson, slowly. "But I
will swear that I remember having seen it just a few minutes before we
started."

"A _few minutes_--only?" insisted the builder.

"Yes, sir. I'm positive."

"For that matter," continued the builder, "there has been no one on
board to-day save those who belong aboard."

"No; no one but ourselves has been on the boat to-day."

"None of us would throw it overboard, knowing how precious a tool it
is," declared Mr. Farnum, glancing about him bewildered. "It was
hardly possible to mislay such a thing by accident. Where on earth
_can_ it be, then?"

Again all hands started to hunt. Henderson was the first to sink to
a seat as a sign that he gave up the search. The others barely glanced
at him, so intent were all on the hunt that meant their only chance
for life.

Yet at last they all sat down, panting, perspiring.

"Good heavens!" quivered the inventor. "We must soon begin to think of
our very breath here. We can't exert ourselves as we have been doing.
Whoever moves now, let him remember that he is using up the very life
of others in the act of breathing!"

All but devoid of hope, they all remained sitting. At first they
studied the floor, gloomily. At last they looked up, to read each
other's faces. No hope was to be seen in any countenance.

"Thank heaven the electric light doesn't eat up air," shuddered Hal
Hastings, at last. "It would be fearful to be alive--conscious--after
it had become dark!"

"Don't!" shivered David Pollard, convulsively.

"Come, come, old chap," urged Farnum, laying a hand on his friend's arm,
"_you_ are not going to lose your courage?"

"I feel as if I ought to bear the whole pu