d Grace Desmond. "I can
turn on the air more quickly than I can set you free to do it."

"Yes," breathed the boy, rapidly, "because I'm manacled, anyway.
But save yourself, Miss Desmond."

"We must both go down if you don't tell me quickly where to find the
wrench," cried the girl, stamping her foot with impatience.

Then Jack told her, only when he realized that she would not save
herself at his expense. Fortunately, Josh Owen had overlooked securing
that wrench and throwing it overboard. In another moment Miss Desmond
had the implement.

"The forward compressor, first," Jack directed.

With a quick comprehension that asked only bare details, Miss Desmond
fitted the wrench just where it should go.

"A hard turn forward," called Benson.

The girl gave the twist, as directed, as hard a turn as she could make.
To her horror she fancied the muscles of her wrist not quite equal to
the need of that dread movement. The floor was slanting so that she
was obliged to throw out her left hand to clutch at a support in order
to hold herself up.

"Don't try it any longer. Get overboard, Miss Desmond, if there's yet
time. In heaven's name do!" begged Jack, in a horrified tone. "I can
stand going to the bottom if I don't have to drag you down with me.
Escape!"

"Not and leave a fellow human being here in your plight," retorted the
girl quietly, though with sublime heroism.

"But you can't save me, anyway."

"Then I'll go down at my post, just as a man would," she retorted,
throwing all her frantic strength into her task. How she blamed herself
that her muscles were so weak!

"Please go! There may be time."

"I'm not thinking of that. Oh, for a man's strength!"

Jack's breath was bated. His dread for himself was forgotten now, as
he watched the efforts of this splendid girl.

"We'll take the last plunge at any instant, now!" screamed Jack Benson.
"There may be time for _you_--"

"Then there'll be time for us both," came the undaunted answer. Grace
Desmond did not turn her head as she spoke, but Jack, his intense
gaze upon her, knew the light that was flashing in her eyes at this
moment.

A sound above told the submarine boy the worst. The water was gently
rippling against the edges of the platform deck. That told him, all
to plainly, how near the diving boat was to doing the work for which
it had been built.

Could Jack have been close enough to see just why Grace was failing
in her effort he migh