that gray craft, won't
they?"

"If we don't make any slip in our calculations," answered Benson,
gravely.

"Well, we're not going to make any slip," asserted Eph Somers, stoutly.

"Now, keep quiet, please, old fellow. I want to do a little calculating
before we take the last, desperate step."

All this time the conning tower of the submarine was just a bit below
the surface. Nothing but the slender shaft and the small head of the
periscope was above the wash of the lazy waves.

Captain Jack soon had his calculation made. Then, with a quiet smile,
he remarked:

"I guess you'd better get below, Eph, for your part. I'll take the
wheel, now, and Mr. Pollard will attend to the submerging mechanisms."

Eph laughed joyously as he darted below. He had a part assigned to him
that was bound to be enjoyable.

"Mr. Pollard!" called down the young skipper, a few moments later.

"Aye, Captain Jack!"

"Let her down slowly, please, until the gauge shows just fourteen feet.
That's the greatest depth I dare try for the course we're going to
follow."

"Aye, Captain Jack. Fourteen feet it shall be."

For the benefit of some readers who may not understand, it is to be
stated that the charts of harbors bear markings that show the exact
depth of water at every point in the harbor at low tide. Thus, the
chart of the harbor just north of Spruce Beach had already told the
young submarine skipper just how far below the surface he could travel
with safety to his craft.

Further, he knew the draft of the "Waverly" to be eleven feet. So the
youthful commander could feel quite certain that he would be in no danger
of colliding, below the water-line, with Uncle Sam's gunboat.

On the deck of the "Waverly" itself there was the same spirit of
expectancy that there had been an hour earlier in the afternoon.

Lieutenant Featherstone, executive officer of the gunboat, was not,
however, impatient. In fact, he stood at the rail, aft, a pretty girl
beside him, and both were looking down musingly at the rippling water
below.

"As I was saying," drawled the lieutenant, "when--"

Just then he stopped, though he did not appear startled.

Straight up out of the watery depths shot a Carroty-topped boy, his wet
skin glistening in the sun.

"Good gracious!" gasped the girl. "Where did that boy come from?"

"Say, sir," called up Eph Somers, distinguishing the lieutenant in his
swift look, "where do you want the submarine boat to an