"Tell us," insisted one woman.

"Yes, tell us," insisted a man.

Just then, there came a shout over the waters. "Say, you lubbers, what
did you move that boat for?"

There was an instant gasp from all who turned so swiftly to look out
over the water.

Only Jack Benson's brown-haired head showed above the surface of the
harbor, but his look was laughing, utterly care-free.

The boatmen who had allowed their craft to drift while waiting, now
thrust out their oars, making quick time to where the submarine boy
stood treading water.

In his sudden revulsion of feeling the inventor all but fainted. Jacob
Farnum, his gnawing suspense over, felt as though his knees must give
way under him. Then, by a mighty effort, just as the deafening cheering
started, he led the race around the harbor.

"Here, you--Jack Benson!" gasped the yard's owner. "You come in here
mighty quick! Give an account of yourself. What was wrong below?"

"Wrong?" hailed back Benson, standing in the bow of the shore boat as
it made for shore.

"What were you doing down below, all this time?" demanded Mr. Farnum.