Farnum again conducted
his guests back to the state-room. When Captain Jack summoned them
forth, they returned to find Hal Hastings, laughing in a way that showed
his white teeth, standing there in his dripping garments.

"From what you have seen, gentlemen," said the builder, seriously, "I am
sure you will understand that we have mastered a new feature, of great
value in submarine boating." The three Navy officers struggled to
conceal their wonder.

"Make for the surface, Captain Benson," directed the owner.

When the passengers aboard the submarine stood once more on the platform
deck, the yard's owner signaled for the shore boat to lay alongside.
Into this small boat he took his guests. The boat was rowed away two or
three lengths, immediately after which the "Pollard" again sank.

Two or three minutes passed. Then Captain Jack's head shot above the
surface. He made for the boat, hanging onto the gunwale.

"It would be bad judgment to call you young fellows mermaids," said
Commander Ennerling, dryly, "but you are surely _merboys_."

A moment later Hal Hastings's head came above the surface.

"Mr. Pollard and young Somers could as easily leave the boat and join
us," explained Mr. Farnum. "However, if the last man aboard leaves
the boat then there is no way provided for a return to the 'Pollard,'
and we would be placed at great expense in raising her. I think we
have, however, shown you enough to make you believe that we have mastered
some new wrinkles in submarine work."

"You have shown us more than we can quite digest," admitted Lieutenant
Commander Briscoe. "But how is this all done?"

"That," responded Mr. Farnum, gravely, "the Government will know when
the boat is purchased for the American Navy."

The anchor being again lowered, both Jack and Hal dived below. In five
minutes the "Pollard" was on the surface. Mr. Farnum asked:

"Have we shown you enough at one time?"

"Yes," admitted the officers. "This evening, after dark, we may ask you
to take us out and show us your boat's diving powers."

"Jack, my boy," whispered Jacob Farnum, when the young captain joined the
party on shore, "your trick of leaving and returning to the boat when it
lies on the bottom has gotten our friends of the Navy into a state of
hard guessing. Do you think we'd better show them some more of it at
another time?"

"If you want my opinion, sir, I think we'd better not. We've puzzled
them this time, but if we