the marine
glasses from the conning tower, the shipbuilder was now well forward on
the platform deck, scanning what was visible of the steam craft to the
southward. At last the yard's owner turned around to say:

"I don't believe you young men can have things ship-shape a second too
soon. The craft heading this way has a military mast forward. She must be
the 'Hudson.' If there's anything to be done, hustle!"

Jack and Hal sprang below, to scan their respective departments. Five
minutes later Grant Andrews hailed from the "Pollard," and Eph rowed over
in the shore boat to ferry over the machinists.

Half an hour later Andrews and his men had put in the few needed touches
aboard the newer submarine boat. The sun, meanwhile, had gone down,
showing the hull of a naval vessel some four miles off the harbor.

Darkness came on quickly, with a clouded sky. As young Benson stepped on
deck Grant Andrews followed him.

"All finished here, Grant?" queried the yard's owner.

"Yes, sir. There's mighty little chance to do anything where Hal Hastings
has charge of the machinery."

"That's our gunboat out there, I think," went on Mr. Farnum, pointing to
where a white masthead light and a red port light were visible, about a
mile away.

"Dunhaven must be on the map, all right, if a strange navigating officer
knows how to come so straight to the place," laughed Jack Benson.

"Oh, you trust a United States naval officer to find any place he has
sailing orders for," returned Jacob Farnum. "I wonder if he'll attempt to
come into this harbor?"

"There's safe anchorage, if he wants to do so," replied Captain Jack.

While Somers was busy putting the foreman and the machinists ashore, Mr.
Farnum, Jack and Hal remained on the platform deck, watching the approach
of the naval vessel, which was now plainly making for Dunhaven.

Suddenly, a broad beam of glaring white light shot over the water, resting
across the deck of the "Farnum."

"I guess that fellow knows what he wants to know, now," muttered Benson,
blinking after the strong glare had passed.

"There, he has picked up the 'Pollard,' too," announced Hastings. "Now,
that commander must feel sure he has sighted the right place."

"There go the signal lights," cried Captain Jack, suddenly. "Hal, hustle
below and turn on the electric current for the signaling apparatus."

Then Benson watched as, from the yards high up on the gunboat's signaling
mast, colored electric lights glo