“Aye, aye, sir,” came the response, from both members of the crew.

Erelong the splendid little craft was making the best speed of which she was capable.  That there was a big chance of risk in it all knew.  If the hull of the boat was not of the most perfect construction there would presently come an ear-splitting report through the bursting in of steel plates on account of the tremendous pressure of the water all around the boat.  That would be followed by the inrush of the ocean and prompt destruction.

There was another danger, not so great.  Wrecks of ships often sink below the surface, there to drift tediously about as long as the timbers hold together.  If the “Pollard,” traveling under present conditions, should collide with such a hull, there would be no future for anyone aboard.

Yet, though all three of the submarine boys fully comprehended the chances that now confronted them, all three did their work without faltering.

In fact, none of the eight human beings aboard during this extremely hazardous undertaking betrayed any cowardice, nor even alarm.

Lieutenant McCrea watched the gauge, the other two officers going forward to make record of the number of revolutions per moment at which the electric motor could drive the propeller shafts.

After ten minutes the president of the board approached Mr. Farnum to say: 

“We are satisfied with this part of the work.  Let us return to the surface for a welcome look at the sky.”

“Will you hold your watches, gentlemen,” inquired Captain Jack, “in order to see how much time passes before we are running on the surface?”

One of the members of the board, watch in hand, climbed up the staircase to stand beside Eph in the conning tower.

“Awash, sir,” Eph soon called down.

The time was noted.

“Now, show us anything that you wish,” suggested Commander Ennerling.

Captain Jack looked significantly at Messrs. Pollard and Farnum.  Both nodded.

“Then, sir,” rejoined Captain Benson, “if don’t mind, we’ll run back to Dunhaven, and show you a specialty of ours in the harbor at Dunhaven.”

“Very good,” agreed the president of the board.

Not until they were in sight of the little harbor was the manhole opened.  Now, some of the party stepped out onto the platform deck and remained there a few minutes.

“I’ll have to ask you to come inside, now, gentlemen,” requested Jack Benson, courteously, after making an unobserved signal to someone on shore.  “We’re going down to the bottom of the harbor.”

As soon as the “Pollard” had sunk, and rested on bottom, Jacob Farnum invited the members of the board into one of the staterooms aft.

“For just a few minutes, gentlemen,” he explained, “we want to keep you from seeing something.”

As soon as the visitors were out of the way, Captain Jack sprang forward to the torpedo tube.  Hal Hastings, stripping off his outer clothing, stood forth in his bathing suit.