"Hal is safe, gentlemen," reported Captain Benson, from the tower.
An instant later he opened the manhole of the tower, allowing all hands to step out on deck.
Grinning delightedly, Hal stood in the bow of the small shore boat.
"How did he get there, from a submarine on the bottom?" asked Commander
Ennerling, in astonishment.
"That is one of the secret features of this boat," laughed Mr. Farnum. "Now, gentlemen, if you will kindly come below again, we're going to sink."
Hardly had the submarine touched bottom before Mr. 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.