“Not much of a place, this deck, to stand on and handle a vessel through rough weather?” he inquired, looking sharply at Mr. Farnum.

“No,” admitted the builder, adding with a smile:  “Of course, it takes the cream of our seafaring men to travel in such craft, anyway.  Such men can stand discomfort and any amount of danger, at need.  Ask Captain Benson.”

Young Captain Jack smiled quietly.  He and his two comrades guessed that George Melville was one of the capitalists whom Farnum was trying to interest in the business.

“Let us go below,” suggested Mr. Melville.  “Don, use your eyes to good advantage.  You may have need of all you can learn about such boats.”

Don Melville inclined his head, but said nothing.  Farnum led them below.  Captain Jack helped the builder in explaining the general working details of the boat.  Hal and Eph answered such questions as were put to them by father or son.

“It’s all very interesting,” said Mr. Melville, slowly, at last.  “Farnum, let us go up on deck a few minutes.  Don, you might remain below.  I have no doubt there is still much that you want to see.”

So Don remained below.  The boys of the submarine’s crew, feeling that Mr. Farnum would want to be alone with his guest, also remained below.

“Do you—­er—­like this sort of thing, Benson?” asked Don Melville.

“The submarine boat work, you mean?” asked Captain Jack, brightly.  “Why, it’s my life—­my very life!”

The glow that came to the cheeks of the young submarine captain bore out his words fully.  Jack did love this fine craft.  He gloried in having the command of her, though he never made the weight of his authority felt by his two comrades, who, indeed, virtually shared in the command.  Captain Benson was especially proud and grateful at the confidence shown in himself and in his mates in being allowed full charge of the “Pollard.”  Love the life?  It wouldn’t be life, for him, without the “Pollard!”

Don began to ask some further questions about the boat.  His tone was slightly supercilious.  It was plain to be seen that he looked upon these daring, tried and proven youngsters as being decidedly his inferiors.  Yet Jack fought against a growing feeling of irritation, giving good-humored and attentive answers.

Then Don went over to the little door of a compartment in the wall.  Behind this door was some of the delicate mechanism—­invention of David Pollard—­by means of which the compressed air supply was better regulated than on any other type of submarine craft.

“Why, this place is locked,” observed Don.

“Yes,” nodded Captain Jack.

“You have the key?”

“I—­I believe so.”

“Then be good enough to unlock this little door,” ordered Don Melville.

“I hope you’ll pardon me,” said Captain Jack, quickly, yet politely.  “It wouldn’t be just the thing for me to do.”