rful menace on the waves--or
under them--to any foreign foe, Jacob Farnum had now begun to look
about for the necessary capital with which to expand what he believed
to be a highly promising business.

Thus it happened that the two Melvilles now came upon the scene. The
elder possessed a good deal of spare money, and could influence several
business friends into investing heavily. It was George Melville's habit
to acquire control, gradually, of any business in which he invested
heavily. He had wonderful skill in that line of conduct, and combined
much tact with it. Mr. Melville, going into a new business, and
contributing capital heavily, was accustomed to securing whole control
of the business before his associates quite realized what was happening.

Now, as this capitalist climbed up the side and stood on the platform
deck, looking about him, he began to picture himself as selling a fleet
of such boats--all of them practically his--to the Government.

"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 c