into the treasure-hunting business, Tom, we'll have to get
right to work. In the first place, we must find out more
about this ship, and just where it was sunk."

"I can do that part," said Mr. Sharp. "I know some sea
captains, and they can put me on the track of locating the
exact spot. In fact, it might not be a bad idea to take an
expert navigator with us. I can manage in the air all right,
but I confess that working out a location under water is
beyond me."

"Yes, an old sea captain wouldn't be a bad idea, by any
means," conceded Mr. Swift. "Well, if you'll attend to that
detail, Mr. Sharp, Tom, Mr. Jackson and I will finish the
submarine. Most of the work is done, however, and it only
remains to install the engine and motors. Now, in regard to
the negative and positive electric plates, I'd like your
opinion, Tom."

For Tom Swift was an inventor, second in ability only to
his father, and his advice was often sought by his parent on
matters of electrical construction, for the lad had made a
specialty of that branch of science.

While father and son were deep in a discussion of the
apparatus of the submarine, there will be an opportunity to
make the reader a little better acquainted with them. Those
of you who have read the previous volumes of this series do
not need to be told who Tom Swift is. Others, however, may
be glad to have a proper introduction to him.