es your ship would need repairs then."

Berg turned away, scowling, but did not reply. He began directing the
crew what to do about the broken rudder.

"Come on," proposed Tom in a low voice, for sounds carry very easily
over water. "Let's go below and skip out while we have a chance. They
can't follow now, and we can get to the sunken treasure ahead of them."

"Good advice," commented his father. "Come, Captain Weston, we'll go
below and close the conning tower."

Five minutes later the Advance sank from sight, the last glimpse Tom
had of Berg and his men being a sight of them standing on the deck of
their floating boat, gazing in the direction of their successful rival.
The Wonder was left behind, while Tom and his friends were soon once
more speeding toward the treasure wreck.

Chapter Nineteen

Captured

"Down deep," advised Captain Weston, as he stood beside Tom and Mr.
Swift in the pilot house. "As far as you can manage her, and then
forward. We'll take no more chances with these fellows."

"The only trouble is," replied the young inventor, "that the deeper we
go the slower we have to travel. The water is so dense that it holds us
back."

"Well, there is no special need of hurrying now," went on the sailor.
"No one is following you, and two or three days difference in reaching
the wreck will not amount to anything."

"Unless they repair their rudder, and take after us again," suggested
Mr. Swift.

"They're not very likely to do that," was the captain's opinion. "It
was more by luck than good management that they picked us up before.
Now, having to delay, as they will, to repair their steering gear,
while we can go as deep as we please and speed ahead, it is practically
impossible for them to catch up to us. No, I think we have nothing to
fear from them."

But though danger from Berg and his crowd was somewhat remote, perils
of another sort were hovering around the treasure-seekers, and they
were soon to experience them.

It was much different from sailing along in the airship, Tom thought,
for there was no blue sky and fleecy clouds to see, and they could not
look down and observe, far below them, cities and villages. Nor could
they breathe the bracing atmosphere of the upper regions.

But if there was lack of the rarefied air of the clouds, there was no
lack of fresh atmosphere. The big tanks carried a large supply, and
whenever more was needed the oxygen machine would supply it.

As t