ey would have imagined the craft was a big fish disporting itself.

Captain Weston remained at Tom's side, giving him instructions, and
watching the compass in order to direct the steering so as to avoid
collisions. For an hour or more the craft was sent almost straight
ahead at medium speed. Then Mr. Swift, joining his son and the
captain, remarked:

"How about depth of water here, Captain Weston?"

"You've got more than a mile."

"Good! Then I'm going down to the bottom of the sea! Tom, fill the
tanks still more.

"Aye, aye, sir," answered the lad gaily. "Now for a new experience!"

"And use the deflecting rudder, also," advised his father. "That will
hasten matters."

Five minutes later there was a slight jar noticeable.

"Bless my soul! What's that?" cried Mr. Damon. "Have we hit something?"

"Yes," answered Tom with a smile.

"What, for gracious sake?"

"The bottom of the sea. We're on the bed of the ocean."

Chapter Twelve

For a Breath of Air

They could hardly realize it, yet the depth-gage told the story. It
registered a distance below the surface of the ocean of five thousand
seven hundred feet--a little over a mile. The Advance had actually come
to rest on the bottom of the Atlantic.

"Hurrah!" cried Tom. "Let's get on the diving suits, dad, and walk
about on land under water for a change."

"No," said Mr. Swift soberly. "We will hardly have time for that now.
Besides, the suits are not yet fitted with the automatic air-tanks, and
we can't use them. There are still some things to do before we start on
our treasure cruise. But I want to see how the plates are standing
this pressure."

The Advance was made with a triple hull, the spaces between the layers
of plates being filled with a secret material, capable of withstanding
enormous pressure, as were also the plates themselves. Mr. Swift, aided
by Mr. Jackson and Captain Weston, made a thorough examination, and
found that not a drop of water had leaked in, nor was there the least
sign that any of the plates had given way under the terrific strain.

"She's as tight as a drum, if you will allow me to make that
comparison," remarked Captain Weston modestly. "I couldn't ask for a
dryer ship."

"Well, let's take a look around by means the searchlight and the
observation windows, and then we'll go back," suggested Mr. Swift. "It
will take about two days to get the stores and provisions aboard and
rig up the diving suits; then we w