ust before
the tower went under water, he had a glimpse of the astonished face of
the man on the bridge. The latter had evidently not expected such a
move as that.

Lower and lower in the water went the craft, until it was about two
hundred feet below the surface. Then Mr. Swift left the conning tower,
descended to the main part of the ship, and asked Tom and Captain
Weston to take charge of the pilot house.

"Send her ahead, Tom," his father said. "That fellow up above is
rubbing his eyes yet, wondering where we are, I suppose."

Forward shot the Advance under water, the powerful electrical plates
pulling and pushing her on the way to secure the sunken gold.

All that morning a fairly moderate rate of speed was maintained, as it
was thought best not to run the new machinery too fast.

Dinner was eaten about a quarter of a mile below the surface, but no
one inside the submarine would ever have known it. Electric lights made
the place as brilliant as could be desired, and the food, which Tom and
Mr. Damon prepared, was equal to any that could have been served on
land. After the meal they opened the shutters over the windows in the
sides of the craft, and looked at the myriads of fishes swimming past,
as the creatures were disclosed in the glare of the searchlight.

That night they were several hundred miles on their journey, for the
craft was speedy, and leaving Tom and Captain Weston to take the first
watch, the others went to bed.

"Bless my soul, but it does seem odd, though, to go to bed under water,
like a fish," remarked Mr. Damon. "If my wife knew this she would worry
to death. She thinks I'm off automobiling. But this isn't half as
dangerous as riding in a car that's always getting out of order. A
submarine for mine, every time."

"Wait until we get to the end of this trip," advised Tom. "I guess
you'll find almost as many things can happen in a submarine as can in
an auto," and future events were to prove the young inventor to be
right.

Everything worked well that night, and the ship made good progress.
They rose to the surface the next morning to make sure of their
position, and to get fresh air, though they did not really need the
latter, as the reserve supply had not been drawn on, and was sufficient
for several days, now that the oxygen machine had been put in running
order.

On the second day the ship was sent to the bottom and halted there, as
Mr. Swift wished to try the new diving suits. Th