ill start for the sunken treasure."

There were several powerful searchlights on the Advance, so arranged
that the bow, stern or either side could be illuminated independently.
There were also observation windows near each light.

In turn the powerful rays were cast first at the bow and then aft. In
the gleams could be seen the sandy bed of the ocean, covered with
shells of various kinds. Great crabs walked around on their long,
jointed legs, and Tom saw some lobsters that would have brought joy to
the heart of a fisherman.

"Look at the big fish!" cried Mr. Damon suddenly, and he pointed to
some dark, shadowy forms that swam up to the glass windows, evidently
puzzled by the light.

"Porpoises," declared Captain Weston briefly, "a whole school of them."

The fish seemed suddenly to multiply, and soon those in the submarine
felt curious tremors running through the whole craft.

"The fish are rubbing up against it," cried Tom. "They must think we
came down here to allow them to scratch their backs on the steel
plates."

For some time they remained on the bottom, watching the wonderful sight
of the fishes that swam all about them.

"Well, I think we may as well rise," announced Mr. Swift, after they
had been on the bottom about an hour, moving here and there. "We didn't
bring any provisions, and I'm getting hungry, though I don't know how
the others of you feel about it."

"Bless my dinner-plate, I could eat, too!" cried Mr. Damon. "Go up, by
all means. We'll get enough of under-water travel once we start for the
treasure."

"Send her up, Tom," called his father. "I Want to make a few notes on
some needed changes and improvements."

Tom entered the lower pilot house, and turned the valve that opened the
tanks. He also pulled the lever that started the pumps, so that the
water ballast would be more quickly emptied, as that would render the
submarine buoyant, and she would quickly shoot to the surface. To the
surprise of the lad, however, there followed no outrushing of the
water. The Advance remained stationary on the ocean bed. Mr. Swift
looked up from his notes.

"Didn't you hear me ask you to send her up, Tom?" he inquired mildly.

"I did, dad, but something seems to be the matter," was the reply.

"Matter? What do you mean?" and the aged inventor hastened to where his
son and Captain Weston were at the wheels, valves and levers.

"Why, the tanks won't empty, and the pumps don't seem to work."

"Let m