was very
strong, however, to allow her to go to a great depth, for the farther
down one goes below the surface of the sea, the greater the pressure
until, at, say, six miles, the greatest known depth of the ocean, the
pressure is beyond belief. And yet is possible that marine monsters
may live in that pressure which would flatten out a block of solid
steel into a sheet as thin as paper.

"Well, we are as deep down as it is safe to go in the river," announced
Tom, as the gauge showed a distance below the surface of a little less
than twenty-nine feet. "Now we'll move into the bay. How do you like
it, Mr. Hardley?"

"Very well, so far. But it isn't very exciting yet."

"Bless my accident policy!" exclaimed Mr. Damon, "I hope you aren't
looking for excitement."

"I'm used to it," was the answer. "The more there is the better I like
it."

"Well, you may get your wish," said Tom.

He turned a lever, and those on board the submarine became conscious of
a forward motion. She was no longer sinking.

She trembled and vibrated as the powerful electric motors turned her
propellers, and Tom, having seen that all was running smoothly in the
main engine room, called Mr. Damon, Ned, and Mr. Hardley to him.

"We'll go into the forward pilot house and give Mr. Hardley a view
under water," he announced. "Of course, you'll see nothing like what
you'll view when we're in the ocean," added the young inventor, "but it
may interest you."

The four were soon in the forward compartment of the craft. She could
be directed and steered from here when occasion arose, but now Tom was
letting his navigator direct the craft from the controls in the main
engine room. A conning tower, rising just above the deck of the craft,
gave the pilot the necessary view.

"Here you are!" exclaimed Tom, as he switched out the lights in the
cabin. For a moment they were in darkness, and then, with a click,
steel plates, guarding heavy plate glass bull's-eyes, moved back, and
Mr. Hardley for the first time looked out on an underwater scene. He
saw the murky waters of river down which they were proceeding to the
bay moving past the glass windows. Now and then a fish swam up,
looking in, and, with a swirl of its tail, shot away again, apparently
frightened well-nigh to death.

"Bless my shoe laces, Tom!" exclaimed Mr. Damon, "this isn't a marker
compared to some of the sights we've seen, is it?"

"I can imagine not," said Mr. Hardley. "But it is intere