.

Wedged on either side of Jack Benson in that little conning tower stood
the builder and the inventor.

"You attend to the first submerging, Farnum," begged the inventor.
"I--I'm afraid I'm too nervous."

The gasoline motor had just been shut off, the submarine now running
at less speed under power from the electric motor.

Handling the controls in the conning tower, Mr. Farnum, not without a
swift, shooting thrill of dread, opened the sea-valves to the water
tanks. As the tanks filled the "Pollard" settled lower and lower in the
water. They were beginning to go down. All who were aboard felt the
keen, apprehensive quiver of the thing, shut in, as they were, as though
soldered inside a huge metal can.

The platform deck was quickly level with the water's surface, though
Jacob Farnum was not rushing things. Then the deck outside, as shown by
the steady glow of the lights in the conning tower, went out of sight,
the water rising around the tower.

They continued slowly to sink until the top of the conning tower was
less than three feet above the waves.

"Now, just a little dive!" pleaded David Pollard. "Oh, merciful heaven!"

"Pass the word to brace yourselves for the dive!" bawled Mr. Farnum
below, and Eph, stationed at the bottom of the spiral stairway, yelled
the word to the engine room.

Now, the sea-valves of the forward diving tanks were opened. As the
water rushed into them, changing the balance of the boat, the bow shot
downward, making it difficult for all to keep their footing. It was as
though they were sliding down an inclined plane.

Another lurch, and down they shot under the water, where men's nerves
may well be tried!

CHAPTER XI

THE TRY-OUT IN THE DEPTHS

Pollard clutched at the stairway railing with both hands, his face
hard-set, his eyes staring.

He was not afraid. In that supreme moment he could not know physical
fear. It was the inventor's dread of failure that possessed him.

Jacob Farnum stood as one fascinated as he felt the boat plunging into
the depths.

"Aren't you going to put us on an even keel, sir?" Jack called.

The warning was needful. In the exhilaration of that plunge Farnum was
in danger of forgetting.

In a twinkling, now, however, he threw open the sea-valves of other
tanks, amidships and aft, until the gauge showed that they were running
on an even keel and forty feet below the surface. Their speed was now
about five miles an hour, but c