d the locomotion of the vessel switched over to the
electric drive of the storage batteries. But their attention was
directed chiefly to Navigating Officer Binns, who had taken up his
position before a row of levers and water gauges amidships.

"Pump three hundred pounds into No. 1," was the command given by Binns.
One of the levers was thrown over, and immediately could be heard the
swirling of water. The boys were unable to grasp the full meaning of
what was going on until Bill Witt shuffled up and said: "I'll put you
fellows wise to what's going on, if you want me to."

Ted and Jack were glad to know what it was all about and listened
attentively to the commands of the navigating officer and the
interpretations given by their new-found friend. Bill explained that
the process of diving was called "trimming" in submarine cruising, and
that the pumping of the water being directed by Binns was done to fill
the ballast tanks, thus increasing the displacement of the _Dewey_ and
causing it to settle in the water. First one tank was filled, and then
another, until the vessel was submerged on an even keel. This was a
revelation to the boys, for they had supposed it was only necessary to
tilt the ship and dive just like a porpoise.

To their great delight the recruits found that the _Dewey_, like other
submarines built since the beginning of the great world war, was
equipped with twin periscopes, and that, furthermore, they would be
allowed to watch the submersion of the _Dewey_ through the reserve
periscope if they so desired. Would they care to? Well, rather! For
the next few minutes they took turn about peering into the mirrors that
reflected the whole panorama before their eyes.

Gradually, they could see, the _Dewey_ was settling into the embrace
of the sea. Now she was down until the waves rolled completely over
the deck and splashed against the conning tower. Down, down they
dropped till only the periscope projected above the waves. Before
them stretched the wide sweep of water, the ocean rising slowly but
surely to overwhelm them. One after another the waves surged by.
Now the eye of the periscope was so close to the crest of the water
that it was only a matter of another moment until they would be under.
Up, up, up came the water to meet them. Ted's heart was in his mouth
while he viewed this awesome spectacle. Then he gave way for Jack to
take a squint through the tube that carried with it a last loo