r when
on the bottom, and with a divers' compartment from which divers can work
on submarine cables or the enemies' explosive mines.]

From time to time, as this whale-like ship plowed the waters of the
Sound, a big wave would flow entirely over her, and the captain would be
looking right into the foaming crest. The boat was built for under-water
going, so little daylight penetrated the interior through the few small
deadlights, or round, heavy glass windows, but electric incandescent
bulbs fed by current from the storage batteries lit the interior
brilliantly.

The boat had not proceeded far when the captain ordered the crew to
prepare to dive, and immediately the engine was shut down and the clutch
connecting its shaft with the electric apparatus thrown off and another
connecting the electric motor with the propeller thrown in; a switch was
then turned and the current from the storage batteries set the motor and
propeller spinning. While this was being done another man was letting
water into her ballast tanks to reduce her buoyancy. When all but the
conning tower was submerged the captain looked at the compass to see how
she was heading, noted that no vessels were near enough to make a
submarine collision likely, and gave the word to the man at his feet to
dive twenty feet. Then a strange thing happened. The diving-helmsman
gave a twist to the wheel that connected with the horizontal rudders aft
of the propeller, and immediately the boat slanted downward at an angle
of ten degrees; the water rose about the conning tower until the little
windows were level with the surface, and then they were covered, and the
captain looked into solid water that was still turned yellowish-green by
the light of the sun; then swiftly descending, he saw but the faintest
gleam of green light coming through twenty feet of water. The _Fulton_,
with six men in her, was speeding along at five knots an hour twenty
feet below the shining waters of the Sound.

The diving-helmsman kept his eye on a gauge in front of him that
measured the pressure of water at the varying depths, but the dial was
so marked that it told him just how many feet the _Fulton_ was below the
surface. Another device showed whether the boat was on an even keel or,
if not exactly, how many degrees she slanted up or down.

With twenty feet of salt water above her and as much below, this
mechanical whale cruised along with her human freight as comfortable as
they would have