room were
the sleeping quarters and the storerooms. The submarine was steered
from the forward compartment, and here were also levers, wheels and
valves that controlled all the machinery, while a number of dials
showed in which direction they were going, how deep they were, and at
what speed they were moving, as well as what the ocean pressure was.

On top, forward, was a small conning, or observation tower, with
auxiliary and steering and controlling apparatus there. This was to be
used when the ship was moving along on the surface of the ocean, or
merely with the deck awash. There was a small flat deck surrounding
the conning tower and this was available when the craft was on the
surface.

There was provision made for leaving the ship when it was on the bed of
the ocean. When it was desired to do this the occupants put on diving
suits, which were provided with portable oxygen tanks. Then they
entered a chamber into which water was admitted until it was equal in
pressure to that outside. Then a steel door was opened, and they could
step out. To re-enter the ship the operation was reversed. This was
not a new feature. In fact, many submarines to-day use it.

At certain places there were thick bull's-eye windows, by means of
which the under-water travelers could look out into the ocean through
which they were moving. As a defense against the attacks of submarine
monsters there was a steel, pointed ram, like a big harpoon. There were
also a bow and a stern electrical gun, of which more will be told later.

In addition to ample sleeping accommodations, there were many
conveniences aboard the Advance. Plenty of fresh water could be
carried, and there was an apparatus for distilling more from the sea
water that surrounded the travelers. Compressed air was carried in
large tanks, and oxygen could be made as needed. In short, nothing that
could add to the comfort or safety of the travelers had been omitted.
There was a powerful crane and windlass, which had been installed when
Mr. Swift thought his boat might be bought by the Government. This was
to be used for raising wrecks or recovering objects from the bottom of
the ocean. Ample stores and provisions were to be carried and, once the
travelers were shut up in the Advance, they could exist for a month
below the surface, providing no accident occurred.

All these things Tom and Mr. Sharp thought of as they looked over the
ship before turning in for the night. The craf