Page:Tom Swift and His Submarine Boat.djvu/45

Rh 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.