"That's a new kind of diving bell," Tom answered. "You know it
isn't easy to get treasure out of a sunken ship. It isn't like
picking it off the bottom of the ocean. We've got to get it out
from inside--perhaps from inside a strong box or a safe. This
bell may come in useful."

"Can't you use the special diving suits that you always used to
carry?" the financial manager wanted to know.

"We might, if the water isn't too deep," replied Tom. "But you
know there is a limit to how far down a man in even my kind of
diving dress can go. With this diving bell a much greater depth
can be reached. And this diving bell is not like any you have
ever seen or read about. My father gave me the idea for it. I'll
demonstrate it to you some day."

A diving bell is shaped like its name. A common glass tumbler
thrust down into a pail of water, with the open side down, will
show exactly the principle on which a diving bell works. It
illustrates the fact that two things cannot occupy the same place
at the same time.

Pushing the tumbler, open end down, into the pail of water,
leaves a space in the upper end of the tumbler which the water
cannot fill, because it is already occupied with air. Imagine a
big tumbler, made of thick steel, lowered into the water. Air
pumped into the upper part not only keeps the water from
entering, but also enables a man inside to breathe and to move
about inside the bell which may be lowered to the floor of the