Chapter 23 - Page 2

armor, a constant equality of pressure on the lungs
between the external and the internal air.

But perhaps the most useful article of all was a new form of diving bell
called the _Nautilus_, a kind of submarine boat, capable of lateral as
well as vertical movement at the will of its occupants. Constructed with
double sides, the intervening chambers could be filled either with water
or air according as descent or ascent was required. A proper supply of
water enabled the machine to descend to depths impossible to be reached
otherwise; this water could then be expelled by an ingenious
contrivance, which, replacing it with air, enabled the diver to rise
towards the surface as fast as he pleased.

All these and many other portions of the submarine apparatus which had
been employed that very year for clearing the channel, lifting the
wrecks and recovering the treasure, lay now at San Francisco, unused
fortunately on account of the season of the year, and therefore they
could be readily obtained for the asking. They had even been generously
offered to Captain Bloomsbury, who, in obedience to a telegram from
Washington, had kept his crew busily employed for nearly two weeks
night and day in transferring them all safely on board the
_Susquehanna_.

Marston was the first to make a careful inspection of every article
intended for the operation.

"Do you consider these buoys powerful enough to lift the Projectile,
Captain?" he asked next morning, as the vessel was briskly heading
southward, at a distance of ten or twelve miles from the coast on their
left.

"You can easily calculate that problem yourself, Mr. Marston," replied
the Captain. "It presents no difficulty. The Projectile weighs about 20
thousand pounds, or 10 tons?"

"Correct!"

"Well, a pair of these buoys when inflated can raise a weight of 30
tons."

"So far so good. But how do you propose attaching them to the
Projectile?"

"We simply let them descend in a state of collapse; the diver, going
down with them, will have no difficulty in making a fast connection. As
soon as they are inflated the Projectile will come up like a cork."

"Can the divers readily reach such depths?"

"That remains to be seen Mr. Marston."

"Captain," said Morgan, now joining the party, "you are a worthy member
of our Gun Club. You have done wonders. Heaven grant it may not be all
in vain! Who knows if our poor friends are still alive?"

"Hush!" cried Marston quickly. "Have more sense than to ask such
questions. Is Barbican alive! Am _I_ alive? They're all alive, I tell
you, only we