,
and partly submerged, that Captain Weston, taking a noon observation,
announced:

"Well, we're here!"

"Do you mean at the wreck?" asked Mr. Swift eagerly.

"We're at the place where she is supposed to lie, in about two miles of
water," replied the captain. "We are quite a distance off the coast of
Uruguay, about opposite the harbor of Rio de La Plata. From now on we
shall have to nose about under water, and trust to luck."

With her air tanks filled to their capacity, and Tom having seen that
the oxygen machine and other apparatus was in perfect working order,
the submarine was sent below on her search. Though they were in the
neighborhood of the wreck, the adventurers might still have to do
considerable searching before locating it. Lower and lower they sank
into the depths of the sea, down and down, until they were deeper than
they had ever gone before. The pressure was tremendous, but the steel
sides of the Advance withstood it.

Then began a search that lasted nearly a week. Back and forth they
cruised, around in great circles, with the powerful searchlight focused
to disclose the sunken treasure ship. Once Tom, who was observing the
path of light in the depths from the conning tower, thought he had seen
the remains of the Boldero, for a misty shape loomed up in front of the
submarine, and he signaled for a quick stop. It was a wreck, but it had
been on the ocean bed for a score of years, and only a few timbers
remained of what had been a great ship. Much disappointed, Tom rang for
full speed ahead again, and the current was sent into the great
electric plates that pulled and pushed the submarine forward.

For two days more nothing happened. They searched around under the
green waters, on the alert for the first sign, but they saw nothing.
Great fish swam about them, sometimes racing with the Advance. The
adventurers beheld great ocean caverns, and skirted immense rocks,
where dwelt monsters of the deep. Once a great octopus tried to do
battle with the submarine and crush it in its snaky arms, but Tom saw
the great white body, with saucer-shaped eyes, in the path of light and
rammed him with the steel point. The creature died after a struggle.

They were beginning to despair when a full week had passed and they
were seemingly as far from the wreck as ever. They went to the surface
to enable Captain Weston to take another observation. It only confirmed
the other, and showed that they were in the right vici