"well," remarked mr. damon, as the submarine hurled herself forward through the ocean, "i guess that firing party will have something else to do to-morrow morning besides aiming those rifles at us."
"yes, indeed," agreed tom. "they'll be lucky if they save their ship. my, how that wind did blow!"
"you're right," put in captain weston. "when they get a hurricane down in this region it's no cat's paw. but they were a mighty careless lot of sailors. the idea of leaving the ladder over the side, and the boat in the water."
"it was a good thing for us, though," was tom's opinion.
"indeed it was," came from the captain. "but as long as we are safe now i think we'd better take a look about the craft to see if those chaps did any damage. they can't have done much, though, or she wouldn't be running so smoothly. suppose you go take a look, tom, and ask your father and mr. sharp what they think. i'll steer for a while, until we get well away from the island."
the young inventor found his father and the balloonist busy in the engine-room. mr. swift had already begun an inspection of the machinery, and so far found that it had not been injured. a further inspection showed that no damage had been done by the foreign guard that had been in temporary possession of the advance, though the sailors had made free in the cabins, and had broken into the food lockers, helping themselves plentifully. but there was still enough for the gold-seekers.
"you'd never know there was a storm raging up above," observed tom as he rejoined captain weston in the lower pilot house, where he was managing the craft. "it's as still and peaceful here as one could wish."
"yes, the extreme depths are seldom disturbed by a surface storm. but we are over a mile deep now. i sent her down a little while you were gone, as i think she rides a little more steadily."
all that night they speeded forward, and the next day, rising to the surface to take an observation, they found no traces of the storm, which had blown itself out. they were several hundred miles away from the hostile warship, and there was not a vessel in sight on the broad expanse of blue ocean.
the air tanks were refilled, and after sailing along on the surface for an hour or two, the submarine was again sent below, as captain weston sighted through his telescope the smoke of a distant steamer.
"as long as it isn't the wonder, we're all right," said tom. "still, we don't want to answer a lot of questions about ourselves and our object."
"no. i fancy the wonder will give up the search," remarked the captain, as the advance was sinking to the depths.
"we must be getting pretty near to the end of our search ourselves," ventured the young inventor.
"we are within five hundred miles of the intersection of the forty-fifth parallel and the twenty-seventh meridian, east from washington," said the captain. "that's as near as i could locate the wreck. once we reach that point we will have to search about under water, for i don't fancy the other divers left any buoys to mark the spot."
it was two days later, after uneventful sailing, partly on the surface, 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 vicinity. but it was like looking for a needle in a haystack, almost, to find the sunken ship in that depth of water.
"well, we'll try again," said mr. swift, as they sank once more beneath the surface.
it was toward evening, on the second day after this, that tom, who was on duty in the conning tower, saw a black shape looming up in front of the submarine, the searchlight revealing it to him far enough away so that he could steer to avoid it. he thought at first that it was a great rock, for they were moving along near the bottom, but the peculiar shape of it soon convinced him that this could not be. it came more plainly into view as the submarine approached it more slowly, then suddenly, out of the depths in the illumination from the searchlight, the young inventor saw the steel sides of a steamer. his heart gave a great thump, but he would not call out yet, fearing that it might be some other vessel than the one containing the treasure.
he steered the advance so as to circle it. as he swept past the bows he saw in big letters near the sharp prow the word, boldero.
"the wreck! the wreck!" he cried, his voice ringing through the craft from end to end. "we've found the wreck at last!"
"are you sure?" cried his father, hurrying to his son, captain weston following.
"positive," answered the lad. the submarine was slowing up now, and tom sent her around on the other side. they had a good view of the sunken ship. it seemed to be intact, no gaping holes in her sides, for only her plates had started, allowing her to sink gradually.
"at last," murmured mr. swift. "can it be possible we are about to get the treasure?"
"that's the boldero, all right," affirmed captain weston. "i recognize her, even if the name wasn't on her bow. go right down on the bottom, tom, and we'll get out the diving suits and make an examination."
the submarine settled to the ocean bed. tom glanced at the depth gage. it showed over two miles and a half. would they be able to venture out into water of such enormous pressure in the comparatively frail diving suits, and wrest the gold from the wreck? it was a serious question.
the advance came to a stop. in front of her loomed the great bulk of the boldero, vague and shadowy in the flickering gleam of the searchlight. as the gold-seekers looked at her through the bull's-eyes of the conning tower, several great forms emerged from beneath the wreck's bows.
"deep-water sharks!" exclaimed captain weston, "and monsters, too. but they can't bother us. now to get out the gold!"
