"Bless my water ballast, but that certainly is a fine boat!" cried Mr. Damon, when he had been shown over the new craft. "I think I shall feel even safer in that than in the Red Cloud."
"Oh, don't go back on the airship!" exclaimed Mr. Sharp. "I was counting on taking you on another trip."
"Well, maybe after we get back from under the ocean," agreed Mr. Damon. "I particularly like the cabin arrangements of the Advance. I think I shall enjoy myself."
He would be hard to please who could not take pleasure from a trip in the submarine. The cabin was particularly fine, and the sleeping arrangements were good.
More supplies could be carried than was possible on the airship, and there was more room in which to cook and serve food. Mr. Damon was fond of good living, and the kitchen pleased him as much as anything else.
Early the next morning Tom set out for Atlantis, to meet Captain Weston at the hotel. The young inventor inquired of the clerk whether the seafaring man had arrived, and was told that he had come the previous evening.
"Is he in his room?" asked Tom.
"No," answered the clerk with a peculiar grin. "He's an odd character. Wouldn't go to bed last night until we had every window in his room open, though it was blowing quite hard, and likely to storm. The captain said he was used to plenty of fresh air. Well, I guess he got it, all right."
"Where is he now?" asked the youth, wondering what sort of an individual he was to meet.
"Oh, he was up before sunrise, so some of the scrubwomen told me. They met him coming from his room, and he went right down to the beach with a big telescope he always carries with him. He hasn't come back yet. Probably he's down on the sand."
"Hasn't he had breakfast?"
"No. He left word he didn't want to eat until about four bells, whatever time that is."
"It's ten o'clock," replied Tom, who had been studying up on sea terms lately. "Eight bells is eight o'clock in the morning, or four in the afternoon or eight at night, according to the time of day. Then there's one bell for every half hour, so four bells this morning would be ten o'clock in this watch, I suppose."
"Oh, that's the way it goes, eh?" asked the clerk. "I never could get it through my head. What is twelve o'clock noon?"
"That's eight bells, too; so is twelve o'clock midnight. Eight bells is as high as they go on a ship. But I guess I'll go down and see if I can meet the captain. It will soon be ten o'clock, or four bells, and he must be hungry for breakfast. By the way, is that Mr. Berg still here?"
"No; he went away early this morning. He and Captain Weston seemed to strike up quite an acquaintance, the night clerk told me. They sat and smoked together until long after midnight, or eight bells," and the clerk smiled as he glanced down at the big diamond ring on his little finger.
"They did?" fairly exploded Tom, for he had visions of what the wily Mr. Berg might worm out of the simple captain.
"Yes. Why, isn't the captain a proper man to make friends with?" and the clerk looked at Tom curiously.
"Oh, yes, of course," was the hasty answer. "I guess I'll go and see if I can find him—the captain, I mean."
Tom hardly knew what to think. He wished his father, or Mr. Sharp, had thought to warn Captain Weston against talking of the wreck. It might be too late now.
The young inventor hurried to the beach, which was not far from the hotel. He saw a solitary figure pacing up and down, and from the fact that the man stopped, every now and then, and gazed seaward through a large telescope, the lad concluded it was the captain for whom he was in search. He approached, his footsteps making no sound on the sand. The man was still gazing through the glass.
"Captain Weston?" spoke Tom.
Without a show of haste, though the voice must have startled him, the captain turned. Slowly he lowered the telescope, and then he replied softly:
"That's my name. Who are you, if I may ask?"
Tom was struck, more than by anything else, by the gentle voice of the seaman. He had prepared himself, from the description of Mr. Sharp, to meet a gruff, bewhiskered individual, with a voice like a crosscut saw, and a rolling gait. Instead he saw a man of medium size, with a smooth face, merry blue eyes, and the softest voice and gentlest manner imaginable. Tom was very much disappointed. He had looked for a regular sea-dog, and he met a landsman, as he said afterward. But it was not long before our hero changed his mind regarding Captain Weston.
"I'm Tom Swift," the owner of that name said, "and I have been sent to show you the way to where our ship is ready to launch." The young inventor refrained from mentioning submarine, as it was the wish of Mr Sharp to disclose this feature of the voyage to the sailor himself.
"Ha, I thought as much," resumed the captain quietly. "It's a fine day, if I may be permitted to say so," and he seemed to hesitate, as if there was some doubt whether or not he might make that observation.
"It certainly is," agreed the lad. Then, with a smile he added: "It is nearly four bells."
"Ha!" exclaimed the captain, also smiling, but even his manner of saying "Ha!" was less demonstrative than that of most persons. "I believe I am getting hungry, if I may be allowed the remark," and again he seemed asking Tom's pardon for mentioning the fact.
"Perhaps you will come back to the cabin and have a little breakfast with me," he went on. "I don't know what sort of a galley or cook they have aboard the Beach Hotel, but it can't be much worse than some I've tackled."
"No, thank you," answered the youth. "I've had my breakfast. But I'll wait for you, and then I'd like to get back. Dad and Mr. Sharp are anxious to meet you."
"And I am anxious to meet them, if you don't mind me mentioning it," was the reply, as the captain once more put the spyglass to his eye and took an observation. "Not many sails in sight this morning," he added. "But the weather is fine, and we ought to get off in good shape to hunt for the treasure about which Mr. Sharp wrote me. I believe we are going after treasure," he said; "that is, if you don't mind talking about it."
"Not in the least," replied Tom quickly, thinking this a good opportunity for broaching a subject that was worrying him. "Did you meet a Mr. Berg here last night, Captain Weston?" he went on.
"Yes. Mr. Berg and I had quite a talk. He is a well-informed man."
"Did he mention the sunken treasure?" asked the lad, eager to find out if his suspicions were true.
"Yes, he did, if you'll excuse me putting it so plainly," answered the seaman, as if Tom might be offended at so direct a reply. But the young inventor was soon to learn that this was only an odd habit with the seaman.
"Did he want to know where the wreck of the Boldero was located?" continued the lad. "That is, did he try to discover if you knew anything about it?"
"Yes," said Mr. Weston, "he did. He pumped me, if you are acquainted with that term, and are not offended by it. You see, when I arrived here I made inquiries as to where your father's place was located. Mr. Berg overheard me, and introduced himself as agent for a shipbuilding concern. He was very friendly, and when he said he knew you and your parent, I thought he was all right."
Tom's heart sank. His worst fears were to be realized, he thought.
"Yes, he and I talked considerable, if I may be permitted to say so," went on the captain. "He seemed to know about the wreck of the Boldero, and that she had three hundred thousand dollars in gold aboard. The only thing he didn't know was where the wreck was located. He knew it was off Uruguay somewhere, but just where he couldn't say. So he asked me if I knew, since he must have concluded that I was going with you on the gold-hunting expedition."
"And you do know, don't you?" asked Tom eagerly.
"Well, I have it pretty accurately charted out, if you will allow me that expression," was the calm answer. "I took pains to look it up at the request of Mr. Sharp."
"And he wanted to worm that information out of you?" inquired the youth excitedly.
"Yes, I'm afraid he did."
"Did you give him the location?"
"Well," remarked the captain, as he took another observation before closing up the telescope, "you see, while we were talking, I happened to drop a copy of a map I'd made, showing the location of the wreck. Mr. Berg picked it up to hand to me, and he looked at it."
"Oh!" cried Tom. "Then he knows just where the treasure is, and he may get to it ahead of us. It's too bad."
"Yes," continued the seaman calmly, "Mr. Berg picked up that map, and he looked very closely at the latitude and longitude I had marked as the location of the wreck."
"Then he won't have any trouble finding it," murmured our hero.
"Eh? What's that?" asked the captain, "if I may be permitted to request you to repeat what you said."
"I say he won't have any trouble locating the sunken Boldero," repeated Tom.
"Oh, but I think he will, if he depends on that map," was the unexpected reply. "You see," explained Mr. Weston, "I'm not so simple as I look. I sensed what Mr. Berg was after, the minute he began to talk to me. So I fixed up a little game on him. The map which I dropped on purpose, not accidentally, where he would see it, did have the location of the wreck marked. Only it didn't happen to be the right location. It was about five hundred miles out of the way, and I rather guess if Mr. Berg and his friends go there for treasure they'll find considerable depth of water and quite a lonesome spot. Oh, no, I'm not as easy as I look, if you don't mind me mentioning that fact; and when a scoundrel sets out to get the best of me, I generally try to turn the tables on him. I've seen such men as Mr. Berg before. I'm afraid, I'm very much afraid, the sight he had of the fake map I made won't do him much good. Well, I declare, it's past four bells. Let's go to breakfast, if you don't mind me asking you," and with that the captain started off up the beach, Tom following, his ideas all a whirl at the unlooked-for outcome of the interview.
Tom felt such a relief at hearing of Captain Weston's ruse that his appetite, sharpened by an early breakfast and the sea air, came to him with a rush, and he had a second morning meal with the odd sea captain, who chuckled heartily when he thought of how Mr. Berg had been deceived.
"Yes," resumed Captain Weston, over his bacon and eggs, "I sized him up for a slick article as soon as I laid eyes on him. But he evidently misjudged me, if I may be permitted that term. Oh, well, we may meet again, after we secure the treasure, and then I can show him the real map of the location of the wreck."
"Then you have it?" inquired the lad eagerly.
Captain Weston nodded, before hiding his face behind a large cup of coffee; his third, by the way.
"Let me see it?" asked Tom quickly. The captain set down his cup. He looked carefully about the hotel dining-room. There were several guests, who, like himself, were having a late breakfast.
"It's a good plan," the sailor said slowly, "when you're going into unknown waters, and don't want to leave a wake for the other fellow to follow, to keep your charts locked up. If it's all the same to you," he added diffidently, "I'd rather wait until we get to where your father and Mr. Sharp are before displaying the real map. I've no objection to showing you the one Mr. Berg saw," and again he chuckled.
The young inventor blushed at his indiscretion. He felt that the news of the search for the treasure had leaked out through him, though he was the one to get on the trail of it by seeing the article in the paper. Now he had nearly been guilty of another break. He realized that he must be more cautious. The captain saw his confusion, and said:
"I know how it is. You're eager to get under way. I don't blame you. I was the same myself when I was your age. But we'll soon be at your place, and then I'll tell you all I know. Sufficient now, to say that I believe I have located the wreck within a few miles. I got on the track of a sailor who had met one of the shipwrecked crew of the Boldero, and he gave me valuable information. Now tell me about the craft we are going in. A good deal depends on that."
Tom hardly knew what to answer. He recalled what Mr. Sharp had said about not wanting to tell Captain Weston, until the last moment, that they were going in a submarine, for fear the old seaman (for he was old in point of service though not in years) might not care to risk an under-water trip. Therefore Tom hesitated. Seeing it, Captain Weston remarked quietly:
"I mean, what type is your submarine? Does it go by compressed air, or water power?"
"How do you know it's a submarine?" asked the young inventor quickly, and in some confusion.
"Easy enough. When Mr. Berg thought he was pumping me, I was getting a lot of information from him. He told me about the submarine his firm was building, and, naturally, he mentioned yours. One thing led to another until I got a pretty good idea of your craft. What do you call it?"
"The Advance."
"Good name. I like it, if you don't mind speaking of it."
"We were afraid you wouldn't like it," commented Tom.
"What, the name?"
"No, the idea of going in a submarine."
"Oh," and Captain Weston laughed. "Well, it takes more than that to frighten me, if you'll excuse the expression. I've always had a hankering to go under the surface, after so many years spent on top. Once or twice I came near going under, whether I wanted to or not, in wrecks, but I think I prefer your way. Now, if you're all done, and don't mind me speaking of it, I think we'll start for your place. We must hustle, for Berg may yet get on our trail, even if he has got the wrong route," and he laughed again.
It was no small relief to Mr. Swift and Mr. Sharp to learn that Captain Weston had no objections to a submarine, as they feared he might have. The captain, in his diffident manner, made friends at once with the treasure-hunters, and he and Mr. Damon struck up quite an acquaintance. Tom told of his meeting with the seaman, and the latter related, with much gusto, the story of how he had fooled Mr. Berg.
"Well, perhaps you'd like to come and take a look at the craft that is to be our home while we're beneath the water," suggested Mr. Swift and the sailor assenting, the aged inventor, with much pride, assisted by Tom, pointed out on the Advance the features of interest. Captain Weston gave hearty approval, making one or two minor suggestions, which were carried out.
"And so you launch her to-morrow," he concluded, when he had completed the inspection "Well, I hope it's a success, if I may be permitted to say so."
There were busy times around the machine shop next day. So much secrecy had been maintained that none of the residents, or visitors to the coast resort, were aware that in their midst was such a wonderful craft as the submarine. The last touches were put on the under-water ship; the ways, leading from the shop to the creek, were well greased, and all was in readiness for the launching. The tide would soon be at flood, and then the boat would slide down the timbers (at least, that was the hope of all), and would float in the element meant to receive her. It was decided that no one should be aboard when the launching took place, as there was an element of risk attached, since it was not known just how buoyant the craft was. It was expected she would float, until the filled tanks took her to the bottom, but there was no telling.
"It will be flood tide now in ten minutes," remarked Captain Weston quietly, looking at his watch. Then he took an observation through the telescope. "No hostile ships hanging in the offing," he reported. "All is favorable, if you don't mind me saying so," and he seemed afraid lest his remark might give offense.
"Get ready," ordered Mr. Swift. "Tom, see that the ropes are all clear," for it had been decided to ease the Advance down into the water by means of strong cables and windlasses, as the creek was so narrow that the submarine, if launched in the usual way, would poke her nose into the opposite mud bank and stick there.
"All clear," reported the young inventor.
"High tide!" exclaimed the captain a moment later, snapping shut his watch.
"Let go!" ordered Mr. Swift, and the various windlasses manned by the inventor, Tom and the others began to unwind their ropes. Slowly the ship slid along the greased ways. Slowly she approached the water. How anxiously they all watched her! Nearer and nearer her blunt nose, with the electric propulsion plate and the auxiliary propeller, came to the creek, the waters of which were quiet now, awaiting the turn of the tide.
Now little waves lapped the steel sides. It was the first contact of the Advance with her native element.
"Pay out the rope faster!" cried Mr. Swift.
The windlasses were turned more quickly. Foot by foot the craft slid along until, with a final rush, the stern left the ways and the submarine was afloat. Now would come the test. Would she ride on an even keel, or sink out of sight, or turn turtle? They all ran to the water's edge, Tom in the lead.
"Hurrah!" suddenly yelled the lad, trying to stand on his head. "She floats! She's a success! Come on! Let's get aboard!"
For, true enough, the Advance was riding like a duck on the water. She had been proportioned just right, and her lines were perfect. She rode as majestically as did any ship destined to sail on the surface, and not intended to do double duty.
"Come on, we must moor her to the pier," directed Mr. Sharp. "The tide will turn in a few minutes and take her out to sea."
He and Tom entered a small boat, and soon the submarine was tied to a small dock that had been built for the purpose.
"Now to try the engine," suggested Mr. Swift, who was almost trembling with eagerness; for the completion of the ship meant much to him.
"One moment," begged Captain Weston. "If you don't mind, I'll take an observation," he went on, and he swept the horizon with his telescope. "All clear," he reported. "I think we may go aboard and make a trial trip."
Little time was lost in entering the cabin and engine-room, Garret Jackson accompanying the party to aid with the machinery. It did not take long to start the motors, dynamos and the big gasolene engine that was the vital part of the craft. A little water was admitted to the tanks for ballast, since the food and other supplies were not yet on board. The Advance now floated with the deck aft of the conning tower showing about two feet above the surface of the creek. Mr. Swift and Tom entered the pilot house.
"Start the engines," ordered the aged inventor, "and we'll try my new system of positive and negative electrical propulsion."
There was a hum and whir in the body of the ship beneath the feet of Tom and his father. Captain Weston stood on the little deck near the conning tower.
"All ready?" asked the youth through the speaking tube to Mr. Sharp and Mr. Jackson in the engine-room.
"All ready," came the answer.
Tom threw over the connecting lever, while his father grasped the steering wheel. The Advance shot forward, moving swiftly along, about half submerged.
"She goes! She goes!" cried Tom.
"She certainly does, if I may be permitted to say so," was the calm contribution of Captain Weston. "I congratulate you."
Faster and faster went the new craft. Mr. Swift headed her toward the open sea, but stopped just before passing out of the creek, as he was not yet ready to venture into deep water.
"I want to test the auxiliary propellers," he said. After a little longer trial of the electric propulsion plates, which were found to work satisfactorily, sending the submarine up and down the creek at a fast rate, the screws, such as are used on most submarines, were put into gear. They did well, but were not equal to the plates, nor was so much expected of them.
"I am perfectly satisfied," announced Mr. Swift as he once more headed the boat to sea. "I think, Captain Weston, you had better go below now."
"Why so?"
"Because I am going to completely submerge the craft. Tom, close the conning tower door. Perhaps you will come in here with us, Captain Weston, though it will be rather a tight fit."
"Thank you, I will. I want to see how it feels to be in a pilot house under water."
Tom closed the water-tight door of the conning tower. Word was sent through the tube to the engine-room that a more severe test of the ship was about to be made. The craft was now outside the line of breakers and in the open sea.
"Is everything ready, Tom?" asked his father in a quiet voice.
"Everything," replied the lad nervously, for the anticipation of being about to sink below the surface was telling on them all, even on the calm, old sea captain.
"Then open the tanks and admit the water," ordered Mr. Swift.
His son turned a valve and adjusted some levers. There was a hissing sound, and the Advance began sinking. She was about to dive beneath the surface of the ocean, and those aboard her were destined to go through a terrible experience before she rose again.
Lower and lower sank the submarine. There was a swirling and foaming of the water as she went down, caused by the air bubbles which the craft carried with her in her descent. Only the top of the conning tower was out of water now, the ocean having closed over the deck and the rounded back of the boat. Had any one been watching they would have imagined that an accident was taking place.
In the pilot house, with its thick glass windows, Tom, his father and Captain Weston looked over the surface of the ocean, which every minute was coming nearer and nearer to them.
"We'll be all under in a few seconds," spoke Tom in a solemn voice, as he listened to the water hissing into the tanks.
"Yes, and then we can see what sort of progress we will make," added Mr. Swift. "Everything is going fine, though," he went on cheerfully. "I believe I have a good boat."
"There is no doubt of it in my mind," remarked Captain Weston, and Tom felt a little disappointed that the sailor did not shout out some such expression as "Shiver my timbers!" or "Keel-haul the main braces, there, you lubber!" But Captain Weston was not that kind of a sailor, though his usually quiet demeanor could be quickly dropped on necessity, as Tom learned later.
A few minutes more and the waters closed over the top of the conning tower. The Advance was completely submerged. Through the thick glass windows of the pilot house the occupants looked out into the greenish water that swirled about them; but it could not enter. Then, as the boat went lower, the light from above gradually died out, and the semi-darkness gave place to gloom.
"Turn on the electrics and the searchlight, Tom," directed his father.
There was the click of a switch, and the conning tower was flooded with light. But as this had the effect of preventing the three from peering out into the water, just as one in a lighted room cannot look out into the night, Tom shut them off and switched on the great searchlight. This projected its powerful beams straight ahead and there, under the ocean, was a pathway of illumination for the treasure-seekers.
"Fine!" cried Captain Weston, with more enthusiasm than he had yet manifested. "That's great, if you don't mind me mentioning it. How deep are we?"
Tom glanced at a gage on the side of the pilot tower.
"Only about sixty feet," he answered.
"Then don't go any deeper!" cried the captain hastily. "I know these waters around here, and that's about all the depth you've got. You'll be on the bottom in a minute."
"I intend to get on the bottom after a while," said Mr. Swift, "but not here. I want to try for a greater distance under water before I come to rest on the ocean's bed. But I think we are deep enough for a test. Tom, close the tank intake pipes and we'll see how the Advance will progress when fully submerged."
The hissing stopped, and then, wishing to see how the motors and other machinery would work, the aged inventor and his son, accompanied by Captain Weston, descended from the conning tower, by means of an inner stairway, to the interior of the ship. The submarine could be steered and managed from below or above. She was now floating about sixty-five feet below the surface of the bay.
"Well, how do you like it?" asked Tom of Mr. Damon, as he saw his friend in an easy chair in the living-room or main cabin of the craft, looking out of one of the plate-glass windows on the side.
"Bless my spectacles, it's the most wonderful thing I ever dreamed of!" cried the queer character, as he peered at the mass of water before him. "To think that I'm away down under the surface, and yet as dry as a bone. Bless my necktie, but it's great! What are we going to do now?"
"Go forward," replied the young inventor.
"Perhaps I had better make an observation," suggested Captain Weston, taking his telescope from under his arm, where he had carried it since entering the craft, and opening it. "We may run afoul of something, if you don't mind me mentioning such a disagreeable subject." Then, as he thought of the impossibility of using his glass under water, he closed it.
"I shall have little use for this here, I'm afraid," he remarked with a smile. "Well, there's some consolation. We're not likely to meet many ships in this part of the ocean. Other vessels are fond enough of remaining on the surface. I fancy we shall have the depths to ourselves, unless we meet a Government submarine, and they are hardly able to go as deep as we can. No, I guess we won't run into anything and I can put this glass away."
"Unless we run into Berg and his crowd," suggested Tom in a low voice.
"Ha! ha!" laughed Captain Weston, for he did not want Mr. Swift to worry over the unscrupulous agent. "No, I don't believe we'll meet them, Tom. I guess Berg is trying to work out the longitude and latitude I gave him. I wish I could see his face when he realizes that he's been deceived by that fake map."
"Well, I hope he doesn't discover it too soon and trail us," went on the lad. "But they're going to start the machinery now. I suppose you and I had better take charge of the steering of the craft. Dad will want to be in the engine-room."
"All right," replied the captain, and he moved forward with the lad to a small compartment, shut off from the living-room, that served as a pilot house when the conning tower was not used. The same levers, wheels and valves were there as up above, and the submarine could be managed as well from there as from the other place.
"Is everything all right?" asked Mr. Swift as he went into the engine-room, where Garret Jackson and Mr. Sharp were busy with oil cans.
"Everything," replied the balloonist. "Are you going to start now?"
"Yes, we're deep enough for a speed trial. We'll go out to sea, however, and try for a lower depth record, as soon as there's enough water. Start the engine."
A moment later the powerful electric currents were flowing into the forward and aft plates, and the Advance began to gather way, forging through the water.
"Straight ahead, out to sea, Tom," called his father to him.
"Aye, aye, sir," responded the youth.
"Ha! Quite seaman-like, if you don't mind a reference to it," commented Captain Weston with a smile. "Mind your helm, boy, for you don't want to poke her nose into a mud bank, or run up on a shoal."
"Suppose you steer?" suggested the lad. "I'd rather take lessons for a while."
"All right. Perhaps it will be safer. I know these waters from the top, though I can't say as much for the bottom. However, I know where the shoals are."
The powerful searchlight was turned, so as to send its beams along the path which the submarine was to follow, and then, as she gathered speed, she shot ahead, gliding through the waters like a fish.
Mr. Damon divided his time between the forward pilot-room, the living-apartment, and the place where Mr. Swift, Garret Jackson and Mr. Sharp were working over the engines. Every few minutes he would bless some part of himself, his clothing, or the ship. Finally the old man settled down to look through the plate-glass windows in the main apartment.
On and on went the submarine. She behaved perfectly, and was under excellent control. Some times Tom, at the request of his father, would send her toward the surface by means of the deflecting rudder. Then she would dive to the bottom again. Once, as a test, she was sent obliquely to the surface, her tower just emerging, and then she darted downward again, like a porpoise that had come up to roll over, and suddenly concluded to seek the depths. In fact, had any one seen the maneuver they would have imagined the craft was a big fish disporting itself.
Captain Weston remained at Tom's side, giving him instructions, and watching the compass in order to direct the steering so as to avoid collisions. For an hour or more the craft was sent almost straight ahead at medium speed. Then Mr. Swift, joining his son and the captain, remarked:
"How about depth of water here, Captain Weston?"
"You've got more than a mile."
"Good! Then I'm going down to the bottom of the sea! Tom, fill the tanks still more.
"Aye, aye, sir," answered the lad gaily. "Now for a new experience!"
"And use the deflecting rudder, also," advised his father. "That will hasten matters."
Five minutes later there was a slight jar noticeable.
"Bless my soul! What's that?" cried Mr. Damon. "Have we hit something?"
"Yes," answered Tom with a smile.
"What, for gracious sake?"
"The bottom of the sea. We're on the bed of the ocean."
They could hardly realize it, yet the depth-gage told the story. It registered a distance below the surface of the ocean of five thousand seven hundred feet—a little over a mile. The Advance had actually come to rest on the bottom of the Atlantic.
"Hurrah!" cried Tom. "Let's get on the diving suits, dad, and walk about on land under water for a change."
"No," said Mr. Swift soberly. "We will hardly have time for that now. Besides, the suits are not yet fitted with the automatic air-tanks, and we can't use them. There are still some things to do before we start on our treasure cruise. But I want to see how the plates are standing this pressure."
The Advance was made with a triple hull, the spaces between the layers of plates being filled with a secret material, capable of withstanding enormous pressure, as were also the plates themselves. Mr. Swift, aided by Mr. Jackson and Captain Weston, made a thorough examination, and found that not a drop of water had leaked in, nor was there the least sign that any of the plates had given way under the terrific strain.
"She's as tight as a drum, if you will allow me to make that comparison," remarked Captain Weston modestly. "I couldn't ask for a dryer ship."
"Well, let's take a look around by means the searchlight and the observation windows, and then we'll go back," suggested Mr. Swift. "It will take about two days to get the stores and provisions aboard and rig up the diving suits; then we will start for the sunken treasure."
There were several powerful searchlights on the Advance, so arranged that the bow, stern or either side could be illuminated independently. There were also observation windows near each light.
In turn the powerful rays were cast first at the bow and then aft. In the gleams could be seen the sandy bed of the ocean, covered with shells of various kinds. Great crabs walked around on their long, jointed legs, and Tom saw some lobsters that would have brought joy to the heart of a fisherman.
"Look at the big fish!" cried Mr. Damon suddenly, and he pointed to some dark, shadowy forms that swam up to the glass windows, evidently puzzled by the light.
"Porpoises," declared Captain Weston briefly, "a whole school of them."
The fish seemed suddenly to multiply, and soon those in the submarine felt curious tremors running through the whole craft.
"The fish are rubbing up against it," cried Tom. "They must think we came down here to allow them to scratch their backs on the steel plates."
For some time they remained on the bottom, watching the wonderful sight of the fishes that swam all about them.
"Well, I think we may as well rise," announced Mr. Swift, after they had been on the bottom about an hour, moving here and there. "We didn't bring any provisions, and I'm getting hungry, though I don't know how the others of you feel about it."
"Bless my dinner-plate, I could eat, too!" cried Mr. Damon. "Go up, by all means. We'll get enough of under-water travel once we start for the treasure."
"Send her up, Tom," called his father. "I want to make a few notes on some needed changes and improvements."
Tom entered the lower pilot house, and turned the valve that opened the tanks. He also pulled the lever that started the pumps, so that the water ballast would be more quickly emptied, as that would render the submarine buoyant, and she would quickly shoot to the surface. To the surprise of the lad, however, there followed no outrushing of the water. The Advance remained stationary on the ocean bed. Mr. Swift looked up from his notes.
"Didn't you hear me ask you to send her up, Tom?" he inquired mildly.
"I did, dad, but something seems to be the matter," was the reply.
"Matter? What do you mean?" and the aged inventor hastened to where his son and Captain Weston were at the wheels, valves and levers.
"Why, the tanks won't empty, and the pumps don't seem to work."
"Let me try," suggested Mr. Swift, and he pulled the various handles. There was no corresponding action of the machinery.
"That's odd," he remarked in a curious voice "Perhaps something has gone wrong with the connections. Go look in the engine-room, and ask Mr. Sharp if everything is all right there."
Tom made a quick trip, returning to report that the dynamos, motors and gas engine were running perfectly.
"Try to work the tank levers and pumps from the conning tower," suggested Captain Weston. "Sometimes I've known the steam steering gear to play tricks like that."
Tom hurried up the circular stairway into the tower. He pulled the levers and shifted the valves and wheels there. But there was no emptying of the water tanks. The weight and pressure of water in them still held the submarine on the bottom of the sea, more than a mile from the surface. The pumps in the engine-room were working at top speed, but there was evidently something wrong in the connections. Mr. Swift quickly came to this conclusion.
"We must repair it at once," he said. "Tom, come to the engine-room. You and I, with Mr. Jackson and Mr. Sharp, will soon have it in shape again."
"Is there any danger?" asked Mr. Damon in a perturbed voice. "Bless my soul, it's unlucky to have an accident on our trial trip."
"Oh, we must expect accidents," declared Mr. Swift with a smile. "This is nothing."
But it proved to be more difficult than he had imagined to re-establish the connection between the pumps and the tanks. The valves, too, had clogged or jammed, and as the pressure outside the ship was so great, the water would not run out of itself. It must be forced.
For an hour or more the inventor, his son and the others, worked away. They could accomplish nothing. Tom looked anxiously at his parent when the latter paused in his efforts.
"Don't worry," advised the aged inventor. "It's got to come right sooner or later."
Just then Mr. Damon, who had been wandering about the ship, entered the engine-room.
"Do you know," he said, "you ought to open a window, or something."
"Why, what's the matter?" asked Tom quickly, looking to see if the odd man was joking.
"Well, of course I don't exactly mean a window," explained Mr. Damon, "but we need fresh air."
"Fresh air!" There was a startled note in Mr. Swift's voice as he repeated the words.
"Yes, I can hardly breathe in the living-room, and it's not much better here."
"Why, there ought to be plenty of fresh air," went on the inventor. "It is renewed automatically."
Tom jumped up and looked at an indicator. He uttered a startled cry.
"The air hasn't been changed in the last hour!" he exclaimed. "It is bad. There's not enough oxygen in it. I notice it, now that I've stopped working. The gage indicates it, too. The automatic air-changer must have stopped working. I'll fix it."
He hurried to the machine which was depended on to supply fresh air to the submarine.
"Why, the air tanks are empty!" the young inventor cried. "We haven't any more air except what is in the ship now!"
"And we're rapidly breathing that up," added Captain Weston solemnly.
"Can't you make more?" cried Mr. Damon. "I thought you said you could make oxygen aboard the ship."
"We can," answered Mr. Swift, "but I did not bring along a supply of the necessary chemicals. I did not think we would be submerged long enough for that. But there should have been enough in the reserve tank to last several days. How about it, Tom?"
"It's all leaked out, or else it wasn't filled," was the despairing answer. "All the air we have is what's in the ship, and we can't make more."
The treasure-seekers looked at each other. It was an awful situation.
"Then the only thing to do is to fix the machinery and rise to the surface," said Mr. Sharp simply. "We can have all the air we want, then."
"Yes, but the machinery doesn't seem possible of being fixed," spoke Tom in a low voice.
"We must do it!" cried his father.
They set to work again with fierce energy, laboring for their very lives. They all knew that they could not long remain in the ship without oxygen. Nor could they desert it to go to the surface, for the moment they left the protection of the thick steel sides the terrible pressure of the water would kill them. Nor were the diving suits available. They must stay in the craft and die a miserable death—unless the machinery could be repaired and the Advance sent to the surface. The emergency expanding lifting tank was not yet in working order.
More frantically they toiled, trying every device that was suggested to the mechanical minds of Tom, his father, Mr. Sharp or Mr. Jackson, to make the pumps work. But something was wrong. More and more foul grew the air. They were fairly gasping now. It was difficult to breathe, to say nothing of working, in that atmosphere. The thought of their terrible position was in the minds of all.
"Oh, for one breath of fresh air!" cried Mr. Damon, who seemed to suffer more than any of the others. Grim death was hovering around them, imprisoned as they were on the ocean's bed, over a mile from the surface.
Suddenly Tom, after a moment's pause, seized a wrench and began loosening some nuts.
"What are you doing?" asked his father faintly, for he was being weakened by the vitiated atmosphere.
"I'm going to take this valve apart," replied his son. "We haven't looked there for the trouble. Maybe it's out of order."
He attacked the valve with energy, but his hands soon lagged. The lack of oxygen was telling on him. He could no longer work quickly.
"I'll help," murmured Mr. Sharp thickly. He took a wrench, but no sooner had he loosened one nut than he toppled over. "I'm all in," he murmured feebly.
"Is he dead?" cried Mr. Damon, himself gasping.
"No, only fainted. But he soon will be dead, and so will all of us, if we don't get fresh air," remarked Captain Weston. "Lie down on the floor, every one. There is a little fairly good air there. It's heavier than the air we've breathed, and we can exist on it for a little longer. Poor Sharp was so used to breathing the rarified air of high altitudes that he can't stand this heavy atmosphere."
Mr. Damon was gasping worse than ever, and so was Mr. Swift. The balloonist lay an inert heap on the floor, with Captain Weston trying to force a few drops of stimulant down his throat.
With a fierce determination in his heart, but with fingers that almost refused to do his bidding, Tom once more sought to open the big valve. He felt sure the trouble was located there, as they had tried to locate it in every other place without avail.
"I'll help," said Mr. Jackson in a whisper. He, too, was hardly able to move.
More and more devoid of oxygen grew the air. It gave Tom a sense as if his head was filled, and ready to burst with every breath he drew. Still he struggled to loosen the nuts. There were but four more now, and he took off three while Mr. Jackson removed one. The young inventor lifted off the valve cover, though it felt like a ton weight to him. He gave a glance inside.
"Here's the trouble!" he murmured. "The valve's clogged. No wonder it wouldn't work. The pumps couldn't force the water out."
It was the work of only a minute to adjust the valve. Then Tom and the engineer managed to get the cover back on.
How they inserted the bolts and screwed the nuts in place they never could remember clearly afterward, but they managed it somehow, with shaking, trembling hands and eyes that grew more and more dim.
"Now start the pumps!" cried Tom faintly. "The tanks will be emptied, and we can get to the surface."
Mr. Sharp was still unconscious, nor was Mr. Swift able to help. He lay with his eyes closed. Garret Jackson, however, managed to crawl to the engine-room, and soon the clank of machinery told Tom that the pumps were in motion. The lad staggered to the pilot house and threw the levers over. An instant later there was the hissing of water as it rushed from the ballast tanks. The submarine shivered, as though disliking to leave the bottom of the sea, and then slowly rose. As the pumps worked more rapidly, and the sea was sent from the tank in great volumes, the boat fairly shot to the surface. Tom was ready to open the conning tower and let in fresh air as soon as the top was above the surface.
With a bound the Advance reached the top. Tom frantically worked the worm gear that opened the tower. In rushed the fresh, life-giving air, and the treasure-hunters filled their lungs with it.
And it was only just in time, for Mr. Sharp was almost gone. He quickly revived, as did the others, when they could breathe as much as they wished of the glorious oxygen.
"That was a close call," commented Mr. Swift. "We'll not go below again until I have provided for all emergencies. I should have seen to the air tanks and the expanding one before going below. We'll sail home on the surface now."
The submarine was put about and headed for her dock. On the way she passed a small steamer, and the passengers looked down in wonder at the strange craft.
When the Advance reached the secluded creek where she had been launched, her passengers had fully recovered from their terrible experience, though the nerves of Mr. Swift and Mr. Damon were not at ease for some days thereafter.
"I should never have made a submerged test without making sure that we had a reserve supply of air," remarked the aged inventor. "I will not be caught that way again. But I can't understand how the pump valve got out of order."
"Maybe some one tampered with it," suggested Mr. Damon. "Could Andy Foger, any of the Happy Harry gang, or the rival gold-seekers have done it?"
"I hardly think so," answered Tom. "The place has been too carefully guarded since Berg and Andy once sneaked in. I think it was just an accident, but I have thought of a plan whereby such accidents can be avoided in the future. It needs a simple device."
"Better patent it," suggested Mr. Sharp with a smile.
"Maybe I will," replied the young inventor. "But not now. We haven't time, if we intend to get fitted out for our trip."
"No; I should say the sooner we started the better," remarked Captain Weston. "That is, if you don't mind me speaking about it," he added gently, and the others smiled, for his diffident comments were only a matter of habit.
The first act of the adventurers, after tying the submarine at the dock, was to proceed with the loading of the food and supplies. Tom and Mr. Damon looked to this, while Mr. Swift and Mr. Sharp made some necessary changes to the machinery. The next day the young inventor attached his device to the pump valve, and the loading of the craft was continued.
All was in readiness for the gold-seeking expedition a week later. Captain Weston had carefully charted the route they were to follow, and it was decided to move along on the surface for the first day, so as to get well out to sea before submerging the craft. Then it would sink below the surface, and run along under the water until the wreck was reached, rising at times, as needed, to renew the air supply.
With sufficient stores and provisions aboard to last several months, if necessary, though they did not expect to be gone more than sixty days at most, the adventurers arose early one morning and went down to the dock. Mr. Jackson was not to accompany them. He did not care about a submarine trip, he said, and Mr. Swift desired him to remain at the seaside cottage and guard the shops, which contained much valuable machinery. The airship was also left there.
"Well, are we all ready?" asked Mr. Swift of the little party of gold-seekers, as they were about to enter the conning tower hatchway of the submarine.
"All ready, dad," responded his son.
"Then let's get aboard," proposed Captain Weston. "But first let me take an observation."
He swept the horizon with his telescope, and Tom noticed that the sailor kept it fixed on one particular spot for some time.
"Did you see anything?" asked the lad.
"Well, there is a boat lying off there," was the answer. "And some one is observing us through a glass. But I don't believe it matters. Probably they're only trying to see what sort of an odd fish we are."
"All aboard, then," ordered Mr. Swift, and they went into the submarine. Tom and his father, with Captain Weston, remained in the conning tower. The signal was given, the electricity flowed into the forward and aft plates, and the Advance shot ahead on the surface.
The sailor raised his telescope once more and peered through a window in the tower. He uttered an exclamation.
"What's the matter?" asked Tom.
"That other ship—a small steamer—is weighing anchor and seems to be heading this way," was the reply.
"Maybe it's some one hired by Berg to follow us and trace our movements," suggested Tom.
"If it is we'll fool them," added his father. "Just keep an eye on them, captain, and I think we can show them a trick or two in a few minutes."
Faster shot the Advance through the water. She had started on her way to get the gold from the sunken wreck, but already enemies were on the trail of the adventurers, for the ship the sailor had noticed was steaming after them.