"This is annoying, and may cause us delay," he announced, "but there is no danger."

"How are we to get free from the weed?" asked Mr. Damon. "We can't move if it's wound around our propellers, can we?"

"Not very well," Tom answered. "But all that will have to be done will be for some of us to put on diving suits, go out and chop the strands of weed away. We can do it more easily than could an ordinary vessel, for they would have to go into dry dock for the purpose. I think I'll go out myself. I want to look around a little."

"I'll go with you," said Ned. "As long as we haven't seen any sharks I don't mind."

"Nor gigantic starfish, either," added Tom with a smile, and Ned nodded in agreement.

"We might try reversing the propellers," suggested the man from the engine room, who had come in with the information about the serpent weed. "The chief didn't like to try that. We saw the weed from our observation windows and stopped as soon as we felt we had fouled it."

"That was right," commended Tom. "Well, try reversing. It can't do any harm, and it may make it easier for us to free the propellers when we go out."

He went to the engine room himself to see that everything was properly attended to. Slowly the motors were reversed, and only a slight current was given them, as, with the resistance of the tightly wound weed, too powerful a force might burn out the insulation.

Slowly the starting lever was thrown over. There was a low humming and whining as the current jumped from the batteries, and a slight vibration of the craft. Tom looked at the movable pointer which showed the speed and direction of the propellers. The hand oscillated slightly and then stopped.

"Shut off the current!" cried Tom. "It's of no use. The propellers are held as tight as a drum! We've got to go out and cut loose the serpent weed!"

The experiment of reversing the propellers had failed. But still Tom did not believe his craft was in danger. He gave orders for the engine room force to stand by and then arranged for himself, Ned, and Koku to go outside in diving dress and cut the weed off the shafts. There were twin propellers on the submarine, each revolving independently by separate motors, and each capable of being sent in forward or reverse direction.

"Start the engines as soon as we give the signal," Tom told the machinist. "Two knocks on the hull with an axe will mean go ahead, and three will mean reverse."

"I understand," said Weyth, the machinist. "But stand away from the propellers after you give the signal. I'll give you three minutes to move clear."

"That will be enough," Tom said. "But better make it half speed in either case. My idea is that if we can partly cut the weed off, starting the propellers, either forward or in reverse, will finish the trick."

"It may," agreed Weyth.

Armed with axes and sharp steel bars, Tom, Ned, and Koku were soon ready to step outside the submarine.

They entered the diving chamber. In the usual manner water was admitted, and, when the pressure was equalized, the outer door was opened and they walked out on the floor of the ocean, the submarine having been allowed to settle down again on the bottom of the Atlantic.

The powerful searchlight had been turned so that the beams were diffused toward the stern. In addition to this Tom and his two companions carried, attached to their suits, small, but brilliant, electric torches. Of course they had their air tanks with them, and also the telephones, by means of which they could communicate with one another.

As they emerged into the warm waters surrounding the submarine they disturbed thousands of small fish which were feeding all about. Like ocean swallows, the creatures scattered in all directions, some even brushing the divers as they slowly made their way toward the stern of the craft.

"Nice place here," said Ned to Tom, as they walked along, Koku coming just behind them.

"Yes. If we could take this up above and exhibit it in some city park it would make a hit all right," answered the young inventor.

They were walking on the pure, white, sandy floor of the ocean, some seven hundred feet below the surface, protected from the awful pressure of the water by means of the specially constructed suits which Tom had invented. About them, growing as if in a garden, were great masses of coral, some so thin and sinuous that it waved as do palms and ferns in the open air. Other coral was in great rock masses.

Then, too, there was the unpleasant serpent weed. It did not grow all over, but in patches here and there, as rank grass springs up in a meadow.

And it had been the misfortune of the M. N. 1 that she poked her tail into a mass of this long, tough grass, which was now wound about her propellers.

In addition to the many wonderful vegetable forms that grew on the ocean floor, some rivalling in beauty the orchids of the tropics, and almost as delicate, there were the fishes, which darted to and fro, now swiftly swimming beneath some coral arch, and again poising around some mass of waving sea fronds.

"Well, let's get busy," called Tom to Ned through the telephone. "We want to free the propellers and find the wreck of the Pandora. She may be a hundred feet from us, or a mile away, and in that case it's going to take longer to locate her."

Together they walked to the stern of the disabled craft. One look at the propeller shafts, the examination being made by the diffused glow from the searchlight, as well as from the electric torches carried, showed that the diagnosis of the trouble was correct.

Wound around both propellers was a mass of the serpent weed, tightly bound because the machinery had whirled it around and around after the grass had once been caught. It was almost as bad as though manila cable had been thus accidentally fastened.

"Well, might as well begin to cut it loose," said Tom to his companions. "Koku, you take the port propeller, and Ned and I will work on the other. You ought to be able to beat us at this game."

"Me do," said the giant, as he got his axe ready for work.

Blows struck in water lose much of their force. This can easily be proved by filling a bathtub full of water, rolling up the sleeves, and then taking a hammer in the hand, immersing it fully, and trying to strike some object held in the other hand. The water hampers the blows.

It was this way with Tom and his friends. Nearly half of Koku's great strength was wasted. But they knew they could take their time, though they did not want to waste many hours.

The streamers of weed were like strands of tightly wound rope, and this, under certain circumstances, acquires almost the density of wood. Tom and Ned, working together, had managed to chop a little off their propeller shaft, and Koku had done somewhat better with his task, when Ned became aware of a shadow passing above him.

Instinctively he looked up, and as he did so he could not repress a start of horror. Tom, too, as well as Koku, saw the menacing shadow. Ned grasped more tightly his sharp, steel bar and spoke through the telephone to his companions.

"Devil fish!" he said. "The devil fish are after us."



CHAPTER XXI

A WAR REMINDER

To a large number of people the name devil fish brings to mind a conception of an octopus, squid, cuttle fish, or a member of that species. This is, however, a mistake.

The true devil fish of the tropics is a member of the sting ray family, and the common name it bears is given to it because of two prongs, or horns, which project just in front of its mouth. His Satanic Majesty is popularly supposed to have horns, together with a tail, hoofs and other appendages, and the horns of this sting ray fish are what give it the name it bears.

The devil fish, some specimens of which grow to the weight of a ton and measure fifteen feet from wing tip to wing tip, are armed with a long tail, terminating in a tough, horny substance, like many of the ray family members. This horn-tipped tail, lashing about in the water, becomes a terrible weapon of defense. Possibly it is used for offense, as the devil fish feeds on small sea animals, sweeping them into its mouth by movements of the horns mentioned. These horns, swirled about in the water, create a sort of suction current, and on that the food fishes are borne into the maw of the gigantic creature.

A whale rushes through a school of small sea animals with open mouth, takes in a great quantity of water, and the fringe of whalebone acts as a strainer, letting out the water and retaining the food. In like manner the devil fish feeds, except that it has no whalebone. Its "horns" help it to get a meal.

The "wing tips" of the devil fish have been spoken of. They are not really wings, though when one of these fish breaks water and shoots through the air, it appears to be flying. The wings are merely fins, enormously enlarged, and these give the fish its great size, rather than does the body itself. It is the whipping spike-armed tail of the devil fish that is to be feared, aside from the fact that the rush of a monster might swamp a small boat.

It was two or three of these devil fish that were now floating in the water above Tom and his companions, who were grouped about the stern of the disabled submarine.

"They won't attack us unless we disturb them," said Tom through his telephone, speaking to Ned and Koku. "Keep still and they'll swim away. I guess they're trying to find out what new kind of fish our boat is."

All might have gone well had not Koku acted precipitately. One of the devil fish, the smallest of the trio, measuring about ten feet across, swam down near the giant. It was an uncanny looking creature, with its horns swirling about in the water and its bone-tipped tail lashing to and fro like a venomous serpent.

"Look out!" cried Tom. But he was too late. Koku raised his axe and struck with all his force at the sea beast. He hit it a glancing blow, not enough to kill it, but to wound it, and immediately the sea was crimsoned with blood.

The devil fish was able to observe under water better than its human enemies, and it was in no doubt as to its assailant. In an instant it attacked the giant, seeking to pierce him with the deadly tail.

These tails are not only armed with a tip of horn-like hardness, they are also poisonous, and their penetrating power is great. Fishermen have sometimes caught small sting rays, which are a sort of devil fish. Lashing about in the bottom of a boat a sting ray can send its tail tip through the sole of a heavy boot and inflict a painful wound which may cause serious results.

The beast Koku had wounded was trying to sting the giant, and the latter, aware of his peril, was striking out with the axe.

"Look out, Tom!" called Ned through his telephone, as he saw one of the two unwounded devil fish swirl down toward the young inventor. Tom looked up, saw the big, horrible shape above him, and jabbed it with the sharp, steel bar. He inflicted a wound which added further to the crimson tinge in the sea, and that fish now attacked Tom Swift.

In another instant all three divers were fighting the terrible creatures, that, knowing by instinct they were in danger, were using the weapon with which nature had provided them. They lashed about with their sharp-pointed tails, and more than one blow fell on the suits of the divers.

Had there been the least penetration, of course almost instant death would have followed. For the sea, at that depth and pressure, entering the suits would have ended life suddenly. But Tom had seen to it that the suits were well made and strong, with a lining of steel. And however great a thickness of leather the devil fish could send his sting through, it could not overcome steel.

There was danger, though, that the slender tip might slip through the steel bars across the windows in the helmets and shatter the glass. And that would be as great a danger as if the suits themselves were penetrated.

"We've got to fight 'em!" gasped Tom through his instrument, and, seeing his chance, he gave another jab to the devil fish attacking him. Koku, too, was standing up well under the attack of the monster he had first wounded. Ned, watching his chance, got in several blows, first at one and then at the other of the huge creatures. The third devil fish, which had not been wounded, had disappeared. Finally Koku, with a desperate blow, succeeded in severing the tail from the beast attacking him, and that battle was over.

As if realizing that it had lost its power to harm, the devil fish at once swam off, grievously wounded. Then Koku turned his attention to Tom's enemy. Ned, too, lent his aid, and they succeeded in wounding the creature in several places, so that it sank to the bottom of the sea and lay there gasping.

Slowly the red waters cleared and the three divers, exhausted by the fight, could view the remaining creature—the one wounded to death. It was the largest of the three, and truly it was a monster. But it was past the power to harm, and in a few minutes an under sea current carried it slowly away. Later it would float, doubtless, or be devoured by sharks or other ocean pirates before reaching the surface.

"Thank goodness that's over!" said Ned to Tom. "I don't want to see any more of them."

"There may be more about," Tom said. "We'd better keep watch. Ned, you lay off and Koku and I will work on the propellers. Then you can take your turn."

This plan was followed. Koku, not being tired, did not need to stop working, and he was the first to free his shaft partially of the entangling weeds. Tom rapped a signal, the blades were slowly revolved and then came free. A little later the second was in like condition.

"Now we can move!" said Tom, as they started back toward the diving chamber. "I hope we don't run into another patch of that serpent grass."

"Nor see any more devil fish," added Ned.

"Same here!" echoed the young inventor.

Luck seemed to be with the gold-seekers after that, for as the submarine was sent ahead, no more of the long, entangling grass was encountered.

The search for the sunken Pandora was now begun in earnest, since they were positive that they were at the right spot.

No immediate sign of her was found. But Tom and his friends hardly expected to be as lucky as that. They were willing to make a search. For, as Tom had said, a current might have shifted the position of the wreck.

They followed the plan of moving about in ever-widening circles. Only in this way could they successfully cover the ground. It was the third day after the encounter with the devil fish that Tom, Ned and Mr. Damon were in the forward observation cabin. The eccentric man suddenly pointed to something visible from the starboard window.

"There's a wreck, Tom!" he cried. "Maybe it's the Pandora!"

Tom and the others hurried to Mr. Damon's side and peered out into the sea, illuminated by the great searchlight.

"That isn't the Pandora!" said the young inventor.

"But it's a wreck, isn't it?" asked Ned.

"Yes, it's a sunken vessel, all right," Tom assented. "But it's a reminder of the Great War. Look! She has been blown up by a torpedo!"



CHAPTER XXII

STUDYING CURRENTS

There was no question about Tom's statement. They had approached close to the side of a small, sunken and wrecked steamer, and in her side was torn a great hole. In the light from the submarine it could be seen that the plates bent inward, indicating that the explosion was from outside.

"What are you going to do, Tom?" asked Ned, as he saw his chum move the engine room telegraph signal to the stop position.

"Going to investigate," was the answer. "We might as well take the time. We may learn something of value."

"Do you think there is any treasure in her?" asked Mr. Damon.

"There might be," answered Tom. "We'll put on the diving suits and go outside."

"I hope there aren't any devil fish," remarked Ned.

"Same here," Tom agreed. "But I don't believe we'll meet with any. Will you take a chance, Ned?"

"I surely will! I'd like to find out what sort of ship that is—or rather, was, for there isn't much left of her."

He spoke truly, for indeed the torpedo had created fearful havoc. The full extent of it was not observed until Tom, Ned, Koku and two of the crew had put on diving suits and approached the hulk. She lay on her side on the sandy bottom, heeled over somewhat, and when the investigators had walked around her, as they were able to do, they saw a second, and even larger hole in the opposite side.

"Two submarines must have attacked her," said Ned, speaking through his telephone to Tom.

"Either that, or else one sent a torpedo into her, dived, came up on the other side and sent another."

"Well, let's see if she has any treasure aboard," Ned proposed. "Wouldn't it be queer if we should discover two treasure ships?"

"More queer than likely," Tom answered. "We've got to be careful going inside her."

"Why?" asked Ned. "Do you think we'll set off a hidden mine?"

"No, but part of the wreckage might be loosened if we climbed over it, and we might fall and be pinned down. I've read of divers being caught that way. We must be careful."

"Do you suppose a German sub did this?" Ned asked.

"I think very likely," Tom answered. "Maybe we can tell if we can discover the nationality of this craft."

They made their way to a position just outside the gaping hole in the starboard side of the craft. Evidently; it was, or had been, a tramp steamer, and the torpedo hole on her starboard side was about amidships. She must have filled and sunk quickly with two such great holes torn in her.

Standing near the wound in the steel skin, Tom and his companions tried to see what was inside. Their portable torches did not give light enough to make out clearly the character of the cargo carried, and it was too risky to venture into the mass of wreckage that must be the result of the explosion of the torpedo.

"Let's try the other side," suggested Tom, and they moved around the stern of the craft. When they reached the place where the name was visible Tom raised his electric torch and, in the glow of it, they all read the painted inscription, Blakesly, New York.

"That's the vessel that disappeared so mysteriously!" exclaimed Ned, speaking through his instrument. "I remember reading about her. She sailed from New York for Brest, but was never heard of. At last we have solved the mystery!"

"Yes," agreed Tom, "but without much avail. We are too late to do any good."

"Not one of her crew or passengers was ever heard of," went on Ned. "It was surmised that a German sub attacked her, and that she was either sunk 'without a trace' or else her survivors were taken aboard the submarine and carried to Germany."

"Perhaps we may learn something to that end," said Tom, as they got around to the other side. The hole there was not quite so big, and as it seemed safe to enter Tom and Ned prepared to do so, the others remaining outside to give them aid in case of necessity.

It was comparatively easy to enter by this wound in the side of the Blakesly, and, proceeding cautiously, Tom and Ned made the attempt. They found they could not penetrate far, however, because of the mass of wreckage scattered about by the explosion. They could see through into the engine room, and there the machinery was in every stage of destruction, while below the boilers were disrupted.

"She must have gone down in a hurry," remarked Tom.

"Yes, and with part of her crew," added Ned, as he pointed to where a heap of white bones lay—grim reminders of the Great War. The engine room forces had been trapped and carried down to death.

"I wonder if, by any chance, she did carry gold," suggested Ned.

"It wouldn't be down here if she did," asserted Tom. "And if she was a treasure ship, and the huns knew it, they wouldn't leave any on board."

"That's just it," went on his chum. "They may not have known it, and have ripped a couple of torpedoes at her without any warning. It would be just like them."

"Granted," assented the young inventor. "Well, we can take another look around outside. Maybe there's a way of getting on deck, and so going below from there. I wouldn't chance it from here."

"Me, either," Ned answered.

They looked around a little more, a further view showing how dangerous it would be to attempt to enter the shattered engine room, where a misstep or a sudden change of equilibrium might cause disaster.

"Nothing there," Tom reported to Koku and the others waiting for him outside.

"Rope by up go him stern," said Koku, motioning toward the after part of the wreck.

"What does he mean?" Tom asked one of his crew.

"Oh, he went walking around outside while you were inside, sir," was the answer, "and he seems to have found a rope ladder or a chain, or something hanging from the stern."

"Let's go and see it," proposed Tom. "I've been wondering if we could get on deck."

"Are we going to spend much time here?" Ned wanted to know.

"Not much longer," Tom replied. "Why?"

"Well, I was thinking we'd better keep on looking for the Pandora. I don't want that fellow Hardley to get the bulge on us."

"Oh," laughed Tom, "he isn't likely to. But we won't take any chances. As soon as I see if we can learn anything that may be useful from this hulk, we'll go back and start on our way again."

The party of divers, led by Koku, who wanted to point out his discovery, walked slowly along on the bottom of the sea, around to the stern of the Blakesly.

"See!" said the giant through his telephone, and, as the instruments were interchanging, all heard him.

Koku pointed to several ropes and chains that were dangling from the stern of the sunken craft. Evidently they had been used by those who sought to escape from the sinking ship after she had been torpedoed.

"Wait a minute!" Tom telephoned, as he saw Koku grasp a chain, evidently with the object of hoisting himself up on deck by the simple method of going up hand over hand. He could easily do this by adjusting the air pressure inside his diving suit to make himself more buoyant.

"Koku go up!" said the giant.

"Better make sure that chain will hold you," cautioned Tom. The giant proved it by several powerful tugs, and then began to raise himself from the sandy bed of the ocean.

"Well, if it will hold him it will hold us," asserted Tom. "Ned, we'll go up. You two stay here," he said to the members of his crew. "We can't take any chances of all getting in the same accident if there should be one."

A little later Tom, Ned, and Koku stood on the deck of the sunken craft. Much of what she had carried had been swept off, either in the explosions or by reason of currents generated by storms since the fatality. But what seemed to be the cabin of the captain, or of some of the officers, was in plain view and easy of access from this level.

"Let's take a look!" said Tom.

Ned followed him to the door. It had been torn off, and inside was a table made fast to the floor. From the appearance of the room it was evidently the compartment where the charts were kept, and where the captain or his officers worked out the reckoning. But it was tenantless now, and if any maps or papers had been out they were dissolved in sea water some time since.

"Let's see if we can find the log book," proposed Ned.

"Good idea," assented Tom.

Using the iron bars they carried, they forced open some of the lockers, but aside from pulp, which might have been charts or almost anything in the way of documents, nothing was come upon that would tell anything.

"Unless the log book was kept in a water-tight case the ink would all run, once it was wet," Tom said, when they were about ready to give up their search.

"I suppose so," agreed Ned. "But I would like to know whether she carried treasure."

However, it was impossible to discover this, and dangerous to look too far into the interior. So Tom and his party were forced to leave without discovering the secret of the Blakesly, if she possessed one.

Later, however, when they had returned home, Tom and Ned made a report of what they had seen, and so cleared up the fate of the vessel. They learned that she carried no treasure, and they were glad they had not risked their lives looking for it. What had happened to her crew was never learned.

They returned to the submarine and told what they had viewed. And then, with a last look at the wreck, they passed on in their search for the Pandora.

Several fruitless days followed, and though a careful search was made in the vicinity of the true location given by Mr. Hardley, nothing was discovered.

"How long will you keep at it before you give up?" asked Ned one evening, as they went aloft to replenish the air tanks and charge the batteries.

"Oh, another week, anyhow. I have a new theory, Ned."

"What's that?"

"Ocean currents. I believe there are powerful currents in these waters, and that they may have shifted the position of the Pandora considerably. I'm going to study the currents."

"Good idea!" cried his chum.

And the next day they began observations which were destined to have surprising results.



CHAPTER XXIII

AN UNDERSEA COLLISION

Under the warm, tropical sun the submarine floated idly on the surface of the calm sea. She had risen from the depths, her hatches had been opened, and now the crew, the owner, and his guests were breathing free air. The men were taking advantage of the period above water to wash out some of their garments, hanging them on improvised lines stretched along the deck. For Tom Swift had said he would remain above the surface all day.

Some slight repairs were necessary to the electric motors, and they could be made only when the craft was on the open sea. This, too, would afford a chance to recharge the batteries and repair one of them.

For the time being the search under the sea for the treasure ship Pandora had been abandoned. But it was not given up entirely. As Tom had announced to Ned, a new theory would be worked out. So far, cruising about in the place where the fillibuster ship was supposed to have gone down had resulted in nothing.

Mr. Damon, who had been below, shaving, came up on deck to see Tom and Ned tossing into the water large pieces of cork taken from spare life preservers. Tom tossed his in from one side of the deck, and Ned from the other. Then, as the eccentric man listened, he heard Tom say:

"I think mine is going to beat yours, Ned!"

"Then you've got another guess coming," declared the young financial man. "Mine's going twice as fast as yours is now, though yours did start off better."

"Bless my beefsteak!" exclaimed Mr. Damon, "what's this, Tom Swift? I thought we came on a treasure-hunting expedition, and here I find you and Ned playing some childish game! I hope you aren't laying any wagers on it!" Mr. Damon did not approve of gambling in any form.

"No, we aren't doing that," laughed Tom, as he dropped another bit of cork into the ocean.

"We are trying to arrive at some valuable scientific facts, Mr. Damon."

"Scientific facts—that childish play?"

"It isn't play," said Tom, turning to remark to Ned: "I think we've settled it. The current has a decided twist to the north."

"Yes," agreed his chum. "You were right, Tom."

"If you don't mind explaining," began Mr. Damon, "I should like to know—"

"We're trying to determine the drift of the ocean currents in this locality," Tom said.

"So we'll know better where to look for the Pandora," added Ned.

"Oh, so you haven't given up the hunt, then?" asked the eccentric man.

"By no means!" exclaimed Tom. "It's this way, Mr. Damon. We went down at as nearly the exact spot where the treasure-ship was sunk as we could determine by means of calculations. She wasn't there, nor could we find her by going around in circles. Then it occurred to me, and to some of the others also, including Ned, that the ocean currents might have shifted the position of the craft after she had sunk. There are powerful currents in the ocean, as you know, the Gulf Stream being one and the Japan Current another. Now there may be smaller ones in these waters that would produce a local effect.

"So Ned and I have been dropping bits of cork of different shapes into the water and watching which way they drifted. Our conclusion is that the currents here have a decided set toward the north."

"And what does that indicate?" asked Mr. Damon.

"That we should have begun our search some distance north of the point where we actually did begin," answered Tom.

"How far north?" the eccentric man wanted to know.

"That's just what we have yet to ascertain," the young inventor replied. "So far our conclusions have been arrived at merely from surface data. Now we've got to go below."

"And play with bits of cork there?" asked Mr. Damon.

"No, we'll have to use something heavier than cork," Tom said. "We'll probably use weights, and see how far they move along the bottom in a given time. But we have established one thing, and I begin to have hopes now that we may locate the Pandora."

The remainder of the day was spent in various ways aboard the submarine, which continued to float idly on the waves.

It was toward evening, when the red, setting sun gave promise of a fair day on the morrow that the submarine's deck lookout approached Tom, and, waiting until he had the attention of the young inventor, reported:

"There is a smudge of smoke dead astern, sir."

"Is there?" exclaimed Tom. "Let me have the glasses."

He took them from the lookout and made a long and careful study of the slight, black smudge which was low down on the horizon.

"A steamer," decided Tom, "and coming on fast. We'll go below!" he added. "Please make ready," he said to the officer in charge.

"What's up, Tom?" asked Ned, as his chum gathered up the papers on which he had been figuring on an improvised table set under an awning on deck.

"Some craft is coming, and I'd just as soon she wouldn't sight us," was the answer.

"You mean she might interfere with our search for the treasure-ship?"

"Not exactly. But she might want to start a search on her own account, and there's no use of giving our presence away, or letting them guess at what might be right conclusions as to the location of the Pandora."

"But, Tom, no one knows of the wreck! At least, no one is supposed to but our party and—"

"Hardley. Exactly!" exclaimed Tom, as he saw his chum about to utter the name.

"And you think he is coming?"

"I shouldn't be a bit surprised. Anyhow, it's just as easy for us to submerge and let them do their own guessing. I was going down soon, anyhow, and another hour won't make any difference. Here, take a look, if you like."

Ned peered through the glasses, but his eyes not being trained in sea interpretation, as were Tom's, he could make out nothing but a black smudge, now larger and darker.

"It might be a cloud for all I can tell," he said, as he handed the binoculars back to Tom.

"Well, it's a steamer all right, and she's under forced draft, too, if I'm any judge. We'll go below before she sights us."

"Perhaps she has already," suggested Ned, as the crew began clearing the submarine's deck.

"No, we lie too low in the water for that. Well, now we can start our underwater observations of current trends."

It did not take long, once she started, for the M. N. 1 to go down. Just as the sun sank below the horizon, and while the smudge of smoke was becoming more distinct, the waves closed over the steel deck of the submarine. Half an hour later she was nearly a quarter of a mile below the surface, resting on the bottom of the sea again.

On this trip Tom did not go to any such depths as he did on his former voyage in the Advance. Not that the reconstructed submarine was not capable of it, for she was even stronger than when first built. But the wreck they were seeking did not lie in so great a depth of water, and there was no need of running useless risks.

"Well," remarked Ned, when they came to a stop, "I don't believe any one will find us here."

"Not an ordinary diver, at any rate," Tom agreed. "And after supper I'm going to have another go at the currents."

The meal was served as usual, and a very good one it was, considering the fact that not as many supplies could be carried in the rather limited space of a submarine as may be transported in an ocean liner. Then, as it was still early, Tom and Ned, with the help of some of the officers, got ready for a new series of experiments.

The big searchlight was set aglow, and, going out on the ocean bed in diving suits, Tom and his friends dropped on the sand various weighted objects.

These were made in the shape of the hull of a steamer, and in proportion. Once they were on the sand, an iron rod was thrust into the ocean bed near each object.

"Now," remarked Tom, as they all went into the submarine again, "we'll let them drift until morning. Then we'll make new calculations. I think we'll arrive at some results, too."

"Just what are you aiming to do?" asked Mr. Damon.

"See how far each one of those weighted objects drifts," Tom replied. "We have planted them in different spots on the ocean bed. Some will drift farther than others. Some are large and some are small. By striking an average we may be able to tell about how far from the supposed location of the Pandora we ought to look for her."

The night passed without incident and as calmly and peacefully as though they were all in some deep cave beneath a great mountain. In the morning after breakfast Tom and his friends went outside the submarine again and noted the weighted objects. Some had drifted farther than others. Measurements were carefully taken, and then began a series of intricate calculations.

The distance each object had drifted from the iron bar marker was considered in reference to its size and shape. Also the elapsed time was computed. The results were then compared, an average struck, and then the size and weight of the Pandora, as nearly as they could be ascertained, were figured. The resultant figures were compared, and Tom announced:

"If we are anywhere near right in our conclusions we ought to begin to search for the treasure-ship about four miles from here, in a general northerly direction."

"Do you think she has drifted that far?" asked Ned.

"Fully that," Tom answered. "That is only our starting point—the center of a new series of circles."

A moment later Tom gave the order to rise to the surface.

"Going up?" exclaimed Ned.

"Yes, I want to make some observations to determine our exact nautical position."

"But suppose that other steam—"

"We'll have to take a chance. We can submerge quickly if we have to, and I don't believe she's able to do that."

An observation was taken through the conning tower, however, before the M. N. 1 went all the way up, and there was not a sail nor a smudge of smoke on the horizon.

"So far so good," murmured Tom. "Now we'll 'shoot the sun,' and after we submerge we'll begin our search in earnest. I think we are on the right track now."

The observation was made at noon, and then, as nearly as possible, the submarine was moved to a position approximately four miles north of the place where the Pandora was supposed to have foundered.

"Down we go!" exclaimed Tom, and down they went.

The depth gauge showed more than a thousand feet below the surface when the M. N. 1 came to rest. This was deeper than Tom had thought to find the wreck, but his craft was able to withstand the pressure. A brief wait, to make sure that everything was in readiness, was followed by the beginning of the new search. In gradually widening circles the craft moved about under water.

If the voyagers had expected to locate at once the treasure-ship, they would have been disappointed. For the first day gave no signs. But Tom had not promised immediate results, and no one gave up hope.

It was shortly after noon on the second day of the search at the new location that, as they were proceeding at rather greater speed than usual, something happened.

Ned had just suggested that he and Tom might go out and try the current-setting experiments again, when suddenly they were both thrown off their feet by a terrific jar and concussion. The M. N. 1 seemed to reel back, as if from a great blow.

"Bless my safety razor!" cried Mr. Damon, "what's the matter, Tom?"

"I think we've had a collision!" was the answer. "I must see how badly we are damaged!"



CHAPTER XXIV

THE TREASURE-SHIP

Sudden and forceful had been the underwater collision in which the M. N. 1 had participated. Either the lookout, aided though he was by the focused rays of the great searchlight, had failed to notice some obstruction in time to signal to avoid it, or there was an error somewhere else. At any rate the submarine had rammed something—what it was remained to be discovered.

"Bless my shotgun," cried Mr. Damon, "perhaps it was one of those big whales, Ned!"

"It didn't feel like a whale," answered the young financial man.

"And it wasn't!" declared Tom, who was hastening to the engine room. "It was too solid for that."

Following the collision there had been considerable confusion aboard the vessel. But discipline prevailed, and now it was necessary to determine the extent of the damage. This, Tom and his officers and crew proceeded to do.

There were automatic devices in the various control cabins, as well as in the main engine room, which told instantly if a leak had been sprung in any part of the craft. In that serious difficulty automatic pumps, controlled by an electrical device, at once began forcing out the water. Other apparatus rushed a supply of compressed air to the flooded compartment in order to hold out the water if possible. For further security the submarine was divided into different compartments, as are most ships in these days. The puncturing or flooding of one did not necessarily mean the foundering of the craft, or, in the case of a submarine, prevent her rising.

But Tom had sensed that the collision was almost a head-on one, and in that case it was likely that the plates might have started in several sections at once. This he wanted to discover, and take means of safety accordingly.

"How do you make it, Mr. Nelson?" cried the young inventor to the captain in the engine room.

"Only a slight leak in compartment B 2," he answered, as Tom's eyes rapidly scanned the tell-tale gauges. "The pumps and air are taking care of that."

"Good!" cried Tom. "It doesn't seem possible that there isn't more than that, though. We struck a terrible blow."

"Yes, but a glancing one, I think, sir."

"Send for the lookout," ordered Tom. "I can't under stand why he didn't see whatever we've hit in time to avoid it."

The lookout came in, very much frightened, it must be admitted. Only by a narrow margin had all escaped death.

"It was impossible to see it, Mr. Swift," he said. "We had a clear course, not a thing in sight. The bottom was white sand, and I could almost count the fishes. All at once there was a big swirl of water that threw our nose around, and before I could signal to slow down or reverse we were right into her."

"Into what?" asked Tom.

"Some sort of wreck, I took it to be. I shoved the wheel hard over as quickly as I could, and we struck only a glancing blow."

"That's good," murmured Tom. "I thought that must have been the explanation. But what's that about a sudden swirl of water?"

"It seemed to me like a change in the current," the lookout answered. "It threw us right over against the wreck."

"I can very easily imagine something like that happening," admitted Tom. "Well, as long as we're not badly damaged I think we'll go outside and take a look. If we hit a wreck—"

"Bless my looking glass!" cried Mr. Damon, "it may be the Pandora, Tom."

"That's too good to be true!" cried Ned. "Anyhow, let's get out and take a look."

Tom first made sure that the slight leak was not likely to increase, and then arrangements were made for himself, Ned, Koku, and some of the others to go outside in the diving suits. Mr. Damon wanted to be of the party, but Tom was afraid to permit him in that depth of water. Mr. Damon, in spite of his jollity, was not as young as he had been.

Shortly after the collision, which had missed being a disaster by a narrow margin, Tom and his companions were outside the submarine, walking on the white, sandy bottom of the sea. Around them was a myriad of fishes, some of large size, but seemingly harmless, as they scudded rapidly away after a glance at the strange creatures who appeared to have come to dispute with them for possession of Father Neptune's element.

Moving more slowly than usual, because of the greater pressure of water at that depth, Tom and the others made their way around the nose of the submarine. And then, in the glow of the big searchlight, they saw the dim outlines of a steamer, partly imbedded in the sand. Her stern was toward the undersea craft that had rammed her, and the name was not so obliterated but what the young inventor could read it.

"The Pandora!" exclaimed Tom, speaking into his helmet telephone transmitter, the others all hearing him. "We've found the treasure-ship at last!"

And so they had. An accident had brought them to the end of their quest, though it is probable they would have found the Pandora anyhow, since they were making careful circles in her vicinity.

"Yes, that's the Pandora," said Ned. "And now the thing to do is to find out if she really has any treasure on board."

"That's what I'm going to do," declared Tom. "But first I want to investigate this queer current. We can't feel it here, but we may if we get out beyond the wreck. We don't want to be swept off our feet."

"Yes, we had better be careful," said one of the officers.

Accordingly they proceeded with caution along the length of the sunken Pandora. And as they neared her bow they all began to feel some powerful force in the current.

"This is far enough!" said Tom. "Don't get out beyond the protection of the hull. I see what it is. The steamer has drifted here from where she was originally sunk. And here two currents meet, forming a very strong one. It was that which threw us off our course. As long as we remain behind the wreck we'll be safe. But beyond her we may be in danger. She's firmly held in the sand, or, at best, is drifting only slightly. She'll be a sort of undersea breakwater for us. And now to see if we can get on board!"

This proved comparatively easy. Several lengths of chain and one iron ladder were over the stern, evidently having been used when the crew abandoned the ship in the storm that destroyed her. By means of these Tom and his companions gained the main deck near the stern.

The Pandora was a typical tramp steamer. She was high in the bows and stern and low amidships, and it was evident that the quarters of the officers and passengers, if any of the latter were carried, were in the stern. Tom was glad to find the vessel thus comparatively easy of access.

She lay on an almost even keel, and all he and his companions had to do was to walk along the deck and enter the cabins. As they did not have to look out for life lines or air hose they could enter, and even go below decks, in comparative safety.

"Well, here's for it," said Tom to the others. "Let's go in.

"Where would the treasure be, if she had any?" asked Ned.

"Captain's cabin or the purser's strong room, I imagine," Tom answered. "Hardley didn't actually see it, but he said those two places were constantly guarded. I'm inclined to think the purser would have charge of the gold. But we'll try both places."

It was easy to learn which had been the commander's cabin. It had the name "Captain" on a brass plate over the door. Tom and Ned entered. The place was in confusion, and confusion not all caused by the ocean currents. A small safe in the room stood with rusted door open, and the contents of the strong box were gone. Drawers and lockers, too, were opened and empty.

"I guess the captain took as much with him as he could when he got into his boat," commented Tom.

"And the gold, too," added Ned, pointing to the empty safe.

"That wouldn't have held two million dollars in gold," Tom retorted. "I believe the purser's cabin is the place to look."

Making sure they were not missing anything in the captain's room, they came out, to find Koku and the others waiting for them on deck.

"Nothing there," Tom reported. "Did any of you locate the purser's strong room?" One of the men pointed to an open door to the left.

"That's it!" exclaimed Tom. "Yes, and there's a safe here big enough to hold gold for all the revolutions in South America," he added. "I guess we're on the right track at last."

It needed but a look to show them that they had at last reached the place of the treasure. The great safe stood open, and piled inside were a number of small boxes, such as are generally used to ship gold in. Ned, from his bank experience, recognized them at once.

"There's the gold!" he exclaimed. "We've found the treasure!"

"They tried to take some of it with them," said one of the submarine officers, pointing to some opened boxes which were floating near the cabin ceiling. They were caught on some projections which had prevented them from being washed out.

"Maybe they looted the whole safe," suggested Tom. "We'd better have a look."

He tried to pull out one of the many boxes set in tiers in the safe, but it was beyond his strength.

"Me do!" murmured Koku.

It was easy for the giant to pry out one of the boxes with his iron bar, and with another blow from his bar he opened the cover.

"Gold!" cried Ned, as he saw a gleam of yellow showing in the glow from his torch. "There's the gold!"

There was a table in the purser's cabin, made fast to the floor so it had not floated away. At a sign from Tom, the giant turned the box bottom side up on this table.

And then a murmur of wonder came from all who saw the result. For aside from the top layer of gold pieces, the box was filled with iron disks cut to the size of twenty-dollar gold pieces. In an instant it was borne to all what this meant.

"A fake!" exclaimed Tom Swift. "If all the boxes are like this there isn't enough gold on the treasure ship to pay the expenses of this trip! Somebody has been fooled! Open another box, Koku!"



CHAPTER XXV

THE STEEL BOX

Perhaps the least of all affected by what had taken place was the giant. Gold meant nothing to him. To serve Tom Swift was his whole aim in life. Born in a savage country, he had not acquired an overwhelming desire for wealth.

Consequently he was cool enough as he tore another box from the many that were fitted into the safe. The water had swelled the wood, and it was not easy to get them out.

A pressure of the giant's iron bar broke the sealed lid. On top was the same layer of gold pieces, but when the box was emptied the same trick was discovered. Iron disks made up the remainder of the contents.

"Bilked! That's what I call it! Regularly bilked!" exclaimed one of the divers, an Englishman who had been in Tom's service several years. "Somebody's got the cream of this pudding before we did!"

"I'm inclined to agree with you," said Tom. "Unless it transpires that not all the boxes have been thus camouflaged. We must take time to examine."

Then began a period of hard work. Laboring in relays of divers, every box that had been locked in the purser's safe was brought out on the submerged cabin table, broken open, and the contents examined. The hoax was even worse than indicated at first. For after the front section of boxes had been taken out none of the others remaining contained any gold at all. There were only iron disks.

"Well, Tom, what do you think of it?" asked Ned of his chum, when they had returned to the cabin of the submarine, leaving some members of the crew to complete the examination. For this the diving bell was used, as well as the suits.

"I don't think very much," was the answer. "It looks as though we had been sold."

"Do you think Hardley knew that the gold had been changed to iron—that is, all but a small part of it?"

"No, I don't believe he did," Tom answered. "If he were here I'd warrant he would be as much surprised as we are. He certainly believed the Pandora was a regular treasure-ship."

"Just how much did she really have in gold?" asked Mr. Damon, looking at the double eagles on the table of the M. N. 1.

"Well, at a rough guess I'd say ten thousand dollars," Tom answered. "We haven't brought it all out yet, and it's possible they may find a full box in the safe. But, unless there is one, I guess ten or fifteen thousand dollars will cover it."

"And Hardley said two millions!" exclaimed Ned. "Whew, what a difference!"

"Do you think he was in on the change?" asked one of the officers.

"No," replied Tom. "I guess it was like a good many of these filibustering plots. Somebody put up good money to be used to gain control of a country—perhaps for the country's good. But somebody else made the substitution, and the patriots were left. I don't believe Hardley knew this."

"Well, you'll get a little out of it, Tom," Ned remarked.

"Nothing worth while," was the answer. "But I'm not disappointed; that is, very much. Of course I could use the money, but I don't really need it. The trip has been a wonderful experience, and I have learned something I didn't know before. I'm sorry for you, though, Mr. Damon. You invested considerable with Hardley, didn't you?"

"About twenty thousand dollars, Tom. It will be hard to lose it, but I guess I can stand it."

Tom privately made up his mind to see that his old friend did not suffer financially, for the gold discovered on the Pandora, while it was far from the amount hoped for, would almost reimburse Mr. Damon. But the young inventor did not say anything about that just then.

They were looking at the recovered gold and getting ready to store it in some of the boxes that had been brought from the wreck when the divers that had remained on the Pandora to bring the last of the treasure returned through the chamber. Two of them carried a small steel box.

"What's that?" asked Tom, when they had their helmets off.

"Don't know," was the answer. "It was in the purser's safe. Stuck away in the far corner."

"Maybe it has jewels in it!" exclaimed Ned. "If it has—"

At that moment the lookout who had maintained his position in the conning tower called for Tom on the telephone.

"What is it?" asked the young inventor.

"There's some sort of grappling iron, or cable with a hook on it, being lowered from the surface, and it's near the wreck," was the answer. "If it isn't any of your apparatus it may be some other ship having a try for the gold."

"It must be Hardley!" cried Tom. "He's come back with another ship, as he half threatened to do, and, instead of diving for the wreck, which he can't get ordinary men to do in this depth, he's trying to grapple for it. Come on, we'll have a look!"

Ned and Mr. Damon followed Tom to the conning tower. Looking out through the heavy glass windows, while the searchlight illuminated the waters, the young inventor and his friends saw a great grappling iron swaying this way and that through the sea not far from the wreck, and once, indeed, uncomfortably close to their own craft.

"He's struck it uncommonly near," remarked Tom. "I guess it's time for us to be leaving."

"Suppose it's Hardley up above there?" suggested Ned.

"I don't doubt but it is."

"Well, are we going off and leave the wreck—and possibly other gold that may be hidden on her?"

"I wouldn't give ten dollars for the chance of searching for any more gold!" Tom exclaimed. "We'll take this steel box—it may contain something of value. The rest we'll leave to Hardley."

Preparations for rising to the surface were quickly made. Up and up went the M. N. 1, leaving the ill-starred Pandora to whatever else fate had in store for her.

Tom's craft broke water with gentle undulations of the waves. The top of the hatch was thrown back, admitting the bright sunshine on those who had been long in the shadow of the underseas. And, as the young inventor and his friends went out on deck, they saw a small steamer riding on the ocean not far away.

One look was enough to tell them it was from this craft that the grappling iron had been let down, and as the submarine drifted nearer the form of Hardley was seen on deck. He was directing operations.

Some one must have called his attention to the M. N. 1, for he hurried to the rail of the craft which he had evidently chartered to seek the Pandora, and he exclaimed:

"What are you doing here, Swift?"

"The same thing you are, I believe," coolly answered Tom. "Cleaning up the treasure ship. You might as well save your money though, for we have all the gold there is!"

"Impossible!" cried the now irate man. "You cannot have found the Pandora!"

"That's just what we did, though," answered Tom. "And, for your information, I'll say that we took all the gold we found, though it was considerably less than you stated."

"How dare you?" stormed the adventurer. "I'll have the law on you for this!"

"I guess you forget," replied Tom, "that we parted company at your request and that I told you I was on my own. Finding is keeping. I didn't find what I expected to, and, on the other hand, I got something I didn't look for."

"What do you mean

"The Pandora was rightly named," went on Tom. "If you recall the old story, Pandora had a box of treasures. They all flew out except Hope, which remained in the bottom. Well, most of the gold seems to have flown away, but we found a box on the Pandora. What's in it I don't know yet, as I haven't opened it. Still, if it doesn't contain more than Hope I shall be disappointed."

The face of Hardley showed the rage felt.

"Give me that box! Give me that box!" he cried, shaking his fist at Tom.

"Not today," was the cool answer of the young inventor. "I may let you know what I find in it if you leave your address. Goodbye!"

Tom waved his hand, gave orders to close the hatches and submerge the M. N. 1, and a few moments later the sea closed over her, leaving the other vessel to grapple uselessly for the treasure-ship.

"What are you going to do, Tom?" asked Ned of his chum, as they were all gathered in the main cabin half an hour later.

"Head for home as soon as we can. I've had enough of this, and I want to get at something else I have in mind. But first I'm going to see what's in this box."

It required the strength of Koku to open the small steel box, but when it was torn apart, for the combination was impossible to guess at, all that was seen were bundles of papers. The case having been hermetically closed, no water had penetrated it, though it had been submerged a long time.

"What are they?" asked Ned of his chum.

Tom did not answer for a moment. Then having quickly examined the papers, he cried:

"We've struck it!"

"What?" they all wanted to know.

"The very thing Hardley was after. These are the missing papers in the oil-well deal—the papers that prove Barton Keith has a half share in property worth many millions of dollars. It was these papers that Hardley was after. He may have thought he could get the gold, too, but he wanted most these oil shares. Boys, we've found the fortune anyhow, in spite of the fellows who looted the gold boxes!"

There was no doubt about it. There were all the papers—the certificates of shares, the partnership agreement and other documents—to show that Mary's uncle was a rich man. The wreck of the Pandora held a fortune after all.

"How do you account for Hardley's acts?" asked Ned of his chum.

"Well, there are several explanations. I think we may be certain that he knew these papers were aboard the Pandora, for he must have intrusted them to the purser himself when he made a trip on the ship. When she sank he had not time to get them to take with him."

"He either knew then, or found out later, that the vessel carried, or was supposed to carry, a large amount of gold. He may have been honestly mistaken in thinking it was two millions. In any case he was playing safe, for he only promised me half if the treasure was found. He could have claimed this box as his property, and that is probably what he was after from the beginning. He was using me as a cat's paw, so to speak."

"Well, you beat him to it," observed Ned.

"Bless my necktie, I should say so!" agreed Mr. Damon. "Do you think he really expected to find the gold?"

"Either that or the papers," was Tom's answer. "He must have engaged the vessel and the grappling apparatus, and, possibly, a diver, after we set him ashore at St. Thomas. Well, we'll leave him to his own fun."

The M. N. 1 made good time back to her home port, nothing except a terrific storm occurring to mark the voyage. And as she submerged when that was on she did not feel it. After greeting his father, Tom lost little time in going to Mary's house with the box of securities and other papers.

"I want you to hand these to your uncle with my compliments," he said. "I've got the Air Scout out in the meadow. We'll go over in that. How is Mr. Keith?"

"Not very well," Mary answered, after she had got over her surprise at seeing Tom. "But this good news will restore him, I think."

And it certainly was a great tonic. Mr. Keith could hardly believe the story that Mary and Tom jointly told him. But at length he grasped the idea that he was a wealthy man again, and he exclaimed:

"Tom Swift, I'm going to share half with you!"

"Oh, no," retorted the young inventor. "I couldn't think of that. If you want to pay part of the expenses of the trip I shan't object to that, as I intend giving the gold I recovered to Mr. Damon. But as for taking any of the oil shares—"

"Then, Mary, you shall take half!" exclaimed Mr. Keith. "I have more money now than I'll ever spend. Mary, half of it is yours, and if you don't let Tom Swift have a say in the spending of it— Say, Mary, have you thanked him yet?" he asked with a twinkle of his eyes. "Well, Uncle Barton, I—I don't know—"

"Then do it now!" cried her uncle. "Tom, if you could have any reward you wanted, what would it be?"

Tom took Mary in his arms and—But I refuse to betray any secrets. Anyhow, some time later when Ned asked his chum if he felt entirely satisfied with the result of his undersea search, the young inventor replied: "I certainly do!"

Tom admitted to his father that a mistake had been made in not installing the gyroscope rudder. There was no excuse for not taking it. Tom declared, as it was small and took up little room, and it might have saved them from what was a close call at one time.

"I'll take it on my next submarine trip," the young inventor promised.

Ned wanted to bring suit against Hardley to recover half the expenses of the trip, but Tom would not consent to it. After all, the value of the oil well property was more than the gold the Pandora was reputed to have carried. No attempt was made to take from Tom the comparatively small amount he had salvaged. Perhaps whoever had put it on board did not want to admit the trick that had been played in filling the boxes with iron disks.

Dixwell Hardley made no further trouble. He could not, for he was so entirely in the wrong. He sold out his shares in the oil property, and a company took possession which gave fair treatment to Mary's uncle.

And this is the end of the story. But the future holds further adventures for Tom Swift which, let it be hoped, he will see fit to order recorded.