A curious throng gathered about the little shack as Tom announced that he was about to flash into space the first message calling for help. He took his place at the box, to which had been fastened the apparatus for clicking off the Morse letters.

"Well, here we go," he said, with a smile.

His fingers clasped the rude key he had fashioned from bits of brass and hard rubber. The motor was buzzing away, and the electric dynamo was purring like some big cat.

Just as Tom opened the circuit, to send the current into the instrument, there came an ominous rumbling of the earth.

"Another quake!" screamed Mrs. Anderson. But it was over in a second, and calmness succeeded the incipient panic.

Suddenly, overhead, there sounded a queer crackling noise, a vicious, snapping, as if from some invisible whips.

"Mercy! What's that?" cried Mrs. Nestor.

"The wireless," replied Tom, quietly. "I am going to send a message for help, off into space. I hope some one receives it—and answers," he added, in a low tone.

The crackling increased. While they gathered about him, Tom Swift pressed the key, making and breaking the current until he had sent out from Earthquake Island the three letters—"C.Q.D." And he followed them by giving their latitude and longitude. Over and over again he flashed out this message.

Would it be answered? Would help come? If so, from where? And if so, would it be in time? These were questions that the castaways asked themselves. As for Tom, he sat at the key, clicking away, while, overhead, from the wires fastened to the dead tree, flashed out the messages.



CHAPTER XXII

ANXIOUS DAYS

After the first few minutes of watching Tom click out the messages, the little throng of castaways that had gathered about the shack, moved away. The matter had lost its novelty for them, though, of course, they were vitally interested in the success of Tom's undertaking. Only Mr. Damon and Mr. Fenwick remained with the young inventor, for he needed help, occasionally, in operating the dynamo, or in adjusting the gasolene motor. Mrs. Nestor, who, with Mrs. Anderson, was looking after the primitive housekeeping arrangements, occasionally strolled up the hill to the little shed.

"Any answer yet, Mr. Swift?" she would ask.

"No." was the reply. "We can hardly expect any so soon," and Mrs. Nestor would depart, with a sigh.

Knowing that his supply of gasolene was limited, Tom realized that he could not run the dynamo steadily, and keep flashing the wireless messages into space. He consulted with his two friends on the subject, and Mr. Damon said:

"Well, the best plan, I think, would be only to send out the flashes over the wires at times when other wireless operators will be on the lookout, or, rather, listening. There is no use wasting our fuel. We can't get any more here."

"That's true," admitted Tom, "but how can we pick out any certain time, when we can be sure that wireless operators, within a zone of a thousand miles, will be listening to catch clicks which call for help from the unknown?"

"We can't," decided Mr. Fenwick. "The only thing to do is to trust to chance. If there was only some way so you would not have to be on duty all the while, and could send out messages automatically, it would be good."

Tom shook his head. "I have to stay here to adjust the apparatus," he said. "It works none too easily as it is, for I didn't have just what I needed from which to construct this station. Anyhow, even if I could rig up something to click out 'C.Q.D.' automatically, I could hardly arrange to have the answer come that way. And I want to be here when the answer comes."

"Have you any plan, then?" asked Mr. Damon. "Bless my shoe laces! there are enough problems to solve on this earthquake island."

"I thought of this," said Tom. "I'll send out our call for help from nine to ten in the morning. Then I'll wait, and send out another call from two to three in the afternoon. Around seven in the evening I'll try again, and then about ten o'clock at night, before going to bed."

"That ought to be sufficient," agreed Mr. Fenwick. "Certainly we must save our gasolene, for there is no telling how long we may have to stay here, and call for help."

"It won't be long if that scientist Parker has his way," spoke Mr. Damon, grimly. "Bless my hat band, but he's a MOST uncomfortable man to have around; always predicting that the island is going to sink! I hope we are rescued before that happens."

"I guess we all do," remarked Mr. Fenwick. "But, Tom, here is another matter. Have you thought about getting an answer from the unknown—from some ship or wireless station, that may reply to your calls? How can you tell when that will come in?"

"I can't."

"Then won't you or some of us, have to be listening all the while?"

"No, for I think an answer will come only directly after I have sent cut a call, and it has been picked up by some operator. Still there is a possibility that some operator might receive my message, and report to his chief, or some one in authority over him, before replying. In that time I might go away. But to guard against that I will sleep with the telephone receiver clamped to my ear. Then I can hear the answer come over the wires, and can jump up and reply."

"Do you mean you will sleep here?" asked Mr. Damon, indicating the shack where the wireless apparatus was contained.

"Yes," answered Tom, simply.

"Can't we take turns listening for the answer?" inquired Mr. Fenwick, "and so relieve you?"

"I'm afraid not, unless you understand the Morse code," replied Tom. "You see there may be many clicks, which result from wireless messages flying back and forth in space, and my receiver will pick them up. But they will mean nothing. Only the answer to our call for help will be of any service to us."

"Do you mean to say that you can catch messages flying back and forth between stations now?" asked Mr. Fenwick.

"Yes," replied the young inventor, with a smile. "Here, listen for yourself," and he passed the head-instrument over to the WHIZZER's former owner. The latter listened a moment.

"All I can hear are some faint clicks," he said.

"But they are a message," spoke Tom. "Wait, I'll translate," and he put the receiver to his ear. "'STEAMSHIP "FALCON" REPORTS A SLIGHT FIRE IN HER FORWARD COMPARTMENT,'" said Tom, slowly. "'IT IS UNDER CONTROL, AND WE WILL PROCEED.'"

"Do you mean to say that was the message you heard?" cried Mr. Damon. "Bless my soul, I never can understand it!"

"It was part of a message," answered Tom. "I did not catch it all, nor to whom it was sent."

"But why can't you send a message to that steamship then, and beg them to come to our aid?" asked Mr. Fenwick. "Even if they have had a fire, it is out now, and they ought to be glad to save life."

"They would come to our aid, or send," spoke Tom, "but I can not make their wireless operator pick up our message. Either his apparatus is not in tune, or in accord with ours, or he is beyond our zone."

"But you heard him," insisted Mr. Damon.

"Yes, but sometimes it is easier to pick up messages than it is to send them. However, I will keep on trying."

Putting into operation the plan he had decided on for saving their supply of gasolene, Tom sent out his messages the remainder of the day, at the intervals agreed upon. Then the apparatus was shut down, but the lad paid frequent visits to the shack, and listened to the clicks of the telephone receiver. He caught several messages, but they were not in response to his appeals for aid.

That night there was a slight earthquake shock, but no more of the island fell into the sea, though the castaways were awakened by the tremors, and were in mortal terror for a while.

Three days passed, days of anxious waiting, during which time Tom sent out message after message by his wireless, and waited in vain for an answer. There were three shocks in this interval, two slight, and one very severe, which last cast into the ocean a great cliff on the far end of the island. There was a flooding rush of water, but no harm resulted.

"It is coming nearer," said Mr. Parker.

"What is?" demanded Mr. Hosbrook.

"The destruction of our island. My theory will soon be confirmed," and the scientist actually seemed to take pleasure in it.

"Oh, you and your theory!" exclaimed the millionaire in disgust. "Don't let me hear you mention it again! Haven't we troubles enough?" whereat Mr. Parker went off by himself, to look at the place where the cliff had fallen.

Each night Tom slept with the telephone receiver to his ear, but, though it clicked many times, there was not sounded the call he had adopted for his station—"E. I."—Earthquake Island. In each appeal he sent out he had requested that if his message was picked up, that the answer be preceded by the letters "E.I."

It was on the fourth day after the completion of the wireless station, that Tom was sending out his morning calls. Mrs. Nestor came up the little hill to the shack where Tom was clicking away.

"No replies yet, I suppose?" she inquired, and there was a hopeless note in her voice.

"None yet, but they may come any minute," and Tom tried to speak cheerfully.

"I certainly hope so," added Mary's mother, "But I came up more especially now, Mr. Swift, to inquire where you had stored the rest of the food."

"The rest of the food?"

"Yes, the supply you took from the wrecked airship. We have used up nearly all that was piled in the improvised kitchen, and we'll have to draw on the reserve supply."

"The reserve," murmured Tom.

"Yes, there is only enough in the shack where Mrs. Anderson and I do the cooking, to last for about two days. Isn't there any more?"

Tom did not answer. He saw the drift of the questioning. Their food was nearly gone, yet the castaways from the RESOLUTE thought there was still plenty. As a matter of fact there was not another can, except those in the kitchen shack.

"Get out wherever there is left some time to-day, if you will, Mr. Swift," went on Mrs. Nestor, as she turned away, "and Mrs. Anderson and I will see if we can fix up some new dishes for you men-folks."

"Oh—all right," answered Tom, weakly.

His hand dropped from the key of the instrument. He sat staring into space. Food enough for but two days more, with earthquakes likely to happen at any moment, and no reply yet to his appeals for aid! Truly the situation was desperate. Tom shook his head. It was the first time he had felt like giving up.



CHAPTER XXIII

A REPLY IN THE DARK

The young inventor looked out of the wireless shack. Down on the beach he saw the little band of castaways. They were gathered in a group about Mr. Jenks, who seemed to be talking earnestly to them. The two ladies were over near the small building that served as a kitchen.

"More food supplies needed, eh?" mused Tom. "Well, I don't know where any more is to come from. We've stripped the WHIZZER bare." He glanced toward what remained of the airship. "I guess we'll have to go on short rations, until help comes," and, wondering what the group of men could be talking about, Tom resumed his clicking out of his wireless message.

He continued to send it into space for several minutes after ten o'clock, the hour at which he usually stopped for the morning, for he thought there might be a possible chance that the electrical impulses would be picked up by some vessel far out at sea, or by some station operator who could send help.

But there came no answering clicks to the "E. I." station—to Earthquake Island—and, after a little longer working of the key, Tom shut down the dynamo, and joined the group on the beach.

"I tell you it's our only chance," Mr. Jenks was saying. "I must get off this island, and that's the only way we can do it. I have large interests at stake. If we wait for a reply to this wireless message we may all be killed, though I appreciate that Mr. Swift is doing his best to aid us. But it is hopeless!"

"What do you think about it, Tom?" asked Mr. Damon, turning to the young inventor.

"Think about what?"

"Why Mr. Jenks has just proposed that we build a big raft, and launch it. He thinks we should leave the island."

"It might be a good idea," agreed the lad, as he thought of the scant food supply. "Of course, I can't say when a reply will be received to my calls for aid, and it is best to be prepared."

"Especially as the island may sink any minute," added Mr. Parker. "If it does, even a raft will be little good, as it may be swamped in the vortex. I think it would be a good plan to make one, then anchor it some distance out from the island. Then we can make a small raft, and paddle out to the big one in a hurry if need be."

"Yes, that's a good idea, too," conceded Tom.

"And we must stock it well with provisions," said Mr. Damon. "Put plenty of water and food aboard."

"We can't," spoke Tom, quietly.

"Why not?"

"Because we haven't plenty of provisions. That's what I came down to speak about," and the lad related what Mrs. Nestor had said.

"Then there is but one thing to do," declared Mr. Fenwick.

"What?" asked Captain Mentor.

"We must go on half rations, or quarter rations, if need be. That will make our supply last longer. And another thing—we must not let the women folks know. Just pretend that we're not hungry, but take only a quarter, or at most, not more than a half of what we have been in the habit of taking. There is plenty of water, thank goodness, and we may be able to live until help comes."

"Then shall we build the raft?" asked Mr. Hosbrook.

It was decided that this would be a good plan, and they started it that same day. Trees were felled, with axes and saws that had been aboard the WHIZZER, and bound together, in rude fashion, with strong trailing vines from the forest. A smaller raft, as a sort of ferry, was also made.

This occupied them all that day, and part of the next. In the meanwhile, Tom continued to flash out his appeals for help, but no answers came. The men cut down their rations, and when the two ladies joked them on their lack of appetite, they said nothing. Tom was glad that Mrs. Nestor did not renew her request to him to get out the reserve food supply from what remained in the wreck of the airship. Perhaps Mr. Nestor had hinted to her the real situation.

The large raft was towed out into a quiet bay of the island, and anchored there by means of a heavy rock, attached to a rope. On board were put cans of water, which were lashed fast, but no food could be spared to stock the rude craft. All the castaways could depend on, was to take with them, in the event of the island beginning to sink, what rations they had left when the final shock should come.

This done, they could only wait, and weary was that waiting. Tom kept faithfully to his schedule, and his ear ached from the constant pressure of the telephone receiver. He heard message after message flash through space, and click on his instrument, but none of them was in answer to his. On his face there came a grim and hopeless look.

One afternoon, a week following the erection of the wireless station, Mate Fordam came upon a number of turtles. He caught some, by turning them over on their backs, and also located a number of nests of eggs under the warm sands.

"This will be something to eat," he said, joyfully, and indeed the turtles formed a welcome food supply. Some fish were caught, and some clams were cast up by the tide, all of which eked out the scanty food supply that remained. The two ladies suspected the truth now and they, too, cut down their allowance.

Tom, who had been sitting with the men in their sleeping shack, that evening, rose, as the hour of ten approached. It was time to send out the last message of the night, and then he would lie down on an improvised couch, with the telephone receiver clamped to his ear, to wait, in the silence of the darkness, for the message saying that help was on the way.

"Well, are you off?" asked Mr. Damon, kindly. "I wish some of us could relieve you, Tom."

"Oh, I don't mind it," answered the lad "Perhaps the message may come to-night."

Hardly had he spoken than there sounded the ominous rumble and shaking that presaged another earthquake. The shack rocked, and threatened to come down about their heads.

"We must be doomed!" cried Mr. Parker. "The island is about to sink! Make for the raft!"

"Wait and see how bad it is," counseled Mr. Hosbrook. "It may be only a slight shock."

Indeed, as he spoke, the trembling of the island ceased, and there was silence. The two ladies, who had retired to their own private shack, ran out screaming, and Mr. Anderson and Mr. Nestor hastened over to be with their wives.

"I guess it's passed over," spoke Mr. Fenwick.

An instant later there came another tremor, but it was not like that of an earthquake shock. It was more like the rumble and vibration of an approaching train.

"Look!" cried Tom, pointing to the left. Their gaze went in that direction, and, under the light of a full moon they saw, sliding into the sea, a great portion of one of the rocky hills.

"A landslide!" cried Captain Mentor. "The island is slowly breaking up."

"It confirms my theory!" said Mr. Parker, almost in triumph.

"Forget your theory for a while, Parker, please," begged Mr. Hosbrook. "We're lucky to have left a place on which to stand! Oh, when will we be rescued?" he asked hopelessly.

The worst seemed to be over at least for the present, and, learning that the two ladies were quieted, Tom started up the hill to his wireless station. Mr. Damon and Mr. Fenwick went with him, to aid in starting the motor and dynamo. Then, after the message had been clicked out as usual Tom would begin his weary waiting.

They found that the earthquake shock had slightly disturbed the apparatus, and it took them half an hour to adjust it. As there had been a delay on account of the landslide, it was eleven o'clock before Tom began sending out any flashes, and he kept it up until midnight. But there came no replies, so he shut off the power, and prepared to get a little rest.

"It looks pretty hopeless; doesn't it?" said Mr. Fenwick, as he and Mr. Damon were on their way back to the sleeping shack.

"Yes, it does. Our signal hasn't been seen, no ships have passed this way, and our wireless appeal isn't answered. It does look hopeless but, do you know, I haven't given up yet."

"Why not?"

"Because I have faith in Tom Swift's luck!" declared the eccentric man. "If you had been with him as much as I have, up in the air, and under the water, and had seen the tight places he has gotten out of, you'd feel the same, too!"

"Perhaps, but here there doesn't seem to be anything to do. It all depends on some one else."

"That's all right. You leave it to Tom. He'll get an answer yet, you see if he doesn't."

It was an hour past midnight. Tom tossed uneasily on the hard bed in the wireless shack. The telephone receiver on his ear hurt him, and he could not sleep.

"I may as well sit up for a while," he told himself, and he arose. In the dimness of the shack he could see the outlines of the dynamo and the motor.

"Guess I'll start her up, and send out some calls," he murmured. "I might just happen to catch some ship operator who is up late. I'll try it."

The young inventor started the motor, and soon the dynamo was purring away. He tested the wireless apparatus. It shot out great long sparks, which snapped viciously through the air. Then, in the silence of the night, Tom clicked off his call for help for the castaways of Earthquake Island.

For half an hour he sent it away into space, none of the others in their shacks below him, awakening. Then Tom, having worked off his restless fit, was about to return to bed.

But what was this? What was that clicking in the telephone receiver at his ear? He listened. It was not a jumble of dots and dashes, conveying through space a message that meant nothing to him. No! It was his own call that was answered. The call of his station—"E. I."—Earthquake Island!

"WHERE ARE YOU? WHAT'S WANTED?"

That was the message that was clicked to Tom from somewhere in the great void.

"I GET YOUR MESSAGE 'E. I.' WHAT'S WANTED? DO I HEAR YOU RIGHT? REPEAT." Tom heard those questions in the silence of the night.

With trembling fingers Tom pressed his own key. Out into the darkness went his call for help.

"WE ARE ON EARTHQUAKE ISLAND." He gave the longitude and latitude. "COME QUICKLY OR WE WILL BE ENGULFED IN THE SEA! WE ARE CASTAWAYS FROM THE YACHT 'RESOLUTE,' AND THE AIRSHIP 'WHIZZER.' CAN YOU SAVE US?"

Came then this query:

"WHAT'S THAT ABOUT AIRSHIP?"

"NEVER MIND AIRSHIP," clicked Tom. "SEND HELP QUICKLY! WHO ARE YOU?"

The answer flashed to him through space:

"STEAMSHIP 'CAMBARANIAN' FROM RIO DE JANEIRO TO NEW YORK. JUST CAUGHT YOUR MESSAGE. THOUGHT IT A FAKE."

"NO FAKE," Tom sent back. "HELP US QUICKLY! HOW SOON CAN YOU COME?"

There was a wait, and the wireless operator clicked to Tom that he had called the captain. Then came the report:

"WE WILL BE THERE WITHIN TWENTY-FOUR HOURS. KEEP IN COMMUNICATION WITH US."

"YOU BET I WILL," flashed back Tom, his heart beating joyously, and then he let out a great shout. "We are saved! We are saved! My wireless message is answered! A steamer is on her way to rescue us!"

He rushed from the shack, calling to the others.

"What's that?" demanded Mr. Hosbrook.

Tom briefly told of how the message had come to him in the night.

"Tell them to hurry," begged the rich yacht owner. "Say that I will give twenty thousand dollars reward if we are taken off!"

"And I'll do the same," cried Mr. Jenks. "I must get to the place where—" Then he seemed to recollect himself, and stopped suddenly. "Tell them to hurry," he begged Tom. The whole crowd of castaways, save the women, were gathered about the wireless shack.

"They'll need to hurry," spoke Mr. Parker, the gloomy scientist. "The island may sink before morning!"

Mr. Hosbrook and the others glared at him, but he seemed to take delight in his prediction.

Suddenly the wireless instruments hummed.

"Another message," whispered Tom. He listened.

"THE 'CAMBARANIAN' WILL RUSH HERE WITH ALL SPEED," he announced, and not a heart there on that lonely and desolate island but sent up a prayer of thankfulness.



CHAPTER XXIV

"WE ARE LOST!"

There was little more sleep for any one that night. They sat up, talking over the wonderful and unexpected outcome of Tom Swift's wireless message, and speculating as to when the steamer would get there.

"Bless my pocket comb! But I told you it would come out all right, if we left it to Tom!" declared Mr. Damon.

"But it hasn't come out yet," remarked the pessimistic scientist. "The steamer may arrive too late."

"You're a cheerful sort of fellow to take on a yachting trip," murmured Mr. Hosbrook, sarcastically. "I'll never invite you again, even if you are a great scientist."

"I'm going to sit and watch for the steamer," declared Mr. Damon, as he went outside the shack. The night was warm, and there was a full moon. "Which way will she come from, Tom?"

"I don't know, but I should think, that if she was on her way north, from South America, she'd pass on the side of the island on which we now are."

"That's right," agreed Captain Mentor. "She'll come up from over there," and he pointed across the ocean directly in front of the shacks and camp.

"Then I'm going to see if I can't be the first to sight her lights," declared Mr. Damon.

"She can't possibly get here inside of a day, according to what the operator said," declared Tom.

"Wire them to put on all the speed they can," urged the eccentric man.

"No, don't waste any more power or energy than is needed," suggested Mr. Hosbrook. "You may need the gasolene before we are rescued. They are on their way, and that is enough for now."

The others agreed with this, and so Tom, after a final message to the operator aboard the CAMBARANIAN stating that he would call him up in the morning, shut down the motor.

Mr. Damon took up his position where he could see far out over the ocean, but, as the young inventor had said, there was no possible chance of sighting the relief steamer inside of a day. Still the nervous, eccentric man declared that he would keep watch.

Morning came, and castaways brought to breakfast a better appetite than they had had in some time. They were allowed larger rations, too, for it was seen that they would have just enough food to last until taken off.

"We didn't need to have made the big raft," said Mr. Fenwick, as Tom came down from his station, to report that he had been in communication with the Camabarian and that she was proceeding under forced draught. "We'll not have to embark on it, and I'm glad of it."

"Oh, we may need it yet," asserted Mr. Parker. "I have been making some observations just now, and the island is in a very precarious state. It is, I believe, resting on only a slim foundation, and the least shock may break that off, and send it into the sea. That is what my observations point out."

"Then I wish you wouldn't make any more observations!" exclaimed Mrs. Nestor, with spirit. "You make me nervous."

"And me, also," added Mrs. Anderson.

"Science can not deceive, madam," retorted Mr. Parker.

"Well it can keep quiet about what it knows, and not make a person have cold chills," replied Mary's mother. "I'm sure we will be rescued in time."

There was a slight tremor of an earthquake, as they were eating dinner that day, but, aside from causing a little alarm it did no damage. In the afternoon, Tom again called up the approaching steamer, and was informed that, because of a slight accident, it could not arrive until the next morning. Every effort would be made to keep up speed, it was said. There was much disappointment over this, and Mr. Damon was observed to be closely examining the food supply, but hope was too strong to be easily shattered now.

Mr. Parker went off alone, to make some further "observations" as he called them, but Mr. Hosbrook warned him never again to speak of his alarming theories.

Mr. Barcoe Jenks called Tom aside just before supper that evening.

"I haven't forgotten what I said to you about my diamonds," he remarked, with many nods and winks. "I'll show you how to make them, if you will help me. Did you ever see diamonds made?"

"No, and I guess very few persons have." replied the lad, thinking perhaps Mr. Jenks might not be quite right, mentally.

The night passed without alarm, and in the morning, at the first blush of dawn, every one was astir, looking eagerly across the sea for a sight of the steamer.

Tom had just come down from the wireless station, having received a message to the effect that a few hours more would bring the CAMBARANIAN within sight of the island.

Suddenly there was a tremendous shock, as if some great cannon had been fired, and the whole island shook to its very centre.

"Another earthquake! The worst yet!" screamed Mrs. Anderson.

"We are lost!" cried Mrs. Nestor, clinging to her husband.

An instant later they were all thrown down by the tremor of the earth, and Tom, looking toward his wireless station, saw nearly half of the island disappear from sight. His station went down in collapse with it, splashing into the ocean, and the wave that followed the terrible crash washed nearly to the castaways, as they rose and kneeled on the sand.

"The island is sinking!" cried Mr. Parker. "Make for the raft!"

"I guess it's our only chance," murmured Captain Mentor, as he gazed across the water. There was no steamer in sight. Could it arrive on time? The tremors and shaking of the island continued.



CHAPTER XXV

THE RESCUE—CONCLUSION

Down to where the small raft was moored ran Mr. Parker. He was followed by some of the others.

"We must put off at once!" he cried. "Half the island is gone! The other half may disappear any moment! The steamer can not get here on time, but if we put off they may pick us up, if we are not engulfed in the ocean. Help, everybody!"

Tom gave one more look at where his wireless station had been. It had totally disappeared, there being, at the spot, now but a sheer cliff, which went right down into the sea.

The women were in tears. The men, with pale faces, tried to calm them. Gradually the earthquake tremor passed away; but who could tell when another would come?

Captain Mentor, Mr. Hosbrook and the others were shoving out the small raft. They intended to get aboard, and paddle out to the larger one, which had been moored some distance away, in readiness for some such emergency as this.

"Come on!" cried Mr. Fenwick to Tom who was lingering behind. "Come on, ladies. We must all get aboard, or it may be too late!"

The small raft was afloat. Mrs. Anderson and Mrs. Nestor, weeping hysterically, waded out through the water to get aboard.

"Have we food?" cried Mr. Damon. "Bless my kitchen range! but I nearly forgot that."

"There isn't any food left to take," answered Mrs. Anderson.

"Shove off!" cried Captain Mentor.

At that instant a haze which had hung over the water, was blown to one side. The horizon suddenly cleared. Tom Swift looked up and gave a cry.

"The steamer! The steamer! The CAMBARANIAN!" he shouted, pointing to it.

The others joined in his exclamations of joy, for there, rushing toward Earthquake Island was a great steamer, crowding on all speed!

"Saved! Saved!" cried Mrs. Nestor, sinking to her knees even in the water.

"It came just in time!" murmured Mr. Hosbrook.

"Now I can make my diamonds," whispered Mr. Jenks to Tom.

"Push off! Push off!" cried Mr. Parker. "The island will sink, soon!"

"I think we will be safer on the island than on the raft," declared Captain Mentor. "We had better land again."

They left the little raft, and stood on the shore of the island. Eagerly they watched the approach of the steamer. They could make out hands and handkerchiefs waving to them now. There was eager hope in every heart.

Suddenly, some distance out in the water, and near where the big raft was anchored, there was a curious upheaval of the ocean. It was as if a submarine mine had exploded! The sea swirled and foamed!

"It's a good thing we didn't go out there," observed Captain Mentor. "We would have been swamped, sure as guns."

Almost as he spoke the big raft was tossed high into the air, and fell back, breaking up. The castaways shuddered. Yet were they any safer on the island? They fancied they could feel the little part of it that remained trembling under their feet.

"The steamer is stopping!" cried Mr. Damon.

Surely enough the CAMBARANIAN had slowed up. Was she not going to complete the rescue she had begun?

"She's going to launch her lifeboats," declared Captain Mentor. "Her commander dare not approach too close, not knowing the water. He might hit on a rock."

A moment later and two lifeboats were lowered, and, urged on by the sturdy arms of the sailors, they bounded over the waves. The sea seemed to be more and more agitated.

"It is the beginning of the end," murmured Mr. Parker. "The island will soon disappear."

"Will you be quiet?" demanded Mr. Damon, giving the scientist a nudge in the ribs.

The lifeboats were close at hand now.

"Are you all there?" shouted some one, evidently in command.

"All here," answered Tom.

"Then hurry aboard. There seems to be something going on in these waters—perhaps a submarine volcano eruption. We must get away in a hurry!"

The boats came in to the shelving beach. There was a little stretch of water between them and the sand. Through this the castaways waded, and soon they were grasped by the sailors and helped in. In the reaction of their worriment Mrs. Anderson and Mrs. Nestor were both weeping, but their tears were those of joy.

"Give way now, men!" cried the mate in charge of the boats. "We must get back to the ship!"

The sea was now swirling angrily, but the sailors, who had been in worse turmoils than this, rowed on steadily.

"We feared you would not get here in time," said Tom to the mate.

"We were under forced draught most of the way," was his answer. "Your wireless message came just in time. An hour later and our operator would have gone to bed."

The young inventor realized by what a narrow margin they had been rescued.

"The island will soon sink," predicted Mr. Parker, as they reached the steamer, and boarded her. Captain Valasquez, who was in command, warmly welcomed the castaways.

"We will hear your story later," he said. "Just now I want to get out of these dangerous waters."

He gave the order for full speed, and, as the CAMBARANIAN got under way, Tom, and the others, standing on the deck, looked back at Earthquake Island.

Suddenly there sounded a dull, rumbling report. The whole ocean about the island seemed to upheave. There was a gigantic shower of spray, a sound like an explosion, and when the waters subsided the island had sunk from sight.

"I told you it would go," cried Mr. Parker, triumphantly, but the horror of it all—the horror of the fate that would have been theirs had they remained there an hour longer—held the castaways dumb. The scientist's honor of having correctly predicted the destruction of the island was an empty one.

The agitation of the sea rocked even the mighty CAMBARANIAN and, had our friends been aboard the frail raft, they would surely have perished in the sea. As it was, they were safe—saved by Tom Swift's wireless message.

The steamer resumed her voyage, and the castaways told their story. Captain Valasquez refused to receive the large amount of money Mr. Hasbrook and Mr. Jenks would have paid him for the rescue, accepting only a sum he figured that he had lost by the delay, which was not a great deal. The castaways were given the best aboard the ship, and their stories were listened to by the other passengers with bated breath.

In due time they were landed in New York, and Mr. and Mrs. Nestor accompanied Tom to Shopton. Mr. Damon, with many blessings also accompanied them, going to his home in Waterfield. Later it was learned that the other boats from the RESOLUTE had been picked up, and the sailors and guests were all saved.

Of course, as soon as our friends had been rescued by the steamer, the wireless operator aboard her, with whom Tom soon struck up an acquaintance, sent messages to the relatives of the castaways, apprising them of their safety.

And the joy of Mary Nestor, when she found that it was Tom who had saved her parents, can well be imagined. As for our hero, well, he was glad too—for Mary's sake.

"I won't forget my promise to you, Tom Swift," said Mr. Barcoe Jenks, as he parted from the young inventor, and what the promise was will be told in the next volume of this series, to be called: "Tom Swift Among the Diamond Makers; or, The Secret of Phantom Mountain." In that Tom is destined to have many more surprising adventures, as is also Mr. Damon, who learned new ways to call down blessings on himself and his possessions.

And now, for a time, we will take leave of the young inventor and also of his many friends, who never ceased to wonder over Tom Swift's skill with the wireless.

THE END