"They've got to learn a lot to be real soldiers," was Randy's comment.

By following the directions given to them, it did not take long for the young folks to reach the vicinity of the regiment to which Dick Rover and his brother Sam were attached. The captain and the lieutenant were on the lookout for them, and hurried to meet them.

"We are very glad to see all of you," said Dick Rover, catching his son by the hand and kissing his daughter affectionately. "You can't imagine how much we have missed you."

"Nor how much we have missed you," returned Martha, her eyes growing suddenly misty.

"How are you making it, Dad? Do you feel like a regular soldier yet?" questioned Fred of his parent.

"Oh, we are working into it, Fred," replied Sam Rover.

"How soon do you expect to go to Europe?" questioned Mary quickly.

"There is a rumor that we shall leave in a week or two."

"Oh! as soon as that?" came from several of the others.

"Of course we can't tell positively," went on Fred's father. He turned to Andy and Randy. "By the way, boys, I've got a surprise for you," he added. "Your father will be down here this morning. In fact, we are expecting him any minute."

"Is he coming alone?" asked Andy.

"I don't think so. He spoke about bringing your mother with him, and possibly he may bring your Aunt Dora and your Aunt Grace."

"Oh, that would be fine!" exclaimed Mary. She happened to glance around. "Well, I declare! Here they come now!" And in a moment more the folks from New York City leaped out of a newly-arrived automobile and strode toward the others. There was a great amount of kissing and handshaking, and Tom Rover's face showed his great excitement.

"I've got an announcement to make," said the father of the twins, when he could command the attention of the others. "A very important announcement. I am going to become a soldier and fight with the rest of the fellows in France."



CHAPTER XXV

AT CAMP HUXWELL

For a moment after Tom Rover made the important announcement all of the others stared at him, unable to speak.

"Do you really mean it, Dad?" cried Randy, the first to break the silence. "Are you really going to the front?"

"Yes, Son. I just got word early this morning which makes it possible for me to leave New York and join the army," answered the father, with a smile.

"Hurrah! That's the best ever!" shouted Andy, throwing his cap into the air. "I knew you'd do it, Dad." And, rushing forward, he grabbed his father and gave him a big hug.

"But—but—I really don't understand," stammered Dick Rover, for once so surprised he could scarcely speak. "How did you fix it up, Tom?"

"Allen Charter is going to do the trick for me," answered Tom Rover.

"Allen Charter?" exclaimed Sam Rover. "I thought you said he had declined and was going to volunteer!"

"He did volunteer; but they wouldn't accept him—something the matter with his heart, I believe. Anyway, they wouldn't take him. Of course, Charter was much downcast. But he at once came to me and said he would take hold of our concern. He's going to do it in connection with Mr. Frank A. A. Powell, Songbird's uncle, the lawyer who helped us out so much when we had our trouble with Pelter, Japson & Company," continued Tom Rover, referring to a matter the details of which were given in the volume entitled, "The Rover Boys in New York."

"And he's been just the craziest fellow ever was since he fixed it so he could go," declared Nellie, Tom's wife. "He tore around the house like a wild Indian, trying to get his things into shape. I guess he has an idea he's going to take a kit and a gun and go over to France this afternoon."

Of course the older folks wanted more of the particulars, and as the whole party strolled over to Captain Dick Rover's quarters, Tom related them.

"Of course I'm sorry that Allen Charter can't go to the front," said the father of the twins, "but I am mighty glad that we can get him to take charge, for he is not only a first-class business man, but you know he is honesty itself."

"Yes, I know that," answered Dick. "I wouldn't want a better fellow."

"And if Mr. Frank Powell works with him, I'm sure matters will go along very nicely," put in Sam. He caught his brother by the shoulder. "Say, Tom, this is the best news yet! Don't you know Dick and I have had the worst kind of blues thinking that you must be left behind?"

"But, Dad! aren't you going in for a commission of some sort?" questioned Andy quickly.

"Nothing doing in that line," answered Tom Rover promptly. "I've always been a high private in the rear rank in the past, and I suppose that is what I shall be in the present and the future—although, of course, I don't expect to stay in the rear rank when there is some real fighting ahead," he added quickly. "Then I want to get in the front-line trenches and go over the top."

"Bully for you, Dad!" shouted Andy slangily.

"I've already put in my application, and Major Kirby, who is an old friend of mine, has promised to push it right through; so I think I'll be landed here in a day or two."

The coming of Tom Rover and the ladies from New York City made the party at the camp quite a large one. The boys and girls enjoyed themselves thoroughly. It could be seen that a great weight was lifted from the minds of the twins, and there was no holding them in when it came to making fun.

All too soon it came time for the boys and girls to depart. The Rover boys shook hands warmly with their fathers, and the girls of course came in for a number of hugs and kisses.

"Take good care of yourself, Dad," said Jack to his parent. "Don't let those Huns shoot you."

"I'm sure you'll be coming back a general, Dad," remarked Fred to his father.

"And don't forget to bring back some German helmets, Dad, and things like that!" cried Randy.

"We'll take any kind of souvenir, Dad—even a German sauerkraut masher," put in Andy.

Then the boys and girls said good-bye to their mothers, and all hurried off to the two automobiles awaiting them. In a minute more they were leaving Camp Huxwell and were on their way to Camp Barlight. Martha was openly crying, and tears filled the eyes of Mary, and who could blame them? Even the boys looked mighty serious, and Ruth and the others had quite a task trying to cheer them up.

"There is no use in talking," was the way Fred expressed himself: "Going to France is a serious business. It's all well enough to talk about shooting up the Huns, and all that sort of thing, but don't forget that the Huns may do a little shooting on their own account."

"Oh, they'll come back safe and sound," declared Andy. "They've just got to!" Yet behind it all the fun-loving Rover felt just as bad as any of them, but he was trying hard not to show it.

The boys were dropped off at the encampment, and then the girls continued on the way to Clearwater Hall. They were to remain at the Hall for the best part of a week longer, and then Mary and Martha were going to join their mothers and their aunt for the summer vacation. What the boys were going to do after the encampment came to an end, had not yet been decided.

Sunday was passed quietly by the Rover boys and their chums. Religious services were held in the open air, and were attended by nearly all of the cadets. In the afternoon Fred and Jack took a walk, accompanied by Gif and Spouter, the twins remaining behind to write some letters.

The walk took the cadets to the foot of the cliff nearest to their camp, and in rounding this close to the water front they made a somewhat interesting discovery. They came to quite an opening among the rocks, and, going inside, found themselves in a regular cavern, ten feet high in some places and half again as broad. In the rear was a smaller opening, leading downward and filled at the bay level with water.

"Who would think there would be a cave like this around here!" remarked Jack.

"Good place to come to in case of a storm," said Spouter. "A fellow could play Robinson Crusoe if he wanted to."

By the aid of some matches the cadets examined the cavern, but found nothing in it of value. At some time in the past birds had nested there, but that was all. They were just ready to leave when Jack suddenly put up his hand.

"Listen!" he said. "Am I mistaken, or do I hear something?"

All did as he commanded, and from a great distance a faint tapping reached their ears. Then came a series of muffled explosions and a clanking as of chains.

"That's something like the noise Randy said he heard when he was on sentry duty," remarked Fred. "Don't you remember how worked up he was over it?"

"What do you suppose it is, and where do you suppose it comes from?" put in Gif.

No one could answer those questions. All was now silent, but presently they heard another series of explosions, and then the tapping continued steadily for several minutes. Then, however, the sounds died away.

"That's got me guessing," declared Jack, after the crowd had left the cavern. "We'll have to tell Randy about this, and maybe we had better tell Captain Dale, too."

Monday proved an exceedingly sultry day. The thermometer went so high that drills and exercises in the sun were all curtailed.

"Looks to me as if this was a weather breeder," remarked the young captain to the others.

"Well, I don't care what it does, if only it cools off," grumbled Randy. "Why, I feel as if I was living in a bake oven!"

He had been told of the strange noises heard in the cavern at the bay front, and had been much interested. The boys had also spoken to Captain Dale, who had promised an investigation.

When the hour came for the cadets to retire the sky was so overcast that not a star was showing. A breeze had sprung up, and this was growing brisker every minute.

"I think we are in for a storm, and a good big blow with it," announced Captain Dale. And then he told Major Ralph Mason to give orders that all the tent fastenings should be looked to.

"I'm sure our tent is down tight enough," announced Randy, after he and his tent-mates had made an investigation.

"Well, you want to be sure of it," remarked Fred, who was making the round of the tents. "You don't want that canvas to be sailing skyward or out into the bay."

As was usual with them, Gabe Werner and Bill Glutts growled when ordered to look to the fastenings of the tent they and their cronies occupied. But as the wind increased Glutts pulled Gabe to one side and whispered something into his ear.

"All right—I'm with you," answered Werner promptly. "Let's do it at once. Got your pocketknife handy?"

"Yes. Have you?"

"I have. And it's as sharp as a razor. All we'll have to do is to cut the ropes about half way through. The wind will do the rest," announced Gabe gleefully.

"What's the matter with fixing up both tents?" went on the wholesale butcher's son. "You can slide over to the officers' quarters while I attend to the tent down in the Company C line."

"All right! But hurry up. And come back as soon as you're through," cautioned Werner.

He reached the vicinity of the tent occupied by Jack and Fred just as the first of the rain drops began to come down. The wind was now blowing half a gale, and the canvases of the encampment were flapping and slapping loudly.

Werner had his pocketknife open, and it did not take him long to begin operations. Five of the ropes which held the tent to the pegs were all but severed, and then he began work on the next.

"Stop that! What do you mean, you rascal?"

Gabe Werner turned, and as he straightened up he found himself face to face with Jack. The young captain had been on an errand to the next tent, and had seen the rascally ex-lieutenant in the darkness more by chance than by anything else.

"What's the matter out there?" called Fred from the interior of the tent.

"Here is Gabe Werner! He's cutting the ropes!" And now Jack caught the big youth by the arm.

"Let go of me, Rover!" demanded the ex-lieutenant, and then he raised the hand that held the pocketknife.

It is not likely that he would have used the weapon. But Jack did not care to take any chances. As quick as a flash he hauled back, and then his fist crashed into Gabe Werner's chin, sending him sprawling on his back.

For a second or two the big ex-lieutenant was dazed, but then, with a muttered imprecation, he leaped up, dropping his pocketknife as he did so, and rushed at Jack, hitting him in the shoulder.

By this time the blood of the young captain was up. He dodged a second blow delivered by Werner, and then his fist shot out quickly, landing on the ex-lieutenant's nose, drawing blood.

"Ouch!" spluttered Werner, and then he made a leap and grappled with Jack. There followed a lively mix-up in which blows were given and taken freely.

In the meantime Fred set up a cry of alarm, not knowing who was attacking his cousin. In a few seconds a number of cadets and Professor Brice came hurrying in that direction.

"I've got to clear out, but I'll fix you another time, Rover," hissed Gabe Werner, and attempted to retreat.

"You're not going to get away, Werner!" cried Jack, and, making a leap forward, he gave the ex-lieutenant a blow behind the ear which sent him to the ground all but unconscious.



CHAPTER XXVI

AN ASTONISHING DISCOVERY

"What does this mean, Captain Rover?" demanded Professor Brice, as he rushed up, lantern in hand and followed quickly by Major Ralph Mason and a dozen other cadets.

"I caught this rascal cutting the ropes to our tent," explained Jack.

"Gee, you'd better hold that tent down!" cried one of the cadets. "There go three of the ropes now!" And what he said was true, the ropes in question being those that Werner had partly severed with his knife.

Fred had come out of the tent, and now he and a number of the other cadets held down the canvas so that the wind could not get under it. It was blowing furiously, so that they had no easy job of it to keep the tent from going up.

"Do you mean to say he really cut the ropes here?" demanded Professor Brice sternly, as Werner gathered himself together on the wet ground and slowly arose to his feet.

"Yes, sir," said Jack. "And there is the knife he did it with," he added, pointing to the pocket piece which had fallen under the ex-lieutenant.

"It was—er—it was—er—only a bit of fun," stammered Werner, not knowing what else to say. "And Jack Rover had no right to pitch into me the way he did!"

"I had a perfect right to do so, Professor Brice," announced Jack. "If I wanted to say more—- But I won't do it now," he added. "I'll make a report to you in private."

By this time the camp was in an uproar, for down the line where Company C was located there had been another rumpus. Gif, going out on guard duty, had caught sight of Bill Glutts just as the latter had cut two of the ropes to the tent occupied by him and Spouter and the twins. Gif had treated the wholesale butcher's son rather roughly, and Glutts had finally yelled for mercy, bringing out a crowd of twenty or thirty, including the twins.

"This is a despicable piece of business, Werner," said Professor Brice sternly. "I will at once report the matter to Captain Dale, who, as you know, is in authority in this camp. Come along with me."

Captain Dale had been down to the shore of the bay, to make certain that there was no danger of the tents which were used for bath houses being blown away. He soon came up and looked closely at the ropes which Werner had partly severed.

"I don't like this sort of thing at all," he said to the ex-lieutenant. "If that tent had come down while those inside were asleep somebody might have been seriously injured. More than that, nobody would care to be without shelter on such a night as this, and with all their possessions getting wet. You will report to the corporal of the guard at once." Then Captain Dale passed on to where the others were having trouble with Glutts, and he was also ordered to report to the guard.

In the meanwhile, as the storm seemed to be increasing, Captain Dale gave orders that the fastenings of every tent should be inspected thoroughly and extra ropes and pegs should be put down wherever necessary. He did not want any of the school property damaged.

"Gee, we'll catch it for this!" growled Bill Glutts, when he and Werner had been placed in a small wooden shanty, designated a guardhouse. "I suppose they'll make us do all sorts of disagreeable things as a punishment."

"I won't stand for it!" stormed Werner, whose nose was still bleeding from the blow Jack had dealt. "They can't make me the laughingstock of this camp."

"What are you going to do?"

"I'm going home," announced the ex-lieutenant.

And that is what he did, stealing away from the camp early in the morning just as the heavy storm of the night was passing away. He managed to get a few of his possessions, but the others had to be left behind. He wanted Glutts to go with him, but the son of the wholesale butcher was afraid to do so.

In the morning Jack and the others had to make a full report to Captain Dale of what had occurred. The young captain mentioned the fact that Werner had had his pocketknife in his hand.

"I'm not sure that he was going to use it," said Jack. "In fact, I would rather think that he wouldn't do so. But I wasn't going to take any chances, and so I hit him. Then he hit back, and—well, we mixed it up pretty freely. Finally I gave him a blow that knocked him flat, and then the others came up."

"Captain Rover, you know I do not approve of fighting, especially among officers," declared Captain Dale sternly. "However, the introduction of the pocketknife changes the situation somewhat. I will hear what Werner has to say."

Then it was discovered that Gabe Werner had left the camp. He had written a note saying that he was going home and that he guessed he would never come back to Colby Hall again. This being so, the matter was dropped so far as Jack was concerned. Nor was Gif punished for the way he had treated Bill Glutts. Captain Dale read a stern lecture to that unworthy, and for the remainder of the camp term Glutts was deprived of many liberties he might otherwise have enjoyed.

It must not be supposed that the boys had forgotten the strange noises they had heard while in the woods and in the cavern at the front of the cliff. They had reported to Captain Dale, and several investigations had been made, but without results. The captain had also communicated with the authorities at Rackville, and likewise with the Secret Service men stationed at Camp Huxwell.

"Well, I see they haven't made any progress in the matter of that explosion at the Hasley Shell Loading plant," remarked Spouter one day, after reading a copy of the Haven Point newspaper which had come in. "They are looking all over for those two Germans, but have been unable to spot 'em."

"I see the company is offering a reward of ten thousand dollars for the apprehension of the men," came from Fred, who had likewise read the sheet. "Gee, I'd like to get a chance at that reward!"

The next day the boys were treated to another surprise. As was their custom when the weather and their duties permitted, they went in bathing, and while diving Fred noticed a peculiar knocking sound under water. He called the attention of the others to this, and each cadet heard it quite plainly.

"It must come from the same place as those other noises we heard," declared Jack.

"I move we make a real investigation!" cried Andy. "Let's ask for a day off and scour the woods thoroughly."

"That's the talk," cried Fred.

The others were willing, and received permission to go out two days later, the party consisting of the four Rovers and Gif and Spouter. They took their lunch with them, and also some canteens of water, expecting to be gone until nightfall.

There was quite a discussion as to how they should start the investigation. Some wanted to go along the base of the cliff at the water's edge, while others were for making their way through the forest. The latter suggestion prevailed, and they started near the point where Randy had first heard the strange noises.

The young cadets tramped hither and thither among the trees and over the rough rocks for four hours without coming upon anything unusual. They stirred up a number of birds and small animals, but that was all.

"Looks like a wild-goose chase," remarked Jack, when they sat down to rest and to eat their lunch.

The climbing over the rocks had been very tiring, and all of the lads were glad after eating to take their ease for a while.

Randy was resting on his side, wondering whether it would be worth while to play a trick on Gif and Spouter, who were but a few feet away, when a movement among the trees at a distance attracted his attention. He sat up, and as he did so felt certain that he had seen a man moving along.

"Listen, boys!" he cried in a low voice. "There is some one now!"

"Where?" came from the others, and all aroused themselves on the instant.

Randy pointed out the direction, and, gathering up their things, the cadets hurried off to where he had pointed. There, sure enough, was a man plodding along with a bundle over his shoulder. He was a short, thick-set man, and wore a heavy mustache curled up at the ends.

"Let's see where he goes," said Jack. "Maybe he'll take us to that place where the noises come from."

They followed the man without his being aware of their presence. The fellow climbed over and around a number of rocks, and then pursued his way past a dense clump of bushes. Then, of a sudden, he disappeared from view.

The cadets were amazed, the more so after they had tramped around the spot without ascertaining what had become of the man.

"Looks as if the earth had opened and swallowed him up," remarked Randy.

The cadets had advanced with caution, but now they grew bolder, and made a closer examination. But it was all of no avail—the man had disappeared, and where he had gone to or how, there was no telling.

"One thing is sure," declared Jack. "He didn't walk away from here, and he didn't go up into the air. That being so, he must have gone down somewhere among the rocks and bushes. We had better hunt around for some sort of an opening to a cave, or something like that."

The others were willing enough, and spent the best part of an hour in the task. But no opening presented itself, although the rocks and rough places in that vicinity were numerous.

"Here is something else we can report to Captain Dale," was Fred's comment.

Not knowing what else to do, the boys marked the spot so that they could remember it, and then pushed onward through the forest. Two hours later they reached a sort of gully, with the rough rocks on one side and an overhanging cliff on the other.

"Fine place for snakes," remarked Spouter, as they walked along.

"We're not looking for snakes, so please don't mention them," answered Jack.

Why they did it, the boys could not explain afterwards, but they continued along the gully until they reached a point where there was something of a split in the face of the cliff.

"Here's another one of those caves just like that which we found over on the bay front," declared Fred. "Let's go in and see what it looks like."

With nothing in particular in view, the others were willing, and, turning on a flashlight which they had brought along, they climbed down into the cave-like opening. It was very irregular in shape, and they had to proceed with caution.

And then, while they were climbing down among the rocks, something happened which caused each of the cadets to start wildly. A strange rumbling sound filled the air, a blowing and hissing, and then came a pounding and a clanking, sounding with great clearness in that confined space.

"It's the same noises we heard before, and they are not very far off!" cried Jack to the others. "There must be a workshop of some sort around here."

Hardly knowing what to expect, the boys continued to climb down into the opening they had discovered. Soon they reached a narrow passageway, where going was a little easier. Then they came to a spot where there was considerable wetness, showing that they had reached the level of the water in the bay beyond.

"Here is a regular underground waterway," declared Gif presently. "It looks to be pretty deep, too."

He was right. To the surprise of everybody they had come out upon what seemed to be an underground pond. On the side upon which they had emerged there was a small sandy slope. The other side, and the far end, were covered with jagged rocks.

The strange blowing, pounding, and clanking continued, and almost deafened the cadets. They felt that they were on the point of a great discovery, but could not imagine what it would be.

"It's a workshop, all right enough," declared Fred, a minute later. "Jack, put out that light, quick!" And at this command the flashlight was turned off.

The cadets had rounded a bend of the underground waterway, and now at a distance they saw a number of electric lights shining brightly. There was some machinery set up among the rocks, and several workmen were present, all seemingly busy.

"Look!" exclaimed Jack, his eyes almost starting out of his head at the sight. "What do you think of that, fellows?"

He pointed to a spot beyond where the strange men were working. There the waterway seemed to broaden and deepen, and in the water lay a strange-looking craft more than three-quarters submerged.

"It's a submarine!" breathed Fred excitedly. "A submarine! What do you know about that?"



CHAPTER XXVII

ON BOARD THE SUBMARINE

The Rover boys and their chums were so astonished at the discovery they had made that for a moment they could do little else than stare at the strange object resting in the water ahead of them.

"Get out of sight, every one of you!" whispered Jack, who was the first to recover his self-possession. "Don't let those men see you!"

All backed away as silently as possible until they were once more in the shelter of the rocks of the bend around which they had come.

"Say, do you think those fellows are Germans?" whispered Randy excitedly.

"I certainly do, Randy," answered the young captain.

"Of course they are Germans!" put in Gif. "If they were Americans why would they be concealing themselves in such an out-of-the-way place as this?"

"It's a German submarine, as sure as you're alive!" remarked Spouter. "Fellows, we have made a wonderful discovery!"

"And this accounts for all the strange noises we heard, and the fellows we saw going through the woods with bundles on their backs," added Randy.

"Yes, and I guess it straightens out that story Jed Kessler told about the two Germans in the wagon with stuff that rattled like hardware," said Jack.

"It's as plain as day," cried Fred. "Those two fellows must be connected with this gang here who are working on the submarine. And more than likely they were the same two Jed Kessler saw hanging around the ammunition plant just before the explosion."

"If that's a German submarine, it must have come from the other side of the Atlantic!" exclaimed Andy in a low, excited voice. And then he added, his eyes snapping: "What do you suppose happened to it? Do you think she ran afoul of some of our big warships or our submarine chasers?"

"Either that, or in cruising up and down the coast here she may have run afoul of some of the rocks and maybe knocked a hole in her bottom or side," answered Jack. "And I guess it's true that all the pounding and strange noises we have heard came either from this underground place or from some overhead spot close by."

"What gets me is—how did that submarine get into this underground place?" questioned Gif.

"There must be a much larger outlet than the one by which we entered," answered Jack. "More than likely those fellows don't know anything about the way by which we got in. They must have a large entrance by way of the water from the bay, and they must also have an entrance from the forest—that place where the man disappeared."

"I guess you're right," said Fred. "Gee, this certainly is an important discovery! I guess the best thing we can do is to hurry back to camp as fast as possible and notify Captain Dale. He will probably want to let the Secret Service men and the authorities at Rackville know at once, so they can round up these fellows before they have a chance to get away."

"I'd like to stay here awhile and watch these chaps," said Randy. "Maybe we may learn something more that is worth while."

The matter was talked over by the cadets for fully ten minutes. At the place to which they had withdrawn they could talk freely, because the noises near the submarine continued, so there was little danger of their being overheard. While they talked they peeped out from time to time at the workmen, and saw that they were laboring over several sheets of steel and odd pieces of machinery, using a forge, a lathe, and a small drop hammer for that purpose. They had a gangplank leading over the waterway to the upper portion of the submarine, and from an open hatchway of the U-boat ran a number of coils of insulated wire, evidently carrying power to the electric lights and also to the machinery.

"They must be getting all their power from the engines of the submarine," said Jack. "They've certainly got themselves pretty well fixed down here."

"But how in the world did they manage to find this place?" questioned Spouter.

"That remains to be found out, Spouter. Probably the German authorities had some spies around here who found the place for them, or otherwise they paid some of the natives for the information."

"You know my dad spoke about German U-boat bases along our coast, and also bases for secret wireless telegraphy plants," put in Fred. "There is no telling what those rascals are up to."



It was decided that Andy and Randy, accompanied by Spouter, should make their way back to the opening by which they had gained entrance to the underground waterway, and then return to Camp Barlight as quickly as possible and acquaint Captain Dale with what had been discovered. In the meanwhile, Jack, Fred, and Gif would remain behind on guard in case the Germans should attempt to make a sudden move.

"We don't know how far along they are with their repairs," declared the young captain. "It would be just our luck to have them sail away right under our noses."

"Oh, Jack! couldn't you stop them in some way from doing that?" questioned Andy quickly.

"I should hope so, Andy. That is, if they really did try to get away. Of course, they may not be anywhere near ready to leave—although they have been here for some time according to the noises we have heard. I'd like to find out something about the other end of the passageway."

"Maybe you can find out by going out with us and around to the other end of the bay," suggested Spouter.

"I was thinking of that. But for the present I would rather stay right here and watch these fellows."

It was not long after this when the twins and Spouter departed, stating that they would report to Captain Dale as speedily as possible. Then Jack and his cousin and Gif settled down to watch the Germans.

For Germans they were, beyond a doubt. They were all heavy-set, burly fellows, and once or twice when the machinery was stopped the cadets heard one man, who was evidently in charge, give a number of commands in the German tongue.

For nearly an hour longer the pounding and clanking continued. Most of the work was done on the rocky shore of the waterway, but some took place inside the submarine and also on the forward deck of the craft. The submersible was of good size, being over two hundred feet in length.

"I'd like to get a whack at that U-boat," declared Gif. "I bet I'd make it so she wouldn't do any more cruising in a hurry."

"Exactly what I was thinking, Gif," said Jack. "If we could only injure the propellers, or something like that, there wouldn't be any danger of their sailing away. You see, they may have it all fixed to leave at a minute's notice in case of an alarm."

"If they did that they'd have to leave some of their machinery behind," put in Fred. "But I suppose they'd be willing to do even that rather than risk capture."

When the cadets thought that their ears could no longer bear the awful noise to which they had been subjected, the sounds of the machinery suddenly ceased. They heard a strange humming from the interior of the submarine, but even this presently came to an end, and then there was a silence within the cavern which was absolutely oppressive.

"I guess some kind of a move is at hand," whispered Jack. "Let's lay low and see what they do next."

Several men, including two who were evidently officers and in charge of the work, came out of the submarine. The workmen were now washing up at the underground waterway, and presently all cast aside their working clothes and donned ordinary street garments.

"Looks as if they were going to leave," whispered Fred excitedly. "Maybe they are going out into the open for some fresh air. I can't blame them for that," he added, for throughout the cavern there was a strong smell of used gasoline.

Five minutes passed, and then one by one the Germans walked away from the submarine. They did not come in the direction of the cadets, but passed around another bend of the rocks, and so out of sight.

"That must be the way used by that fellow we saw in the forest," declared Jack.

All but three of the electric lights had been put out, so that the interior of the cavern was now quite gloomy. The only sound that broke the stillness was the soft lap, lap of some distant waves, evidently where they broke on the shore of the bay close to the larger entrance of the cavern.

"I'd like to bet that the entrance is under water," said Fred. "If it was at the surface some one would have discovered this place a long time ago." And in this surmise the youngest Rover was correct. The passageway, which was amply large, was over ten feet below the surface of the bay even at low tide.

"Do you suppose they've all left the submarine?" whispered Gif presently. With the intense silence prevailing, they felt that they must be very cautious in making any noise.

"That's hard to say," answered Jack, with a shrug of his shoulders.

"It looks so to me," put in Fred. "I don't believe any of those fellows would care to stay down here unless it was necessary. They have stopped all the engines and things like that. I guess those electric lights are burning simply from a storage battery."

The three cadets waited for another ten minutes, and then, as no one appeared, and as the submarine seemed to be deserted, they stole forward cautiously, all anxious to get a closer look at the U-boat.

"If we could only throw a chain around the propellers, or something like that, maybe it would keep them from getting away if they tried to run for it," said the young captain.

"We'll look around and see what we can do, anyway," answered his cousin.

"There are plenty of chains around," put in Gif. "Those are what made the awful clanking sounds we heard."

Step by step the three cadets came up until they were at the spot where the Germans had set up their repair plant. Some of the things they had been working upon were still lying about, but other parts had been taken aboard the submarine.

"I guess they have all gone," said Jack, after a look around. "I'm going aboard that craft and take a peep at her."

The others were also anxious to do this, and all three were soon across the gangplank which led to the open hatch of the U-boat. They gazed down this hatch with some awe, and discovered that several electric lights had been left turned on below. A steel ladder ran down into the interior of the submersible.

"What do you say—shall we go below?" questioned Jack.

"I'm willing if you are," answered his cousin.

"And so am I," added Gif. "I don't believe there is any one around."

"Well, we'll take a chance," answered the young captain. "If there is any alarm, we'll have to run for it."

"Yes, and we may have to fight for it," added Fred.

Jack went down the ladder quickly, followed by the others. They now found themselves in what might be termed the main room of the submarine. Beyond were several other compartments, including one where was located much of the machinery which ran the undersea boat.

"It's a good deal like being downstairs on a small warship," declared Fred. "See, there are staterooms and messrooms and everything else!"

"Well, I suppose they have to give the crew some comforts, they take such long, disagreeable trips," remarked Jack.

The three cadets wandered around in the interior of the submarine for over a quarter of an hour. They saw where a number of repairs were being made to the side of the U-boat and also to some of the machinery, and they also saw where some stores had been taken on board, boxes and barrels of various kinds.

"I guess they are stocking up for another cruise," remarked Gif.

"It must be quite a job to get all that stuff to this out-of-the-way place," said Jack.

"Yes, and to do it so secretly, too," added Fred.

"I think I see a way of making this boat stay here for a while, at least," remarked Jack. "It will be an easy matter to put some of that delicate machinery forward out of commission."

"Come on and do it!" cried his cousin quickly.

The three cadets were inspecting the machinery and wondering how they could damage it effectively with the least possible trouble, when there came a sudden interruption.

"What are you doing here?" came in a guttural German voice. "Hands up, or I will shoot you!" And, turning quickly, the three cadets found themselves confronted by a burly German, holding in each hand a pistol.



CHAPTER XXVIII

THE CABIN IN THE WOODS

It was a comparatively easy matter for the twins and Spouter to get out of the cavern by the way they had entered. It was, however, not so easy for them to climb up the face of the cliff fronting that portion of Barlight Bay.

"Some climb, believe me!" panted Spouter, when they had reached a spot where going was easier.

"I came pretty near slipping and breaking my neck at one point," said Randy. "I don't believe those Germans ever use that entrance, do you?"

"Not very often," answered his twin.

The three cadets had reached the woods at a point which was new to them, being almost a mile from the other cliff, where they had had the outing with the girls. Between the two points there was a split in the land, and here the waters from the bay dashed in over a long series of jagged rocks.

"We can't cross there," remarked Randy, when they had reached the brink of this split. "We'll have to go back into the woods and go around."

It was now about five o'clock in the afternoon, and the tramping and climbing had tired all of the boys, yet they set off as rapidly as possible, feeling that it would be best to make a report to Captain Dale as soon as possible.

"I wish we had some trail to go by," remarked Randy, after they had been walking for at least half an hour. "I begin to think we are not moving in the right direction."

"I've been trying to guide myself by the sun," answered Spouter. "Just the same, I don't believe we are headed exactly for the camp."

"I've got to go a bit slower," sighed Andy, who for once was by no means light-hearted. "Both of my feet are beginning to hurt from all that climbing over the rocks. I came pretty close to twisting my ankle this afternoon, and it has been paining ever since."

Another half hour went by, and then, as the declining sun began to cast long shadows through the trees of the forest, the cadets looked at each other in alarm. The same thought had come into the minds of each of them.

"It looks as if we were lost," said Randy laconically. "How about it?"

"Oh, as the Indian said, we're not lost," responded Andy, with a faint smile. "It's only the camp that has gone astray."

"This is no time for joking," said Spouter coldly. "We've got to get back to camp, and do it just as fast as we can!"

"All right then, Spouter, show us the way," answered Andy readily.

"That's something I'm not so sure of," was the slow reply. "Which direction do you think it is in?"

The matter was talked over for several minutes, and finally the cadets moved off once more, this time at an acute angle to the direction they had before pursued. They went forward for perhaps a quarter of a mile, and then, much to their surprise, suddenly came out upon a well-defined wagon road.

"Well, what do you know about this!" cried Randy in astonishment.

"Where do you suppose this road leads to?" questioned his brother.

At this Randy shook his head, and Spouter did likewise. They could see the tracks of a horse and wagon in the road, and also the marks of automobile tires.

"It must be quite a road if it is used by automobiles," was Spouter's comment. "Now the question is—which way shall we go in order to get to our camp?" All had noticed that the road ran in something of a semicircle.

While the cadets were deliberating, they made another discovery. Smoke was coming up from among some of the trees near by, and, walking in that direction, they made out a fair-sized cabin, nestling deep between some trees and brushwood.

"Maybe we can get some assistance at that place," remarked Andy.

"I don't believe it!" returned his brother quickly. "It's more than likely the people who live there are in league with those Germans. They must have heard those noises the same as we did, and probably know all about how they are being made."

"That's it!" warned Spouter. "If I were you, I'd go slow in showing myself to anybody who may be at that cabin."

The boys approached with caution, keeping their eyes wide open, and presently discovered a touring car standing among the trees to one side of the cabin.

"I don't believe that car belongs here," said Randy. "I don't see anything in the way of a garage. And that looks like a nice city car."

Keeping in the shelter of some of the trees and brushwood, the cadets came still closer, and then made another discovery, which was to the effect that two young men were seated in the tonneau of the car. Each was smoking a cigarette, and they were conversing in low tones.

"I tell you I'm going to hit my dad for a hundred dollars on the strength of this," they heard one of the occupants of the car remark. "And I bet I get it, too."

"Well, if you get a hundred, Nappy, I'm going to hit for a hundred myself," was the reply of the other occupant. "I guess my father can afford to give me that amount just as well as your father can afford it."

"Oh, well, Slugger, you must remember that my dad has quite a bunch of money."

"Huh! I don't think he's any better fixed than mine. Here, pass over another cigarette. Don't forget I paid for the last ones we bought."

"Slugger Brown and Nappy Martell!" whispered Randy excitedly. "Would you believe it?"

"What can those fellows be doing away out here in the woods?" questioned Spouter.

"I'll bet I know what they are here for!" cried Andy, in a low voice. "They brought their fathers out here in that touring car."

"What would they be doing that for?"

"Don't you remember, Spouter, our telling you about how we saw Mr. Brown and Mr. Martell down in Wall Street, New York, talking to those fellows who looked like Germans, and how they mentioned supplies, and canned goods, and machinery, and night work, and a whole lot of things like that?"

"Sure I do! And you think——"

"I'll bet Andy has it right!" interrupted Randy. "Brown and Martell must be in league with those Germans, and the goods and machinery and other things they spoke about must be connected with this affair of the disabled submarine! They wanted extra pieces of machinery most likely, and they also wanted extra supplies, having probably used those that they had brought along from Germany."

"You're making a pretty long guess, it seems to me," answered Spouter. "Just the same, you may be right."

Not to be seen by Slugger Brown and Nappy Martell, the three cadets had withdrawn to a safe distance. Now, however, all were anxious to ascertain who might be in the cabin, and so by crouching low and hiding behind one tree and another and then some rocks and low bushes, they at last came up close to the opposite side of the shelter in the forest.

"Now don't show yourselves if you can help it," said Randy in a whisper. "And if any one is discovered, leg it for all you are worth, and keep your faces turned away so that they can't see who you are."

With this understanding, the three cadets surveyed the situation critically. The cabin consisted of three rooms, each boasting of a window on either side. As it was warm, all the windows and doors were wide open to admit the fresh air.

"And that is what I mean when I say I want to settle this matter," they heard, in the voice of Slogwell Brown.

"I think it's a shame that the thing has hung fire so long," said another person in the cabin, and now the three cadets recognized the voice of Nelson Martell. "I would never have gone into it if I had known there would be so much delay. We took a big risk in getting the supplies for you."

"But, gentlemen, we are not keeping you waiting any longer than is necessary," answered a voice with a strong German accent. "We have had a delay in receiving our own remittance. Even now it is not yet arrived."

"Do you mean to say you haven't got the money yet?" demanded Mr. Brown. His tone of voice showed that he felt ugly.

"It was promised to-night sure," was the answer. "Captain Fuerhman was to obtain the money at the Haven Point bank this afternoon."

"Was he to come here with it?"

"Yes."

"Then he ought to be here by now," grumbled Nelson Martell, consulting his watch.

"He had to see about a small piece of machinery that was to be cast for us," resumed the man who spoke with a German accent. "I, however, expect him here by eight o'clock this evening at the latest."

"Well, in that case there isn't anything left for us to do but to wait," said Slogwell Brown, surlily.

"You may do that, or you may come back at that time," said the German. "I am very sorry to keep you waiting, but as I said before, gentlemen, it cannot be helped."

"I don't believe the two boys will want to wait outside for two hours," said Mr. Martell to Mr. Brown. "Suppose we ride into town and get a bite to eat, and then come back here?"

"That will suit me, Martell. Anything to kill off the time," answered Slogwell Brown. He turned to the German. "We'll be back here by eight o'clock. And remember! that money has got to be paid to-night."

"You shall have every dollar that is coming to you, gentlemen," answered the German, who, as it afterwards proved, was the commander of the disabled submarine.

A few more words passed, and then Mr. Brown and Mr. Martell came out of the cabin to where they had left Slugger and Nappy in the touring car. They entered the machine, which was immediately backed to the forest road, and then the whole party set off, Slugger driving the car.

"Say, listen!" cried Spouter excitedly. "I believe that German is here all alone! What do you say if we make him a prisoner?"

"No, no, don't do that!" answered Randy quickly. "We want to bag the whole bunch. Let us get to camp just as soon as we can and notify Captain Dale. Then he can organize a crowd and come back here and give Brown and Martell and the Germans the surprise of their lives."

"But how are we going to find our camp?" questioned Spouter.

"Dead easy. If that is the road to Haven Point, it must pass through Rackville, and if it does that, it must come pretty close to our camp. Come on!"



CHAPTER XXIX

THE FIGHT ON THE SUBMARINE

It must be admitted that Jack, Fred, and Gif were much startled when they suddenly found themselves confronted by an armed German who looked as if he meant what he said when he commanded them to throw up their hands.

On first going aboard the submarine the three cadets had been very cautious, but as they had wandered around without seeing any one aboard the craft, they had come to the conclusion that it was deserted, and consequently they had become less careful both in their actions and their conversation.

Of course their hands went into the air. The German had two pistols, and he looked as if he would be willing to use the weapons upon the slightest provocation. He was a burly, red-faced man, and only about half dressed. Evidently he had been sleeping soundly when they had come aboard.

"You back up there into a corner," growled the German. He spoke English quite well, although his accent was Teutonic.

The young cadets did not know what else to do, and so obeyed the command. As they were in uniform, the German took them to be American soldiers, and this disturbed him greatly.

"Are there any more in your party or are you alone?" he demanded.

This question gave Jack a sudden idea.

"Alone?" he cried. "Not much! There are over a hundred of us," he answered, referring, of course, to the number of cadets at Colby Hall.

"Are you telling the truth?" growled the German, and his voice betrayed his nervousness.

"He sure is telling the truth! Look behind you and see," said Fred, and began to laugh in a suggestive way.

This laugh took the German off his guard, and he turned swiftly to see who might be behind him. It was the opportunity that the young captain and the young lieutenant had hoped would come, and, taking a perilous chance, they threw themselves on the back of the German, each at the same time catching hold of a hand that held a pistol. Then Gif rushed in; and between them the cadets succeeded in hurling the fellow, muscular though he was, to the floor.

"Give up!" cried Jack suddenly, and, bringing out his flashlight, he placed the cold glass of the end against the German's neck.

"Kamerad! Kamerad!" yelled the fellow promptly, thinking that it was a pistol which was pressing upon him, and on the instant he released his hold on the two pistols while he stretched out flat on his chest on the floor of the submarine.

Jack lost no time in picking up one of the pistols, while Fred picked up the other. The flashlight was turned over to Gif, who, meanwhile, had armed himself with a steel bar.

"Now the question is—what are we going to do with this fellow?" remarked Jack, after the short encounter had come to an end. It must be confessed that he and the others were much worked up over the situation, for they had not dreamed of coming in such personal contact with one of the enemy.

"We've got to get out of here, and do it quick," returned Gif. "Those other Germans may come back at any minute."

"Yes, but we'll have to take this fellow along," said Fred. "No use of leaving him here to give an alarm."

"We'll gag him!" declared the young captain. And without loss of time the three cadets fixed up a gag such as they sometimes used when they were initiating a new member of one of the secret societies of the military academy. Then the German's hands were bound tightly behind him, and he was ordered to get up and march.

"Wait a minute," said Fred. "We'll have to fix things here so it won't look suspicious. We'll make it look as if this chap had just stepped out for some fresh air."

This was done, and a few minutes later the whole party left the submarine, Gif going ahead and the Rovers following the prisoner, each with a pistol ready for use. In this fashion they passed over the gangplank, and then made their way alongside of the underground pond until they came to the spot where the cadets had first discovered the Germans.

"I don't believe we ought to leave him here," declared Jack. "That gag might slip and he might have a chance to make considerable noise, and if he did that the others might take the alarm and sail away before we could get help."

"We made a mistake!" cried Gif. "I thought we were going to injure some of the machinery, so that they couldn't use the U-boat."

"You're right, Gif! I got so excited I forgot all about that," declared Jack.

"You can run back now and do it if you want to," said Fred. "I'll watch the prisoner."

The young captain and Gif did as had been suggested. On the submarine they looked over the intricate machinery with care, and presently found some things which they could disarrange and which would probably not be noticed immediately. They went to work with vigor, and came away again in less than ten minutes.

"I guess she's fixed now," declared Jack to his cousin, when they had rejoined Fred and the prisoner. "If they start up those engines, that submarine will perform stunts they never dreamed of."

With the flashlight shining ahead and at times on the prisoner, the Rovers and Gif compelled the German to move along the passageway until they gained the opening near the gully.

"Look out there, will you?" cried Gif suddenly, pointing between the bushes to the bay. "There is a big motor boat cruising up and down! Maybe they can give us aid."

"It looks to me like a revenue boat," declared Jack, after a hurried inspection. "Say, maybe they are patrolling the bay!"

"That's right!"

"I am going to signal to them and find out!" exclaimed Fred; and without waiting for the others to reply, the young lieutenant dashed over the rocks and through the brushwood in the direction of the bay shore. As he did this he took out his handkerchief and waved it wildly, at the same time calling at the top of his lungs.

The motor boat, a long, rakish-looking craft, was cruising quite close to the shore, and presently some of those on board noticed Fred's call for aid. The motor of the craft was shut off, and the boat drifted up to the shore.

"What do you want?" demanded one of the men on board, sharply.

"We want help, and we want it right away!" declared Fred. And then he added as he got a better view of those aboard the boat: "Are you United States officers?"

"What do you want to know that for?" was the counter question.

"Well, if you are, we want your help, and want it right away."

"Why? Have you discovered anything unusual?" demanded one of the officers on the boat, and his manner showed his intense interest.

"We certainly have! And more than that, we have made a prisoner—a German."

"You don't mean it!" said one of the other men aboard the motor boat, and then looked more sharply at Fred than ever. "We'll have to investigate this," he added to his companions.

There were three officers and a crew of eight aboard the boat, which was quickly brought long-side the rock on which Fred was standing. As the officers leaped ashore, the young lieutenant saluted and was saluted in return. Then Fred told who he was and again asked the men if they were United States officers.

"If you've got a German prisoner, and you know he is really a German sympathizer, you had better take us to him at once," said one of the men, and, turning back his coat, he exhibited his badge.

Feeling that the craft was one really belonging to our government and that the officers were Secret Service men, Fred told his story, at the same time leading the way to where he had left Jack, Gif, and the prisoner.

"Bailey was right, after all," said one of the Secret Service men to his fellow officers. "He always declared that that wrecked submarine was in hiding somewhere around these waters."

"Then you know about the submarine?" queried Fred quickly.

"If it's the craft we think it is," was the reply. "That U-boat had an encounter with one of our submarine destroyers, and in trying to escape we think she hit some of the rocks on the reef beyond here. Some of the naval people were of the opinion that she had gone down, but others thought she had escaped to some base, which, of course, was unknown to our authorities. We have always had a suspicion that there was some sort of a base around here. We were cruising to-day trying to locate it."

It was decided that the Secret Service men should take charge of matters, and that they would sail to the nearest town on the bay so that they might obtain additional help with which to round up all the Germans and those in league with them.

"This will prove a very important capture," said Mr. Blarcomb, who was the head officer of the crowd. "And you, young men, can rest assured that you will get full credit for what you have done."

"If you don't mind, I wish you would drop us off at our camp," said Jack. "It will save us a whole lot of tramping."

"We'll do that willingly."

It did not take the motor boat long to cover the distance to the front of the camp where the cadets were in the habit of bathing. A few were now in the water, and they looked in wonder at the sudden appearance of the Rovers and Gif.

"There is Captain Dale now!" cried Jack, when they had landed and the motor boat had gone on its way. "My! won't he be surprised at the story we have to tell?"

"Maybe he has already heard it, from Andy and Randy and Spouter," suggested Gif.

But the old West Pointer had heard nothing, for the others had not yet come in from the forest. He listened in amazement to the story the boys had to tell.

"I would like to be at that round-up myself," he declared. "I trust that they capture every one of the rascals." And then he added with a smile: "This is certainly a feather in your caps, lads."

It was only a little later when the twins and Spouter came in. They, of course, were also excited.

"Got one of the Germans and got the Secret Service men on the trail!" declared Fred proudly.

"Good enough!" cried Andy. "But say! we have got our little story to tell, too;" and then he and the others related what had been discovered at the cabin in the woods.

"This certainly is important," declared Captain Dale. "Who would ever suppose that Mr. Brown and Mr. Martell were in league with these Germans! They certainly ought to be captured."

"And I'd like to be there when they are caught," declared Randy.

"Well, perhaps you will be," answered Captain Dale significantly.



CHAPTER XXX

AN IMPORTANT CAPTURE—CONCLUSION

Even though somewhat old and likewise rheumatic, Captain Dale was still a man of action, and less than half an hour later he had perfected an arrangement with the Secret Service authorities both at Rackville and at Camp Huxwell. Three automobiles were requisitioned and a detail of sixteen men, accompanied by several Secret Service authorities soon left Camp Huxwell, stopping on the way at the edge of Camp Barlight. They took on board the Rovers and their chums, and likewise Captain Dale, all of whom were anxious to see the wind-up of this remarkable happening.

While still some distance from the cabin, the automobiles were brought to a standstill, and the officers and soldiers, as well as the cadets and Captain Dale, alighted, and all took to the shelter of the brushwood.

A wait of nearly half an hour ensued, and during that time the three automobiles were run deep into the woods, where they would not be noticed by any passersby. Then Randy, who had been sent down the road, came back on the run.

"An auto is coming!" he announced.

He was right, and a minute later, the machine, driven by Slugger Brown, came into sight and ran up to the side of the cabin. Mr. Brown and Mr. Martell alighted, leaving Slugger and Nappy in the car as before.

"Don't let 'em keep you here all night, Dad!" cried Nappy.

"Make 'em come to terms quick," said Slugger. "They have no right to hold back on you."

"You leave this business to us—we know what we are doing," answered Mr. Brown.

Of course, those who had come to the place from the two camps had not shown themselves. All were secreted behind the trees and bushes on the opposite side of the cabin. Now they watched intently while Mr. Brown and Mr. Martell entered the cabin, and as they did this they noted a steady put-put on the forest road, and soon a motorcycle came into sight, ridden by a middle-aged man carrying a satchel over his shoulder.

"That must be the fellow who went to the bank to get the money," whispered Andy.

The Secret Service men had arranged their plans with care. At a given signal four of the soldiers from Camp Huxwell surrounded the automobile occupied by Slugger and Nappy, who as before were making themselves comfortable in the tonneau and smoking cigarettes. To say that those two unworthies were surprised, would be putting it mildly. Slugger leaped to his feet in amazement, while Nappy set up a howl of terror, begging the soldiers not to shoot them.

"We haven't done anything wrong!" howled Nappy. "Please don't point that gun at me!"

"I don't understand this," said Slugger nervously. "There must be some mistake."

"The only mistake is the one you made, young man," declared one of the soldiers briefly.

In the meantime there was an interesting scene going on in the main room of the cabin. The German in charge of the place and the fellow who had come in on the motorcycle were talking earnestly to Slogwell Brown and Nelson Martell. The men from New York had a number of documents on a table, and were trying to prove that the Germans owed them over eleven thousand dollars, while the Germans were equally emphatic in declaring that the amount due was less than ten thousand dollars.

"You've got to pay the full amount," growled Mr. Brown. "I won't take off a cent!"

"That's the talk!" broke in Mr. Martell. "And you ought not to kick, either. We have taken terrible chances in having these things supplied to you."

"Yes, and don't forget that you would never have had this secret base on Barlight Bay if it hadn't been for me," put in Slogwell Brown.

"We're not forgetting anything," said one of the Germans. "And if you insist upon it that we owe you that amount, we will pay it."

The man who had come in on the motorcycle had opened his valise, and now he took out several packages of banknotes. Evidently Brown and Martell were to be paid in cash. Probably they had refused to accept anything in the way of a check.

The money had just been paid over and some receipts given when the leader of the Secret Service men gave the order, and the cabin was immediately surrounded.

"Hands up in there, everybody!" was the stern command.

If Slugger and Nappy had been surprised, their fathers were even more so, while the two Germans were taken completely off their guard. Each of the latter was armed, but one look at the United States officers with their pistols and the soldiers with their rifles was too much for them, and with grunts of disgust they threw their hands into the air.

"Who—what—I—er—I don't understand this," stammered Slogwell Brown, turning pale.

"There—there—must be—er—some mistake," faltered Nelson Martell, and then with shaking knees he sank slowly back on a bench.

A brief war of words followed, Brown and Martell doing everything they could think of to explain the situation so that they might not be placed under arrest. But their guilt was so bare-faced that the government officers would hardly listen to them. Both they and the Germans were searched and all their weapons were taken from them. Then the prisoners were handcuffed together, and the officers made a thorough search of the cabin, picking up everything it contained of value. One took charge of the documents found and also the money which had been passed over to Mr. Brown.

"A fine piece of business for a so-called American to be in!" said the head Secret Service man to Brown and Martell sternly. "I wouldn't be in your shoes for a billion dollars."

"It's—it's—all a mistake. I'll—er—explain everything later," said Slogwell Brown weakly.

As for Nelson Martell, he was on the verge of a collapse, and had to be supported when all left the cabin.

In the meanwhile other interesting happenings were taking place in the vicinity of the wrecked submarine. There a number of Secret Service men and other officers of the law under the leadership of Mr. Blarcomb, did what they could to round up all those connected with the U-boat. There was something of a running fight, and quite a few shots were exchanged. In this fight two of the Germans were seriously wounded, and one of the Secret Service men got a bullet through his shoulder. But in the end all of the enemy were captured, and then the authorities took charge of the disabled submarine, and also the underground workshop, where the Germans had been laboring so hard to get their undersea boat once more into shape to sail.

It was after midnight before all these happenings came to an end and the evildoers had either been placed in jail or under a strong military guard. The capture, of course, was kept as secret as possible by the government officials.

"And to think that the fathers of Nappy Martell and Slugger Brown are guilty!" cried Ruth Stevenson, when Jack met her later on and told her some of the particulars. "Isn't it dreadful? What will they do with them?"

"Most likely they will be interned for the period of the war, and maybe they will get regular jail sentences," answered the young captain.

"And what will they do with Nappy and Slugger?"

"Oh, they will probably be interned also."

After the men at the cabin in the forest and the Germans from the wrecked submarine had been rounded up, Jed Kessler was called in, and without hesitation he recognized two of the men he had seen at the ammunition plant just before the explosion occurred. One fellow was a clean-shaven man, but it was proved that he was in the habit of wearing a heavy wig and a heavy false beard.

"That fellow is one of the two we saw in New York talking to Mr. Brown and Mr. Martell!" cried Randy. And he was right, as it afterwards proved.

For catching these two men who, it was later proved, had caused the wreckage at the ammunition plant, the reward offered was divided equally between Jed Kessler, the four Rovers and Gif and Spouter, much to their satisfaction.

"This gives each of us a very neat bank account," declared Spouter. "I'm going to save most of it, but some of it I'll spend this summer on my vacation."

"Maybe we'll all do that," put in Andy.

From the authorities it was learned that Slogwell Brown had owned a large portion of the shore front lying between Camp Huxwell and Camp Barlight. He had sold all his holdings to the government, but this had not prevented the unscrupulous man from making a deal with some German agents for the use of the cave under the cliff by our country's enemies.

"He was a rascal both ways," declared Captain Dale, in talking the matter over with the Rovers. "He took the government's money at one end and the Germans' money at the other. It is right that he goes to jail."

And to jail Slogwell Brown went, accompanied by Nelson Martell, each to serve a number of years at hard labor. Slugger and Nappy were sent to a detention camp in the South; and that for the time being was the last the Rovers heard of them.

Although there was considerable excitement around the encampment caused by the discovery of the German submarine base, the cadets were not allowed to forego their drilling and their army maneuvers. Nor did they give up the athletic contests they had promised themselves. There were swimming races and boat races, and likewise several baseball matches, and also contests in running, high and broad jumping, and in a tug-of-war.

"I'll tell you one thing—this encampment is one long to be remembered," remarked Jack, when the outing had almost come to an end.

The next day came a message from Camp Huxwell. The fathers of the Rovers, as well as many of their friends, were to depart immediately for Hoboken, there to take one of the big transports for France. Of course, the boys, as well as their sisters and their mothers, went to see Dick, Tom, and Sam Rover off.

"The best of luck to you, Dad!" cried Jack, when the time came for parting. "I hope you make a good record for yourselves."

"You can rest assured, Son, we will do our best," answered Dick Rover.

Then there were numerous handshakes, the waving of handkerchiefs, and while the girls and the women were trying hard to smile and to keep back the tears, the soldiers departed on the train.

"Gee, I wish I was going along!" sighed Fred. But this, of course, could not be, for all the boys were much too young to join the army.

By leaving Camp Barlight that day the Rovers had missed one of the important baseball games, but for this they did not care. They tried to join in the festivities that evening, but it was a failure. Their thoughts were with their fathers. Would they come back from the war in safety?

"All we can do is to hope for the best," remarked Randy; and there the matter was allowed to rest.

Of course, the boys were eager for news concerning the Browns and the Martells, and also the Germans who had been captured, and they eagerly devoured every shred of information that came their way.

"Well, one thing is certain—we are well rid of Slugger and Nappy and their fathers," remarked Jack.

"Yes, and I guess we are rid of Gabe Werner, too," returned Fred. "He seems to have dropped out entirely."

But in his remark concerning Werner the young lieutenant was mistaken. Gabe Werner turned up in their path most unexpectedly, and how will be related in the next volume in this series, to be entitled "The Rover Boys on a Hunt; or, The Mysterious House in the Woods."

In that volume we shall learn what the Rover boys did on a most important outing, and also learn something of what happened to their fathers while fighting on the great battlefields of France.

"Well, boys, I've got pretty good news to-day," remarked Randy, rushing into the camp one afternoon and holding up a letter. "Mr. Powell has invited all of us to spend ten days or two weeks at his camp on Lake George this summer. May is going to have all the girls there, including Mary and Martha and Ruth, and Mr. Powell wants every one of us to come up and take part in the good times."

"Gee, that suits me right to the top of the flagstaff!" burst out his twin brother. And then, in high spirits, Andy turned several flipflaps, and ended by beginning a wrestling match with Fred.

"Well, we'll be there, all right enough!" cried Jack.

"Will we?" came from Fred. "Just wait and see!"

Then the drums rattled, and the young captain and the young lieutenant, followed by the others, rushed off to get ready for the evening roll call and parade. And here, for the time being, we will leave the Rover boys and say good-bye.

THE END

* * * * *

WESTERN STORIES FOR BOYS

By JAMES CODY FERRIS

Each Volume Complete in Itself.

Thrilling tales of the great west, told primarily for boys but which will be read by all who love mystery, rapid action, and adventures in the great open spaces.

The Manly boys, Roy and Teddy, are the sons of an old ranchman, the owner of many thousands of heads of cattle. The lads know how to ride, how to shoot, and how to take care of themselves under any and all circumstances.

The cowboys of the X Bar X Ranch are real cowboys, on the job when required, but full of fun and daring—a bunch any reader will be delighted to know.

THE X BAR X BOYS ON THE RANCH THE X BAR X BOYS IN THUNDER CANYON THE X BAR X BOYS ON WHIRLPOOL RIVER THE X BAR X BOYS ON BIG BISON TRAIL THE X BAR X BOYS AT THE ROUND-UP THE X BAR X BOYS AT NUGGET CAMP THE X BAR X BOYS AT RUSTLER'S GAP THE X BAR X BOYS AT GRIZZLY PASS THE X BAR X BOYS LOST IN THE ROCKIES THE X BAR X BOYS RIDING FOR LIFE THE X BAR X BOYS IN SMOKY VALLEY

* * * * *

THE HARDY BOYS SERIES

By FRANKLIN W. DIXON

Illustrated. Every Volume Complete in Itself

The Hardy Boys are sons of a celebrated American detective, and during vacations and their off time from school they help their father by hunting down clues themselves.

THE TOWER TREASURE—A dying criminal confessed that his loot had been secreted "in the tower." It remained for the Hardy Boys to clear up the mystery.

THE HOUSE ON THE CLIFF—Mr. Hardy started to investigate—and disappeared! An odd tale, with plenty of excitement.

THE SECRET OF THE OLD MILL—Counterfeit money was in circulation, and the limit was reached when Mrs. Hardy took some from a stranger. A tale full of thrills.

THE MISSING CHUMS—Two of the Hardy Boys' chums disappear and are almost rescued by their friends when all are captured. A thrilling story of adventure.

HUNTING FOR HIDDEN GOLD—in tracing some stolen gold the trail leads the boys to an abandoned mine, and there things start to happen.

THE SHORE ROAD MYSTERY—Automobiles were disappearing most mysteriously from the Shore Road. It remained for the Hardy Boys to solve the mystery.

THE SECRET OF THE CAVES—When the boys reached the caves they came unexpectedly upon a queer old hermit.

THE MYSTERY OF CABIN ISLAND—A story of queer adventures on a rockbound island.

THE GREAT AIRPORT MYSTERY—The Hardy Boys solve the mystery of the disappearance of some valuable mail.

WHAT HAPPENED AT MIDNIGHT—The boys follow a trail that ends in a strange and exciting situation.

WHILE THE CLOCK TICKED—The Hardy Boys aid in vindicating a man who has been wrongly accused of a crime.

FOOTPRINTS UNDER THE WINDOW—The Smuggling of Chinese into this country is the basis of this story in which the boys find thrills and excitement aplenty.

* * * * *

TED SCOTT FLYING STORIES

By FRANKLIN W. DIXON

Illustrated. Each Volume Complete in Itself.

No subject has so thoroughly caught the imagination of young America as aviation. This series has been inspired by recent daring feats of the air, and is dedicated to Lindbergh, Byrd, Chamberlin and other heroes of the skies.

OVER THE OCEAN TO PARIS; or, Ted Scott's Daring Long Distance Flight.

RESCUED IN THE CLOUDS; or, Ted Scott, Hero of the Air.

OVER THE ROCKIES WITH THE AIR MAIL; or, Ted Scott Lost in the Wilderness.

FIRST STOP HONOLULU; or, Ted Scott Over the Pacific.

THE SEARCH FOR THE LOST FLYERS; or, Ted Scott Over the West Indies.

SOUTH OF THE RIO GRANDE; or, Ted Scott On a Secret Mission.

ACROSS THE PACIFIC; or, Ted Scott's Hop to Australia.

THE LONE EAGLE OF THE BORDER; or, Ted Scott and the Diamond Smugglers.

FLYING AGAINST TIME; or, Breaking the Ocean to Ocean Record.

OVER THE JUNGLE TRAILS; or, Ted Scott and the Missing Explorers.

LOST AT THE SOUTH POLE; or, Ted Scott in Blizzard Land.

THROUGH THE AIR TO ALASKA; or, Ted Scott's Search in Nugget Valley.

FLYING TO THE RESCUE; or, Ted Scott and the Big Dirigible.

DANGER TRAILS OF THE SKY; or, Ted Scott's Great Mountain Climb.

FOLLOWING THE SUN SHADOW; or, Ted Scott and the Great Eclipse.

BATTLING THE WIND; or, Ted Scott Flying Around Cape Horn.

GROSSET & DUNLAP, PUBLISHERS, NEW YORK

THE END