While the boys had been watching, Barton had lain down, as though tired, on the summit of a near-by dune. As the red light came close in shore, however, he arose, and once more waved his lantern.

At the signal the course of the red light shifted and headed directly toward him. The boys' hearts beat thickly; the time for action was at hand. The bow of the boat they had seen approaching grated on the beach, and two figures sprang out while Barton advanced to meet them.

"Get as close as you can," whispered Rob, as he wriggled forward; "we want to get every word."

Merritt merely nodded; but his silent advance was as rapid as his leader's. Owing to the nature of the ground, they were able to run forward in an almost upright position when they reached the hollows of the dunes, being compelled to cast themselves down only when they topped a rise. Therefore, they were within ear shot when Barton greeted the two men who had disembarked from the boat.

"Well," said one of the newcomers in a voice which plainly betrayed his foreign origin; "well, did you do as you said you would?"

"Yes," responded Barton; "I've got the drawings here. They are not complete, however, and you will have to give me more time."

"As you were told at Bridgeport, before you left for this island, you can have all the time you want, only make the job complete."

"You can depend upon me to do that," was the response. "So long as I'm well paid, I'll sell out all I know, and that's about everything about the Barr submarine."

Here another voice, that of the second man who had left the boat, struck in:

"What about the models?"

"I've got them hidden up here in the sand," came Barton's voice in reply. "I'd have had them ready but two blooming kids trailed me here."

"Trailed you? What do you mean?" demanded the voice of the man who had first spoken and who, with the solitary exception noted, had carried on most of the conversation.

"Why, this Ensign Hargreaves, this Navy dude, saw fit to bring a band of Boy Scouts down here. They're the nosiest kids ever, and I half think they suspect me of not being all I appear to be."

"That's a good guess," whispered Rob to Merritt.

Merritt could not refrain from a quiet chuckle.

"As a long distance and local guesser, Barton takes the palm," he breathed.

"Hush!" murmured Rob under his breath: "What are they up to now?"

"Going to dig up those models, I guess. Barton must have stolen them from the workshop at odd moments."

Right then something happened that gave Merritt a shock. Rob rose to his feet and started toward the beach. The men that the two Boy Scouts were watching had headed inland, evidently to aid Barton in uncovering the hidden models.

"Have you gone crazy, Rob? Lie down here," cautioned Merritt.

"Not much," was the response; "I'm going to do some reconnoitering while I've got the chance."

"What do you mean?"

"That I'm going down to have a look at that boat, and if I can I'm going to shove her off and thus leave those men prisoners on the island."

"By ginger, Rob, you are a great fellow for ideas. If only you can cast the boat adrift, we'll have those chaps bottled up as securely as if they were in a jail."

"Wait here till I come," responded the boy leader. "I won't be gone more than ten minutes."

"I'd like to come with you, Rob."

"No; this is a job I can do best alone."

Rob noiselessly slipped away. The boat from which the mysterious men had landed was plainly discernible as a black blot on the sandy beach. Rob tried to make himself as inconspicuous as possible, but against the white strip of sand he felt as noticeable as an elephant. However, he gained the boat without interruption.

Its bow had been built up, apparently, to make it more seaworthy, and the boy noticed that a small door had been cut leading into the space beneath the raised bow. He had hardly discovered this when he was startled to hear voices close at hand.

It was Barton and his crooked accomplices coming back. Fortunately for Rob, they were behind a dune, so that it was impossible for them to observe him. But in a moment, the boy realized with a thrill, they would be upon him.

Quick as a flash, and hardly realizing what he was doing, Rob sought the only place of concealment close at hand – the space under the raised bow of the boat. He had hardly squeezed into his cramped quarters before the trio of rascals topped the rise.

Rob, with a sinking of the heart, realized at that moment that it would have been better for him to have taken his chances and run away from the scene. But it was too late now. With something that was not exactly fear, but very like it, Rob recognized the fact that he was a concealed passenger, a stowaway, on board a boat on which his presence might cost him his life.

As these reflections ran through his mind the men drew closer, talking about the "clever" work they had done.

"I guess Barr and his Peacemaker can say good-bye to Uncle Sam now," laughed one of them.

"Yes, and the best of it is that Barton will never be suspected," responded the other. "Our government will be manufacturing submarines of the Barr type, while Barr and the United States Government are still in blissful ignorance of the fact that all efforts are for nothing."

"You can bet I never put through a job unless I do it right," struck in Barton with great self-complacency.

Rob, crouched in his cramped place of concealment, flushed with anger. Right then and there he determined that, come what might, he would see this strange adventure of his through to the bitter end. This resolve was still in his mind when the two men shoved the boat off, bade good-night to the rascally Barton, and, all unconscious of their secreted passenger, got under way.

"If I get out of this alive, I'll be lucky," soliloquized Rob as he heard the oars and felt the boat moving through the water. "I wonder if I've done right? At any rate I'm in it now, and, as a Boy Scout, I'm going to see it through."

CHAPTER XVIII.
THE ISLAND HUT

Rob, in his place of concealment, could hear the two men talking as they rowed.

Their conversation related, in the main, to the affairs of the night. Apparently, so far as Rob could gather, the stealing of the plans of the submarine was not yet complete. It appeared that Barton was to remain on the island in his capacity as trusted aide to Mr. Barr, and to gather up all he could of the details of the new submarine, down to the smallest particular.

Scarcely daring to breathe, Rob listened with all his might to the conversation of the oarsmen.

At the same time the thought was running through his mind that he had acted rashly in taking the step he had. But the boy pluckily made up his mind to stick to his resolution of discovering just what was going on inimical to the plans of the United States Government and Mr. Barr.

Before very long the prow of the boat grated on a sandy beach, and the two men, gathering up some rolls of paper and several bulky-looking objects, left the craft, first securing it by an anchor and line.

As their footsteps died away, Rob ventured to raise his head above the gunwale of the boat and follow them with his eyes. He saw them ascend the beach and enter the hut, apparently a structure once used by fishermen or hunters.

After an interval a light shone from the solitary window of the hut, and Rob came to a sudden resolve to find out just what was going forward. With this object in view he clambered out of the boat, taking every precaution against making unnecessary noise. On hands and knees he then approached the lighted window.

The night was dark, and, standing at a fair distance from the casement, he did not feel much fear of being seen from within. It is hard for persons in a brightly lighted chamber to perceive what is going on outside.

Seated around a rough table in the hut, which consisted of only one room, Rob saw three men. Two of them, undoubtedly, were those who had unconsciously rowed him to the island. The other he recognized with a start as the possessor of the face which had peered through the transom on the memorable night in Hampton, when plans for the experiments on the island were in process of being formulated. In other words, the third member of the party was none other than Nordstrom Berghoff, the spy.

Instantly many things that had been vague to Rob crystallized into a clear understanding of the situation. The signals from the island, the indignation of Barton over the presence of the Boy Scouts, and the stealing of the plans and models, all stood out plainly now as being part of an elaborate plot of which Berghoff was the mainspring.

A wave of indignation swept over the boy as he contemplated the rascals within the hut gloating over the things they had obtained from the treacherous Barton.

"The scoundrels," he thought; "so they think they can rob Uncle Sam of one of the greatest submarines ever invented, and do so with impunity! I don't care what happens, I'll fool them if I can."

With this resolve firmly embedded in his mind, Rob crept closer to the window. By skillful maneuvering he was at last almost under the casement. In this position every word uttered within the hut was clear to him.

He heard Berghoff chuckling gleefully over the manner in which the night's work had been carried out.

"Undt not a vun of dose Boy Scouts knew anting aboudt idt," he exclaimed.

"No," rejoined one of his companions, a swarthy man with a pallid face on which there stood out a bristly beard; "those kids were out of the game so far as we were concerned. That Barton is a slick one, all right."

"Well, he's getting well paid for the job," struck in the third man, who was short and stocky, with a crop of rough, reddish hair and a protruding chin that gave him a "bull doggy" aspect.

"Of course, he gedts vell paid," rejoined Berghoff; "dis job is vorth de naval supremacy of the worldt to der country vot I represent."

"As if we didn't know that as well as you," rejoined the red-haired man. "It was lucky we worked in the same machine shop in Bridgeport with Barton and knew he was a man who could be bought."

"Yes, there isn't much that he wouldn't do for money," chimed in the pallid-faced man.

"Vell, ledt us see if dese plans are all righdt, or if ve must get some more of dem," remarked Berghoff.

From his manner of examining the intricate prints and plans, Rob knew that the man, as were most probably his two companions, was an engineer of no mean ability. With a small pocket scale he went over every scrap of paper and then fell to examining the models. From his expression, Rob judged that Barton had served the rascal well. Berghoff declared the plans and the models all that would be required to produce a Peacemaker almost the exact duplicate of Mr. Barr's diving-boat.

"Well, when do we make our getaway?" queried the red-haired man when the examination was concluded.

"To-morrow ve go," declared Berghoff. "In New York I catch der steamer for Europe undt you two scatter verefer you like."

Rob felt his face flush with indignation, and at the same time he experienced a sort of hopeless feeling of indecision. The plans and the models lay there, almost within his reach, but so far as the possibility of recovering them was concerned, they might as well have been in China.

"If only all the boys were here," he thought, "it would be possible to 'rush' those scoundrels and secure all their loot."

Finally Rob came to the decision to remain where he was for the present and see if some opportunity would not present itself to recover the articles of such vital importance to Uncle Sam's Government.

The men talked on, conversing in low tones, and presently the red-headed man started to prepare some food on an oil stove, which must have been brought from the motor boat earlier in the day. Till sundry appetizing odors began to drift out to him from the plotter's cookery, Rob did not realize that he was hungry. Before long, however, his desire for food became almost overwhelming. It was tantalizing to lie out there in the dark, tired and hungry, and hear within the hut the clatter of knives and forks and inhale the odors of what was evidently a hearty meal.

At length the men stopped eating, and Rob heard them discussing whether they should sleep in the hut or on board their motor boat. The boy pricked up his ears as he listened. If only they decided to sleep on the boat and leave the models and plans in the hut, he would have a chance to recover the stolen property and make away with it in the beached rowboat before dawn.

Rob could hardly restrain an exclamation of delight when the men came to the decision to pass the night on their boat.

"What are you going to do with this stuff?" inquired the pallid-faced man with the stubbly beard, indicating the mass of papers and models.

"Oh, we'll leave that here till morning," was Berghoff's response; "dere is no use in taking idt by der boat now."

"Goodness," thought Rob, "I sure am in luck! It will be no trick at all to get that stuff as soon as they have gone, and carry it back to the island. I almost wish it was going to be a harder task. It's a bit too much like burglary to suit me."

But Rob was not to have such an easy time of it as he anticipated.

CHAPTER XIX.
A CHASE IN THE NIGHT

The men left the hut, banging the door behind them. Rob waited till the sound of their voices grew dim in the distance, and then raising himself cautiously he crept around to the door of the hut.

The light had been extinguished, but as the boy had matches in his waterproof case this fact did not worry him. Pushing the door open Rob entered the place. Before striking a light he did all he could to assure himself that he was not likely to be interrupted by the sudden return of the men.

Having established to his satisfaction that he was safe, which was not until he perceived a light on the motor boat, which lay not far from the hut, he proceeded to light up the lantern the men had left behind.

Anxious not to lose any time on his risky task, he began stuffing papers and plans into his pockets at once. The models, or most of them, he decided he would have to convey to the boat in his arms.

He had hardly completed the task of stowing the papers in his pockets, when he was startled at hearing footsteps coming toward the hut. Hastily he extinguished the light, uttering an inward prayer that it had not been seen. Luckily for himself he had taken the precaution of closing the door as soon as he had the lantern lighted.

Just before extinguishing the lamp, he had gazed about the place for some spot of concealment. But the hut, as has been said, was a crude affair, and no closets or cupboards presented a chance of hiding. The only thing that Rob could think of to do was to slip under the table and trust to a miracle that he would not be discovered. Hardly had he carried out his intention when the door opened and two men entered.

They were the red-headed man and the pallid-faced individual, who appeared to act as assistants to Berghoff. At any rate, judging by their accents, they were foreigners.

Rob had placed the lantern on the table in a position as much resembling that in which the men had left it as he could. He heard a match scratched and then the sputter of the flame.

"Don't see why Berghoff sent us back to get that stuff," grumbled one of the men angrily; "it's as safe here as it would be anywhere."

"Well, as we're getting good pay fer this job, we might as well obey orders," was the reply.

"Gee whillakers!" came a sudden exclamation from the man who had attempted to light the lantern.

"What's up?" asked the other.

"Why, the plagued thing is red hot!"

"Red hot?" exclaimed his companion in tones of amazement. "How can that be when it's a good half hour since we put it out?"

"Dunno, but it burned my fingers, all right."

"Say, Mike, do you think anyone has been here since we left?"

"Who could have been here? And yet, come to think of it, it's blamed queer. Tell you what we'll do."

"What?"

"Search this place. It won't take long."

"Good for you," rejoined the other, while Rob quaked in his place of concealment.

"There ain't many nooks or crannies, so the job won't take long."

"That's right. We'll begin by looking under the table – Jeehosophat!"

The sudden exclamation was caused by Rob's suddenly springing up, upsetting the table and planting his fist full in the fellow's face. The lantern was dropped in the excitement and the hut was plunged in darkness. Rob had come to his sudden decision to act as he did as the only way to escape the men.

For a time it looked as if he would be successful. Dashing past the man who remained on his feet he made for the direction in which he knew the door lay. In fact, as the men had not closed it, he had no difficulty in locating it by the starlight outside.

"Hey! Stop! Stop!" roared the fellow behind him.

Rob sped on like the wind, using every ounce of running ability he possessed. Straight for the beach he made, devoting all his energies to a swiftly formed plan to get into the beached boat and row to safety. It was a desperate plan, but he had no other resources.

He was within a few yards of the beach when a dark form loomed suddenly before him. In the starlight Rob saw something glittering in the newcomer's hand. This object was leveled at him, and a stern voice commanded him to stop or be shot.

Rob, with a throbbing heart, pulled up. He recognized the voice as that of Berghoff and knew that if he did not obey the order the desperate ruffian would have no hesitation in sending a bullet into him.

Berghoff, who had been aroused by the cries of his aides when Rob escaped from the hut, came up to the lad, keeping him covered with his wicked-looking "gun."

"Who are you? What you doing here?" he demanded sternly.

The next moment, and before Rob could reply, the fellow noted the Boy Scout uniform.

"Oh, ho!" he exclaimed in a malignant tone. "So you are one of dose Boy Scouts, eh? You think you pretty smart, eh? You vait. I may make you pay for your fun."

There was a cold sort of malice in the man's way of speaking that actually sent a chill down Rob's spine.

But he plucked up courage to make a bold reply.

"I know the sort of illegal trafficking you are engaged in, Berghoff," he said boldly, "and I tell you, you had better leave me alone."

"Is dot so?" sneered the fellow. "You haven't seen the last of me for a long time yet."

"My friends will punish you for this," exclaimed Rob, in as confident a tone as he could assume.

"It vill be a long time alretty before you see your friendts again," jeered the other. "Ah, here comes Mike and Gyp, now. Now ve findt out what you vos doing up by der hut."

As the spy had said, the two men who had been in the hut came up at the moment.

Berghoff instantly demanded to know what had occurred in the hut.

"By gosh, cap," said the red-headed man who, it seemed, was "Mike," "it happened so sudden I can hardly tell you. We goes up there to get them papers as you told us, and the first thing you know out jumps this young catamount and hits me a swat on the jaw that 'most put me out fer the count."

"That's right," corroborated his companion; "that's just what he done, cap."

"How did he get here?" demanded Berghoff angrily.

"Dunno, unless he flew," rejoined Mike helplessly. "Hadn't we better search the young varmint and see what he's got in his pockets?"

"Yes, you had better search him at once."

"My last chance has gone," thought Rob as the two fellows seized him roughly and began rummaging his pockets.

It would have been worse than useless to resist, so Rob submitted to the search, while Berghoff stood looking grimly on as the papers were extracted from his pockets by the two ruffians.

"If only I'd hurried a little more," thought Rob to himself bitterly. "If only I'd hurried, I'd not have been in this predicament now."

"So you almost got avay mit vot you came after," exclaimed Berghoff as the last of the papers was removed from Rob's pockets and handed over to the spy; "it voss an inspiration dot made me send my men back by der huts."

"What will we do with the kid?" asked the man known as Mike.

"I don't know yet," was the rejoinder in a harsh voice. "Ve ought to throw him in der sea. He knows too much aboudt us."

"That's right, cap," came from Gyp, the pallid-faced man, "it's just as Barton told us, these blamed Boy Scouts are on to us."

"Vell, it don't be goodt to get ridt of him righdt now. Better bring him aboard the boat."

"All right, cap. Come on, you young sneak!" said the man known as Mike.

He gave Rob's arm a vicious twist, and with one of the men on either side of him, and Berghoff walking close behind with the revolver, there was no recourse for Rob but to accept the situation as it came. But in mind he was casting about desperately for a means of escape. None had occurred to him by the time they reached the motor boat, which was moored at a tumble-down wharf, or jetty.

The motor boat proved to be a sixty-foot affair, with a cabin amidships. Into this Rob was gruffly ordered.

"Get aboard now, and look slippy about it," was Mike's way of urging the Boy Scout on board the craft.

Rob obeyed the order with a sinking heart Things looked about as black as they could be, so even his optimistic nature was compelled to admit.