Jack was the first to recover from the shock.

“I don’t believe it,” he declared stoutly.

“It would have been like their knavery to pull off just such a trick, though,” struck in Tom; “what do you think, captain?”

“Just this, that a bird in the hand is worth two in the bush,” declared the stout old seaman. “Maybe they did land the model in the night; but in that case what are they doing away down the coast? And again, even if they did land it, I propose to keep on their heels till we bring them to justice.”

The seaman’s words put new heart into the boys, and instead of slackening in their pursuit, they kept up the Sea Gull’s speed which, do what they could, was slightly slower than the speedy Tarpon’s. About an hour after the hail from the Tarpon’s after-deck had come, the craft ahead suddenly changed her course.

“They’re heading in toward land,” cried Jack excitedly.

“Yes; I guess they realize that they can’t shake us and are going to land and make a run for it,” decided Captain Andrews. “Great sea serpents, but they are putting on speed!”

The Tarpon certainly was flying. Great jets of spray shot up on each side of her bow, and the roar of her motor could be heard like the incessant discharge of a whole battery of gatling guns.

Jack sprang down to Tom’s side at the Sea Gull’s engine. He tinkered with the carburetor and speeded up both spark and gasolene supply. Like an arrow from a bow the Sea Gull sprang forward gallantly. Every timber in her shook under the vibration. But like a greyhound after a rabbit, she hung tenaciously in the wake of the Tarpon.

It was a marine race, filled with the keenest excitement. Jack’s heart pounded. The blood rushed hotly through his veins. With burning eyes he straightened up from the engine and gazed ahead. The distance between the two crafts was still the same, the Tarpon maintaining her lead.

“Can’t you get any more speed out of her?” almost groaned Captain Andrews. “If once they reach that coast and land, we’ll have a tough job getting them again.”

“I’m afraid that I can’t do any more with the motor,” responded Jack; “it’s heating up now, and if I force it any more it may stick altogether.”

The coast toward which both boats were heading at racing speed was a wild and desolate-looking stretch of beach, with cliffs towering up to some height from a rocky base, and pine woods and hills on top.

“Like as not old Flinders knows just where he is heading for,” said Captain Andrews, with some uneasiness; “but I don’t like the look of this at all. See those rocks and that shoal water all about us. We may run aground any minute, and at this speed that would mean ‘good-bye, Sea Gull.’”

Jack nodded. He fully saw the dangers of navigation so close to that rocky coast. But Captain Flinders seemed to have no fears. He kept right on without reducing speed, dodging in and out of shoals incessantly. Captain Andrews, with his heart fairly in his mouth for the safety of his craft, followed his every move. He knew that the Tarpon drew more water than his craft, and that where Captain Flinders could go with safety he could follow.

The chase through the watery maze kept up for an hour or more, and then, so far as the Sea Gull was concerned, it came to a disastrous conclusion. Without the slightest warning Captain Andrews’ craft rammed her nose at full speed into a sand bank, and at the same moment the boys and the captain were thrown flat on their backs. Tom was up in a jiffy and shut off the engine. The others were as quick in recovering themselves. But alas for the Sea Gull! Her nose was jammed hard into the sand, and although the engine was reversed and run at full power, it could not move her.

“Well, if the bad luck isn’t holding out to the end!” exclaimed Tom despairingly; “what on earth can we do now?”

“What, indeed?” echoed Jack. “I guess that they win this time.”

“What, giving up already?” exclaimed Captain Andrews. “Why, boys, there’s lots of luck left. I see that the tide is rising. That’s lucky, for it means that at high water we can get the Sea Gull off. In the meantime I’ve got a plan.”

Both boys hung eagerly on his next words. “We’ll take the dinghy and row ashore. It can’t be so very far to some village or town where we can summon the authorities. That will give us a chance to land those miscreants yet.”

“It seems about all there is left to do,” said Tom, who didn’t seem to be very much impressed with the plan.

“Hello, the Tarpon’s dropped her anchor,” exclaimed Jack, pointing to the other craft, which had come to a standstill about five hundred yards off.

“Then there’s no time to lose in getting ashore,” declared Captain Andrews; “we’ve got to beat them to it. Come on, lads, help me get the dinghy over.”

The dinghy referred to was a small, light flat-bottomed boat, carried athwart the stern of the Sea Gull. It took but a short time to get her overboard. In the meantime Jack had dived into the cabin, leaving the task of lowering the small boat to his two companions.

“Come in here,” he shouted, as soon as the boat was over and floating astern. Tom and Captain Andrews obeyed.

To their astonishment they found Jack in his underclothes busily engaged in stuffing his discarded suit with old bits of canvas and anything he could find to give the clothes the semblance of being on a living frame.

“What on earth have you got in mind now?” demanded Tom wonderingly.

Jack explained.

“I was just thinking,” he said, “that there was no use in our all going ashore. Somebody must be aboard to guard the Sea Gull from attack. But at the same time it’s important that those fellows on the Tarpon should think that there is no one here. My plan is that you, Captain Andrews, and you, Tom, row ashore with this dummy of myself sitting in the stern of the dinghy. You can easily dispose of it in some bushes when you get there. Then you make off at top speed for some telegraph office or telephone and summon help, and I’ll stay here on guard.”

“But they may attack you,” objected Tom. “That’s not likely. In the first place, there are three revolvers that I have at hand, and I guess that I could stand off quite a bunch of them if they should venture on an assault. But I guess they won’t.”

At first Captain Andrews would not listen to Jack’s plan; but when the lad represented to him that it might be necessary to have some one on board in case the Sea Gull floated on a rising tide, he changed his mind. The dinghy was brought around to the side of the launch away from the view of the Tarpon crowd, and Jack’s dummy carefully lowered into it.

Then, with Captain Andrews at the oars and Tom supporting the counterfeit Jack, the row to shore was begun. Jack, in the meantime, had found an old suit of clothes which he had put on in place of the garments he had sacrificed.

He did not, of course, show himself outside, but from the porthole he watched the dinghy’s progress. He could hardly keep from laughing as he looked at “himself” propped up in the stern.

“That’s a good dummy, if I do say it myself,” he chuckled; “maybe it has more brains than I have, at that,” he added, with a grim smile.

But his attention was speedily distracted from watching the Sea Gull’s dinghy by the fact that from the Tarpon’s side another small boat now shot out. In it were five men—the total ship’s company of the Tarpon.

“Well, that disposes of the theory that the model was landed in the night,” mused Jack, as he watched them row off; “unless a sixth confederate ashore took charge of it.”

His expression suddenly changed to one of anxiety as he saw that the Tarpon’s dinghy was clearly in pursuit of the Sea Gull’s small boat.

“If they catch up there’ll be a fight more than likely,” he exclaimed, “and five to two, and with the two unarmed, is terrific odds. Hello, Tom’s seen them. Captain Andrews is pulling faster now! So are the Tarpon’s, though! It’s a race for the shore!”

Jack fairly glued his face to the porthole as he watched the two boats. A few moments later he gave a sigh of relief as the Sea Gull’s dinghy grazed the beach, and Captain Andrews and Tom sprang out. Jack noted, with a sort of grim amusement, that Tom supported the dummy up the beach, and managed it so skillfully that from a distance it really looked as if it were Jack walking beside him.

A moment later the two figures of Jack’s friends vanished in the brush which grew down to the foot of the cliffs, and the Tarpon’s boat touched the shore. Jack heard her occupants give a yell as they leaped out and ran up the beach, almost in the footsteps of Tom and Captain Andrews. The next instant the brush swallowed them likewise, and Jack was left to conjecture what was taking place behind that leafy curtain. That it was a drama of a pretty strenuous sort he was certain.

The cabin was insufferably hot, and Jack was too restless to remain still. As he knew that no one was left on board the Tarpon, he saw no objection to his emerging on deck for a breath of fresh air. He sat in the cockpit, looking dreamily at the Tarpon swinging at anchor, and wondering how things were faring with Captain Andrews and Tom.

Suddenly his reverie was broken off. The boy sprang to his feet and slapped his hand down on his knee. A sudden idea had come to him—an idea that was an inspiration.

“It’s worth trying,” said the boy to himself; “it’s worth trying. I may find out nothing, and then again—well, it may mean a whole lot.”

Jack secured the door of the cabin, and then divested himself of his clothes. This done he let himself over the side of the Sea Gull and struck out with a long, steady stroke for the Tarpon. It was quite a swim, and the tide ran swiftly. The Maine water is cold, too, but Jack was strong and vigorous and did not mind this in the least. In fact, after his long spell in the stuffy cabin the water felt delightfully refreshing.

It was not long before he reached the side of the Tarpon, and swimming around her finally found a dangling rope by which he hauled himself on board. Once in her cockpit, he started for the cabin door. As he had expected, it was locked. But a big wrench lay by the engine box, and Jack, without hesitating an instant, picked it up and with one blow smashed the lock in.

Then he opened the cabin door and found himself in a compartment bigger than the Sea Gull’s, but in a wild state of untidiness.

“Phew! what a stuffy hole,” thought the lad; “I guess those fellows don’t clean it out once a year. I wonder——”

Jack almost did a back somersault as he broke off his soliloquy. From out of a corner of the cabin something had sprung at him with a fierce growl and a savage display of teeth. It was a bulldog and a powerful brute, which appeared quite determined to drive Jack off the boat.

“Gracious,” exclaimed the boy, as the dog stood snarling at him, its ugly teeth exposed and its hair bristling angrily, “this is a fix. I never dreamed they’d have left a guardian here.”

“Gr-r-r-r-r-r-r-r!” came from the dog, as its nose crinkled up into a fierce snarl.

Suddenly the growl stopped, and the animal gave a spring at Jack’s throat. But, luckily, the boy had picked up the wrench with which he had broken in the door, and was prepared for the attack. As the dog was in mid-spring he raised it and brought the weapon down with crushing force on the animal’s head. The dog seemed to crumple up, and fell in a limp heap at the boy’s feet.

“He’s not dead,” said Jack, after an examination, “but I guess when he comes to he’ll feel pretty sick. I’m glad I didn’t kill him, although it might have been my life or his.”

He stepped over the dog’s body and entered the cabin. Then, without wasting time, he began a search. From the eager light in his eyes it was evident that Jack had an object in view, and was bent on accomplishing it as speedily as possible.

In the meantime Captain Andrews and Tom had been plunging through the brush on the steep cliffside, trying to work their way to the top. This appeared to be a task difficult of accomplishment. For one thing, the ground was loose and scaly, and for another, the brush grew very densely.

They were forced to be cautious in their ascent, too, as any undue noise was likely to bring the rascals who were trailing them about their ears in a hurry. At length they struck a sort of path, and before long gained the summit; But at about the same time that they found the trail their enemies struck it, too, and were close on their heels. Just at the top of the cliff a big rock lay poised beside the path.

Captain Andrews saw that this gave them an opportunity to hold their foes at bay, and he was quick to take advantage of it.

“Tom,” he whispered, “make off at top speed and get help as soon as possible. Jump now!”

“But what are you going to do?” Tom wanted to know.

“I’m going to keep those fellows from getting up, by this path at any rate,” was the response.

Tom knew that it was no time for argument, and although he did not much like leaving Captain Andrews alorie, he made off in all haste across the country. Before long he struck a road, and soon after got a lift in a passing wagon to a near-by village.

In the meantime an exciting scene had been enacted at the cliff top. Tom had not left Captain Andrews five minutes before Jake Rook, in advance of the others, straggled up the trail. As he reached the top he was amazed to hear a voice proceeding apparently from behind a big boulder, which was poised on the summit.

“You’ll have to go around the other way, gentlemen,” said Captain Andrews suavely; “if you advance any further I’m mightily afraid that this rock may roll down on you.”

“See here, Andrews,” came back the voice of Captain Flinders, “you’ve been imposed upon by those boys.”

“I know all about that, Flinders,” came back the reply, “but just you tell your friends there not to come any further this way, or they’ll land in trouble. I guess this rock would make quite a dent in the anatomy of anybody it happened to fall on.”

He shoved the rock suggestively, and it gave an ominous quiver. A hasty consultation followed among the men. It was impossible to dislodge the doughty captain by shooting at him, for he was shielded behind the rock. On the other hand, if they did not reach the cliff summit by that way the gang of rascals would have to make a long detour, and that, for reasons of their own, they were not anxious to do.

But it was the course they had finally to adopt, and Captain Andrews, with a grim smile, heard their retreating footsteps. It was not till they had gone that he realized that, in all probability, the model and the papers had gone with them. He was pondering this aspect of the case when Tom returned. He brought with him the village constable of Rumson, the town he had reached, and half a dozen deputies.

“Whar be them roustabouts?” demanded the constable, as he came up.

“I guess they’ve headed to the south,” said Captain Andrews; “I drove ’em off this trail by threatening to get careless with this rock.”

“Good for you! If they’ve gone south they’ll be bound to come up that path by Rumson Point,” declared the constable; “come on, boys, thar’s a re-ward for ketching them fellers.”

Thus stimulated, the posse set off at top speed for the Point, while Captain Andrews and Tom decided to return to the Sea Gull and find out how Jack was faring. They arranged to meet the constable and his men later on in the village, and learn how they had succeeded.

They found the dinghy as they had left it, and rowed off to the Sea Gull without loss of time. As they neared the grounded boat Jack’s head appeared out of the cockpit, and he waved his hand excitedly.

“He’s got some sort of news,” declared Tom; “wonder what it can be?”

They were soon to find out. As they boarded the Sea Gull, Jack, with dancing eyes, produced the long-missing model. Then, as if to cap the climax, he held up a sheaf of papers.

“Hurray, lad! You’ve done the trick!” shouted Captain Andrews.

“But how—what—where”—stammered Tom. “How?—by taking a swim over to the Tarpon. Where?—in a secret locker under the cabin floor,” laughed Jack. “You see,” he went on, “I had a hunch that it might pay to investigate the Tarpon, for I concluded that it was likely that Melville’s outfit would leave the model there till they found a safe place to take it ashore, and so—I got ’em.”

“And I guess that posse is getting our friends,” cried Captain Andrews. “Hark!”

From the direction of the Point came the sound of several shots and then silence.

“I have an idea that that is the finish of Mr. Melville and his outfit,” said Jack. But Tom interrupted him.

“The Sea Gull is afloat,” he cried.

Sure enough, the tide had been rising during the last hour, and now they could feel a quiver of life in the Sea Gull. The engine was started, and after a short time the craft was backed off into deep water and anchored. Not long after the three friends rowed ashore and made their way into Rumson. They found that village in a state of turmoil. The five marauders had all been captured after a bloodless battle, in which, however, a few shots had been fired by Rook and Melville.

But Rumson was not to have the honor of their presence long. After a brief examination before a local magistrate, they were consigned to the Boston authorities. They were tried for their crimes in that city, and received various jail sentences. Captain Flinders alone escaped on the plea that he did not know what kind of men he had taken as passengers. This was palpably false, but as he aided the State’s case by his testimony, he was released with a stern warning.

After the hearing at Rumson the boys telegraphed the glad news of the recovery of the model and papers to Mr. Peregrine, and notified their parents of the termination of their adventurous quest. The next day they started back for Boston on the Sea Gull, towing the Tarpon behind. Captain Flinders had asked Captain Andrews to look after the latter craft while his case was pending, and the boys’ good-hearted friend could not refuse. The bulldog, now completely subdued, went as a passenger on the Sea Gull, and Jack ultimately bought the animal from Flinders.

At Boston, the inventor, both the boys’ fathers, and Ralph and Jupe in a state of wild excitement, all met the boys, and many and hearty were the greetings and congratulations. After a few days in the city Jack found all the appliances he needed, and in a very short time afterward the Peregrine Vanishing Motor Gun was accepted by the government as a weapon for use against aËroplanes.

But Mr. Peregrine always says that, had it not been for the Boy Inventors, his machine would have remained and rusted in its shed. So with his authority we have linked their names with his invention.

One other thing of interest must be told. The Vanishing Motor Guns are being manufactured by the United States Artillery Devices Company, whose nominal head is now young Ralph Melville. The business was found to be in a bad way, but the contract for building the guns, which came to it after all, assisted in putting it on its feet again. Dr. Tallman, as Ralph’s guardian, had charge of the work of reconstruction. Prosperity has not changed Ralph, and he is as warm a friend of the boys as ever, and never has forgotten his rescue in mid-air. Dick Dangler has a post in the Melville works, and fills it right well.

And so the time has come when, for the present, we must bid good-bye to the Boy Inventors. But we shall meet them again ere long, and learn something more about their mechanical skill and clever daring. The next volume of their adventures will deal with a particularly enthralling subject—that of submarine work. Of the dangers and difficulties our young heroes faced under the water you may read in The Boy Inventors’ Diving Torpedo Boat.