As the others turned to follow, Sim held back, but Mr. Lockyer turned to him and beckoned for him to make one of the party. Leaving Anderson in the midst of the gang of workmen, they made their way to the office, where Mr. Lockyer, unlocking a safe, drew forth a roll of bills. Selecting one, he presented it to Sim, who gave a cry of surprise as his eyes fell on its denomination.

“A hundred dollars! Oh, Mr. Lockyer, I couldn’t think of it! Why, sir——”

“Now, see here,” laughed the inventor, “I’m getting off cheap. If you hadn’t shut off that gas, I might have lost many times the amount of that bill.”

The lad was not proof against this line of reasoning, and finally placed the bill in his pocket. Soon afterward Anderson presented himself at the wicket, and was paid off by Mr. Lockyer’s solitary clerk and bookkeeper. His sullen face was unusually ferocious as he glared in at the inventor and his young friends.

“I ain’t through with you yet, Lockyer,” he roared, apparently in an insane access of fury. “I’ll fix you. You’ll see. I hope you and your submarine go to rust and ruin on the floor of the Sound. I hope——”

“That will do, Anderson,” said the inventor quietly. “I wish to hear no more from you.”

“But you will. Don’t you fool yourself on that,” exclaimed the furious man, flinging out of the office with muttered imprecations on his lips.

“That feller needs a short cruise in ther brig,” commented old Tom, as Anderson dashed out of the place.

“I’m sorry to have had to get rid of him, for he was a competent workman,” said Mr. Lockyer. “But he has been becoming altogether too aggressive of late. By the way, I wonder where that chap Gradbarr is. I want to interview him, too, and find out how he happened to turn on that gas. It’s a horrible suspicion to have; but it looks to me almost like a deliberate attempt to wreck the craft.”

“That’s the way it looks to me, too, sir,” agreed Ned.

“By the way,” said Mr. Lockyer suddenly, “do you boys know anything about thread-cutting? I’d like to get that pipe connection fitted up to-night.”

“I guess we can help you,” said Ned, and, accordingly, they retraced their steps to the submarine shed. The workmen had all left by this time, but they found the tools they needed, and soon had the measurements of the connection, and the required pitch of the screw to be cut on the new pipe. This done, they started for the machine shop to finish up the work. Sim, however, who was still white and shaky after his experience, was ordered home by Mr. Lockyer.

“You’ve done enough for one day, Sim,” he said. “Be off home now, and report bright and early to-morrow.”

As Sim made off, the inventor looked after him.

“There’s a lad that has the makings of a fine man in him,” he said. “He applied here for work some weeks ago, and, being short of a helper, I gave him a job. He knew something about metal working, as his father was formerly blacksmith here. The man died some time ago, and since then I guess Sim and his mother have had a hard time to get along. That hundred dollars will look very large to them.”

“He certainly did a plucky thing,” agreed Ned. “It takes courage of the right sort to put through what he did.”

“Bother it all,” exclaimed the inventor, after a few minutes’ work on the pipe. “I’ve just recalled that we have no red lead to make the joint tight with. We used up our last yesterday. I wonder if one of you would mind going up to the village for some.”

“Not a bit,” said Ned. “I’m pining for exercise. Herc, here, and myself will be up there and back in no time.”

Thanking them, Mr. Lockyer gave them directions where to go, and some money. The Dreadnought Boys were soon off on their errand. The shop found, it did not take long to make their purchases and, with the parcel under Ned’s arm, they started back.

“There’s a short cut to the water, through that field there,” said Ned, as they came to a turning. “Let’s take it and save time.”

Accordingly, they presently emerged in a low-lying meadow, thickly grown with clumps of alders and other swamp shrubs. A path threaded among them, however, which apparently led almost direct to the boat yard.

“We’d have saved time if we’d known about this before,” observed Ned, and was about to add something more when he stopped short. From what was apparently only a short distance ahead, there had come a cry of pain.

“Oh, don’t, please don’t, Mr. Anderson.”

“You young blackguard, I’ll break your arm for you if you don’t tell me everything,” growled out a voice they recognized as that of the recently discharged foreman. “It was you that told on me, wasn’t it?”

Another cry of pain followed.

“It’s Anderson. He’s ill-treating that young Sim!” cried Ned, his face flushing angrily. The Dreadnought Boy hated to hear of anything weak and small being badly used.

“Come on, Herc, we’ll take a hand in this,” he said.

They advanced rapidly, yet almost noiselessly, and in a second a turn of the path brought them upon the two whose voices they had heard. Anderson had hold of Sim’s arm and was twisting it tightly while he pounded on the back of it with one burly fist to make the agony more excruciating.

“Here you, let go of that boy!” exclaimed Ned.

Anderson looked up furiously.

“Oh, it’s you interfering again, is it? Now you take my advice and keep out of this. I don’t know who you are and I don’t want to, but just keep on your way, or you’ll get hurt.”

“Oh, I don’t know,” rejoined Ned easily. “If you don’t stop ill-treating that boy, it’s you that will get hurt.”

“Is that so?” snarled Anderson. “Well, Mister Busy-body, I’ll just do as I please.”

So saying, he gave Sim’s arm, which he had not released, an additional twist, causing the frail lad to cry out again. But before the cry had completely left the boy’s lips, Ned’s hand had closed upon Anderson’s wrist, and that worthy, with a snort of pain, suddenly found himself staggering backward under the force of the quick twist the boy had given him.

“I’ll show you!” he cried, recovering himself and bellowing with rage. “Mind yourself!”

But it was Anderson who should have minded. As he spoke, he made a mad rush at Ned, who, not wishing to hurt the man, simply sidestepped as the other came on. But he left one foot extended, and as Anderson came in contact with it he tripped.

Floundering wildly, he sought to retain his balance. But the effort was in vain.

Splash!

Over he went, spread-eagle fashion, face down into a pool of stagnant swamp water.

“Haw! Haw! Haw!” laughed Herc. “Say, mister, you’re so fond of water that you just have to wallow in it like a hog, don’t you?”

Anderson scrambled to his feet a sorry sight. Mud daubed his face and the front of his clothing. Mud was in his hair, his eyes, his nose, and his mouth.

“I’ll fix you,” he cried, making another dash at Ned, but this time the Dreadnought Boy simply caught the enraged fellow’s wrists and held them to his sides as easily as if he had been restraining a fractious child.

“Now, see here, Anderson,” he shot out, “you’ve had trouble enough for one day. Don’t look for more. Now get!”

Cowed by Ned’s determined manner, but more especially by the easy fashion in which the boy had quelled him, holding him helpless as an infant, Anderson “got.” But as he strode off through the bushes there was a dark look on his face, a look that boded no good to the Dreadnought Boys, who, however, hardly gave the matter a further thought. Seeing Sim safe on his way home, they turned once more to their path and arrived at the boat yard in due time.

“Took you fellows longer than you expected, didn’t it?” asked Mr. Lockyer, as they appeared.

“We attended to a little business on the way,” replied Ned quietly; “and now if you are ready, Mr. Lockyer, we’ll fit that pipe.”

In the meantime, Anderson, instead of going home, had hied himself to the village hotel, which boasted of a drinking bar. In this place he sought solace for his woes as many another foolish or weak man has done before him. In the midst of his angry musings, a man stepped in who, apparently, recognized Anderson, for he stopped short and gave a low whistle.

“Anderson! Wonder what he is doing here at this time of day.”

Stepping forward, he came up behind the disgruntled foreman with an appearance of great cordiality.

“Why, hello, old man,” he exclaimed. “Work through at the yard? What are you doing here at this hour?”

“Gradbarr!” exclaimed Anderson, surprised in his turn, as he faced the other. “Why ain’t you down at the yard?”

“Oh, after that blow-up I decided to quit. Too risky a job for a family man like me.”

“Where is your family?” inquired Anderson. “Never knew you had one.”

“Oh, in California,” was the reply.

“Hum, you keep far enough away from them,” commented Anderson; “and, by the way, I’ve got a bone to pick with you. You got me discharged over your borrowing of that key.”

“What!” exclaimed Gradbarr, with genuine surprise. “Fired? How’s that? Although, now I come to notice it, you do look a bit mussed up. Bin in a fight?”

“Why no,” was the sullen rejoinder. “What made you think that?”

“Well,” grinned Gradbarr, “men don’t generally roll in the mud if they can help it, and by the looks of you that’s what you’ve bin a-doin’. But tell me about how you come to be fired. If it’s my fault, I’ll make it right with you.”

Anderson soon related his own version of how he came to be discharged. He was in an angry, reckless mood, and did not care how loud he talked, so that he had for a listener Jeb Sproggs, the landlord of the hotel. Jeb listened with open mouth and ears to Anderson’s description of the “young whelps,” as he termed them, who had accompanied Mr. Lockyer, meaning, of course, Ned and Herc. “And there was an old geezer, too,” he went on; “looked like some sort of a retired fisherman.”

“Why them fellows is registered here,” put in the landlord, as Anderson concluded. “Yep,” he continued, “their names is Strong, Taylor, and the old feller’s called Marlin.”

“Then they weren’t mere butt-in visitors to the yard as I had them figgered out to be,” cried Anderson.

“Why no,” said Sproggs, discarding a badly mangled toothpick. “As I understand it, them lads is here on special duty connected with that diving boat. They’re in the Navy.”

“The Navy!” exclaimed Gradbarr. “Then I may be too late.”

“What’s that?” asked Anderson eagerly. “Do you know them?”

“No,” rejoined Gradbarr, “I don’t know them and I don’t much care to, from what you’ve told me about them. But I’ve got to be going on. Say,” he continued, in a whisper, bending over till his mouth was quite close to Anderson’s ear, “do you want to be put in the way of revenging yourself on Lockyer and that whole bunch?”

“Do I?” Anderson’s eyes lit up with a vicious flare. He involuntarily clenched his fists.

“Well, walk up the street with me a way and I’ll tell you how to get even.”

For a moment Anderson wavered. After all, this man was a stranger to him. It might be a trap to draw him out and discover if he cherished any harm to the submarine. But then his evil, vindictive nature asserted itself. He ached and palpitated with his every sense to avenge himself on the man who had humiliated him before the whole crew of workmen, and particularly was he desirous of making Ned Strong and his companion smart for the indignities they had thrust upon him.

“All right,” he said. “I’m with you.”

“A tool ready to my hand,” was the thought that flashed across Gradbarr’s mind as, arm in arm, the two worthies strolled from the hotel and slowly walked up the village street.

That evening, as the Dreadnought Boys and their weather-beaten comrade were returning to the hotel, they encountered Zeb Anderson. They would have avoided him if they could, but as he planted himself in their path there was no way of escaping a meeting. But that they were not anxious to court such an encounter, our party was showing by hurrying on, when Anderson caught Ned by the arm.

“I s’pose you think you and me had a brush and you win,” he said in a voice harsh with hate. “Well, just you wait. Our score ain’t evened up yet. You’re going ter sea on that old submarine I hear. Well,” he said, raising his voice, “I know more about her than you do. You’ll all go to the bottom every last man of you and leave your bones rotting there. That’s what I hope and that’s what will be.”

With this amiable prophecy, Anderson strode off down the street, casting back ever and anon a glance of hatred at the naval party.

“Wall,” exclaimed Tom Marlin, who had been made acquainted by the boys with what had occurred in the alder swamp, “if words could drown we’d be dead by this time, all right.”

“Somehow, though, I think that that man Anderson is a good fellow to watch out for,” replied Ned. “He has the look in his eye of a man who might become insane from brooding upon his fancied wrongs.”

“Hullo, there is the Lieutenant and Midshipman Stark, and there’s good old Stanley, too,” cried Herc suddenly, pointing to a group in front of the hotel. Hastening their steps, our party was soon respectfully saluting Lieutenant Parry and his aide.

The next morning work was resumed at the yard, with Andy Bowler, a capable workman, in Anderson’s place as superintendent. Sim was made his assistant, and work was rapidly rushed ahead. Sim proved himself, in spite of his tender years, to be a genius with machinery, and he and the Dreadnought Boys became firm friends. All this time the naval party was acquainting itself thoroughly with the principles of the Lockyer engine so that when the time came they could take sole charge of the craft and test her in every way.

All this time nothing further had been heard of Gradbarr, who, as we have seen, had failed in his first attempt to damage the submarine. He did not even appear to collect his money. Mr. Lockyer, with an idea of having him arrested, notified the police, but they could find no trace of him. Anderson was seen about the village and appeared to have plenty of money, although the source of his income was more or less of a mystery. But things were so busy at the yard that the boys or any one connected with the plant had little time to waste on speculations concerning the rascally pair. Work in the craft was rushed day and night. Rapidly it narrowed down to mere details.

One bright afternoon Mr. Lockyer seized up a megaphone and by its agency announced throughout the yard that the work was practically finished. What a cheer went up as the men gathered about him! Another shout arose when it was given out that each man that evening would find a ten-dollar bill awaiting him at the office.

“When is the launching set for, sir?” inquired Ned of Mr. Lockyer that evening.

“There will be no formal launching, with invited guests, a brass band, and all that; but we’ll run her off the ways to-morrow, if it’s a good day,” was the reply. “I can hardly believe that the crucial test is so near. I wonder, will she make good?”

“You’ll win out, sir, never fear,” Ned assured the inventor, who was beginning to show the effect of his long strain.

Herc echoed his comrade’s assurances, and they came from hearts that meant every word of them, too. Both lads had come to have a strong liking and respect for the young inventor. The feeling was mutual. Channing Lockyer had grown to feel that he had near him at least three staunch, loyal hearts, upon whom he could depend in an emergency.

How soon that emergency was to come not one of them guessed.