THE RADIO BOYS

WITH THE REVENUE GUARDS

By GERALD BRECKENRIDGE

Author of

"The Radio Boys on the Mexican Border," "The Radio Boys on Secret Service Duty," "The Radio Boys' Search for the Inca's Treasure," "The Radio Boys Rescue the Lost Alaska Expedition."



A. L. BURT COMPANY

Publishers New York



THE RADIO BOYS SERIES

A Series of Stories for Boys of All Ages

By GERALD BRECKENRIDGE

The Radio Boys on the Mexican Border The Radio Boys on Secret Service Duty The Radio Boys with the Revenue Guards The Radio Boys' Search for the Inca's Treasure The Radio Boys Rescue the Lost Alaska Expedition

Copyright, 1922

By A. L. BURT COMPANY

THE RADIO BOYS WITH THE REVENUE GUARDS

Made in "U. S. A."



CHAPTER I

TWO MYSTERIES

"Not much like last summer, is it, Jack?"

"Not much, Frank."

"No Mexican bandits. No Chinese bad men. No dens in Chinatown. Say, Jack, remember how you felt when we were licked in our attempt to escape from that dive out in San Francisco? Boy, that was the time when things looked mighty blue. Jack?"

No answer.

"Jack?" In a louder tone.

Still no answer.

Frank turned around impatiently from where he lounged in the open doorway of the radio station, and faced his chum at the receiver.

"Oh, listening-in," he exclaimed, and fell silent. Facing about, he gazed southward to where, less than a mile away, sparkled in the bright July sunshine the clear waters of the open Atlantic.

Frank Merrick was thinking of the adventures crowded into the lives of himself and his two chums, Jack Hampton and Bob Temple, during their summer vacation the previous year. All three boys were sons of wealthy parents and lived on country estates at the far end of Long Island. Jack's mother was dead. Frank who was an orphan, lived with the Temples. All had attended Harrington Hall Military Academy, but Jack, a year older and a class ahead of his chums, had graduated the previous spring and already had spent his Freshman year at Yale.

The previous year Jack had gone to New Mexico with his father, an engineer, who was then superintendent in charge of field operations of a syndicate of independent oil operators. Mr. Hampton had been captured by Mexican rebels, and rescued by the boys, for Frank and Bob with Mr. Temple had joined Jack after his father's loss. Later Mr. Temple had taken the boys on to San Francisco with him, and there they had become involved in the plottings of a gang of Chinese and white men, smuggling coolies into the country in violation of the Exclusion Act.

It is not to be wondered at that Frank, dreaming of those adventurous days as he lounged in the doorway, felt a twinge of regret at what promised to be a dull vacation by comparison.

It was true, he thought, they had everything to make them happy and keep them interested, however. Here was the powerful radio station built by Mr. Hampton under government license to use an 1,800 meter wave length, for purposes of trans-oceanic experiment. Then, too, Frank and Bob jointly owned a powerful all-metal plane, equipped with radio, and adapted for land or water flying. Besides, there was the new and powerful speed boat bought for the three of them this summer by Mr. Hampton and Mr. Temple.

And their homes were admirably located for vacationing, too. On the far end of Long Island, miles from another human habitation, with dense woods, miles of lonely beach, and the open sea—all at their command. Well, Frank thought, after all it might not be so exciting a summer as the last, yet the three of them ought to be able to have a pretty good time.

An exclamation of anger from Jack caused Frank to face about. His chum had taken the receiver from his head.

"That interference again?" asked Frank.

"Yes," replied Jack, rising and joining his chum in the doorway. "Oh, there comes Bob," he added, pointing to a tall, broad figure swinging over the top of a low sandhill from the beach.

Frank's glance followed in the direction Jack indicated. Although Bob was still distant there was a purposefulness about his stride and about the way he waved a response to their greetings that caught his chum's attention.

"Bob's got something on his mind," he said, with conviction. "Wonder what it is?"

"Maybe, he found something, hiking along the beach."

"Maybe, he did," agreed Frank. "I didn't feel like hitting it up with him this morning, felt kind of lazy, as if I had spring fever. It would be just my luck to have him make a discovery on the one morning I wasn't along with him."

Bob's figure disappeared in a fold in the sandhills, and Frank remembering Jack's disgust over interference in the radio receivers, began to question him about it while waiting for Bob to arrive.

"What was it like this time, Jack?" he asked.

"Just the same, only worse," answered Jack. "Tune up to 1,375 meters for receiving and then comes that snarling, whining, shrieking sound. It's steady, too. If it were dot and dash stuff, I might be able to make something out of it. But somebody somewhere is sending a continuous wave, at a meter length, too, that is practically never used. From 1,100 meters to 1,400 meters, you know, is reserved and unused wave territory."

"I wonder what it can be," said Frank.

Bob by now had approached within calling distance, and he was so excited that he began to run.

"What's the matter?" called Frank.

"Somebody chasing you?" asked Jack, as the big fellow ploughed through the sand and halted before them.

Bob grinned tantalizingly.

"What would you give to know?"

"At him, boys. At him," cried Jack, making a flying tackle.

His arms closed about Bob's waist. At the same time, Frank who had been standing to one side, dived in. His grip tightened about Bob's legs below the knees. All three lads rolled over in the sand in a laughing, struggling heap. Presently, Jack and Frank bestrode the form of their big chum and Frank, who sat on his chest, gripped Bob's crisply curling hair.

"Now will you tell?" he demanded in mock ferocity. "If you don't——"

"All right, you big bully," answered Bob. "Why don't you pick on a fellow your size?"

With which remark, he gave a mighty heave—as Frank afterwards described it "like a whale with a tummyache"—and Frank and Jack went sprawling. Then he stood upright, brushing the sand from his khaki walking clothes.

"Oh, is that you down there?" he asked. "Why, where did you come from?"

Then, as Frank made a clutch for his ankle, he brushed him aside and sat down on the sand:

"Say, listen, cut out the fooling. I've got something to tell you fellows."

Bob was so plainly excited that his chums were impressed. Scrambling up they seated themselves beside him.

"Fire away," said Jack.

"What would you say to my finding the tracks of a peg-legged man coming up out of the sea, crossing the sands of Starfish Cove and disappearing into the trees beyond there?"

The inlet which Bob thus referred to was some three miles distant, with a patch of timber some twenty yards back from the water and a ring of low sandhills behind the woods.

"A peg-legged man?" said Frank. "That certainly sounds piratical. Go on. Your imagination is working well to-day."

"Did he arrive in a boat?" asked Jack.

Bob nodded.

"Yes. I found where the boat had been run up on the sand. But—he didn't leave. The boat went away without him. He disappeared inland, and there were no tracks marking his return."

Jack whistled.

"Whew. Did you follow?"

"Did I follow? Huh. You can just bet I did follow. And, say, fellows——"

"What?"

"I know now where that strange interference in our radio receivers comes from."

"Is that so?" demanded Jack, excitedly. "It was cutting up didoes just a few minutes ago, just before you arrived. Had been for some time, too."

"Well," said Bob, "that's not to be wondered at. For when I followed Peg Leg's tracks through the trees I discovered a radio station tucked away in a hollow behind the timber, with sandhills hiding it on the landward side. I watched for a while from behind a tree, but couldn't see anybody. Then I hustled here to tell you fellows about it."

Puzzled, the trio regarded each other in silence. Presently Jack spoke.

"Look here, fellows. There's something queer about this. A mysterious radio station, hidden away, that sends a continuous wave on a hitherto unused wave length. This has been going on for a week. What does it mean? Then there is this man, this Peg Leg, whom Bob discovers arriving from the sea."

"Let's go together and investigate," cried Frank, jumping to his feet.

"I'm with you," declared Bob, also arising. "I would have gone up to the station and done that very thing, by myself, but—I don't know—there was something about it all—something sinister."

"Wait a minute, you fellows," said Jack, also springing upright. "We can't go putting our heads into trouble recklessly. Bob's good sense prompted him when he refrained from pushing up to that radio station by himself. There is something sinister about this. That place is isolated, there are no roads near it, nobody ever hikes along that beach except us. How did the station ever come to be built? Why, the material and supplies must have been brought by boat. They couldn't have been transported overland very well."

"What shall we do, though, Jack?" asked Frank, impatiently. "You can't reasonably expect to have a thing like this rubbed under our noses without our going ahead and investigating."

There was so much plaintiveness in his voice, as of a child from whom a toy was being withheld, that Bob and Jack both burst into laughter. Then Jack sobered.

"Tell you what I think," he said. "It's only mid-afternoon. Let's get out your plane, and take a look at this place from the air."

"I guess the old boat is working all right now," said Frank. "How about it, Bob? You know we haven't been up for two or three weeks, Jack. Bob's been tinkering with it. When I last saw him at work, he seemed to have the engine entirely dismantled. Looked to me as if he had enough parts for three planes. Did you get it together again, Bob?"

"Yes," said Bob. "And she'll fly now, boy, believe me. Well, come on," he added, starting for the hangar, not far distant but out of sight behind the sandhills.

The others followed.



CHAPTER II

A STRANGE AIRPLANE APPEARS

From the Hampton radio station to the hangar on the Temple estate where Frank and Bob kept their plane was a short jaunt, and the ground soon was covered. Then Bob unlocked the big double doors and rolled them back, and the three trundled the plane out to the skidway where Jack spun the propeller while Bob manipulated the controls. As the machine got under way, Jack ran alongside and was helped in by Frank.

Out over the sandy landing field trundled the plane rising so quickly that Bob nodded with satisfaction. The loving work he had put in on the machine had not been wasted. It was in fine flying condition.

They were not far from the coast and in a very short time were flying over the water, whereupon Bob made a sweep to the right and the plane headed westward. The Atlantic rocked gently below, serene under a smiling sun and with only the merest whisper of a breeze caressing it. On the southern horizon a plume or two of smoke, only faintly discernible, marked where great liners were standing in for the distant metropolis. To the north, far away, showed a sail or two, of fishing craft or coastwise schooner.

An exclamation escaped Frank and he leaned sidewise, gripping Jack by the arm and pointing with his free hand. But Jack had a radio receiver clamped on his head and was frowning. He glanced only hastily in the direction indicated by Frank, then shut his eyes as if in an effort at concentration.

Frank continued to gaze, then bent down and unlashed a pair of binoculars from a pocket in the pit and, putting the glasses to his eyes, threw back his head and began scanning the sky. After staring long minutes, he hastily put aside the glasses, lifted the radio transmitter strapped to his chest and spoke in it to Bob:

"Bob, there's a plane overhead. So high you can't see it with the naked eye. But I spotted it before it rose too high, and followed it with the glasses. The fellow's up where the sun plays tricks with your eyesight. And, Bob, I've got a hunch he's watching us. There's Starfish Cove below us now. Keep right on flying. Don't turn inland."

Bob nodded, and the plane continued its way westward offshore. Frank again took up the glasses and searched the sky, gradually increasing the focal radius. An exclamation from Frank and a hurried request in the transmitter presently reached Bob's ears:

"Shut her off, Bob, and let's land on the water. Quick. I'll explain in a minute."

Obediently, big Bob shut off the engine, and the plane coasted on a long slant to a safe landing some hundreds of yards out from the sandy, deserted shore.

Bob and Jack snatched the headpieces off, and turned inquiringly to their chum.

"Here," cried Frank, pressing the glasses into Bob's hands. "Take a look. That plane is landing way back there, and I believe it is at Starfish Cove."

Bob was too late to see if the situation was as Frank described, however. Putting up the glasses, he turned to his chum.

"Tell us about it," he said.

"Yes," said Jack. "I heard what you told Bob, but not having the glasses I couldn't see. At first, when you punched me, besides, I was thinking over that business of the strange interference with our radio and wondering what it could be. So I didn't get to see. I suppose you were trying to point out this other plane to me then?"

Frank nodded.

"Yes," he said, "it was just a tiny speck at that time, but I could see it with the naked eye. However, it disappeared immediately afterwards."

"Well, what made you believe the other plane was watching us?" inquired Bob.

Frank laughed in half-embarrassed fashion.

"Oh, one of my hunches," he said.

His two chums grinned understandingly at each other. It was a recognized fact among them that Frank was super-sensitive and frequently, as a result, received sharp impressions concerning people and events which were unsupported by evidence at the time, but which later proved to be correct. Frank was the slightest of the trio, of only medium height but wiry build, while Bob and Jack both were six feet tall and Bob, besides, had a broad and powerful frame.

"Seeing spooks again?" chaffed Bob.

Immediately, they became more serious as Frank, ignoring the banter, leaned forward and made his proposal:

"That plane landed, and I believe it landed at Starfish Cove. Let's fly back and take a look. See what's it like, at any rate."

"Good idea," approved Jack.

Bob had been taxying about slowly since landing, in order to keep the engine going and the propeller slowly revolving. Now he picked up speed, straightened out, shifted the lifting plane, and the machine shot forward, skirled over the water and presently took the air.

For some minutes they flew in silence, at no great height, and a little distance out from the coast. Bob's attention was devoted to the plane, but Frank and Jack scanned the shore with eager eyes. Presently they saw what they were looking for. A strange plane rode in the lazy swell offshore in Starfish Cove. There was nobody aboard. Not a soul was in sight on land. The little stretch of sandy beach, between the two horns of the cove, stretched untenanted back to the thick fringe of trees.

Bob swooped so low the plane almost skimmed the water, and all three obtained a good view of the stranger, before once more Bob soared aloft and forged ahead. Looking back, Frank trained the glasses on the scene. But nobody appeared from among the trees, and, far as they could determine, they were unobserved.

They made a quick run to their own landing field, descended and put the plane away. Not until the doors were closed and locked did they sit down on the skidway outside the hangar to discuss what they had seen. There had been remarks made by all after they had seen the strange plane at close range and on the hasty trip home, but all had been too busy with their own thoughts for extended discussion.

Discovery of the plane had altered their original plans to fly over the secret radio station. They had decided not to advertise their presence as, if Frank was correct in his surmise that the other plane had been watching them, their return would create suspicion and put the mysterious strangers on guard against them.

"They may be on a perfectly legitimate enterprise, whoever they are," Jack said, as all three took seats on the skidway.

"And we may be fools for butting in where we have no business to be," said Bob. "That your idea?"

"Yes."

"But look here," said Frank. "I have the feeling that there's something about all this business that isn't open and aboveboard. I, for one, vote that we do our best to find out what is going on."

Jack sat silent for several moments.

"That isn't what concerns me at the present moment, after all," he said. "Whether these people with their strange plane and their secret radio are on legitimate business or not, doesn't interest me so much. What puzzles me—and I reckon it puzzles the rest of you, too—is the design of that plane."

The others nodded vigorously.

"What a tiny thing," was Frank's comment.

"I was busy and couldn't see much," supplemented Bob. "But what impressed me was her short hood. Why, she looked as if she had no engine at all."

"That's right," agreed Frank. "I never saw a plane like it. And I can't recall any designs of that nature, either. It must be a foreign-built plane, one of those little one-man things the Germans and French have been building."

Jack shook his head, puzzled.

"There's something strange about it," he said, "a little thing like that, with practically no engine space. Another thing that you fellows want to remember, too, is that probably it has been flying about here for some time, yet we have never heard it. Now, down here the sound of most planes would travel far, in this quiet and secluded place, where there are no competing noises."

"Why do you say it has been flying about here for some time?" asked Bob.

"Well, the familiarity with which the aviator landed shows he's been at Starfish Cove before. Evidently, after landing he struck inland to that secret radio station, because we saw no sign of him."

"We haven't been up in the air for three weeks," said Frank. "That plane might easily have come and gone in that time without our seeing it. But, surely, as Jack says, we would have heard it at some time or other. Haven't either of you heard the sound of a plane lately?" he appealed to the others. "I know I haven't."

Bob and Jack both shook their heads in negation.

"No planes ever come out this way," Bob said. "They fly south or north of us, but not out here. I haven't heard anything."

Jack rose and stretched.

"Well, I, for one, vote that we do not pursue our investigations into this mystery by going back and, perhaps, getting peppered with gunshot."

"But, Jack," protested Bob, the impetuous, "we want to know what's going on. You can't have a mystery dumped right in your own dooryard without digging into it."

Frank was thoughtful.

"That's true, Bob, old thing," he said. "Just the same, I agree with Jack. What do you say to laying the matter before Uncle George and Mr. Hampton at dinner? Jack and his father are coming over to our house to-night, you know."

"Good," said Jack. "We can put it up to them, and, perhaps, they will know something about the man who owns that land around Starfish Cove, where this secret radio is located."

Big Bob grumbled. Delay irked his soul.

"All right, you old grumbler," laughed Frank. "Come on, I'll give you some action. We have several hours of good daylight left before dinnertime. I'll take you on at tennis. Della and I will play you and Jack, and we won't give you time to worry about anything."

Della was Bob's sister, two years younger than he. Frank, whose parents were dead and who lived with the Temples, referring to Mr. Temple, his guardian, as "Uncle George," was very fond of her. The others joshed him about Della frequently. Bob took occasion to do so now, as the three walked away from the hangar toward the Temple home and tennis courts.

"Huh," he said, "you'll be looking at your partner so often you won't be able to play. Why, you won't even be good practice for Jack and me."



CHAPTER III

THE HAUNTED HOUSE

Della was lithe-limbed, quick of eye and strong of wrist, a born tennis player. As for Frank, tennis was the one sport at which he could excel his chums. The result was that, despite the strong game played by Jack and Bob, Frank and Della won two sets, 7-5, 8-6.

Mr. Hampton appeared on the scene when the second set stood at six-all, bringing with him an alert, thin-faced man of middle age, clad in the uniform of a colonel in the United States Engineers. Mr. Temple with his wife emerged from the house to greet their guests, and all four were interested spectators of the two concluding games which were bitterly contested, went to deuce a number of times, but finally were won by Della and Frank.

"Well, Jack," said Mr. Hampton, jokingly, as the players joined the spectators at the conclusion of the set; "I suppose you were just being chivalrous and that's why Della beat you."

Jack grinned. He and Bob knew they would be in for a certain amount of twigging because of their defeat, but he knew how to take it in good part.

"Chivalrous? Oh, yes," he scorned. "We'd have beaten that pair of kids if we had been able. But it couldn't be done. Della's got a serve there that would put Mlle. Lenglen to shame. As for Frank, the boy goes crazy when he plays tennis."

A general laugh greeted his generous praise of his opponents. Then Mr. Hampton turned to his companion and introduced him to the players as "Colonel Graham."

After that the players hurried away to brush up and prepare for dinner.

"Shall we speak of our discoveries this afternoon?" asked Frank, brushing his hair while big Bob peered over his shoulder into the mirror, adjusting his tie.

"Why not?" asked Bob.

"Well, on account of this Colonel Graham. Who is he, by the way, Jack?"

Jack did not know. He recalled, or believed he recalled, that his father had spoken of a friend named Colonel Graham who was a famous engineer.

"But if he's a friend of Dad's," added Jack, with calm confidence, "you can count on it that he's a good sport. It will be safe to speak about our discoveries before him."

At dinner it developed that Colonel Graham was, indeed, a friend of Mr. Hampton. They had been classmates years before at Massachusetts Institute of Technology. During the World War, Colonel Graham had obtained a reserve commission in the Engineers and, at the conclusion of hostilities, while thousands of other officers were being demobilized, he had been given a commission in the regular army because of his distinguished record.

At dinner, the older people took the lead in the conversation, while the boys and Della were content to listen unless addressed. Colonel Graham was a brilliant conversationalist, and once he became launched on a series of war stories there was no time for the boys to interrupt, nor had they any inclination. He had been one of the handful of American engineers impressed into a make-shift army by General Byng to stop the Germans when they smashed through at Cambrai, and his gripping account of those days and nights of superhuman effort to hold back the enemy until reinforcements arrived, had the boys neglecting their dinner and sitting on the edges of their chairs.

Mr. Hampton was a radio enthusiast. It was his interest in radio development, in fact, which had caused him to build the station on his estate, for purposes of trans-oceanic experiment. Eventually, therefore, the talk came around to the subject of radio. Colonel Graham was well-informed, and he told of several army officers then at work on behalf of the government at Massachusetts Institute of Technology, experimenting with radio-controlled automobiles, tanks and water craft.

An exclamation from Jack drew attention to him and covered him with confusion.

"Well, Jack," said his father, in mild reproof. And he looked expectantly at his son as if awaiting an explanation.

Frank came to his rescue. His quick mind also had grasped the significance of Colonel Graham's remark.

"I know what Jack is thinking of, Mr. Hampton," he said. "He's thinking of a radio-controlled airplane."

Colonel Graham smiled.

"Oh, yes," he said, tolerantly. "I mentioned only that these government experts were experimenting with radio-controlled automobiles, tanks and water craft. Of course, airplanes are being studied, too. Is that what you mean?" he asked, looking inquiringly at Jack. "I understand you lads are interested in flying."

"No, sir," answered Jack, flushing a bit. "To tell you the truth, we saw a plane to-day of strange design. And we had reason to believe it was controlled by radio. I was puzzled at the time. I didn't think of radio controls. But your remarks about the officers at Massachusetts Tech. were illuminating. I see now that this plane must have been radio-controlled."

Frank and Bob nodded approval. Their eyes were shining. Mr. Hampton, Mr. Temple and Colonel Graham showed startled interest. Della leaned forward close to Frank and looked at him reproachfully, a hand on his arm.

"And you never told me a thing about it," she said.

"Didn't have any time to tell you," whispered Frank, in an undertone.

Mr. Hampton was speaking.

"Where did you see this plane, Jack?"

"Well, Dad," said Jack, "it was this way." Then he paused and looked at his chums. "Shall I tell?"

"Go ahead, Jack," urged Frank.

Bob nodded approval.

With that Jack told as briefly as possible the circumstances of their day's adventure, and also spoke of the recent interference in their radio receivers by a sharp and continuous dash sounded over a wave length of 1,375 meters. A frown of growing concentration fastened on Mr. Temple's brow as Jack proceeded. When it was apparent that Jack had concluded, Mr. Temple leaned forward.

"I suspected there was something mysterious about that man," he said.

"What man?" asked Mr. Hampton.

The others at the table looked blank.

"Why, the chap who bought the old Brownell house and property. You know the place. There are about 750 acres of land, mainly timber. This inlet, Starfish Cove as the boys call it, is on the property. And there is an old house back in the trees. It is isolated, there is no habitation near, and the house has a bad name to boot. Some of the old-timers in the settlement at the crossroads declare the place is haunted."

"So that is part of the Brownell property?" asked Mr. Hampton.

The boys looked at each other. Della surreptitiously squeezed Frank's hand beneath the table. This promised to be interesting. The Brownell place was one of the delightful bugaboos of their childhood. Old Captain Brownell, a Yankee whaling skipper, was long since dead. The house had stood boarded up and untenanted for years. Tradition declared he had committed acts of piracy on the high seas during the period of his whaling voyages and that, having retired uncaught, he had come down to this secluded nook and built the great house in order to hide there from some of his old associates whom he had cheated, but that they had found and slain him. It was his ghost, it was said in the countryside, which haunted the place.

"Yes," replied Mr. Temple, in answer to Mr. Hampton's question. "Starfish Cove and all that land around there, where Bob found this secret radio plant located, is part of the Brownell property."

"And who is this man who bought it?" asked Bob, putting the question in all minds.

"I don't even know his name," confessed Mr. Temple. "But what I do recall are some things told me by McKay, a real estate dealer in the city who had the Brownell property on his list for a long time. He said this chap who bought the place impressed him as a man who only recently had come into the possession of money, and he wondered what he wanted with the Brownell property. The newly-rich man usually wants to make a splurge, he doesn't want to buy a country home away off somewhere, in an out of the way nook, where people can't see him. He wants to be seen.

"This man, on the contrary, apparently wanted seclusion—and he wanted a place in a secluded spot on the seacoast. That was his impressing requirement. So McKay sold him the Brownell place.

"Afterward, said McKay, he learned the new owner had put up signs all around the property, warning away trespassers. McKay said he even understood guards were to be employed to keep out intruders."

"On the landward side of that old Brownell place, Dad, they've built a high fence of heavy strands of wire on steel poles," said Bob. "I bumped into it the other day. They haven't quite reached the shore with it, however, although I suppose they intend to."

"Well, this is interesting," said Mr. Hampton. "I wonder——"

He paused, looking thoughtful.

"What, Dad?" asked Jack.

"Oh," said his father. "New York undoubtedly is the center of powerful groups of men seeking to evade the prohibition law by bringing liquor illicitly into the country. Much of the liquor is brought by ship from the Bahamas and the West Indies, and then smuggled ashore in various ways. Perhaps, the old Brownell house, built by a pirate of yesterday, is the home of a modern pirate, who directs activities from this secluded spot."



CHAPTER IV

ON THE TRAIL

After a rather late breakfast next morning for, it being vacation, the boys were under no necessity to rise early and being healthy lads took full measure of sleep, Jack appeared at the Temple home, and the three went into conference. Mr. Temple, head of a big exporting firm, had left early for the city by automobile. Mr. Hampton, reported Jack, had done likewise with his guest.

"Fellows," said Jack, "when I got up this morning, it was with the feeling that this mystery was too good to be overlooked."

Frank's eyes brightened.

"Just the way I feel about it," he declared. "I told Bob when we were dressing that we were in luck, because right at the moment it was beginning to look as if we were in for a dull summer, Fortune went and put an exciting mystery on our doorstep."

Big Bob yawned.

"Oh, you fellows don't know when you have a good thing," he said. "I suppose you want to go and stir up a lot of trouble as you did last summer. Why can't you let well enough alone?"

They were in the sitting room shared by Bob and Frank, and the latter picking up a handy pillow promptly smothered his big chum with it and then sat on him.

"Don't mind him, Jack," he panted, in the resulting tussle. "He's always like this when he gets up in the morning."

A spirited engagement followed, from which Jack discreetly kept apart. Presently, when the couch was a wreck and Bob had Frank over his knees and was preparing to belabor him, Jack interfered.

"Listen to reason, you fellows," he pleaded. "I've got a proposal."

"Shall we listen to the proposal, Frank?" asked Bob, now fully awake, and grinning broadly. "Or shall we muss him up a bit?"

"'Ark to his Royal 'Ighness," shouted Frank, his equilibrium restored. "'Ear. 'Ear."

"Very well," said Bob, addressing Jack with mock solemnity. "My friend says you are to be spared. But, mind you, it must be a good proposal. Now, out with it."

Jack, ensconced in a deep easy chair, uncrossed his knees and leaned forward.

"You remember what was said last night about the operations of the liquor smugglers in and around New York?" he inquired.

The others nodded.

After the conversation the previous night had been directed by the revelations of the boys regarding their mysterious neighbors, and by Mr. Hampton's comments on the operations of liquor smugglers, the boys had learned from the older men surprising facts regarding the situation.

Since the adoption of prohibition, they had been told, liquor-smuggling had grown to such an extent that a state of war between the smugglers and the government forces practically existed. Single vessels and even fleets were engaged by the smugglers to bring liquor up from the West Indies and land it on the Long Island and New Jersey coasts, and to combat these operations the government had formed a so-called "Dry-Navy" comprising an unknown number of speedy submarine chasers. A number of authentic incidents known to Colonel Graham and to Mr. Hampton and Mr. Temple had been related in which the daring of the smugglers had discomfited the government men, in one case a cargo of liquor having been landed at a big Manhattan dock by night and removed in trucks while a sub chaser patrolling the waterfront passed the scene of operations several times, unsuspecting. There were other stories, too, of how the tables were turned, an occasion being cited when a sub chaser put a shot across the bow of what appeared to be a Gloucester fishing schooner which thereupon showed a clean pair of heels and tried to escape but was run down and captured inside the three-mile limit and proved to contain a $30,000 cargo of West Indian rum.

Some of these facts, of course, had appeared in the newspapers. Others had not been made public. But, far from New York City as they were and not interested in reading about news events, for they had their own interest to engage their attention, the boys were not familiar with the situation. What they had been told came as a tremendously interesting revelation.

"Very well," continued Jack, as Bob and Frank prepared to listen; "remembering what we heard last night about the liquor smugglers, it certainly seems likely, doesn't it, that the man who has bought the haunted Brownell house, built a secret radio plant and introduced a radio-controlled airplane into our exclusive neighborhood, may be involved with the smugglers?"

"Righto, Jack," Frank declared. "But what's your proposal?"

"Simply that we do a little investigating on our own account."

"If you intend to propose that we go nosing around the Brownell place, trying to spy and snoop, I vote against it," declared Bob. "I ran away yesterday, after discovering that radio plant, because I felt danger in the air. With a wire fence built to keep out intruders and with New York gunmen posted in the woods, I have a feeling it wouldn't be healthy to do any investigating. If I were tiny as Frank here"—reaching over to rumple his chum's hair—"it might do. They couldn't hit me. But, as it is, I'd make a fine target."

Jack smiled and nodded agreement.

"Agreed on that," he said. "Dad always tells me it is only a foolhardy idiot who puts his head into danger unnecessarily. But that isn't the kind of investigating I had in mind."

"Then what?" asked Frank.

"Well, first of all, this is a fine day for flying," answered Jack, pointing out the open window, to where warm sunshine lay over the country and the sparkling sea in the distance. "You fellows lie abed so long. You haven't had a chance yet to see what an ideal day it is; warm, cloudless, and with hardly a trace of wind."

"What's flying got to do with it?" asked Bob. "We saw yesterday about all we can see from the air. Any more flying over there will make somebody suspicious."

"I was thinking of a little trip to Mineola," said Jack. "Then we can leave the old bus on the flying field there and motor into the city in an hour. Once in the city we might ask Mr. McKay, your father's real estate friend, who the fellow is who has bought the old Brownell house."

"Then what, Hawkshaw?"

"Oh, Bob, don't be such a grouch," protested Jack. "What if nothing comes of it? We'll have had a good trip, anyhow."

Bob grinned.

"I'm not grouching, Jack," he said. "Only I wanted to see what you had in mind. If it's just a flying trip you're after, well and good. I'm with you. The plane is limbered up since I worked it over, and yesterday's little spin gave me a taste for more, too. But if you are really intent on getting at the bottom of this mystery, I have a proposal, too. What's the matter with our hunting up the Secret Service men? Maybe they would be glad of our tip."

"Good for you, old ice wagon," cried Frank, slapping his chum's broad shoulder.

Jack likewise nodded approval. The previous summer the boys had been instrumental in thwarting the plots of an international gang on the California coast to smuggle Chinese coolies into the country in violation of the Chinese Exclusion Act. As a consequence, they had made the acquaintance of Inspector Burton of the Secret Service and had even been called to Washington to receive the personal thanks of the Chief for their service and to be introduced to the President. Their adventures during that exciting period are related in "The Radio Boys on Secret Service Duty."

"Very good," said Jack, bounding to his feet. "Come on, let's go. It's ten o'clock now. If we hurry, we can cover the sixty miles to Mineola, put up the plane, and be in the city by noon. That will give us two or three hours there, and we can be home easily in time for dinner."

"All right," said Bob. "I'll tell Della where we are going, in case Mother isn't up yet. She had a bad headache, and may be staying in bed. You fellows go down to the hangar, and start getting out the plane. I'll join you right away."

Jack and Frank hurried away, while Bob went to execute his mission. When he rejoined them at the hangar, the plane already was on the skidways.

"You take the wheel going up, Bob," said Frank. "I'll pilot her home."

The trip to Mineola flying field, where Bob and Frank and Mr. Temple as well had taken their flying lessons, was made without incident. Planning not to arouse the suspicions of anybody who might be on watch, Bob was careful to steer a course over the water a good mile out from Starfish Cove. Watching through the glass, Frank reported the little plane missing and no sign of life on the tiny beach or in the woods beyond where the radio plant was hidden.

Mechanics at the flying field, who knew them, took the plane in charge when they alighted. Although they had planned to hire an automobile to take them into the city, they learned they were in time to catch an express train, and boarded it. After a fast run, they emerged from the train which had borne them through the tunnel under the East River and under Manhattan and ascended to the main waiting room of the Pennsylvania Terminal. The hour still lacked several minutes of noon.

"I'm not particularly hungry," said Jack. "If you fellows feel the same way about it, suppose we defer luncheon until we have seen Mr. McKay. Probably we can catch him at his office now. But if we lunch first, there is no telling when we can get to see him. These business men take three or four hours for lunch lots of times."

"Lead on," said Frank. "Do you know where his office is located?"

"At Times Square," said Bob. "I've been there once with Dad. Come on. We'll take the Subway. It's only one station up the line."

The three boys were familiar with the great city, having lived on Long Island all their lives. Although many miles distant from New York, they were frequent visitors. Crossing the big waiting room, they entered the West Side subway, and a few minutes later disembarked from an express train at the Times Square station. Mounting to the surface, Bob led the way to a towering office building. An express elevator shot them to the twentieth story, and there they entered the anteroom of a handsome suite of offices occupied by the J. B. McKay Realty Corporation, and inquired of the information clerk—a young woman—for the head of the firm. Here, however, they met disappointment. Mr. McKay was not in the city.

"Mr. McKay's secretary is here, however," said the clerk, taking pity on their evident dismay. "Wait a moment and I'll call him."

She spoke into the telephone receiver, and then nodded brightly.

"Mr. Higginbotham will see you," she said. "He is in that corner office."

Jack was undecided. He looked to his companions.

"Shall we try him?"

"May as well," said Frank. "Probably he can give us the information we want, just as well as Mr. McKay."

Following directions, they entered a roomy office, furnished in walnut and with walnut panelling on the walls. Two big windows gave a commanding view up Broadway below and west to the Hudson river and the Jersey shore. A small, sharp-eyed man, with graying hair, immaculately dressed in gray, rose from the desk as they entered and regarded them inquiringly.

Jack wasted no time on preliminaries, but after introducing himself and his companions, stated their mission. They wanted to know who was the man who had bought the old Brownell place, and what was known about him.

His name? Mr. Higginbotham could not recall it. He doubted whether there was a record of it at hand. The old Brownell place? Yes, he remembered the property. Why were the young men interested.

Sharp-eyed Frank detected a slight start at Jack's query. Moreover, he thought there was an air of guarded watchfulness about Higginbotham, for no apparent reason. That mysterious sixth sense which so often had been of value in the past now came to the fore. Before Jack could reply, he took over the conversation.

"Oh," said he, lightly, "being neighbors, we were just curious, we wondered who had bought the haunted house. That's all. My uncle, Mr. Temple, is a friend of Mr. McKay. So, being near, we thought we would stop in and ask him. That's all. Sorry to have bothered you. Good day."

And taking the bewildered Jack and Bob by their arms, he gently propelled them to the door.



CHAPTER V

PURSUING THE "RADIO" PLANE

Not before they had reached the street did Frank vouchsafe an explanation of his amazing conduct. Then Jack, refusing to be put aside any more, gripped him by the arm and swung him about so that they stood face to face.

"Out with it, now," he demanded. "Why did you hurry us away from that office? And why didn't you tell Mr. Higginbotham our reason for trying to discover something about this man who has taken the Brownell place?"

Big Bob quizzically regarded his smaller companion.

"Guess I know," he said. "Frank had another hunch. Didn't you?"

"Yes," confessed Frank, "and that's about all I had to go on, too. But it was a strong one. Something inside of me kept saying that man Higginbotham wasn't to be trusted. There was a look in his eyes, watchful and cunning. And he made a little start when we asked him about the Brownell place. I don't know. There was nothing definite, nothing I can point out to you now. I feel almost ashamed of myself, as a matter of fact."

Bob put an arm over his shoulder.

"You needn't," he said. "Forget it. I'll put my faith in your hunches every time. Well, what'll we do now? Look up the Secret Service men, or have lunch first?"

"Let's eat," said Jack.

He was a bit out of sorts because his plan to pump Mr. McKay had miscarried. Bob who read him aright, grinned and slapped him resoundingly on the back.

"How much money you got, old thing?" he asked. "I came without any. Do we eat at a Child's restaurant or at the Knickerbocker Grill."

They stood on the corner of Broadway and Forty-second street, immediately in front of the Knickerbocker. Toward it Bob, who was fond of good eating, gazed with longing.

"Too high-priced for my purse," said Jack. "Besides, we haven't the time to waste over eating there. Takes too long. We must be on our way. However, I can do you better than a lunch counter, so come on. I know a place around here on Forty-second street."

Taking the lead, Jack led the way through the busy throng that congests traffic at Times Square at all hours of the day and practically all of the night, too. They turned in at a small restaurant on Forty-second street, and despatched lunch in double-quick time.

During the course of the meal, Bob gave an exclamation.

"I planned to call Dad and tell him we were in town and why," he said. "But it's too late now. He'll have gone out to lunch."

Jack knew it would be impossible to reach his father by telephone. Mr. Hampton the night before had announced he planned to spend the day going over certain engineering plans with Colonel Graham, and Jack had only a vague idea where they would be in conference.

"Now for the Secret Service men," said Jack, at conclusion of the meal. "Luckily I have a card of introduction from Inspector Burton in my purse. Also it gives the address—down on Park Row. Well, the Subway again. Only this time, the East Side branch to Brooklyn Bridge."

Once more stemming the torrent of human traffic flowing along Forty-second street, the boys made their way eastward to the Grand Central station, boarded a southbound express train on the Subway tracks, and were whisked to their destination at lightning-like speed.

Park Row also was crowded, the noon hour crowds of workers, from the towering skyscrapers of the financial district to the south, loitering in City Hall Park and sauntering up and down the thoroughfare to which the park gives its name. Jack and Bob felt their spirits react to the impulse of the busy life around them, but the sensitive Frank, who hated crowds, became peevish.

He urged his companions to hurry.

"Forget the sight-seeing," he said, "and let's move along. The quicker I'm out of this mass of humanity, the better pleased I'll be. These crowds of New Yorkers don't give a fellow a chance to take a deep breath for fear he'll crush in somebody else's ribs."

"Here we are," said Jack, turning in at a tall office building, near lower Broadway, with old St. Paul's and its churchyard, filled now with loitering clerks spending their dinner hour among the graves, just across the way.

Once more an express elevator whisked the trio skyward. At the fourteenth floor they alighted, made their way to an office, the glass door of which bore no lettering except the number "12," and entered.

"Inspector Condon, please," said Jack, to a fat young man, smoking a long black cigar, who sat in his shirtsleeves at a desk, reading through a mass of papers.

The latter got to his feet, and held out his hand. He had a jolly face which broke into a grin of welcome, as he extended his hand.

"That's me," he said.

Jack was rather taken aback. He had not expected to meet so young a man in a position of such responsibility. This man could not have been more than 26 or 28 years of age. Passing over his astonishment, however, Jack introduced himself and his companions and then extended the card of introduction given him a year before by Inspector Burton, when they left Washington, but which heretofore had not been presented.

"So," said Inspector Condon, reading the note on the back of the card; "you are the three chaps who made such a stir in that business in California? Mighty glad to meet you. Sit down. What can I do for you?"

"That remains to be seen," said Jack. "However, we have run into something rather curious, and we thought you might be interested. So if you have time to listen, we'll spin the yarn."

"All the time in the world, friend," said Inspector Condon, genially. "Shoot."

Thereupon, Jack proceeded to relate the story of the secret radio plant, the mysterious plane probably controlled by radio and thus able to operate in silence, and the facts as they had obtained them from Mr. Temple regarding the occupant of the old Brownell place known as the "haunted house."

"Ha," said Inspector Condon; "if that fellow is a liquor smuggler, the 'haunted house' has spirits in it, all right, all right."

And he laughed uproariously at his own joke.

"But, now, boys," he added, sobering; "an investigation into this matter would be somewhat outside of my province. However, I'll place this information before the prohibition enforcement officials, who will be glad to get it, I can assure you. Let me thank you, in behalf of the government, for coming to us with your information."

After a few more moments of conversation, during which Inspector Condon made a note of their names and addresses, the boys left.

At the door, Jack turned for a last word.

"If we can be of any help," he said, "call on us. We have a radio plant and an airplane at our command, and, besides, are admirably situated near the scene."

"Fretting for more adventure, are you?" asked Inspector Condon, clapping him on the shoulder. "Well, that's a kind offer, and I'll pass it along to the proper people to handle this matter. If they need any help, you'll hear from them shortly. I expect they won't let any grass grow under their feet on this case."

When once more they stood on the sidewalk, Jack's gaze lifted to the clock in the tower of St. Paul's. Two o'clock.

"Well, we haven't gotten very far with our adventure," he said, a bit dispiritedly. "I thought we would start something that would give us a bit of excitement. But, apparently, all we have done has been to let the whole business slip out of our hands."

"Oh, forget it," said Frank irritably. The noise, the heat and the bustle of the city had irritated his nerves. "Come on. Let's get out of this. I hate all this hurly-burly. If we take the Subway over to the Flatbush Avenue terminal of the Long Island Railroad, we'll just about have time to make an express to Mineola."

The roar of the Subway was not conducive to conversation, and little further was said until the trio boarded the train in Brooklyn, and pulled out for the short run to Mineola. Early editions of several afternoon newspapers were purchased at the terminal newsstand, and the boys settled down to glance at the day's happenings when once ensconced in the train.

Presently Frank, his irritation forgotten now that the city was being left behind, called the attention of his companions to a first page story under flaring headlines which read:

RUM RUNNERS LAND BIG LIQUOR CARGO; ELUDE "DRY NAVY."

"Say, I haven't been reading any of this stuff," said Frank. "But after what the men told us last night about the size of these operations, and with my interest aroused by developments at Starfish Cove, I'm beginning to see that this defiance of the prohibition law is just about the most stirring thing before the Nation to-day. At least, here on the Eastern seaboard, where these smugglers are organized and have a handy base in the West Indies."

The others nodded agreement, and the conversation proceeded in similar vein until they tumbled from the train at Mineola. Speeding to the flying field in a taxi, they were soon aboard the plane. This time Frank took the wheel. And to the friendly farewells of the mechanics, they took off and began the homeward journey.

After forty minutes of speedy flying, Bob, idly scanning the sky through the glass, focussed upon a tiny speck in the distance. All three had clamped on their radio receivers and hung the transmitters by straps across their shoulders. Speaking into the transmitter now, Bob announced:

"I think that radio-controlled plane is flying away from us, out to sea, off to the right. I'm going to tune up to that 1,375-meter wave length, and we'll see if there's a continuous dash in the receivers."

"All right," answered Jack, "but look out for your eardrums. The interference at that wave length is very sharp and you want to be ready to tune down at once, or your head will feel as if it were ready to burst."

A moment later the high crashing shriek, with which Jack had become familiar of late, signalled in the receivers, and Bob promptly tuned down.

"Wow," said he. "That's it, all right. That's the continuous dash which is being sent out from the secret radio plant to control that little plane. Let's keep it in sight, Frank, and see where it goes. Don't close in on it. Keep just about this distance. I can watch it through the glass, and I'll give you your bearings if you lose sight of it. Probably there is only one man aboard, and he won't have a glass, and won't know we are following him."

"All right," responded Frank. "Here's where we'd turn toward shore. But we'll stick to his trail a while."

With that he began edging the plane out to sea.



CHAPTER VI

A FALL INTO THE SEA

Out over the shining sea flew the glistening all-metal plane, and the spirits of the boys lifted to the chase. The oldest fever of the blood known to man is that of the chase. It comes down to us from our prehistoric ancestors who lived by the chase, got their daily food by it, wooed and won by it, and fought their battles by it in that dim dawn of time when might was right and the law of tooth and claw was the only rede.

Gone was the irritability that had possessed Frank in the noise and din, the crowding walls and swarming hordes of human beings, back in the city. Below him lay the broad Atlantic, from their height seeming smooth as a ball-room floor, with the surface calm and unruffled. No land was in sight ahead. The water stretched to infinity, over the edge of the world. For a wonder, not a sail broke that broad expanse due south, although to the west were several streamers of smoke where ships stood in for port, hull down on the far horizon, while closer at hand was a little dot which Bob, swinging the glasses, made out to be a four-masted schooner.

It was a long distance off, ten or fifteen miles, judged Bob. The tiny plane was heading in that direction. Was it bearing away for the schooner? The question leaped into Bob's mind. He put it into spoken words, into the transmitter.

"There's a schooner southwest," he said. "The plane is going in that direction. Bear up a trifle, Frank, and slow her down. Let's see whether the plane is heading for it."

Frank slowed the engine and altered the course sufficiently to keep the plane in view on the new tack, but not to bring them so close to it as to arouse suspicion. In a few moments, all could see the tiny speck coasting down on a long slant and Bob, watching through the glasses, exclaimed excitedly:

"The little fellow is going to land. There, he's on the water now. He's taxying close to the ship."

"I'm going to climb," stated Frank, suiting action to word.

"Good idea," said Jack. "Let me have the glasses a minute, Bob, will you?"

Bob complied.

"I don't believe they know of our presence," Jack presently declared. "Do you fellows consider the plane was forced to land? Is that how it happened to come down near the schooner? There doesn't seem to be any attempt to put out a boat and get the pilot."

"Forced to land, my eye," said Bob, repossessing himself of the glasses. "Do you want to know what I think? I believe the pilot is holding a confab with the schooner. By Jiminy, that's right, too. And it's ended. He's taxying again, and starting to rise."

Frank, at Bob's words, had swung away again to the south. After describing a long circle, which carried them so far aloft and so wide of the ship as to lose it from sight, he again turned the plane toward home.

"I expect they never saw us, either from the schooner or the plane," Jack said. "There was never any indication of alarm. Of course, we were too far off to tell exactly, even spying through the glass."

"Somehow, however," replied Frank. "I have the feeling that they didn't."

"Didn't what?" asked Bob.

"Didn't see us," answered Frank.

Frank had accelerated the speed of the engine, and was driving at eighty miles an hour, straight for home. Suddenly, an exclamation from Bob, who again was swinging his glasses over the sea below, smote the ears of the boys.

"Something's the matter with that little plane. Say"—a breathless pause—"it's falling. Come on, Frank. We'll have to see if we can help. Swoop down. There, to the left."

Rapidly Frank began spiralling and in a very short time was near enough to the small plane for it to be seen clearly with the naked eye. It had been flying at a considerable height. As the boys watched, it went into a dive, with the pilot struggling desperately to flatten out. He succeeded, when not far from the surface of the ocean. As a result, instead of diving nose foremost into the water, the plane fell flat with a resounding smack, there was a breathless moment or two when it seemed as if the little thing would be swamped, then it rode lightly and buoyantly on the little swells.

Descending to the water, Frank taxied up close to the other plane. The figure of the pilot hung motionless over the wheel. Probably, considered the boys, the man had been flung about and buffeted until he lost consciousness.

"I'll close up to him head on," Frank said. "Then, if necessary, one of you can climb into the other plane and see what we can do to help. Probably the thing to do will be to get him aboard here, and carry him ashore."

"Righto," said Bob, climbing out to the fuselage, behind the slowly revolving propeller. "Now take it easy. We don't want to smash. I can drop into the water and swim a stroke or two, and get aboard."

As the boys swung up close, however, the figure at the wheel of the other plane stirred. Then the man lifted his head and looked at them, in dazed fashion.

"Mr. Higginbotham," exclaimed Frank, under his breath. "Well, what do you know about that?"

It was, indeed, the man they had interviewed earlier that day in the McKay realty offices, back in New York.

"How in the world did he get here?" asked Jack, who also had recognized the other.

Frank had brought their plane to a halt. It bobbed up and down slowly on the long ground swell, not far from the smaller machine.

Bob was still astride the fuselage.

"Hello," he called. "We saw you fall and came over to see if we could help. Engine gone wrong, or what was it?"

Higginbotham was rapidly recovering his senses. He stared at his interlocutor keenly, then at the others. Recognition dawned, then dismay, in his eyes. But he cloaked the latter quickly.

"Why, aren't you the lads who were in my office to-day?" he asked, ignoring Bob's proffer of help.

"You're Mr. Higginbotham, aren't you?" answered Bob. "Yes, we are the fellows you spoke to."

"What in the world are you doing out here?" Higginbotham demanded, sharply.

"Why, we told you we lived near here. We had flown to Mineola and then motored to the city. And we were just flying home when we saw you fall, and came over to do what we could."

"Oh."

Higginbotham stared from one to the other. Had he seen them pursue him and spy on him as he visited the schooner? That was the question each boy asked himself. Apparently, he had not done so, for his next question was:

"Do you fly around here often in your plane?"

Frank took a hand in the conversation. If big Bob were left to carry on alone, he might blunderingly give this man an inkling of what the boys knew or suspected about their mysterious neighbors. Frank felt that his chill of suspicion, experienced when he encountered Higginbotham in New York, was being justified. Decidedly, this man must be in with the mysterious inhabitant of the old Brownell place. Equally certain was it that he had lied in stating he did not know the name of the man who had bought the property.

"Oh," said Frank, "we haven't had the plane out for weeks until a day or two ago, when we made a trial spin, and again to-day. We've been busy for a month overhauling it."

That, thought Frank, ought to stave off Higginbotham's suspicions. Evidently, the other was feeling around to learn whether they had flown sufficiently of late to have spied out the secret radio plant or seen the radio-controlled plane in operation.

"And I'll bet," Frank said himself, "that it is a complete surprise to him to find there is a plane in his neighborhood. Probably, he thought he could operate without fear of discovery in this out-of-the-way neighborhood, and it's a shock to him to find we are here."

Some such thoughts were passing through Higginbotham's mind. How could he get rid of these boys without disclosing to them that his was a radio-controlled plane?

"I'm very much obliged to you, gentlemen," he said, smoothly, "for coming to my aid. As it is, however, I do not need help. This is a plane of my own design, I may as well state, for I can see its surprising lines have aroused your curiosity. I would prefer that you do not come any closer but that, on the other hand, you would leave me now. I want to make some minor repairs, and then I shall be able to fly again."

"Very well, sir," answered Bob composedly, climbing back from the fusilage to his seat in the pit. "We don't want to annoy you. Good day."

With that, Frank swung clear, the propeller to which Bob had given a twist began anew to revolve, the plane taxied in a circle, then rose and started for the shore.

"We certainly surprised him," chuckled Jack. "He didn't know what to say to us. In his excitement and his fear of discovery of some secret or other, he acted in a way to arouse suspicion, not dispel it. Well, Frank, you win the gold medal. Your hunch about Higginbotham being untrustworthy certainly seems to have some foundation."

"I'll say so, too," agreed Bob. "But what do you imagine happened to him?"

Bob sat with the glasses trained backwards to where the little plane still rode the sea.

"That's easy," answered Jack. "Something went wrong at the secret radio plant and the continuity of the dash which provides the juice for the plane's motor was broken. That's the only way I can figure it. I say. Let's tune up to 1,375 meters, and see whether that continuous dash is sounding."

"It's not there," Bob announced presently. "Not a sound in the receivers. Neither does the plane show any signs of motion. Look here. Suppose that whatever has happened at that fellow's radio plant cannot be fixed up for a long period, what will Higginbotham do? Ought we to go away and leave him?"

"Well," said Jack, doubtfully, "it does look heartless. He's four or five miles from shore. Of course, we might shoot him a continuous dash from our own radio plant."

"Zowie," shrieked Bob, snatching the receiver from his head, and twisting the controls at the same time, in order to reduce from the 1,375-meter wave length. "There's his power. No need for us to worry now. Oh, boy, but wasn't that a blast in the ear?"

Ruefully, he rubbed his tingling ears. Jack was doing the same. Poor Frank, whose eardrums had been subjected to the same shock, also had taken a hand from the levers at the same time and snatched off his headpiece.

"She's rising now," cried Bob.

Without his headpiece, Frank could not hear the words and kept his eyes to the fore, as he swung now above the line of the shore. Jack, however, also was straining his eyes to the rear, and he snatched the glasses from Bob and trained them on the plane.

True enough, Higginbotham was rising.



CHAPTER VII

A CALL FROM HEADQUARTERS

It was not yet five o'clock when, the airplane safely stowed away and the doors of the hangar closed and locked, the boys once more stood on the skidway.

"What say to a plunge before we go up to the house?" proposed Frank. "There's nobody to see us. We can strip down at the beach, splash around for ten minutes, and then head home. It's a hot, sticky day and that trip to the city left me with the feeling that I wanted to wash something away."

The others agreed to the proposal and they started making their way to the shore, discussing the latest turn of events on the way.

"It certainly looks as if your hunch about Higginbotham, when we met him in his office, was justified," said Jack, clapping Frank on the shoulder.

"The boy's a wonder," agreed Bob. Then, more seriously, he added:

"But, I say. Higginbotham isn't the man who flew the radio-controlled plane before. I mean the fellow whose tracks I found in the sand. That chap was peg-legged."

"That's right," agreed Jack. "And where does Higginbotham figure in this matter, anyhow? It's some mystery."

"Well, let's see what we do know so far," suggested Frank. "It's little enough that we have found out. But I like mysteries. First of all, Bob finds a secret radio plant, and——"

"No," interrupted Jack. "First of all, I discover interference in the receivers at a 1,375-meter wave length."

"Yes, that's right," said Frank. "Well, second is Bob's find of the radio plant to which he is led by tracks in the sand made by a peg-legged man. Look here. Bob thought at the time that man had arrived in a boat. He saw marks on the sand indicating a boat had been pulled up on the shore. Might not that have been the indentation made by the radio plane?"

"Just what I was thinking to myself a minute ago," said Bob.

"Anyhow," continued Frank, "we then discovered the radio plane in Starfish Cove. From Uncle George we learned a mysterious stranger had recently bought the Brownell place, the 'haunted house,' and had built a fence about the property and set armed guards to keep out intruders. The plot was thickening all the time."

By now the boys had reached the shore and well above the tide mark they began to strip, dropping their clothes in heaps. Frank continued talking as he shed his garments:

"So we decided to go up to the city and ask Mr. McKay who it was had taken the Brownell place. Instead of Mr. McKay we found his secretary, Higginbotham, who professed to know nothing about the matter. Yet, when we arrive down here, we find Higginbotham in the radio plane, visiting a schooner well off shore.

"Say, fellows," he added, as having dropped the last article of clothing, he stood prepared to plunge in; "that man Higginbotham must have left his office immediately after we interviewed him, and probably came down by motor car. We spent two or three hours longer in the city, which gave him the chance to beat us. Now what brought him down here?"

"Search me," said Bob. "There may be a big liquor plot, and he may be in it. Probably, is. Perhaps he was alarmed at our inquiries and hurried down to keep things quiet for a while."

"That's just what he did, Bob, I do believe," said Jack, approvingly. "I believe you've hit it."

"Oh, well, come on," said Bob. "Let's have this plunge."

Scooping up two handsful of wet sand he flung it at his companions. Then the fight began.

Forty-five minutes later, as they strolled across the lawn of the Temple home, Della came running to join them from the tennis court where she was playing with a girl visitor.

"Where have you been?" she cried. "Some man has been calling for the three of you on the telephone. Two or three times in the last hour."

"Calling for us, Sis?" said Bob. "Who is he?"

"I don't know," she said. "He hasn't given his name. I believe he's calling from New York."

The boys looked at each other, puzzled. Who could it be?

"Oh, there's Mary again," said Della, pointing to a maid who at that moment emerged on the side veranda, overlooking the tennis court.

"Mister Robert, you're wanted on the telephone," came the maid's voice.

Bob hurried indoors, Jack at his heels. Frank hung behind.

"Well, Mr. Frank Merrick," said Della pertly. "Give an account of yourself, if you please. What were you boys doing in the city to-day? You think you're grand, don't you, to go flying off in your airplane, on the very day I invite a girl down here to meet you?"

"Is she good looking, Della?" asked Frank, anxiously. "I won't meet her if she isn't good looking."

Della realized he was merely teasing, but she made a cruel thrust in return.

"You don't expect a good looking girl to be interested in you, do you?" she said.

Frank laughed, then reached out to seize her by the shoulders, but she eluded his grasp and went speeding off across the lawn with him in pursuit. They reached the tennis court, laughing and flushed, Della still in the lead. There Della beckoned the other girl to them, and managed introductions.

"This is that scatter-brained Frank Merrick, I told you about, Pete," she said. "Frank, this is my own particular pal at Miss Sefton's School, Marjorie Faulkner, better known as Pete. If you can beat her at tennis, you will have to play above your usual form."

"That so?" said Frank, entering into the spirit of badinage. "Give me a racquet, and I'll take you both on for a set. About 6-0 ought to be right, with me on the large end. Never saw a girl yet that could play passable tennis."

"You scalawag," laughed Della. "When it was only my playing that enabled us to beat Bob and Jack last light. Well, here's your racquet, all waiting for you. Come on."

Della was a prophet. The slender, lithe Miss Faulkner, with her tip-tilted nose, freckles, tan and all, proved to be almost as good a player as Della herself. The result was that, although both games were hotly contested, Frank lost the first two of the set. He was about to start serving for the third game, when Bob and Jack, giving evidences of considerable excitement, approached from the house.

"Hey, Frank, come here," called Bob.

Frank stood undecided, but Della called to her brother:

"He's a very busy boy, Bob. You and Jack better come and help him."

Noting the presence of the other girl, Bob and Jack came forward, whereupon Della once more managed introductions. Bob, usually rather embarrassed in the presence of girls, seemed at once at ease, and apparently forgot entirely his urgent business with Frank. He and Miss Faulkner fell into the gay chatter from which the others were excluded. Jack seized the opportunity to pull Frank aside.

"Look here," he said. "Something has happened already. That call was from one of the government prohibition enforcement agents up in New York. He said Inspector Condon had carried our information and surmises about our neighbors to him immediately after seeing us. He's coming down to-night to the house. Said he thought he could make the trip in about three hours, and would be here at 9 o'clock."

"Is that so?" said Frank. "Has Uncle George come home yet?"

"No, and he won't be home. It seems he telephoned earlier that he was running down to Philadelphia on business for a day or two. He always keeps a grip packed at his office, you know, for such emergencies."

Frank nodded, then looked thoughtful.

"He ought to be here, however," he said. "Well, anyway, there's your father."

Jack shook his head.

"No, Dad planned to stay in town to-night at his club."

"Well," said Frank. "We'll have to handle this alone. I suppose, however, this man just wants to talk with us at first hand and, perhaps, by staying until to-morrow, get an idea of what's down here for himself. He might even ask us to take him up in the plane over the Brownell place, to-morrow."

"What did Bob say to him?"

"Told him to come on down," said Jack. "What else could he say? We had told Inspector Condon that we placed ourselves at the government's service. I expect I had better put him up at our house overnight. Then we won't have to make any useless explanations to Mrs. Temple."

Frank nodded. Mrs. Temple, though kindly soul enough, was so involved in social and club duties that she had little time to give the boys. As a matter of fact, Frank was not at all certain that she would be at home for dinner that night. As to putting up the stranger at Jack's home, that would be an easy matter. Jack's mother was dead, and a housekeeper managed the house and servants for himself and his father. She was an amiable woman, and all Jack would have to do would be to prefer a request that a guest room be prepared, and it would be done.

"Hey, Frank," called Bob, interrupting their aside; "see how this strikes you? Miss Faulkner and I will play you and Della. We shall have time for a set before dressing for dinner."

"Righto," agreed Frank, taking up his racquet, while Jack sank to the turf bordering the court, to look on.

Bob really outplayed himself, and several times, when he approached Della, Frank whispered to her that her brother was smitten and trying to "show off" before the new girl. Della, well pleased, nodded agreement. Nevertheless, Frank and Della played their best, and the score stood at three-all when Jack hailed them from the sidelines with the information that, unless they preferred being late to dinner, it behooved them to quit playing and hasten indoors. Dinner at the Temples was served promptly at 7 o'clock, and never delayed. Accordingly, the game was broken up.

"Come along, Jack," said Frank, linking an arm in that of his pal; "your father's not at home, and we won't let you dine in solitary splendor. You are coming to dinner with us."



CHAPTER VIII

A CONSULTATION

"This man Higginbotham is not the chief figure in the liquor smuggling ring," stated Captain Folsom emphatically.

Captain Folsom sat in the Temple library, with the boys grouped about him. The time was nearing ten o'clock. From the moment of his arrival, shortly after the hour of nine, he had been in conference with the boys, and they had explained to him in detail all that they had discovered or surmised about their neighbors of the old Brownell place.

An army officer with a distinguished record, who had lost his left arm in the Argonne, Captain Folsom upon recovery had been given a responsible post in the prohibition enforcement forces. His was a roving commission. He was not attached permanently to the New York office, but when violations of the law at the metropolis became so flagrant as to demand especial attention, he had been sent on from Washington to assume command of a special squad of agents. Lieutenant Summers, U. S. N., in command of the submarine division known as the "Dry Fleet," was operating in conjunction with him, he had told the boys.

Still a young man in his early thirties, he had a strong face, an athletic frame and a true grey eye, and had made a good impression on the boys.

"No," he repeated emphatically, "this man Higginbotham is not at the bottom of all this devilment. There is somebody behind it all who is keeping utterly in the dark, somebody who is manipulating all the various bands of smugglers around this part of the world. I believe that when we unearth him we shall receive the surprise of our lives, for undoubtedly, from certain evidences that have come to my attention so far, he will prove to be a man of prominence and importance in the business world."

"But why should such a man engage in liquor smuggling?" asked Jack, astonished.

Captain Folsom smiled.

"My dear boy," he said, "wherever 'big money,' so to speak, is involved, you will find men doing things you would never have suspected they were capable of. And certainly, 'big money' is involved in bootlegging, as liquor smuggling is termed.

"Evidently, you boys have not been interested in watching developments in this situation, since the country became 'dry.' Well, it's a long story, and I won't spin out the details. But, as soon as the prohibition law went into effect, in every city in the country bootleggers sprang up. Many, of course, were of the lawless type that are always engaged in breaking the laws. Others, however, were people who ordinarily would not be regarded as law-violators. In this case, though, they felt that an injustice had been done, that human liberty had been violated, in the foisting of prohibition on the country. They felt it was a matter the individual should be permitted to decide for himself, whether he should take a drink of liquor or not, you know.

"These people, therefore, did not regard it as a crime to break the law.

"Another salve to conscience, moreover, was the fact that tremendous sums of money were to be made out of bootlegging. Liquor was selling for prices that were simply enormous. It still is, of course, but I am speaking about the beginnings of things. People who never had drunk liquor in any quantities before, now would buy a case of whiskey or wine, and pay $100 a case and up for it, and consider themselves lucky to get it. They would boast quietly to friends about having obtained a case of liquor.

"The bootlegging industry, accordingly, has grown to astonishing proportions to-day. Right in New York City are men who are rated as millionaires, who a few years ago did not have a penny, and they have acquired their money through liquor smuggling.

"At first these bootleggers operated individually, and elsewhere in the Nation that is still largely their method. But here in New York there have been increasing evidences lately that some organizing genius had taken charge of the situation and was swiftly bending other bootleggers to his will. For some time, we have been of the opinion that a syndicate or ring, probably controlled and directed by one man, was responsible for most of the liquor smuggling here."

"And do you believe," interrupted Frank, "that this man who has bought the old Brownell place may be that central figure?"

Captain Folsom nodded.

"It is entirely possible," he said. "Moreover, what you have told me about the construction of a secret radio plant, and about the appearance of this radio-controlled airplane, fits in with certain other facts which have puzzled us a good deal lately."

"How so?" asked Jack.

"For one thing," said Captain Folsom, "my colleague, Lieutenant Summers of the submarine division, tells me that his radio receivers aboard the boats of his fleet have picked up any number of mysterious series of dots and dashes lately. Code experts have been working on them, but they have proved meaningless.

"He was puzzled by them. He still is puzzled. But, we have noticed that after every such flooding of the ether with these dots and dashes, a shipment of liquor has appeared on the market. And one theory advanced is that the liquor was landed along the coast of Long Island or New Jersey in boats controlled by radio from a powerful land station. The boats, of course, according to this theory, were launched from some liquor-laden vessel which had arrived off the coast from the West Indies. Radio-driven boats, automobiles or planes, Lieutenant Summers tells me, are directed by a series of dots and dashes. So you see, our theory sounds plausible enough, and, if it is correct, the direction probably has come from this secret radio station."

Big Bob's brow was wrinkled in thought. He seldom spoke, but usually when he did so, it was to the point.

"In that case," he asked, "what would be the necessity for this radio-driven airplane? Apparently, the airplane is for communication from ship to shore. But, with a radio land station, why can't such communications be carried on by radio in code?"

Captain Folsom looked thoughtful.

"There is something in that," he said.

"Perhaps, these plotters are playing safe," suggested Frank. "They may figure that code would be intercepted and interpreted. Therefore, they confine their use of radio to the transmission of power waves, and do not employ it for sending messages. The airplane is the messenger."

Jack nodded approvingly.

"Yes," he agreed, "Frank's idea is a good one. Besides, by using a radio-controlled plane, the plotters can scout over the surrounding waters for miles whenever a ship is about to land a cargo. The plane can make a scouting expedition over the shore, too, for that matter. You see a radio-controlled plane has an immense advantage for such scout work, inasmuch as it proceeds practically without noise."

Captain Folsom slapped his knee resoundingly with an open palm.

"By George," he cried, "I believe you boys have hit it. This scout plane is the answer to what has puzzled us the last few weeks. We know liquor is being landed somewhere from ships, but despite our best efforts both ashore and on the water, we have been unable to run down the smuggling ships or the receiving parties ashore. Well, this plane warns the ships away from the vicinity of the sub chasers, and also directs the landing of the radio-controlled boats with their cargo at lonely spots where there are no guards. Yes, sir, I believe that is the way it has been worked."

He fell silent, and sat with brow wrinkled in concentrated thought. The boys respected his silence, and also were busied with their own thoughts.

"There is one thing that has got to be done," said Captain Folsom, presently.

There was a gleam of determination in his eye.

"You mean the radio-controlled plane must be put out of commission?" asked Frank quickly.

"You have read my thought," accused Captain Folsom. "Yes, that is just what I was going to suggest. But how to do it, with no evidence against Higginbotham or this mysterious individual living at the Brownell house, is beyond me."

"Jack's a shark at the use of radio," declared Bob. "Perhaps he can suggest some method."

All turned toward Jack.

"It wouldn't do, of course, to make a raid and capture the plane and their radio plant?" Jack asked.

Captain Folsom shook his head.

"No," he said. "That wouldn't do, for a number of reasons. In the first place, as I said, we have no evidence that would stand in court that Higginbotham or anybody else connected with the matter is a law-breaker. It may even be that whoever is behind the plot has obtained a government license for the operation of the radio station. The power of these bootleggers reaches far, and goes into high places. Therefore, we cannot afford to make an open attack.

"But, in the second place," he added, leaning forward and uncrossing his legs; "what good would that do? It would only warn the Man Higher Up that we were on his track. We don't want him warned. We want to close in on him. For I do believe you boys have given us a lead that will enable us to do so. At the same time—we do want to put that plane out of commission."

"Look here," said Jack, suddenly. "It's strange, if with our airplane and our own radio plant, one of the most powerful private plants in the world, certainly in America, it's strange, I say, if with this equipment we are not enabled to work out some method for accomplishing your ends.

"But, let's think it over. Let's sleep on it. I have the glimmerings of an idea now. But I'm tired. It's been a hard day. Suppose we all turn in and talk it over to-morrow morning."

"Good idea, Jack," declared Bob, yawning unrestrainedly. "I'm tired, too."

"Very good," said Captain Folsom. "Meanwhile, I shall have to take advantage of your kind offer to put me up for the night."

"No trouble at all," said Jack, heartily. "Come along. Night, fellows. Come over to my house after breakfast. Night."

With mutual farewells the party broke up, Frank and Bob retiring to their rooms, and Jack and his guest starting to make their way to the Hampton home. On the part of none of them was there any prevision of the strange events the night would bring forth.



CHAPTER IX

THE ENEMY STRIKES

In the middle of the night, Jack awoke with a start, and lay silent a moment, listening, wondering what had aroused him. The next moment he heard a cry outside his window of "Jack, Jack, wake up."

It was Frank's voice. Leaping from bed, Jack sprang to the upflung window overlooking the side lawn nearest the Temple house. Outside in the moonlight stood Frank, a pair of trousers pulled over his pajamas, hands cupped to his mouth. He was preparing to yell again.

"What's the matter?" called Jack.

"The hangar's afire. Tom Barnum saw the blaze from your radio station and called the house. I'm off. Come as fast as you can."

Turning, Frank plunged away toward the airplane hangar, clutching at his trousers as he ran. Jack could not help laughing a little at the ridiculous spectacle which his chum provided. Then he turned back to the room and started feverishly to dress, ignoring everything except trousers, shirt and shoes. While he was thus engaged, the voice of Captain Folsom hailed him sleepily from next room.

"You up, old man? Thought I heard voices. Anything the matter?"

"Yes, there is," replied Jack, going to the communicating door. "Tom Barnum, the mechanic-watchman in charge of our radio plant, which isn't far from the Temples' airplane hangar, says the latter is afire. Frank and Bob already are on the way down, and stopped to warn me."

"Afire?" cried Captain Folsom, leaping from his bed, and reaching for his trousers. "That's bad. Just when we need the airplane, too, to spy on these rascals. Half a minute, old man, and I'll be with you. Not so devilish easy to get into trousers with one arm."

"Can I help you?" proffered Jack. "I'm all fixed. Here, let me lace your shoes."

"Well, if you insist," said Captain Folsom.

As Jack deftly laced up the other's shoes, he said in an anxious tone:

"Do you think, sir, those people set the fire? It would be a catastrophe if the plane burned just at this particular time, wouldn't it? There. All ready."

"Mighty good of you," said Captain Folsom. "Lead on, then, and I'll follow. As to the fire, I'll reserve opinion until I get the facts. But these liquor smugglers are unscrupulous, and if they feared the airplane was being used against them, they would have no compunctions about burning it."

From the side of the house on which their rooms were located, Jack and his guest were unable to see anything of the fire, as the hangar lay in an opposite direction. But the moment they emerged outdoors, the blaze showed dully against the sky above an intervening grove of trees.

Without wasting breath in further speculation, Jack and Captain Folsom started running for the scene. The hangar stood a considerable distance away, and so fast had they covered the ground that they arrived pretty well blown.

They found the airplane standing like a singed bird on the sands in front of the hangar, and gathered about were Frank and Bob, Tom Barnum, and Old Davey, Mr. Hampton's gardener.

"The wings are gone, Jack," said Bob, turning as his chum approached. "But, thanks to Tom's rapid work with the extinguisher, the fire did not reach the tank, and the old bus will be able to fly again after she sprouts new wings."

Jack turned his gaze to the hangar. The sides and roof were of corrugated iron. Practically the only wood in the construction was that employed in the skidway. It needed only a glance to tell him the latter had been torn up and piled inside the hangar where it was still smouldering.

"What happened?" he asked.

There were excited answers from all, but presently the story was made clear. Some miscreant apparently had forced open the doors of the hangar, torn up the wooden planks and flooring of the skidway, piled them inside and then set them afire. Probably whoever was guilty employed this method in order to give himself time to escape before the fire should attract attention. He had overlooked, however, the presence of a large tank of chemicals with which to fight fire stored at the rear of the hangar, and Tom Barnum, after telephoning the Temple home, had appeared so quickly at the hangar that, by employing the chemical extinguisher, he had managed to save the airplane from being blown up. Old Davey, a light sleeper, had hurried over from his cottage and the pair were in the act of pushing apart the burning brands in order to wheel out the plane, when Bob and Frank arrived to help them.

"Et's mighty cur'ous," said Old Davey, shaking his head dolefully; "mighty cur'ous, the trouble you boys hev with thet airyplane. D'ye think now et was them Mexicans comin' back?"

"No, Davey," said Jack. "Not this time. Some other set of rascals was responsible."

"What does he mean, may I ask?" inquired Captain Folsom, his curiosity aroused.

Briefly, Jack related to him how the previous summer two representatives of a faction of Mexican bandits engaged in making war on a group of independent oil operators headed by his father in New Mexico, had appeared at the quiet Long Island home, stolen the airplane, and flown with it to Old Mexico where they had employed it in kidnapping Mr. Hampton. The boys, said Jack, not only had effected Mr. Hampton's release but also had recovered the plane, as related in "The Radio Boys On The Mexican Border."

"It's too long a story to be told now, however," he concluded, after giving the above bare outline. "Some other time I'll give you the details if you are interested."

"I certainly am interested," said Captain Folsom, regarding Jack with increased respect. "To think of you boys having done all that!"

"Oh, it was fun," said Jack hastily, embarrassed by the other's praise. "Come on, let's see what the fellows are doing."

The others proved to be engaged in spraying the last of the chemical on the expiring embers of the blaze, and in stamping and beating out the last of the fire. As the light died out, Bob fumbled for and found the switch in the hangar and the electric lights sprang on.

"Whoever did this made a hurried job of it," said he. "I wonder——"

"What?" asked Jack.

"Oh, I was just wondering why the job was left uncompleted? Tom," he added, turning to Tom Barnum; "how big was the blaze when you saw it?"

"Nothin' much," answered the other, his round, good-natured face shining through a fog of pipe smoke. "I was restless. Somethin' I et for dinner, I guess. So I got up to smoke a pipe an' stroll around outside the station a bit, to see if I couldn't get myself sleepy. My room's back o' the power house, ye know. Well, as I come outside I see a light over here. Not much bigger than a flashlight. But it was 2 o'clock in the mornin' an' I knew none o' you could be there. So I thinks either that's fire or some rascal, an' telephoned you, then hustled over here."

"That's it," said Bob. "That explains it. I was wondering why whoever set this fire didn't make a more complete job of it, but I see now. You probably scared him away."

"Might be," said Tom. "He might a heard me callin' to Old Davey as I run past his cottage."

"Well," said Frank, "let's push the bus inside. She's not much good till we get new wings, but we don't want to leave it out here all night."

All lent a hand, and then as he started to swing shut the doors Bob examined the lock and gave an exclamation.

"Not even broken open," he said, disgustedly. "I must have forgotten to lock up when we left. Good night."

This time, he fastened the lock, and then fell in with his comrades and the party started for their homes.

"Whoever did that wasn't far away," Captain Folsom said, thoughtfully. "If we had made a search we might have gotten some trace of him. But it is too late now. I imagine, of course, as I said to Mr. Hampton here earlier, that our bootlegger friends set the fire. When they discovered your airplane in their neighborhood, they feared it would interfere with their plans and decided to get rid of it."