THE BOY INVENTORS' RADIO- TELEPHONE

BY

RICHARD BONNER

AUTHOR OF "THE BOY INVENTORS' WIRELESS TRIUMPH," "THE BOY INVENTORS AND THE VANISHING GUN," "THE BOY INVENTORS' DIVING TORPEDO BOAT," "THE BOY INVENTORS' FLYING SHIP," "THE BOY INVENTORS' ELECTRIC HYDROAEROPLANE," ETC., ETC.

WITH ILLUSTRATIONS BY CHARLES L. WRENN

NEW YORK HURST & COMPANY PUBLISHERS

CONTENTS

CHAPTER

I. THE POWER OF THE AIR

II. AN ENCOUNTER WITH A CHARACTER

III. THE PROFESSOR'S DILEMMA

IV. "WHERE IS HE?"

V. CHESTER CHADWICK—INVENTOR

VI. THE RADIO TELEPHONE

VII. THE GREAT TEST

VIII. TALKING THROUGH SPACE

IX. THE BOYS FACE TROUBLE

X. AN INVOLUNTARY AERONAUT

XI. BY THE ROADSIDE

XII. MAKING ENEMIES

XIII. THE LEADEN TUBE

XIV. IN THE HOSPITAL

XV. A TALE OF THE COLORADO

XVI. ZEB CUMMINGS

XVII. IN THE LABORATORY

XVIII. INTO THE STORM

XIX. THE "LIGHTNING CAGE"

XX. THROUGH THE AIR

XXI. VAULTING TO THE RESCUE

XXII. "Z. 2. X."

XXIII. ON THE BORDER LINE

XXIV. "THE THREE BUTTES"

XXV. INTO THE BEYOND

XXVI. THE START FOR THE UNKNOWN

XXVII. THE PROFESSOR'S SECOND DILEMMA

XXVIII. THE UPPER REGIONS

XXIX. A MUD BATH

XXX. NIGHT ON THE COLORADO

XXXI. THE ISLAND OF MYSTERY

XXXII. THROUGH THE WOODS

XXXIII. THE SECRET AT LAST

XXXIV. THE INTERLOPERS

XXXV. TRIUMPH

XXXVI. THE HOMECOMING



The Boy Inventor's Radio-Telephone.



CHAPTER I.

THE POWER OF THE AIR.

"That's it, Jack. Let her out!"

"Suffering speed laws of Squantum, but she can travel!" exclaimed Dick Donovan, redheaded and voluble.

"I tell you, electricity is the thing. Beats gasoline a million ways," chimed in Tom Jesson. Tom sat beside his cousin, Jack Chadwick, on the driver's seat of a curious-looking automobile which was whizzing down the smooth, broad, green-bordered road that led to Nestorville, the small town outside Boston where the Boy Inventors made their home.

The car that Jack Chadwick was driving differed in a dozen respects from an ordinary automobile. There was no engine hood in front. Instead of a bonnet the car, which was low slung, long and painted black, had a sharp prow of triangular shape. Its body, in fact, might be roughly compared to the form of a double-ended whaleboat.

As it sped along outside the city limits, and immune from hampering speed laws, the car emitted no sound.

It moved silently, without the usual sharp staccato rattle of the exhaust. Behind it there was no evil-smelling trail of gasoline and oil smoke. The car glided as silently as a summer breeze on its wire-wheels, like those of a bicycle enlarged.

"I'll get a great story out of this," declared Dick Donovan, who, as readers of other volumes of this series know, was a reporter on a Boston paper. "That is, if you'll let me write it," he added, leaning forward over the front seat from the tonneau as he spoke.

"How about it, Jack?" asked Tom with an amused smile. "Shall we let Dick here get famous at our expense again?"

"I don't see why not," said Jack. "Everything about the Electric Monarch is patented. The new reciprocating device, and the self-feeding storage batteries are fully covered. If Dick wants to write a romance about it he can, provided he leaves our pictures out."

"Oh, I'll do that," Dick readily promised. "Are you making top speed now, Jack?"

"Nowhere near; I wouldn't dare to. I believe that the Monarch is capable of ninety miles an hour. I wish we had a place like Ormond Beach to try her out on."

"You can count me out on that," chuckled Dick. "This is fast enough for me."

The boys were trying out their latest invention, an electric car capable of making the speed of a gasoline-driven vehicle, and one which could be operated at a minimum of cost, almost a nominal expense, as compared with the high price of a vehicle run by an explosive engine.

It was the trial trip of the Electric Monarch, as they had decided to call it, and so far the performances of the machine had exceeded, instead of fallen below, their expectations. Dick, who had been invited to the "tryout," was full of questions as they sped silently, and with an absolute lack of vibration, along the road.

"How do you generate your electricity?" he asked eagerly.

"By a device geared to the rear axle," answered Tom. "It runs a sort of dynamo, though it would be difficult for you to understand it if I went into details. It's something like the ordinary generator and turns a constant stream of 'juice' into the storage batteries that, in turn, feed the engines."

"Yes, that's all plain enough," said the inquisitive Dick, "but how do you get your power for starting?"

"If there is not enough juice in the storage batteries for the purpose we resort to compressed air," was the reply from Tom, for Jack, with keen eyes on the unrolling ribbon of road, was too busy to have his attention distracted.

"And that?" Dick paused interrogatively.

"Is pumped into a pressure tank as we go along. See that gauge?" he pointed to one on the dashboard of the car in front of the driver's seat.

Dick nodded.

"Well, that's a pressure gauge. You see, we have sixty pounds of air in the tank now. That can generate enough electricity to start the car going. After that the process is automatic."

"Yes, you explained that. Suppose the tank should, through an accident, be empty, and you wanted to start?"

"We've provided for that"

"I expected so. Wabbling wheels of Wisconsin, you fellows are certainly wonders."

"Nothing very wonderful about it," disclaimed Tom. "Well, if we find the tank is empty we have a powerful, double-acting hand pump by which, without much effort, we can get up any pressure we need."

"And then you turn a valve?"

"Exactly, and the air-motor turns over the dynamo which starts generating electricity right away."

"Then, except for the first cost of the car, the expense of operating it is comparatively nothing?" asked Dick.

"Yes, you might say we get our power out of the air, and that's free—so far."

"And there's no limit, then, to what you can do or where you can go with the Electric Monarch?"

"None; that is, so long as the machinery holds out. We are independent of fuel and the lubricating system is so devised that the oiling is automatic and requires attending to only once a month. We could easily carry a year's supply of lubricant."

"Tall timbers of Taunton!" burst out Dick enthusiastically. "You've solved the problem of the poor man's car. All the owner of an Electric Monarch has to do is to pump a little pump-handle or press a little button and he's off without it costing him a cent. My story will sure make a big sensation!"

"Well, you want to tone down that part about its not costing a cent," chimed in Jack as they coasted down a hill. "The expense of the motor and the self-lubricating bearings and so on is pretty steep. But we hope in time to be able to cheapen the whole car."

They were shooting swiftly down the hill as he spoke. The next moment he looked ahead again as they shot round a curve. As they did so his hand sought a button and an ear-splitting screech arose from a powerful siren.

In the center of the road, quite oblivious to the oncoming automobile, was an odd figure, that of a small man in a rusty, baggy suit of black.

He had a hammer in his hand and was hitting some object in the roadway over which he was bending with a concentrated interest that made him quite unconscious of the onrushing car.

"Hi! Get out of the way!" yelled the boys.

But the man did not look up. Instead, he kept tapping away with his hammer at whatever it was that absorbed his attention so intently.



CHAPTER II.

AN ENCOUNTER WITH A "CHARACTER."

Jack jammed down the emergency brakes, which were pneumatic and operated from the pressure tank, with a suddenness that sent Dick Donovan almost catapulting out of the tonneau.

"Jumping jiggers of Joppa!" he shouted, for he had not yet seen the obstacle in the road, "what's happened? Are we bust up?"

"No, but if I hadn't stopped when I did we'd have bust someone else up," declared Jack. "Look there!"

"Can you beat it?" exclaimed Tom.

As the brakes brought the car to a stop within a foot of his stout, rotund figure, the little man in the center of the road looked up with a sort of mild surprise through a pair of astonishingly thick-lensed eyeglasses secured to his ears by a thick, black ribbon. He wore a broad-brimmed black hat and wrinkled, baggy clothes of bar-cloth, and a huge pair of square-toed boots that looked as if their tips had been chopped off with an ax.

Over his shoulder was slung a canvas bag which appeared to be heavy and bulged as if several irregularly shaped, solid substances were inside of it. The spot where this odd encounter took place was some distance from any town, but a bicycle leaning against a tree at the roadside showed how the little man had got there.

"Say, would you mind letting us get by?" asked Jack.

The little man raised a hand protestingly.

"I'll be delighted to in just a moment," he said, "but just now it's impossible. You see, I've just discovered a vein of what I believe to be Laurentian granite running across the road. I am trying to trace it and—what's that? Good gracious! Back up your machine, please. I believe it runs under your wheel. I must make sure."

Jack obligingly threw in the reverse to humor the little man, who darted forward and began scraping up the dust in the road with his hands as if he had been a dog scratching out a rabbit hole. He began chipping away eagerly with his hammer at some rock that cropped up out of the road.

He broke off a piece with his hammer, which was an oddly shaped tool, and drawing out a big magnifying glass scanned the chip intently. He appeared to have forgotten all about the waiting boys. But now he seemed to remember them. He looked up, beaming.

"A magnificent specimen. One of the finest I have ever seen. Most remarkable!"

And with that he popped the bit of stone into his bag, which the boys now saw was filled with similar objects.

"Maybe he'll let us get by now," remarked Tom, but a sudden exclamation from Dick Donovan cut him short.

"Why, hullo, professor," he said, "out collecting specimens?"

The little man peered at him sharply. And then broke into a smile of recognition.

"Why, it's Dick Donovan!" he beamed, hastening up to the car, "the young journalist who wrote an article about my specimens once and woefully mixed them up. However, to an unscientific mind——"

"They are all just rocks," finished Dick with a grin.

"I have had unusual success to-day," said the professor, who appeared not to have heard the remark. "I must have at least fifty pounds of specimens on my back at this minute."

He broke off suddenly. The next moment he darted off to the side of the road and chipped off a fragment of rock from a bank that overhung it.

"This is lucky, indeed," he exclaimed, holding it up to the light so that some specks in the gray stone sparkled. "An extremely rare specimen of mica that I had no idea existed in this part of New England."

The odd little man opened his bag and introduced his latest acquisition into it While he was doing this Dick had been explaining to the boys:

"He's a queer character. Professor Jerushah Jenks. They say he's a great authority on mineralogy and so on. I interviewed him once. He's always out collecting."

"Does he always carry a quarry like that around on his back?" asked Tom.

"Always when he's getting specimens," Dick whispered back.

By this time the professor, his eyes agleam over his latest discovery, was back at the side of the car.

"Ah, my beauty, I have you safe now," he said, patting the side of the bagful of specimens. "Boys, this is my lucky day."

The boys could hardly keep from smiling at the little man's delight. It appeared hard to believe that anyone could find pleasure in packing about a sackful of heavy rocks on a hot day. But the professor's eyes were sparkling. It was clear he considered himself one of the most fortunate of men.

Dick introduced the boys and, to their surprise, the professor declared that he had read of their various adventures and inventions.

"We are actually fellow adventurers in the field of science," he cried, rattling his bag of specimens enthusiastically. "Some time I should like to call on you and see your workshops."

"You will be welcome at any time," said Jack cordially, and then the professor declared that he must be getting home.

"If we are going your way we can give you a ride," said Tom.

"Thank you, I'll accept that invitation. But what an odd-looking automobile you have there."

The boys explained to him that it was a new type of car that they were trying out for the first time and then Dick helped the scientist lift his bicycle into the tonneau. He would have helped him with his weighty load of specimens, but the professor refused to be parted from them. As they started off again he sat with the bag firmly gripped between his knees, as if afraid someone would separate him from it.

The professor lived with a spinster sister to whom his specimens were the bane of her life. As the car rolled swiftly along, he occupied his time by peeping into the bag at frequent intervals to see that none of the specimens, by some freak of nature, flew out.

All at once he reached forward and clutched Jack by the shoulder.

"Stop! My dear young friend, please stop at once!"

"What's the matter?" asked Jack, slowing down at the urgent summons.

"Look! Look there at that rock!"

To Jack the rock in question was just an ordinary bit of stone in a wall fencing in a pasture in which some cattle were grazing. But evidently the professor thought otherwise.

"It's a fine specimen of green granite," he exclaimed. "I must have it. How did such a fine piece ever come to be placed in a common wall?"

The car having now been brought to a stop, he leaped nimbly out, clutching his geological hammer in one hand and his precious sack of specimens in the other. He rushed up to the wall and stood for a minute with his head on one side, like an inquisitive bird.

"Too bad. That stone's a large flat one and goes right through the center of the wall," he mused. "The wall must come down."

And then, to the boys' consternation, he began demolishing the wall, pulling down the stones and throwing them right and left.

"Professor, you'll get in trouble," warned Dick in alarm. "Those cattle will get out. The farmer will be after us."

But the professor paid not the slightest attention. Taking off his coat, he resumed his operations with even greater vigor than before. The cattle in the field eyed him curiously. Then they began to move toward him. In front of the rest of the herd was a big black-and-white animal with sharp horns and big, thick neck.

It gave a sudden bellow and then rushed straight at the considerable gap the man of science had made in the stone fence.

"It's a bull!" yelled Dick suddenly. "Run, professor! Run or he'll toss you!"

With lowered horns the bull rushed down upon the unconscious scientist at locomotive speed. But the professor was oblivious to everything else but uncovering the odd-looking green stone embedded in the heart of the wall.

The boys shouted to him but he didn't hear them. On rushed the bull, bellowing, charging, ready to annihilate the scientist.

"Run!" yelled the boys at the top of their lungs. "Run!"

But the professor, with his precious bag in one hand and his hammer in the other, stood staring at the advancing bull through his thick glasses as if the maddened creature had been some sort of new and interesting specimen.

"Gracious! He's a goner!" groaned Dick.



CHAPTER III.

THE PROFESSOR'S DILEMMA.

But the professor was seen to suddenly dart, with an activity they would hardly have expected in him, across the road. He was only in the nick of time.

Almost opposite to the gap in the fence he had made was a tree with low-hanging boughs. As the bull charged through the gap, right on his heels, the professor, still with his bag, slung by its leather strap across his shoulders, swung himself up into the lower limbs.

The boys set up a cheer.

"Good for you, professor!" cried Dick, as the bull, with lowered head and horns, charged into the tree and made it shake as if a storm had struck.



"Wow! That's the time he got a headache!" cried Tom excitedly, as the professor, clinging desperately to his refuge, was almost flung from it by the shock.

"Gracious, boys, what shall I do?" he asked, looking about him from his leafy perch with a glance of despair that would have been comical had the situation not been serious, for the bull, instead of accepting his defeat, stood under the tree pawing and ramping ferociously.

"Well, here's a fine kettle of fish!" exclaimed Jack. "What are we going to do now?"

"Blessed if I know," said Dick helplessly. "By the bucking bulls of Bedlam, this is a nice mess."

"Maybe we could throw rocks at him and chase him away," suggested Tom.

"No chance; he's got his eye on the professor," returned Jack, "and if we did get out he would chase us and that wouldn't do the professor any good."

"Can't you help me, boys," inquired the professor in an agonized tone. "This tree limb is not exactly—er—comfortable."

"You're in no danger of falling, are you?" called Jack, in an alarmed voice.

"No—er—that is, I don't think so. But this is an extraordinary position. Most—er—undignified. I'm glad my sister can't see me."

"Try throwing some of the rocks out of your satchel at him," suggested Dick.

But the professor waxed indignant at this proposal.

"And cast my pearls before swine! or rather my specimens before a bull!" exclaimed the professor, in helpless indignation. "No, young gentlemen, not a pebble from this bag is wasted on that creature."

"I'd drop the whole bag on him," said Dick, "if I was in that position. It's heavy enough to knock out an elephant, let alone a bull."

"Can't you suggest anything?" wailed the professor.

"I'm trying to think of something right now," declared Jack, racking his brains for some way out of the predicament.

"I wish the farmer that owned him would come along and get his old bull out of there," said Dick.

"Yes, and then there would be fresh complications," declared Jack.

"How do you make that out?" came from Dick.

"He'll probably know how to handle him," supplemented Tom.

"Yes, he would if he's a bull-fighter," scoffed Dick, "and I never heard of there being any matadors in the vicinity of Nestorville."

"Lots of doormats, though," grinned Tom.

"Say, if you do that again I'll throw you out of the car," cried Jack at this atrocious pun.

"Sorry, couldn't help it. Just slipped out," said Tom contritely.

"Well, you'll slip out if the offense is repeated," retorted Dick. "But," he went on, "seriously, fellows, we've got to do something."

"Try blowing the horn," suggested Tom. "It has scared everything else we met. Horses shy at it, so do other autos. Maybe it will get the bull's goat."

"I'll try it, at all events," said Jack.

He pressed the button and the unearthly screech of the electric auto's siren split the air. But the bull merely cast an inquiring glance in their direction and then resumed his vigil over the professor.

"Boys," wailed the unhappy geologist, "can't you do something, anything? I can't roost in this tree all night, like a bird."

The boys couldn't help grinning at this. With his sharp nose, big spectacles and flapping black garments, the professor did look like a mammoth black crow.

"Reminds me of the fox and the crow," said Dick, in a low voice, to his companions.

"Only, in this case, the fox is a bull, and the piece of cheese is the bag of specimens," added Tom.

They looked about helplessly. There was no farmhouse in sight and the road did not appear to be much traveled.

"We'll have to go for help," declared Jack.

"The only thing to do," agreed Tom.

The professor was hailed. He had climbed to another limb with infinite difficulty, because of the encumbering bag of rocks on his back. He declared that he could manage to get along till the boys came back.

"By a merciful provision of providence," he said whimsically, "bulls can't climb trees. The situation might be worse if it was a bear."

"It would be unbearable," declared Dick to Tom.

"But just the same there's trouble a brewin'," retorted Tom. "I wish that farmer would show up."

"As I said before—I don't," responded Jack, as he prepared to start off.

"Why?"

For answer Jack waved an eloquent hand toward the gap in the stone fence.

"I guess he wouldn't be best pleased to find that his fence had been torn down," explained Jack, as the car drove off, leaving the professor marooned in his tree with the sentinel bull waiting patiently below.

Some distance down the road the boys came to a farmhouse. Several men were working in the field under the direction of a stout, red-faced man. Jack shouted to them, and when the red-faced man came up he explained the situation to him. The man was good-natured, or perhaps he rather liked the idea of a ride in such a novel-looking car. Anyhow, he called three of his hands and told them to get pitchforks.

"Never see a bull I couldn't handle," he said as the men, having returned, scrambled into the car.

"Do you know who it belongs to?" asked Jack, as he turned round and headed back to where they left the luckless professor.

"I reckon it's that big Holstein of Josh Crabtree's. He's pretty near as mean as his owner, and that's considerable."

Jack thought of the hole in the wall and hoped they would reach there before farmer Crabtree, and so avoid serious complications.

He drove at top speed, while the friendly farmer and his workmen clung to the sides of the car and looked rather scared at the rate they were going.

"There's the tree," exclaimed Jack, as they came in sight of it, "and there's the gap in the fence."

"And where's the bull?" asked Tom.

"And where's the professor?" added Dick.

Not a trace of the man of science or of the ferocious animal was to be seen.

"Are you sure you boys didn't dream all this?" asked the red-faced farmer suspiciously.

"There ain't even a cow in sight in the pasture lot," said one of the men.

"I reckon this is some sort of a fool joke," added another.

"It isn't. Indeed, it isn't," protested Jack.

"The professor is some place around," said Tom.

But a lengthy search of the vicinity failed to show anything except that the professor had vanished as if the earth had swallowed him.



CHAPTER IV.

"WHERE IS HE?"

"Professor!" hailed Dick, at the top of his lungs.

"Professor!" bawled the farm hands.

The red-faced farmer himself regarded the boys quizzically.

"What sort of a chap is this professor of yours?" he asked with an odd intonation.

"He's a geologist," replied Dick. "Why?"

"Oh, I thought he might be a conjurer," was the rejoinder. "He seems to be pretty good at hiding himself."

"Hark!" exclaimed Jack suddenly, standing at pause and listening intently.

"What's up?" demanded Dick, instantly on the alert, too.

"I heard something. It sounded like——"

"There it is again," cried Tom.

A faint, far-off cry, impossible to locate, was borne to their ears.

"It's a call for help," declared Dick.

"That's what it is," agreed the red-faced farmer. "Must be that perfusser of yours, but where in the name of Sam Hill is he?"

It was a puzzling question. The faint cries appeared to be muffled in some way. They looked about them, endeavoring to locate their source. Suddenly one of the farm hands spoke.

"I used to work fer old Crabtree," he said. "There's an old well hereabouts somewheres and maybe he's fell down that."

"Where is it?" demanded Jack.

"Back in the meadow yonder," said the man, pointing in the direction of the pasture lot.

"Let's go over there and see at once," said Dick. "Frantic frogs of France, if the professor's tumbled into a well he may be in serious trouble."

They set off on the run to where a pile of stones showed a well-curb had once been. The hoards at the top, which had covered it over, had rotted, and there was a jagged hole in them. Jack cautiously bent over and placed his mouth at the edge of the hole.

"Professor, are you down there?" he hailed.

"Y-y-y-y-yes," came up in feeble, stuttering tones. "I'm almost frozen. I'm hanging above the water but I can't hold on much longer. The bag of specimens is too heavy."

"Throw it away," urged Jack.

"N-n-n-not for worlds," was the reply. "I was looking for another rare bit of quartz when I fell in here."

"I'll run to the car," said Jack, who had made out that the well was not very deep. "Fortunately, we've got a rope and tackle in there. Hold on, professor, we'll soon have you out."

He hurriedly explained the situation to the others and ran at top speed to the car, in which the boys—like most careful motorists, who never know when such a piece of apparatus may come in useful for hauling a car out of mud or sand, for instance, or for towing an unlucky autoist home—had a block and tackle stowed.

He was soon back, and the rope was lowered to the professor, who made it fast under his arms. Then, aided by the husky muscles of the farm hands, they soon drew him to the surface. But his weight was materially added to by the stones, and it was no light task to rescue him, dripping and shivering, from the dark, cold shaft.

He explained that soon after they had gone some men came up and drove the bull away. But they had seen the gap in the stone wall first.

"They were positively violent," declared the professor, "and said that they'd have the man who did it arrested if they could find him. Under the circumstances, I deemed it prudent to stay up in the tree, where they could not see me. They drove the bull off into another pasture. As soon as the coast was clear I climbed down, but I happened to see a rare bit of quartz sparkling in the sun on the edge of the well-curb. Imprudently I stood on the planking and fell in."

"Gracious, it's a lucky thing you weren't drowned, with all that weight round your neck," declared Jack.

"It was fortunate," said the scientist mildly, as if such a thing as drowning was an everyday occurrence. "As a matter of fact, if I hadn't succeeded in grasping a projecting stone and held on, I might have gone down. It was an—er—a most discomforting experience."

"Well, of all things," exclaimed the red-faced man, "to go trapesing round the country collecting rocks!"

"Not rocks, sir—geological specimens," rejoined the professor with immense dignity, "and—great Huxley! Under your foot, sir! Under your foot!"

"What is it, a snake?" yelled the farmer, jumping backward as the scientist dashed at him with a wild expression.

"No, sir, but a remarkably fine specimen of what appears to be a granolithic substance," exclaimed the professor, and he began energetically chipping at a rock upon which the farmer had been standing.

"Crazy as a loon," declared the farmer, winking at his men. "Gets nearly drowned in a well and then begins chopping at a rock as soon as he gets out."

"Oh, this has been a lucky day for me," said the professor with huge satisfaction, as he placed his latest acquisition in the satchel. "As fine a specimen, boys, as ever I encountered," he declared, turning to the boys.

"Gracious," exclaimed Tom and Dick in low tones, "does he call getting chased by a bull and then tumbling down a well a satisfactory day?"

"I should call it a rocky time," grinned Dick.

But at this moment further conversation was cut short by the sudden arrival of a gray-haired, short little old man with a tuft of gray whiskers on his chin.

"Josh Crabtree!" exclaimed the red-faced farmer.

"Wow! now the music starts," declared Dick.

Josh Crabtree, his face ablaze, and his small, malignant eyes sparkling angrily, emitted a roar like that of his Holstein that had caused the professor so much tribulation.

"Say, be you the pesky varmints that tore down my fence and scared my bull out'n two years' growth?" he bellowed.

"I removed some stones from your fence, sir," said the professor, "but it was in the interests of science. You may not have been aware of it, but embedded in your enclosing structure was a fine specimen of green granite."

"Great hopping water-melyuns!" roared Old Crabtree, "and you tore down my fence to git at a pesky bit of rock?"

"Rock to you, sir," responded the scientist calmly, "like the man in the poem a 'primrose by the river's brim, a yellow primrose is to you, and it is nothing more.'"

"Dad rot yer yaller primroses," yelled Old Crabtree, dancing about in his rage. "You make good for tearing down my fence, d'ye hear me?"

"I shall take great pleasure in forwarding you a check for any damage I may have done," said the professor.

"I want ther money now," said the farmer truculently.

"I regret that I have left my wallet at home," said the professor. Then he brightened suddenly. "I can leave my bag of specimens with you as security," he said, "if you will promise to be careful with them."

He unslung his bag and tendered it to the angry farmer who received it with a look of amazement that the next moment turned to wrath when he saw its contents.

"By hickory, what kind of a game is this?" he demanded. "Nothing but a lot of old rocks. By heck, thar's enough here to build a new fence!"

He flung the bag down indignantly just as the professor darted forward with one of his odd, swift movements. He shoved Old Crabtree back without ceremony and bending swiftly to the spot where the angry farmer had been standing he picked up and pocketed a small rock.

"Wa'al land o' Goshen," gasped out the farmer, bewildered. "What in ther name of time is this?"

"A splendid specimen of gneiss," explained the professor triumphantly, "and now, Mr.—er—you were saying?"

"That I wants ter be paid fer ther damage ter my fence."

"How much do you want?" asked Jack, coming to the rescue.

"Reckon a dollar'll be about right."

"If you will let me lend it to you till we reach your home, I'll be very glad to pay him," said Jack aside to the professor.

"But, my dear young friend, there is no necessity. He has ample security till I can send him a check. Why, that bag of specimens is worth fifty dollars at least."

"Them old rocks," sniffed the farmer, who had overheard this last remark, "I wouldn't give yer ten cents fer a cartload uv 'em. They're too small fer fences an' too big to throw at cows."

"You'd better let me pay him," said Jack, and the professor finally consented to this arrangement.

This done, they started back on the run to the professor's home, which was about three miles off. On the way they dropped the red-faced farmer and his hands, who clearly regarded the professor as some sort of an amiable lunatic. But that worthy man, supremely happy despite his wet clothes, was quite contented, and from time to time dipped into his satchel, like a bookworm into a favorite volume, and drew out a particularly valued specimen and admired it.

They soon reached his home, a pretty cottage on the outskirts of Creston, a small town with elm-shaded streets. The professor invited the boys to accompany him into the house. They were met in the passage by a shrill-voiced woman who looked like the professor in petticoats.

"My sister, Miss Melissa," said the professor. "My dear, these are——"

But he got no further in his introduction. Miss Melissa's hands went up in the air and her voice rose in a shrill shriek as she saw her brother's condition.

"Lan's sakes, Jerushah, where have you been?" she exclaimed.

"My dear, I must apologize for my condition," said the professor mildly. "You see I——"

"You're dripping a puddle on my carpets. You're wringing wet through!" shrilled Miss Melissa.

"Yes, you see, my dear, I've been down a well," explained the man of science calmly.

"Do tell! Down a well, Jerushah? At your time of life!"

"You see I was after specimens, my dear," went on the professor.

"Specimens!" exclaimed Miss Melissa. "The whole house is full of old rocks now, Jerushah, an' you have ter go down a well to get more."

"These are very valuable, my dear," said the professor, floundering helplessly.

"Oh, don't tell me. A passel of old rocks. I'm going to get you a hot mustard footbath and some herb tea right away," and without another word, except something about "death of cold, passel of boys," the good lady flounced off.

"She's like that sometimes, but she means well, Melissa does," explained the professor, with a rather sheepish look as he stood in the midst of a puddle that was rapidly converting him into an isolated island in the midst of Miss Melissa's immaculate hall carpet. Suddenly, with one of his impulsive movements, he darted off into a room opening off the hall and came back with a dollar bill he had unearthed from a desk. He handed it to Jack, and then, raising his finger to his lips, he said:

"Don't let Melissa see it. She's the best of women, is Melissa, but peculiar about some things—er—very peculiar."

"Je-ru-shah!" came Miss Melissa's voice.

"Yes, my dear, coming," said the professor, and shouldering his bag of specimens he shook hands with the boys and hastened off to answer his sister's dictatorial call.

"I guess we'd better be going," said Jack, with a smile that he could not repress.

The others agreed, and they were soon speeding back to High Towers, as the estate of Jack's father, also a noted inventor, was called, with plenty to talk about as a result of the events of the day.



CHAPTER V.

CHESTER CHADWICK—INVENTOR.

As readers of the preceding volumes of this series, know, Jack Chadwick and Tom Jesson, his cousin, had won the titles of Boy Inventors through their ingenuity and mechanical genius. Jack's father, Chester Chadwick, was an inventor of note, and unlike the majority of inventors, he had turned his devices to such good account that he had accumulated a substantial fortune and was able to maintain a fine estate, already referred to as High Towers where, with splendidly equipped workshops and a miniature lake, he could experiment and work out his ideas.

In the first book of this series it was related how Tom Jesson, Jack's cousin, came to make his home at High Towers. Tom's father, an explorer of international fame, had departed on an expedition to Yucatan and had not been heard from since that time. This volume, which was called the Boy Inventors' Wireless Triumph, told of the boys' exploits in the radio-telegraphic field and the uses to which they were able to turn them. In a flying machine, the invention of Mr. Chadwick, they discovered Tom's father, under remarkable circumstances, a prisoner of a tribe of savages, and also found a fortune in precious stones.

In the succeeding story of their adventures, the boys helped an inventor in trouble. The Boy Inventors' Vanishing Gun, as this volume was entitled, set forth in a graphic way the triumph of the boys over the machinations of a gang of rascals intent on stealing the plans of the wonderful implement of warfare which they had helped bring to successful completion.

We next encountered the lads in the Boy Inventors' Diving Torpedo Boat. Here they were placed in a new environment on the surface and in the depths of the ocean. The way in which the wonderful diving craft aided Uncle Sam in a crisis with enemies of the United States was told, and their ingenuity and bravery played no small part in the affair.

The Boy Inventors' Flying Ship was devoted to a detailed narrative of the boys' long and unexpected cruise to the unexplored regions of the Upper Amazon. The boys were shipwrecked and cast away without an apparent hope of rescue on a yacht belonging to a German scientist, the crew of which had mutinied. The boys' capture by a strange tribe and subsequent escape in their Flying Ship formed thrilling portions of this story, while Dick Donovan's researches in natural history provided the boys with a lot of fun.

The volume immediately preceding this showed the boys coming to the rescue of a poor lad, a waif and orphan, who yet had a fortune in the plans and specifications of a new type of craft invented by his dead father who had lacked the capital to develop it. Enemies strove desperately to secure the papers, and even went to the length of forging a will for the purpose, but partly through the agency of an odd German lad, Heiney Pumpernickel Dill, their schemes were frustrated and the invention was developed and set upon a working basis. This book was called the Boy Inventors' Hydroaeroplane, and dealt with some astonishing adventures and perils all of which the boys encountered with plucky spirits and resourceful minds.

For some weeks preceding the opening of the present book relating of the Boy Inventors, Mr. Chadwick had been closeted in his own private laboratory. The boys had seen him only at rare intervals, and then he had appeared abstracted and preoccupied. This, the boys knew, was a sure sign that he was at work on a new idea.

Sometimes the lights burned in his laboratory far into the night and in the morning he would appear at breakfast pale and silent. The boys had indulged in much speculation as to what the new invention could be, but had arrived at no satisfactory conclusion when, two days after their experience with the eccentric professor, Mr. Chadwick summoned them to his private workshop. The boys, who had been at work on the Wondership, the flying automobile with which they had met such surprising adventures in Brazil, obeyed the summons with alacrity. It was delivered to them by Jupe, the negro factotum of the place.

"Massa Chadwick send me on de bustelbolorium," explained Jupe, who had a vocabulary that was all his own, "for yo' alls to come right away by his laburnumtory."

"All right, Jupe, we'll be right over," said Jack, "just as soon as we've got some of this grease off our hands."

The boys' workshop was equipped with a washbasin and they soon made themselves presentable. Then they hurried to Mr. Chadwick's workshop. They found him standing before a roughly-built table on which were ranged some odd-looking bits of apparatus.

There was a gasoline motor in one corner, geared to a generator—or what appeared to be one—from which feed wires led to a square metal box on the table. Attached to this metal box was a sort of horn-shaped mouthpiece something like the transmitter of a telephone. Hanging from its side was what looked like an enlarged telephone receiver. Jack regarded his father questioningly.

"You sent for us, dad?"

"Yes, Jack," was the reply. "I'm in a quandary. Have you any idea what this apparatus is?"

Both boys shook their heads.

"Looks like some kind of a telephone," ventured Tom.

"It is a telephone," replied Mr. Chadwick.

"But—but—where are the wires?" asked Jack, glancing about him, "or haven't you connected it up yet?"

"It's connected up as much as it will ever be," said Mr. Chadwick with a smile. "Can't you guess what it is?"

"I've got it," cried Jack suddenly. "It's a wireless telephone."

"That's right," admitted his father, and, in response to a flood of questions from the boys, he told them how he had been working day and night to bring the device to perfection.

"Now," he said, as he concluded, "I want you boys to go down to that shed that was put up last week at the northwest corner of the orchard."

"The one that was put up to store gasoline?" asked Tom.

"I said it was for that purpose in order to avoid questions till I had my work completed," said Mr. Chadwick with a smile. "Here is the key to it. Inside you will find an apparatus similar to this one. Start the dynamo and then stand in front of the transmitter and place the receiver to your ear. If you don't hear anything at once use the inductor to tune your aerial earth circuit to the transmitted current from my end just exactly as you would tune up a wireless telegraph instrument to catch certain wave lengths from another instrument"

"Then the principle of the radio telephone is the same as that of the wireless telephone?" asked Tom.

"I'll explain that to you later in as plain language as I can," said the inventor, "but now I am anxious to see how this instrument will transmit sound."

The boys were excited. Anything novel in the way of science attracted their bright, active minds as an electromagnet attracts steel. The idea of a wireless telephone, of the possibility of transmitting actual speech through space, just as the dots and dashes of the wireless telegraph are sped through the ether, quickened their inventive faculties to the highest pitch. Both felt a glow of pride that they had been selected, even before their father's scientific friends, to make the first test of this wonderful new invention.

They hurried across the broad lawn that intervened between the workshops and the orchard where the newly erected shed stood, and which, it had been given out, was to serve for the storage of gasoline. Unlocking the door, they found inside an apparatus resembling in almost every detail the one in Mr. Chadwick's workshop.

Jack's hands fairly trembled as he started up the motor and the generator began to buzz. With shining eyes and throbbing pulses he placed the receiver to his ear as his father had directed. But the next moment a flood of disappointment swept through him.

"Well?" demanded Tom, himself a tiptoe with expectation.

"Nothing doing," replied Jack, shaking his head. "I guess the thing isn't at a practical stage yet."

"Wait a minute, give it a chance," urged Tom. "By the way, how about that tuning device, have you tried that yet?"

"No, good gracious, my head must be turning into solid ivory from the neck up. I guess that's just what the trouble is."

Jack began carefully sliding a small block connected to the instruments up and down the coiled wire which formed the tuning apparatus, and brought the sending and receiving ends into harmony just as if they had been two musical instruments. When the right electric "chord" was struck he should be able to hear, just as in wireless he would be able to catch the message of an instrument whose wave lengths were attuned to his.

Suddenly Tom saw his chum and cousin give a start and then a shout. Over the space between the workshop and the small shed a human voice had been borne on electric waves. Sharp and clear as though he had been listening to a "wire" 'phone, Jack caught and recognized his father's voice:

"Hul-lo!"



CHAPTER VI.

THE RADIO TELEPHONE.

Back and forth through space they talked for quite a time. The boys were jubilant. The despair of many inventors, the wireless or radio telephone appeared to be an accomplished fact. But they didn't dream how much yet remained to be done. At length Mr. Chadwick told them to "hang-up" and come back to the workshop.

The boys were glad to do this for they were extremely anxious to learn something of the forces controlling this aerial method of conversation. So far, they had not the least understanding, beyond a general idea, of how the thing was done. Of the details by which Mr. Chadwick had worked out this radical departure in telephony, they knew nothing.

"Well, what did you think of it, boys?" asked Mr. Chadwick when they returned to the workshop.

"Wonderful, beyond anything I could have imagined," declared Jack.

"How far will it work?" asked Tom.

"That's just the point," said Mr. Chadwick. "That's where I'm at sea. I need a metal of greater conductivity than any attainable to get real results. The carbon that I am using does not throw off enough radio activity to produce a sufficient number of electric impulses to the atmosphere."

Jack and Tom looked puzzled.

"You don't understand me I see," said Mr. Chadwick.

"No, I must say I don't," said Jack; "you see——"

"It's pretty technical," broke in Tom.

"Well, then I'll try to explain to you, in simple language, the general principles of radio telephony," said Mr. Chadwick. "In the first place you know, of course, from your wireless studies, that an electric wave sent into the air will travel till it strikes something, such as an aerial."

"To use the old illustration, an electric impulse sent into the air spreads out in all directions just like the ripples from a stone chucked into a mill-pond," said Jack.

"That's it," said Mr. Chadwick. "Now then, as you also know the wire telephone works by a metal disc in the receiver, vibrating in exactly the same way as does the microphone in the transmitter. According to the vibrations of the voice of the person sending the spoken message, the electric current along the wire, acted upon by the microphone in the transmitter, increases or decreases. This increasing and decreasing current acts on a thin metal disc or diaphragm in the receiver which is held to the ear of the person listening to the message."

"That's plain sailing so far," said Jack. "For instance, when you say 'Hullo' over a phone, the microphone or transmitter gets busy and records it in electrical impulses and shoots it all along the wire where the receiver picks it up and wiggles the metal disc inside it to just the same tune."

"That's it exactly," said Mr. Chadwick. "Now we are ready to go a step further. Now, as this metal disc is attracted or released by the current coming over the wire, it compresses or rarefies the air between it and the ear-drum of the person to whose oral cavity it is held. In this way the sensation of the same sound as was spoken at the transmitter end is reproduced at the receiver end. In other words, the transmitter jerks and jumps just as the needle of a phonograph does in traveling over a record, and transmits these jerks and jumps over the wire to the metal disc which by aerial pressure on the ear drums of the receiver of the message, causes the aural membrane to translate the words, or vibrations along the nerves, to the brain.

"Following up this line," said Mr. Chadwick, "we find that the problem in radio telephony is the same as that met with in ordinary wire telephony. That is to say, we are required to cause a distant metal disc to repeat every inflection of the transmitter. But in the case of radio telephony the result is to be obtained by Hertzian waves, instead of by a current passing through an insulated wire."

"The same sort of waves that are employed in wireless telegraphy?" asked Tom.

"Just the same, only in radio telephony we are confronted by a problem not met with in wireless telegraphy. We have not only to transmit sound, such as isolated dots and dashes, but to send through the air every rise and fall and inflection of the human voice just as it is recorded in the minute lines of a phonographic record.

"Experiments have shown that articulation, that is, understand, a speech, depends upon overtones and upper harmonies of a frequency of 5,000 or 8,000 or more."

"What do you mean by frequency?" asked Tom.

"Speaking in reference to radio telephony it means the number of electrical vibrations per second required to produce a certain sound. In electric currents 100 per second is a low frequency current, 100,000 per second is spoken of as high frequency. In early experiments with radio telephony it was found that the chief difficulty lay in obtaining a current of sufficiently high frequency to transmit the human voice, the currents used in wireless telephony being much too weak for this purpose.

"I had, therefore, to invent my own alternator, which is attached to that gasoline motor. There is a similar one in the shed from which you just talked with me."

"But why does radio telephony require a stronger current than wireless telegraphy?" Tom wanted to know.

"Because, up to the present, no way has been found of utilizing in radio telephony the entire energy of the electric waves sent out," replied Professor Chadwick. "Only the variations in the waves can be detected, or transformed into sound at the receiving end of a radio telephone system. Therefore an immense amount of electrical energy has to be manufactured in order that the voice vibrations may register their variations as powerfully as possible."

"What percentage of the electrical energy manufactured by a high frequency alternator can be transformed into variations of sound?" asked Jack.

"Not more than five to eight per cent. of the total energy. So therefore the waste is enormous. In wireless telegraphy, on the other hand, the entire energy radiated from a sending station can be picked up to the limit of the receiver's capacity to detect it."

"Isn't there any way in which this difficulty could be overcome?" inquired Tom.

"Yes, there is," said Mr. Chadwick, after a moment's thought, "and I believe that I am the only man in the world employed with radio telephonic problems who knows of it."

"Why can't you use it, then?" asked Jack.

"Because there are almost insurmountable difficulties in the way. There is a substance chemically known Z. 2. X. which, if it could be applied to purposes of transmission and detection, has such immense powers of electrical absorption that messages could be sent almost any distance, and with far greater economy of power than at present."

"How far can you send them now?" asked Jack.

"About five miles. At least I think so. I'm not even sure of that," was Mr. Chadwick's reply.

But Jack was impatient to get back to Z. 2. X.

"Why can't you use this Z. 2. X.," he questioned, "if it would practically wipe out your troubles in sending and receiving?"

"Because there is even less of it in the world than there is of radium," was the startling reply. "At present Z. 2. X. costs far more than radium. It is the most intensely radio-active stuff in the world. It is capable of being wrought into metal if anybody had ever found enough of it, but except for a small deposit in South Africa, which has been devoted to experimental purposes, nobody has any.

"But enough of that now. That is only a dream. I am anxious, though, to test out my present apparatus thoroughly, and to do it I shall need the help of you boys."

"In what way?" asked Jack.

"In giving it a thorough trial to ascertain over how great a space I can transmit wireless speech."

"Are you going to put up another station outside the grounds?" asked Tom.

"No; I don't want to attract attention to my experiments. You boys have a wireless telegraph outfit on your Wondership?"

Jack nodded. He was curious, as was Tom, to know the Professor's plan. They did not have long to wait.

"I wish you would get the machine ready to install a radio-telephone outfit in its place. In that way I can gauge the limits of my invention without attracting undue attention, as everybody in this vicinity has seen you in flight and would imagine that you were merely taking a trip through the air."

"But can you get out an apparatus light enough for us to take up?" asked Jack.

"I am working on that now," said Mr. Chadwick. "I'll have it ready in a week."

"We'll be ready for you," promised Jack.



CHAPTER VII.

THE GREAT TEST.

A week later to the day on a sunshiny, windless morning, the Wondership was run out of its shed, glistening with new paint and with every bit of bright work burnished till it shone and sparkled like newly-minted silver. Amidships on the craft, the general construction of which is familiar to readers of foregoing volumes of this series, was a square metal box with small wires leading to long copper wires stretched from end to end of the Wondership's body.

These long copper wires were to form the aerials by which the messages from Mr. Chadwick's workshop were to be caught. The smaller wires underneath were connected with the metal work of the engine. These wires formed a "ground" similar to the kind employed in aerial wireless telegraphy.

The details of the Wondership having been fully described in the Boy Inventors' Flying Ship, we shall not enter here into any but a brief and general description of the craft. The Wondership, then, was a combination of dirigible balloon, automobile and boat. Her motive power was furnished by engines driven by an explosive volatile gas which was also used when occasion arose to inflate the bag of the balloon feature of her design. The gas was generated in the lower part of the craft's semi-cylindrical metal body.

On land two big aerial propellers, geared to the engine, drove the Wondership swiftly along on four solid-tired wheels. When it was desired to take to the air the balloon bag, which was neatly folded on a framework supported by upright stanchions above the body of the car, was inflated by turning on a valve connecting with the gas tanks in the base of the body.

When the Wondership was intended to navigate the water she was driven by the same aerial propellers that afforded her motive power on land or in the air. She then became what may be called a hydromobile. If it chanced to be rough weather, special hermetically sealed panels could be drawn together, completely enclosing the body and making the craft a water-tight "bottle." Ventilation was provided in such a case by a hollow telescopic tube which reached twenty-five feet into the air. It was divided in two. Fresh air was drawn by a fan down one section, while the stale air in the "cabin" was forced out by a similar device up the other part of the tube. Stability was afforded by hollow pontoons, which worked on toggle joints, and could be raised or lowered as desired.

With the aid of Jupe, the gas bag was inflated to a point where only a slight additional quantity of gas would cause the craft to shoot upward to the sky. When all was ready a test of the instruments was made and they were found to be working perfectly. The powerful alternator on the Wondership was, of course, worked by the same motor that drove the big propellers.

"Well, I guess there's nothing to keep you back now," said Mr. Chadwick, who looked pale and ill after his long days and nights of work on his invention.

"No, we're as ready as we ever will be," said Jack, making ready to climb into the machine above which the big yellow balloon bag was billowing and sending impatient quiverings through the Wondership.

"I want you to promise me one thing, dad," said Jack, when he had climbed into the driver's seat, in front of Tom, whose duty it was to look after the engine.

"What is that, my boy?" asked the inventor.

"That after this test, whatever the result may be, you will take a long rest."

"Yes, I will, I must," agreed his father. "I've been working too hard, I guess, but in the excitement of perfecting the radio telephone I hardly noticed it. But recently I've had dizzy spells."

"Two weeks' rest will make you well," declared Jack, as he adjusted the controls.

"Good-by and good luck," said his father.

Both boys waved their hands.

"All ready, Tom?" hailed Jack.

The other boy nodded and then turned on a valve so that with a hissing sound additional gas rushed into the bag. Jack pulled a lever. The big motors roared and a queer, sickly smell of burned gas filled the air. The propellers began to revolve slowly and then increased their speed till they became a mere blur.

"Dere she go! Gollyumption, dere she go!" cried Jupe, capering about.

As the old black spoke, the Wondership shot up like a rocket, tilting her nose slightly into the air. But the next moment Jack had her on an even keel. In an incredibly short space of time those watching below saw her only as a glinting, golden speck against the blue sky, circling like some strange bird far above their heads.

"Now for the tests," said Mr. Chadwick, as he hastened to his workshop.

He set the big alternator at work at top speed. It droned like a gaunt bee. The inventor's face, worn by his anxious vigils at his experiments, was as keen as a hawk's, while he adjusted the instruments and placed his long, lean fingers on the tuning device.

Far above the earth Jack and Tom could look down upon a patchwork of villages, farms, green pastures, yellow grain fields and stretches of woodland. They were too far up to distinguish figures, but they could see the white steam of rushing trains along the railroad tracks, and even catch the sound of the engines' whistles.

Beyond glinted the blue of the sea flecked with sails and with here and there a steamer's smoke smudging the horizon. Both lads were in high spirits. It seemed good to be navigating the air again. Every now and then inquisitive, high-flying crows would swoop toward the machine and then dash off again with alarmed squawks.

Although they were making a high rate of speed, they hardly seemed to be moving as they soared in long circles. To get a sense of rapid motion, stationary objects must be in sight. In the lonely air it was hard to tell that they were moving at all except by looking down at the earth which, as they rose, appeared to be rushing from them, as if it were sinking through space.

But novel as all these sensations would be to an aerial novice, they were an old story to the boys. Jack devoted his attention to testing a new steering appliance he had equipped the craft with, and Tom watched his engines with an eagle eye to detect a skip or a "knock."

"How high now?" asked the young engineer after an interval.

Jack glanced at the barograph on the dashboard in front of him.

"Three thousand feet," he said.

"Might as well connect the alternator?" said Tom interrogatively.

Jack nodded, and Tom threw a lever which brought the generator of high frequency currents in contact with the motor by means of a friction fly-wheel. The alternator began to buzz and spark, crackling viciously.

A sort of metal helmet with two receivers attached to it, one on each side, lay handy at Jack's hand. In front of him was the transmitter joined to the metal box which contained the microphone, transformers and inductance tuning coil. Tuning in the aerial apparatus was effected by means of a small knob projecting through a slit in the metal box enclosing the delicate instruments including the detector. By working this knob the tuning block was moved up and down the coil till a proper "pitch" was obtained.

Jack experienced an odd thrill as he prepared to send the first spoken word ever exchanged between an airship in motion and a station on land. He and Tom had sent plenty of wireless messages while soaring through the ether, but somehow, the dot and dash system had not half the fascination and mystery of the possibility of exchanging coherent speech between land and air.

He placed his lips close to the receiver, and with his hand on the tuning knob sent forth a loud, clear hail:

"Hullo, High Towers!"

There was no answer for a few seconds while he patiently adjusted the tuning knob. But then came a faint buzz like the humming of a drowsy bee. Suddenly, sharp and distinct, as if his father was at his elbow, came Mr. Chadwick's voice in reply:

"Hullo!"

"This is the Wondership. Three thousand feet in the air," cried Jack.

"Congratulations, my boy. It's a success so far."

"What shall we do now?" asked Jack.

"I want you to fly in the direction of Rayburn, and try to keep in communication all the way."

"All right, dad," responded Jack, and altered the course of the Wondership.

Rayburn was a small village some twenty-five miles to the north of Nestorville. Jack kept the receivers on his ears as he flew along. From time to time he exchanged conversation with his father. So far everything appeared to be working as if there were no limit to the distance over which the voices from the air and land could converse.

But suddenly there came a startling interruption to the experiments.

Jack felt a sharp "Bang" at his ears as if a small cannon had been fired close at hand.



CHAPTER VIII.

TALKING THROUGH SPACE.

As the distance increased between air and land stations, the currents became stronger, and frequent tuning was necessary. But Jack was able to keep up a constant conversation with his father, telling him all the details of the country as they flew along. The sudden explosion, however, for it sounded like nothing else, startled him into a sharp exclamation.

"What in the world was that?"

As if he had spoken the question to someone close at hand, came back the explanation.

"Wireless telegraph wave crossing ours," said his father. "Some powerful land station is sending out a message, possibly to some ship."

"It almost broke my ear drum," said Jack, and inwardly resolved to devote some time to trying to solve the problem of avoiding such "collisions" in the future. It occurred to him that some sort of a circuit breaker might be devised to cut off, temporarily, the telephone talk by automatic means when a cross-wave of high energy struck its current.

The shock was not repeated, and the conversation went on, still as sharp and as clear as when they had started out. A few minutes later Jack was able to report they were passing over Rayburn.

"You'd better keep on," said his father, his voice aglow with enthusiasm. "It's working beyond my wildest expectations."

"It's dandy," agreed Jack.

They talked without raising their voices to any great extent, but it was necessary to articulate very clearly so that each variation of sound might be sent out into space as clearly as the notes of a singer come from the record of a phonograph. But it was amazing, almost uncanny to Jack that such results could be obtained at all.

"Goodness, if only we could get that mineral substance that dad was talking about I believe you could rig up a radio telephone that would talk across the ocean," he said to Tom, "and think what that would mean. For instance, instead of bothering with the cable you could step into a radio-telephone office and say: 'Give me the London Exchange.' In a few minutes the central would answer and you could tell her what number you wanted on some regular wire line. Before long you'd get it, and be talking to whoever you had called just as if they were twenty-five miles off instead of three thousand!"

"It seems like a dream," said Tom.

"Not much of a dream about it. All it needs is development. We've proved to-day it can be done," declared Jack, bubbling over with enthusiasm.

They flew over meadow land and pasture, farmhouses where tiny figures emerged from buildings and looked up at them, over rivers and railroads, and still the alternator spat and sparked and the messages between Jack and his father were interchanged in a steady stream. Rayburn had been left behind. They were now over a small town Jack believed to be Hempstead.

He looked at his map to make sure. It was one that he had specially plotted out himself from observations he had made when flying in the vicinity. Having verified their whereabouts he found that they had flown about fifty miles, possibly a fraction more.

But at this juncture he noticed that the voice of his father pulsing through space began to grow thin and weak. Obviously the limit of the radio 'phone's capacity had been reached.

"Better turn back," said Mr. Chadwick.

Jack turned to Tom and gave him the necessary instructions. Then he set over his guiding wheel, turning the big rudder at the stern of the Wondership and she acted as obediently as a sea-going craft answering her helm. Never had she behaved better.

They flew swiftly back toward High Towers and were soon in sight of Rayburn. In order to test what effect the magnetism of the earth had upon the radio messages, Jack brought the great flying craft close to the ground. They almost grazed the treetops as they flew along.

Skimming a patch of trees they roared above a farmhouse with a great red barn adjoining it. The barn attracted Jack's attention because of the fact that it had a flat roof, an almost unique feature in that part of the country. He supposed it was used to dry some sort of produce on and noted that there were several hop-fields near at hand. Undoubtedly the roof was used for exposing them to the sun and thus drying the moisture from them without the expense of wood for the drying fires usually used for the purpose.

He had hardly noted all this when there came a sudden tug at the Wondership as if a titanic hand had reached up from below and grasped her. She pitched wildly and, but for Jack's skill as an airman, there might have been a serious accident. But he brought the big craft under control by skillful manipulation.

The next instant he discovered what had occurred. The grapple of the aircraft had, in some way, dropped from its fastenings and, trailing behind the Wondership, had caught in the roof of the farmer's barn.

A great section of it was torn away and as Jack brought the Wondership to rest on the roof, the only available place, for the rope was in danger of fouling the propellers if he descended to the ground, the farmer and a number of his men came running from the farmhouse.

In the hands of the farmer was a formidable looking shotgun. As the Wondership settled on the roof of the barn the man began shouting angrily.



CHAPTER IX.

THE BOYS FACE TROUBLE.

"Phew! looks as if we are in for trouble," exclaimed Tom, as he saw the warlike expression on the farmer's face.

"It does that," agreed Jack. "Hop out, will you, Tom, and get that grapple clear? Confound it, I don't see how it came loose."

"Wore through the lashing," said Tom, who had been examining the place where the big hooked steel anchor was usually tied.

"We ought to have seen to it before we started out," said Jack. "We haven't had it loose since that time we anchored above the Brazilian forest."

The farmer's angry voice hailed them from below.

"Hey there! Don't yew move a foot till we've had a reck'nin'."

"I am awfully sorry," said Jack. "It was an accident you see. We——"

"Don't care what it was. Thet thar was a new roof. Don't you move a step till Si here gits ther constabule."

"We'll pay you for the roof," said Jack apologetically. "After all it isn't much damaged."

Indeed it appeared as if the damage was not so great as they had at first imagined. After tearing off some shingles the grapple had caught in a beam and was prevented from doing further harm.

"Yes, yew'll pay, and yew'll go ter jail tew," declared the farmer. "Consarn it all, what's the country comin' tew? Las' week tew pesky dod-ratted balloonists hit Hi Holler on ther head with a bag of sand, and now yew come along in thet thar contraption and try to bust up my dryin' roof. I'll have ther law on yer."

Matters began to look serious. Jack had no doubt but what the farmer would accept a money payment for the damaged roof. But it appeared that the old fellow was bent on more stringent vengeance.

In the meantime Tom had been busy in the stern of the craft and had succeeded in getting the grapnel loose from the beam into which its sharp points had dug. It was not till that moment that the farmer observed him.

He leveled his shotgun at the balloon of the Wondership.

"Don't yew dare ter move er I'll bust a hole right plumb through that ther airbag of yourn," he said.

"Can't you be reasonable?" asked Jack. "Here's my name." He wrote his name and address on a slip of paper and threw it down.

But the irate farmer paid no attention to the missive. He kept his gun steadily trained on the Wondership.

"Move an' I'll bust yer!" he said grimly.

A buggy drove out of the yard. It raced through the gate and then struck the highroad leading to Rayburn.

"Thar' goes Si arter ther constabule," said the farmer, licking his thin lips as if with relish. "Hi Ketchum is a rare one arter automobubblists. I reckon he'll be right smart tickled to death when he hears I got a whole airship fer him ter 'rest."

"Bother the old grouch," muttered Tom, as he climbed back into the Wondership, the bag of which was deflated just enough to keep her at rest on the roof.

"He's evidently mighty serious in his intentions," said Jack, with a troubled face. "What are we going to do?"

There was a sudden puff of wind and the big yellow balloon bag swayed slightly.

Instantly the farmer's finger crooked on his trigger. He thought the boys were going to give him the slip.

"No you don't," he shouted, "you don't fool Ezry Perkins that 'er way!"

"We're not trying to fool you," said Jack disgustedly. "Why can't you be sensible. You've our names and addresses on that paper I threw down to you. If you like I'll make a cash settlement right here for any damage we've done."

"I'm goin' ter git yer in ther court," insisted the farmer sullenly. "Las' week some autermobubblists killed three uv my chickens, week afore thet I had a hog knocked off ther road. I'm er goin' ter git even on yer fer ther lot uv them."

It was plain that the man was not to be moved by promises or persuasion. He had conceived in his mind a hatred against automobiles, with which, in a vague way, he classed airships and all such modern inventions. Jack thought, too, that Ezra Perkins was the kind of man who liked to shine out among his neighbors, and what better opportunity could he have to satisfy this ambition than by blossoming forth as a man who, single handed, had captured a great aircraft?

The boys looked down. The farmer was pacing grimly up and down like a sentry, his eyes never leaving the Wondership.

"I'd like to drop a bag of ballast on his head, the same as those balloonists did on Si's," muttered Tom.

"Wouldn't do any good," said Jack. "It would only bounce off again."

"I guess it would at that," agreed Tom with a grin.

"I've half a mind to take a chance," said Jack suddenly.

"And get a hole blown in the balloon bag," protested Tom. "We wouldn't be better off than before in that case."

"I wonder if he'd really shoot or if he's only bluffing," mused Jack.

"Take a look at him," advised Tom.

Jack did. One glance was enough. There was no bluffing about the grim, overalled farmer. The very way in which he held his gun expressed positive determination not to let the boys escape.

But as it so happened, by no action of the boys', matters were suddenly brought to a sharp crisis. Over the patch of woods beyond the farm there came a vagrant puff of wind. It was followed by a sharper gust.

The Wondership swayed and then, before Jack could check the motion, drifted off the roof like a piece of thistledown blown by the wind. Instinctively, to check the downward motion, Jack's hand sought the gas valve. With a hiss the volatile vapor rushed into the bag.

The big aircraft shot up like an arrow. For a second the farmer stood paralyzed at the suddenness of it all. His farm hands lounged about, gaping and looking upward like country folks at a fireworks display.

Then, without any warning:

"Bang!"

The farmer let loose with both barrels at once. But the Wondership still rose.

All at once, from below, came a yell of surprise and terror. The boys looked over the side. As they did so they uttered simultaneous gasps of consternation.

The trailing grapnel, for Tom had forgotten to tie it back in place in the excitement, had caught the farmer by the waistband of his overalls and he was being carried skyward by the Wondership, dangling at the end of the anchor rope like some sprawling spider.

His wife, screaming at the top of her voice, rushed from the kitchen door.

"Hey, you come back with my husband!" she shouted.

"Lemme go! Lemme go!" bawled the farmer as loudly as he could, for, held securely by his stout overalls, he was carried high above his own buildings. He kicked and struggled furiously.

"Keep still," shouted Jack, in serious alarm, from the side of the Wondership. "Keep still or you'll kick yourself off."

The farmer had sense enough to obey. He hung upside down like a limp scarecrow, while his farm hands gaped up at him and the hired girl was busy pouring buckets of water over his wife who was in hysterics.

"Gracious, now we've done it!" gasped Tom in dismay.



CHAPTER X.

AN INVOLUNTARY AERONAUT.

"Steady, Tom, steady," warned Jack, as he set the pumps to work drawing gas from the bag into the reservoir.

The Wondership, her buoyancy thus diminished, began to descend.

"What are you going to do?" asked Tom.

"Drop our passenger," said Jack, with a grin he could not suppress, for the struggling farmer was within a few feet of the ground now and even if he did kick himself loose, for his struggles had begun again, he could not have hurt himself much.

"Back up till we get over that haystack," said Jack, "and then play out rope till we lower him. It'll make a nice soft jumping-off place."

Tom obeyed, pulling a reverse lever. The Wondership, steered with skill by Jack's practiced hand, backed slowly up. At length they hung directly over the haystack. Jack turned and nodded. Tom sprang to the rope and lowered the indignant farmer into the soft hay. The man lost no time in disentangling himself. Then he sprang to his feet and began hurling vituperation at them at the top of his lungs.

"I'll have ther law on yer fer this," he yelled. "Tryin' ter kidnap me and bustin' down my barn. I'll see whether such goin's on is allowed in ther sufferin' state uv Massachusetts, yew see if I don't, consarn yer. I'll——"

But the Wondership, bearing the two boys who could not help laughing heartily, although they feared serious consequences might come of the accident, was winging its way onward out of earshot of the not unnaturally indignant Ezra Perkins.

They passed Rayburn before Jack noticed a peculiar smell in the atmosphere.

It was leaking gas. Then, for the first time, he recollected that the farmer might have hit the gas bag above them with his double shots, although, till then, there had been no indication that such was the case.

He called Tom to the wheel, explaining his suspicions and clambered out on the rigging to see if he could find any holes in the balloon. It would have made a less steady boy dizzy and sick to stand on the edge of the Wondership, clinging to one of the supports that held the body of the craft to the gas-bag, while the whole affair plunged and swayed five hundred feet above the earth. But Jack, used as he was to navigating the air, felt none of these qualms.

His suspicions were speedily confirmed. There was a jagged hole in the underbody of the balloon, from which gas was rushing. Jack's face grew grave. The situation was dangerous.

He knew, as does every balloonist, that out-rushing gas can make an electric spark in the atmosphere which, in turn, ignites the gas itself, sometimes with fatal results. Experts in aeronautics attribute the disasters befalling the long series of Zeppelins, the giant German dirigibles, to this cause.

"Tom, we must go down. Drop at once," he said. "That old fellow succeeded in blowing a hole in us all right."

The pumps were set to work and the Wondership fell rapidly. They dropped in a field by the roadside, landing on the running wheels as lightly as a feather, thanks to the shock absorbers, similar to those of an automobile, with which the Wondership was equipped.

"Now for the repair kit," said Jack, rummaging a locker.

He soon had balloon silk, big shears, a quick-drying gum solution and a pot of gasproof varnish, ready for the job of patching up the hole. But first they had to empty the big bag of gas. This was speedily done, for already enough had escaped to wrinkle the bag like a walnut, with hollows and creases.

Jack cut out a patch of balloon silk large enough to fit the hole and spread it with the adhesive gum solution. This he placed inside the hole, spreading it out so that when pressure was applied it would be pressed firmly against the aperture. Then he coated the patch with the gasproof varnish, and both boys sat down to give the job time to "set."

Their eyes turned idly to the high-road. It was about noon and there was a heavy sort of silence in the air. Far on the horizon they could make out great billowy masses of white cloud. Piled and castellated against the sky they assumed all kinds of odd shapes.

"Thunder heads," said Jack. "We shall have a storm before to-night."

"It's sultry enough for anything," said Tom, taking off his cap and mopping his forehead. "I'd hate to be walking in this weather like that fellow yonder."

A man had come into sight, plodding along with bent head and eyes on the ground as if he was very tired. The gray dust of the road coated him from head to foot. He walked with a kind of dragging gait.

Over his shoulder he carried some sort of a bundle on a stick. His hat was a broad sombrero, like a cowboy's. It was a kind of headgear seldom seen in the east and attracted the boys' attention. Round the man's neck was a red handkerchief, the only spot of color on his dust-covered person. He had a great yellow beard and rather long, unkempt hair.

"Tramp," hazarded Tom.

Jack shook his head.

"Doesn't look like that to me somehow," he said. "I rather think——"

Round the corner whizzed a big red automobile. It was coming fast. The driver, a young man, had his head turned and was talking to three companions who sat in the tonneau. He did not see the dusty traveler in the road ahead.

The boys set up a shout.

"Look out! you'll run him down. Look out——"

But their caution came too late. At top speed the auto struck the wayfarer, and before the boys' horrified eyes he was thrown high in the air, to fall, a confused sprawl of legs and arms, at the wayside.



CHAPTER XI.

BY THE ROADSIDE.

The boys ran forward across the few yards of meadow that intervened between the Wondership and the roadway. The autoists did not, apparently, notice them. They had stopped the car and were looking back.

"Come on and let's get out of this quick," one of them, a hawk-faced youth, with a long motoring duster on, was shouting to the driver.

"Yes, let's beat it while the going's good, Bill," came from his companion as he addressed the driver of the car.

"I guess we'd better," said the man addressed as Bill.

Before the boys could intervene the car was on its way again, at top speed, leaving the unconscious form of its victim at the roadside.

"Of all the cold-blooded scoundrels!" gasped Jack, horrified at such callousness.

"Never mind them now," advised Tom. "Let's see if this poor fellow is badly hurt. He may even be——"

He did not finish the sentence, but Jack knew what he meant. Hastily the boys scrambled down the low bank that separated the field from the road. They ran quickly to the man's side. To their great relief, for they had feared that he might have been killed, the man was breathing. But his breath came pantingly from his parted lips and there was a bad cut on his forehead.

"Get some water from the creek yonder," said Jack, and Tom hastened up the road to where, beneath the small wooden bridge, there flowed a rivulet of water.

He was soon back, with his handkerchief well soaked, and with an old can, that he had been lucky enough to find, filled with water. They bathed the man's wound and then bound it up as best they could. But he still lay senseless.

"Now what's to be done?" asked Tom.

"We ought to get him over to the Wondership and rush him to the hospital at Nestorville," said Jack.

"Yes, that would be the thing to do. But he's too heavy for us to carry," objected Tom.

"Why not fly over here alongside him. I guess we could lift him in; that patch ought to hold by this time," suggested Jack.

"That's a good idea. What a pack of cowardly sneaks those chaps in that car were."

"I wish we could have stopped them. It would give me real pleasure to see a gang like that get its just deserts. They might have killed this poor fellow."

The unconscious man was powerfully built, with face tanned brown above a yellow beard, from exposure to sun and wind. As Jack had said, he did not look like a tramp. Suddenly the boy noticed lying near him an object which had evidently fallen from the man's pocket when he was struck and flung through the air by the auto.

It was a small cylinder, apparently made of lead, and about three inches long. Jack picked it up, and for the time being did not attempt to examine it but thrust it into his pocket for safe keeping. Little did either of the boys think how much that little cylinder was to mean to them, and how it was to influence some of the most important adventures of their lives.

Making the man as comfortable as they could, by rolling up their coats and placing them under his head, the boys hurried back to the Wondership. When they arrived there they saw that a feature of the radio 'phone, which has not yet been mentioned, was working in urgent appeal. This was a tiny red electric light attached to the top of the case containing the sensitive parts of the apparatus.

By an ingenious device, worked as a call signal from the transmitting station, the electric waves converted a lighting circuit for this purpose.

It was winking and twinkling, and Jack knew that his father was trying to call them.

He sent out some flashes by starting the dynamo going and pressing a key devised for the purpose. This, he knew, would cause a similar light attached to his father's apparatus to flash a reply. This done he waited a second and then adjusted the receivers to his ears.

"What's the matter?" came his father's voice.

Jack gave him a rapid account of the accident, not stopping just then to say anything about the incident of the farmer and his barn.

"What are you going to do about it?" asked his father.

"He appears to be seriously hurt," said Jack. "I was thinking of rushing him to the hospital at Nestorville."

"That seems to be the best plan," said his father. "By the way, did those autoists get clear away?"

"I'm afraid so. They never even waited a second to see if the man was badly injured. They——"

Jack suddenly stopped short. An inspiration had come to him. The accident had happened on a road that, as he knew, led straight through Nestorville. He had thought of a plan to bring the autoists to book for their callousness and negligence.

"Dad—oh, dad!" he called.

"Yes, what is it?" came back Mr. Chadwick's voice.

"Those fellows will pass through Nestorville. I had a flash of the number of the car. It was 4206 Mass. It's a red car and a powerful one, with three men in it."

"What do you want to do?" asked Mr. Chadwick.

"Can't you 'phone to the Nestorville police, telling them what has happened and have those fellows stopped. I'm not vindictive, but they ought to be brought to book for running down a man and then speeding off and leaving him like that."

"I agree with you," replied Mr. Chadwick. "I'll do so at once. Good-by."

"Good-by," said Jack and "rang off."

"That was a great idea of yours, Jack, old boy," approved Tom. "I hope they land those fellows."

"Of course it was an accident," said Jack, "but that fellow who was driving was too busy talking to watch the road, and then going off like that—they deserve all they get."

Examination of the patch showed that it would hold fast and the bag was refilled. As soon as it was sufficiently inflated, the Wondership sailed over to the road and was brought down alongside the still unconscious man.

"Looks as if he's badly hurt," said Tom with some anxiety.

"It does. His skull may be fractured," agreed Jack. "If he is seriously injured those fellows may get into trouble."

It required all the boys' strength to raise the man and get him into the Wondership. Here they laid him out on the floor of the rear section. They had just done this when the red light signaled Jack again. It was Mr. Chadwick. He had notified the Nestorville police force, consisting of a chief and two men, and they were on the lookout for the offending auto.

"Good," said Jack. "Say, dad, the radio telephone has shown its usefulness on the first day out, hasn't it?"

They were soon in the air once more. The run to Nestorville was made quickly. On the outskirts of the town they came to earth and deflated the balloon bag, since the hospital stood in a group of trees and it would have been impossible to make a landing there. The Wondership was converted into an auto and sent speeding toward the main street of the village.

Suddenly they heard a whir of wheels behind them and an impatient tooting of a horn. They looked back and uttered a simultaneous cry of astonishment.

The red auto that had run down the yellow-bearded man was behind them. Its occupants were shouting and sounding their horn impatiently for the right of way.



CHAPTER XII.

MAKING ENEMIES.

The road was narrow where they were, and unless the boys' machine was run to one side of the road there was no chance for the red machine to pass. Jack made it clear that he didn't intend to let them.

He paid no attention to the shouts that came from behind.

"Hey, you kids, with that queer-looking car, get off the road and give a real machine a chance to get by," shouted the driver, he who had been addressed as Bill.

Jack did not turn his head.

"I'll knock your head off if you don't turn out—and turn out quick!" came another shout.

Still the boys did not pay any attention. In this order they came into Nestorville. Lined up, with a look of stern determination on his face, and with his nickel star of office newly polished, was Chief Biff Bivins. Behind him were Lena Hardy and Joe Curley, his "force."