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' Hydroaëroplane, 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 aërial 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!"
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 aërial 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 aërial."
"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 aërial 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.
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 aërials 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 aërial 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 aërial 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 aërial 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 aërial 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 aërial 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.
Illustration: (Frontispiece) Jack experienced an odd thrill...
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.
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.
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.
AN INVOLUNTARY AËRONAUT.
"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 aëronautics 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.