The Radio Boys at Ocean Point, Allen Chapman, 1922, pages v - vi:
FOREWORD

BY  JACK  BINNS

    IN these days of Radio broadcasting, when the country has gone wild over wireless music and entertainment, there is a tendency to overlook the other phases of radio--such as its use as a means of saving life at sea, and for navigational purposes generally. There is no doubt about the interesting character of broadcasting, and equally, there is no doubt about the importance of radio as a means of life saving.
    With this thought in mind, I think that the present volume, detailing the adventures of the Radio Boys, serves a very useful purpose in that it forcibly portrays the use of wireless to bring aid to a disabled ship on the high seas in a storm.
    By doing this it will inculcate a desire among boys to learn the wireless code and transmit wireless telegraphy messages themselves, and in doing so will tend to develop that nucleus of communication experts in the coming generation, which is always an imperative necessity to every nation.
Binns signature

Pages 9-15:
THE  RADIO  BOYS  AT  OCEAN  POINT

CHAPTER  I

TAKEN  UNAWARES

    "JIMINY, but this is hot work!" exclaimed Bob Layton, as he laid down the hammer he was using and wiped his perspiring forehead.
    "Hot is right," agreed his friend, Joe Atwood, as he also took a moment's breathing space. "You might almost think it was August instead of early June. Old Sol must have got mixed up in his calendar."
    "I'd call it a day and knock off right now if we were doing anything else," remarked Bob. "But, somehow, when I get going on this radio business I can't seem to quit. There's something about this wireless that grips a fellow. Work seems like play."
    "Same here," said Joe. "I guess we're thirty third degree radio fans all right. I find myself talking radio, thinking radio, dreaming radio. If there was any such thing as radio breakfast food I'd be eating it."
    "I'm afraid we'll get thin if we wait for that," laughed Bob, picking up his hammer and resuming work on the aerial that they were stringing on the top of his father's barn. "But come along now, old scout, and get a hustle on. We're going to finish this job to-day if it takes a leg."
    Joe stretched himself lazily.
    "I hope it won't come to that," he replied. "I need both legs in my business."
    "Well, come along and shake a leg anyway," counseled Bob: "I'm not asking you to lose one."
    "I'm glad we decided to make this aerial in umbrella shape," remarked Joe, as, following his friend's example, he set busily to work. "I think it has it all over the vertical one. We'll be able to hear the messages from the broadcasting station a heap better than we ever did before."
    "I'm sure we shall," returned Bob. "That's the kind Doctor Dale is using on his set, and he tried both the vertical and the flat-top kind before he finally settled on this. It's better for longwave work. It stands to reason that since it has the greatest surface area it also has the greatest capacity. Then, too, the end of the antenna that has the greatest potential is nearest the ground. The doctor gave me a lot of dope about it that sounded reasonable. He knows by actual experience, and that's better than all the theory in the world."
    "What Doctor Dale says goes with me all right," replied Joe. "He's never been wrong yet in any of the tips he's given us. It's funny, isn't it," he continued, as he deftly drove a nail, "that we're never satisfied with what we've got in this radio work? That first set we put together looked pretty good to us at the time. Then the ones with which we won the Ferberton prizes looked a good deal better yet. But now here we are making it still better."
    "That's the beauty of radio," said Bob, with enthusiasm. "The surface of it hasn't been more than scratched so far. It's practically a brand new thing with a million features to be explored and countless improvements to be made. I suppose a few years from now we'll be laughing at the instruments we're using now. They'll seem as old fashioned as the stage coach and the kerosene lamp. Some of the best brains in the world are working at it now, and there's hardly a day that you don't hear of something new in connection with it. It keeps you guessing all the time as to what will turn up next."
    "Right you are," agreed Joe. "Did you read the other day about that man in Paris who runs his house by radio? You know they have a powerful radio outfit on the Eiffel Tower. That starts operations at six o'clock every morning. This fellow has rigged up things all over his house that are controlled by the waves that come from the tower. First the shutters fly open, then the curtains are drawn back, then electric heaters get into action and begin to make the coffee----"
    "Say," interrupted Bob, turning to look at his friend, "what are you giving me? Trying to get me on a string?"
    "Honest to goodness, I'm not trying to kid you," replied Joe. "This is straight goods. The coffee begins to bubble in the percolators, the breakfast is started cooking, and the people are waked up by electric bells placed alongside their beds. If the weather is hot, the electric fans are started working."
    "Does it wash and dress the baby, too?" demanded Bob, with a laugh.
    "I don't know whether they've got as far as that yet," replied Joe, with a grin; "but it starts a lullaby at night and sings the baby to sleep. It sure does wonders. There seems to be no limit to what it can be made to do."
    "We'll have to tell Jimmy about that," chuckled Bob. "Anything that will save work will make a hit with him. He'll want to hitch it up so that it will saw wood for him and mow the front lawn. By the way, Joe, when did Jimmy say he'd be around? He promised to help us out with this."
    "He said he wouldn't be able to get here before three," replied Joe. "He had to go on an errand for his father. But to-day's baking day at his house, and I smelled doughnuts cooking as I came past. Ten to one he's filling up on those. That beats working on a roof in a hot sun."
    "I shouldn't wonder if you were more than half right," agreed Bob. "But what's keeping Herb? He promised to help out on the job."
    "There's company at his house," explained Joe. "But he said he'd slip away as soon as he could and get over here."
    "Sounds mighty uncertain," said Bob. "Looks like a case of doing it ourselves if we want it done. And it's got to be done this afternoon. They've got a dandy program on at the broadcasting station to-night, and I don't want to miss it."
    The two boys set to work with redoubled energy, despite the sweat that rolled down their faces and made them have frequent recourse to their handkerchiefs.
    "What's the idea of all those rocks down at the side of the barn, Bob?" inquired Joe, at the moment that his work brought him close to the edge of the roof.
    "They're for some repairing that dad's going to do to the barn," replied Bob. "The side of it has settled some, and he's going to put in a new stone foundation. The old shebang needs a lot of fixing, anyway. The water pipes are rusty, and they'll have to be replaced. He wants to get the place in shape before we go down to Ocean Point for the summer."
    "Ocean Point!" repeated Joe, With a sigh. "Why do you want to bring that up now when I'm dripping with sweat? It's cruelty to animals. Say, Bob, what would you give just at this minute to be taking a dip in the briny? Just imagine yourself at the end of the pier with your hands above your head, ready to dive down into that cool green water, down, down, down, and feel it closing all around you and----"
    "Who's cruel now?" groaned Bob. "Stop right where you are or I'll throw something at you. Don't you suppose I'm just as crazy as you to get down there? It's only last night that I dreamed I was there. Oh, boy! The swimming, the fishing, the boating, the games on the sand, the----"
    "Radio," suggested Joe.
    "Righto!" agreed Bob "That will be a new thing there that we've never had before. And instead of being in a hot, stuffy room, we can sit on the veranda, with the sea breeze blowing all around us, and the ocean stretched before us in the moonlight, and the lights of ships passing up and down the coast and----"
    "Back up," laughed Joe. "You're getting poetical. You could almost set that to music. But you're dead right that it will be just what the doctor ordered to listen to a radio concert under such conditions. Where can we put up our radio set? In your cottage or mine, I suppose."
    "I've got an idea it would be a good thing to put it up in the community hall," replied Bob. "Then everybody could enjoy it, and there's a broader and bigger piazza there than any of the cottages have. We're all like one big family there anyway."
    "That's a dandy plan," agreed Joe. "I shouldn't wonder, too, if we caught a good many messages from ships while we are down there. Almost all the vessels now are equipped with wireless, and we ought to be able to listen in on lots of talk going on with the shore."
    "I only wish we could talk back to them," said Bob "I'm keen for the time when we can send messages, as well as listen in on them. But that will be possible, too, before the end of the summer. I'm studying up hard on the code and I know you are too, and we ought to be able to pass our examinations soon and get the right to have a sending station."
Pages 30-39:
CHAPTER  III

MARVELS  OF  RADIO

    "DON'T forget now," Bob reminded them, as his friends passed out of the gate on the way to their respective homes. "Be over at the house a little before eight, for the concert begins at eight o'clock sharp, and there aren't many things in it that we want to miss. It's the best program that I've seen for a month past. There's violin music and band marches and opera selections and a bit of jazz mixed in."
    "Sounds as if it were going to be the cat's whiskers," said Jimmy.
    "Jimmy, I'm ashamed of you," said Bob, with mock severity. "When are you going to leave off using that horrible slang?"
    "He might at least have said the 'feline's hirsute adornments,' " muttered Joe. "That would have been a little more dignified. But dignity and Jimmy parted company a long time ago."
    "I didn't know they'd ever met," remarked Herb. "But if they were 'lovers once they're strangers now.' "
    They laughed and parted with another admonition by Bob to be on time. He himself went into the house and solaced himself with the cold bath and change of clothes that he had been promising himself all through that hot afternoon. A brisk rubdown with a rough towel did wonders, and by the time his mother returned he was feeling in as good shape as ever, with the exception of a touch of lameness in the right arm that had been subjected to such an unusual strain that day.
    By a quarter to eight that evening the boys began to come, and even the tardy Jimmy was on hand before the time scheduled for the concert to begin. In addition to the pleasure they anticipated from the unusually fine program, they were keenly curious to learn what improvement, if any, had been made by the installation of the umbrella aerial.
    They were not long left in doubt. From the very first tuning in there was an increase in the clearness and volume of the sound that surpassed all their expectations. The opening number chanced to be a violin solo, played by a master of the instrument. It represented a dance of the fairies and called for such rapid transitions up and down the scale as to form a veritable cascade of rippling notes, following each other with almost inconceivable swiftness. And yet so dearly was each note reproduced, so distinctly was each delicate shading of the melody indicated, that the player might have been in the next room or even in the same room behind a screen.
    The boys and the others were delighted. They listened spellbound, and when in a glorious burst of what might have been angel music the selection ended, the lads clapped their hands in enthusiastic applause.
    "That's what you can call music!" ejaculated Bob.
    "That player knows what he's about," was Herb's tribute.
    "And how perfectly we heard every note," cried Joe. "We certainly made a ten strike, Bob, when we rigged up that new aerial. It's got the other beaten twenty ways."
    "I guess you're right about that," said Jimmy. "I don't grudge a minute of the time you spent this afternoon in putting it up. It was worth all the trouble."
    Bob looked hard at him, but Jimmy was as sober as a judge, and before either Bob or Joe could frame a suitable retort the crashing notes of a military band came to their ears and put from them the thought of anything else. It was a medley that the band played, composed of well known airs ranging from "Hail Columbia" to "Dixie" and so inspiring was it that the boys' hands were moving and their feet jigging in time with the music all through the performance.
    For fully two hours they sat entranced through a varied program that included things so dissimilar as famous grand opera selections, the plaintive melodies of Hawaiian guitars, and some jazz, and when at last the list was ended the boys sat back with a sigh of satisfaction, their faces flushed and their eyes shining.
    "Ever hear anything like it?" asked Bob, as he relaxed into his chair and took off his ear pieces.
    "It's the best ever!" declared Joe. "And to think that we can have something like it almost any night we choose, and all of that without going out of this room!"
    "That's the beauty of it," Bob assented. "To hear a concert that included such fine talent as that we'd have to go to New York. That would mean all the time and trouble of dressing up, the long ride on the railroad train, the getting back home at two or three o'clock in the morning, to say nothing of the ten dollars apiece or thereabouts that we'd have to pay for train fare and tickets for the concert. For us four that would mean about forty dollars. Now we haven't paid forty cents, not even one cent, we haven't had to dress, we've sat around here lazy and comfy, we can go to bed whenever we like, and we've had the concert just the same. And what we did to-night we can do any night. I tell you, fellows, we haven't begun yet to realize what a wonderful thing this radio is. It's simply a miracle."
    "Right you are," agreed Joe. "And just remember that what's true of us four is true of four thousand or perhaps four hundred thousand. Take the biggest concert hall in the United States and perhaps it will hold five thousand. When it's full, everybody else has to stay away. But there's no staying away with radio. And every one has as good a seat as any one else. Think where that concert's been heard to-night. People out as far as Chicago and Detroit have heard it. They've listened to it on board of ships out at sea. In lonely farmhouses people have enjoyed it. Men sitting around campfires up in the Adirondacks have had receivers at their ears. Sick people and cripples lying on their beds have been cheered by it. Lonely people in hotel rooms far away from home have found pleasure in it. There's absolutely no limit to what the radio can do. It seems to me that it throws in the shade everything else that's ever been invented."
    "You haven't put it a bit too strong," chimed in Herb. "But talking about a lot of people hearing it makes me think that perhaps we fellows have been a bit selfish."
    "What do you mean?" asked Jimmy in some surprise. "It isn't so long ago that we got the old folks and sick folks together and gave them a concert at Doctor Dale's house--Joel Banks and Aunty Bixby and the rest of them."
    "I don't mean that," explained Herb. "That was all right as far as it went, and I hope we'll do it soon again. But what I have in mind are our own folks and our friends. Our fathers and mothers haven't heard much of this concert tonight, and there are some of the fellows that we might have invited in."
    "But we have only four sets of ear pieces," objected Jimmy. "I suppose of course we could attach a few more----"
    "I get Herb's idea," interrupted Bob, "and it's a good one. He thinks that we ought to have a loud speaker--a horn that would fill the room with sound and do away with the ear pieces altogether."
    "You hit the bull's-eye the first time," Herb conceded. "In other words, instead of having a concert for four have it for fourteen or forty."

CHAPTER  IV

FACING  THE  BULLY

    THE radio boys ruminated over Herb's suggestion for a little while.
    "The idea itself is all right," pronounced Joe slowly, "but the trouble is that we couldn't do it very well with this set, which is the best we've been able to make so far. We can hear the sound that comes over the wire well with these earpieces glued to our ears, but the sound would be lost if it were spread all over the room."
    "Wouldn't the horn help out on that?" asked Herb.
    "Not by itself, it wouldn't," answered Bob. "It's a mistake to think that the horn itself makes the sound or increases its loudness. The only use of the horn is to act as a relay for the diaphragm of the receiver and connect it with the air in the room. But the sound itself must first be in the receiver. And with a crystal detector, such as we're using in this set, I'm afraid that we couldn't get volume of sound enough. It would be spread out over the room so thinly that no one would be able to hear anything. We'll have to amplify the sound, and to do that there's nothing better than a vacuum tube. That's the best thing that the world has discovered so far."
    "I guess it is," remarked Jimmy. "Doctor Dale has one in his set."
    "Yes," chimed in Joe. "He even has more than one. The more there are the louder and clearer the sound."
    "I don't suppose we could make one," Herb remarked.
    "No; that's one thing that costs real money," replied Bob. "But don't let that bother you. I've got quite a lot left of that hundred dollars of the Ferberton prize, and there's nothing I'd rather spend it for than to improve the radio set."
    "Count me in on that, too," said Joe. "I've scarcely touched my fifty."
    "How about the horn?" queried Jimmy. "Will that have to be bought, too?"
    "No," replied Bob. "That's something you can make. That is, if you're not too tired from the work you did on setting up the aerial this afternoon."
    "But," objected Jimmy, ignoring the gibe, "I don't know anything about working in tin or steel. I haven't any tools for that."
    "The horn doesn't have to be made of metal" answered Bob. "In fact, it's better if it's not. Some horns are even made of concrete----"
    "Use your head for that, Jimmy," broke in Herb irreverently.
    "But best of all," Bob continued, while Jimmy favored the interrupter with a glare, "is to make the horn of wood. Take some good hard wood, like mahogany or maple, polish the inside with sandpaper after you've hollowed it out, give it a coat of varnish or shellac, and you'll have a horn that can't be beaten. It's very simple."
    "Sure!" said Jimmy sarcastically. "Very simple! Just like that! Simple when you say it quick. Simple as the fellow that tells me how to do it."
    "Just imagine you're hollowing out a doughnut," put in Joe grinning. "You're an expert at that."
Pages 45-63:

CHAPTER  V

A  BIG  ADVANCE

    By this time the principal was only a few yards away.
    "Good afternoon, boys," he said, as he came abreast of them. "You seemed to be a little excited about something"
    "Yes, we were having a little argument," admitted Joe.
    The principal looked at them sharply and waited as though he expected to hear more. But as nothing further was said, he did not press the matter. If the trouble had taken place in the school or on the school premises, he would have felt it his duty to go to the bottom of the affair. But he had no jurisdiction here, and he was too wise a man to mix in things that did not directly concern him or his work.
    "Well, how goes radio?" he asked, changing the subject "Are you boys just as enthusiastic over it as you were the night you won the Ferberton prizes?"
    "More so than ever," replied Bob, and Joe confirmed this with a nod of the head. "It's getting so that almost every minute we have out of school we're either tinkering with our set or listening in. We've just finished putting up a new umbrella aerial, and it's a dandy."
    "I use that kind myself," said Mr. Preston. "I get better results with it than I do with anything else."
    "Why, are you a radio enthusiast, too?" asked Bob, in some surprise. "I didn't have any idea you were interested in it."
    "Oh, yes," affirmed the principal, with a smile. "I'm one of the great and constantly increasing army of radio fans. I understand there are more than a million of them in the United States now, and their ranks are being swelled by thousands with every day that passes. I use it for my own personal pleasure and for that of my family, but I also have an interest in it because of my profession."
    "I understand it's becoming quite a feature in education," remarked Joe.
    "It certainly is," replied Mr. Preston. "Many colleges and high schools now have radio classes as a regular part of their course. College professors give lectures that go by radio to thousands where formerly they were heard by scores. I've been thinking of a plan that might be of help in the geography classes, for instance. Suppose some great lecturer or traveler who has been in faraway lands should give a travel talk from some broadcasting station. Then while he was describing China, for instance, we might have moving pictures thrown on a screen in the classroom showing Chinese cities and customs and types. Both the eye and the ear would be taught at the same time, and in a most interesting way, it seems to me. What do you think of the idea?"
    "Fine," said Bob.
    "Dandy," agreed Joe. "There wouldn't be any lack of interest in those classes. The boys would be eager to have the time for them come."
    "Well," smiled Mr. Preston, "it's only an idea as yet, but it's perfectly feasible and I shouldn't be surprised to see it in general use in a year or two."
    He turned into a side street just then with a pleasant good-bye, and the boys went on their way together, picking up Jimmy, who was just emerging from a store.
    "What was Mr. Preston talking to you about?" asked Jimmy, with some curiosity, for he had witnessed the parting. "Hauling you over the coals, was he, for something you've done or haven't done?"
    "Nothing like that," replied Joe. "We just found out that he is a radio fan like the rest of us."
    "Funny, isn't it, how that thing is spreading?" murmured Jimmy musingly. "You couldn't throw a stone now without hitting somebody who is interested in radio."
    They told him all the details of the meeting, and became so engrossed in it that they almost ran into Dr. Dale, who was just coming up from the railroad station.
    He greeted them with great cordiality, which met with quite as hearty a response on their part, for the minister was a prime favorite with them and they always felt at their ease with him. There was nothing prim or professional about him, and his influence among the young people was unbounded.
    He chatted with them for a few minutes until they reached Bob's gate.
    "Won't you come up on the porch for a few minutes, Doctor?" asked Bob. "There are some things we'd like to ask you about radio."
    "Certainly I will," replied the doctor, with a smile. "There's not much that I'd rather talk about. In fact, I was just about to tell you of an interesting experience that I had this very afternoon."
    He went with the boys up the steps and dropped into the chair that Bob drew up for him.
    "Tell us about that first, Doctor," urged Bob. "Our questions can come afterward."
    "I just had the luck to get on a train coming home that had a car attached to it where they were trying out a new radio system," replied the minister. "I heard about it from the conductor, whom I know very well, and he arranged it so that I could go into the car where they were making the experiments. They had a radio set in there with a horn, and the set was connected with an aerial on the roof of the car. They sent out signals to various stations while the train was going along at the rate of forty miles an hour, and got replies that we could hear as plainly as though one of the people in the car were talking to the others. The whole thing was a complete success, and one of the officials of the road who happened to be in the party told me that the express trains on the road were going to be equipped with it.
    "Of course, if one road does that, it will not be any time before all the others will, too. It'll not be long before we can be sitting in a car traveling, let us say from New York to Albany, and chat with a friend who may be on another train traveling between Chicago and Denver. Or if a business man has started from New York to Chicago and happens to remember something important in his office he can call up his manager and give him directions just the same as though he pressed a buzzer and called him in from the next room."
    "It sounds like magic," remarked Bob, drawing a long breath.
    "If we'd even talked about such things a few hundred years ago we'd have been burned at the stake as wizards," laughed the doctor.
    "The most important thing about this railroad development," he went on, "is not the convenience it may be in social and business life, but in the prevention of accidents. As it is now, after a train leaves a station it can't get any orders or information until it gets to the next station. A train may be coming toward it head on, or another train ahead of it and going in the same direction may be stalled. Often in the first case orders have come to the station agent to hold a train until another one has passed. But the station agent gets the message just a minute too late, and the train has already left the station and is rushing on to its fate. Then all the agent can do is to shudder and wait for news of the crash. With the radio equipment he can call up the train, tell of the danger, and direct it to come back.
    "Or take the second case where a train is stopped by some accident and knows that another train is coming behind it on the same track and is due in a few minutes. All they can do now is to send back a man with a red flag to stop the second train. But it may be foggy or dark, and the engineer of the second train doesn't see the flags and comes plunging on into the first train. With the radio, the instant a train is halted for any reason, it can send a message to the second train telling just where it is and warning of the danger. Hundreds have been killed and millions of dollars in property have been lost in the past just because of the old conditions. With the radio installed on trains, that sort of thing will be made almost impossible in the future.
    "But there," he said, with a smile, "I came up here to answer your questions, and I've been doing all the talking. Now just what is it you wanted to ask me about radio?"

CHAPTER  VI

THE  WONDERFUL  TUBE

    "IT'S about getting a vacuum tube," replied Bob, in answer to the doctor's question. "The crystal detector is all right when we use the ear pieces. But we got to thinking about a horn so that lots of people could enjoy the concerts at the same time, and we figured that the crystal wouldn't be quite good enough for that."
    The doctor smiled genially.
    "I knew you'd be wanting that sooner or later," he said. "It's the second natural step in radio development. While you were still getting familiar with the working of the wireless, the crystal would do very well. But there comes a time to all amateurs when they get to hankering after something that is undeniably better. And the vacuum tube is that thing."
    "It seems funny to me that the vacuum tube could have any use in radio," put in Jimmy. "I never thought of it in any way but as being used for an electric light."
    "Neither did lots of other people," replied the doctor, smiling. "Even Mr. Edison himself didn't realize what its possibilities were. He did, though, discover some very curious things about it. In fact, he made the first step that led to its use for radio. He put a plate in one of his lamps. The plate didn't touch the filament, but formed part of a circuit of its own with a current indicator attached. Then when he turned on the light and the filament began to glow, the needle of the indicator began to twitch. Since the filament and the plate weren't touching, the movement of the needle indicated that the electricity must have jumped the gap between the two. But this simply showed that an invisible connection was established between the filament and the plate and nothing more came of it at the time.
    "Now, it's likely that even yet we shouldn't have had that discovery of Edison's used for the development of radio if it hadn't been for the new theory of what electricity really is. That theory is that everything is electricity. This chair I'm sitting on, the railing to this porch, the hat that Jimmy is holding in his hand--all that is electricity."
    Jimmy gave a little jump at this, and held his hat rather gingerly at arm's length and looked at it suspiciously.
    The doctor joined in the laugh that followed.
    "Oh, you needn't be afraid that you'll get a shock," he said. "Electricity won't hurt you as long as it's at rest. It's only when it gets stirred up that high jinks are apt to follow."
    Jimmy looked relieved.
    "Now," continued the doctor, "the theory is that all matter is composed of an infinite number of electrons. An electron is the smallest thing that can be conceived, smaller even than the atom which used to be thought of as the unit. There may be millions, billions, quadrillions of them in a thing as big as a hickory nut. And when these electrons get busy you can look out for things to happen.
    "Every hot object sends out electrons. That's the reason that the filament in the electric light tube sends them out."
    "I suppose a red-hot stove would send them out, too," suggested Joe. "If that is so, I should think that people would have found out about them long ago."
    "Ah, but there's this difference," explained the doctor. "The red-hot stove does send them out, but the air stops them. Remember that the atoms of which the air is composed are so large that the poor little electrons have no chance against them. It's like a baby pushing against a giant. It can't get by.
    "Now the vacuum tube comes along, knocks out the giant of the air, and lets the baby electrons get past him. The air is pumped out of the tube and the electrons have nothing to stop them. That's why Mr. Edison saw the needle on the plate begin to move, although the plate wasn't touching the filament. The electrons jumped across the gap between the filament and the plate because there was nothing to stop them.
    "With this discovery of Mr. Edison's to aid him, a man named Fleming came along, who found that the oscillations caused by the flow of electrons to the plate could be utilized for the telephone by the use of what he called an oscillation valve that permitted the passage of the current in one direction only. That was the second important step.
    "But these two steps alone wouldn't have made radio what it is to-day if it hadn't been for the wonderful improvement made by DeForest. He mounted a grid of wire between the filament and the plate connected with a battery. He found that the slightest change in the current to the grid made a wonderfully powerful increase in the current that passed from the filament to the plate. Just as when you touch the trigger of a rifle you have a loud explosion, so the grid magnifies tremendously the sound that would otherwise be weak or only ordinary. And by adding one vacuum valve to another the sound can be still further magnified until the crawling of a fly will sound like the tread of an elephant, until a mere whisper can become a crash of thunder, until the ticking of a watch will remind you of the din of a boiler factory, and the sighing of the wind through the trees on a summer night will be like the roar of Niagara.
    "But there," he broke off, with a little laugh, "I'm letting my enthusiasm carry me away. It's hard to keep calm and cold-blooded when I get to talking about radio."
    "Well, you don't care to talk about it more than we care to hear about it, you can be sure of that," said Joe warmly.
    "Yes," chimed in Jimmy, "to me it's more interesting than a--a pirate story," he added rather lamely.
    "With the advantage," laughed Dr. Dale, "that the pirate story usually has lots of pain and misery in it for somebody, while the radio has nothing but benefit for everybody. Why, you can scarcely think of any experience in which the radio won't help. Take an Arctic expedition for instance. It used to be that when a ship once disappeared in the ice floes of the Arctic regions it was lost to the world for years. Nobody knew whether the explorers were alive or dead, were failing or succeeding, were safe and snug on board their ship or were shipwrecked and freezing on some field of ice. Look at the Greeley expedition, when for months the men were freezing and starving to death. If they had had a radio outfit with them, they could have communicated with the outside world, told all about their plight, given the exact place they were in, and help would have gone to them at once. Not a man need have perished. So if a crew were shipwrecked on a desert island, they wouldn't to-day have to depend on a flag or bonfire to catch the attention of some ship that might just happen to be passing near the island. All they would have to do would be to send out a radio message--provided, of course, they had one from the wrecked ship's stores or had material to make one--and a dozen vessels would go hurrying toward them. Those naval balloonists that were lost in the wilds of Canada a couple of years ago, that other expedition that perished in the heart of Labrador, and similar cases that might be counted by the dozens--all could have been helped if they had been able to tell their troubles to the outside world. I tell you, boys, we haven't half begun to realize what the discovery of radio means to the world.
    "Now all this leads us back to vacuum tubes, for it's only with them that all these things would be possible. Perhaps in the future something better yet will be invented, but they're the best we have at present. I'm heartily in favor of you boys using a tube instead of a crystal, because it will give you vastly more enjoyment in your work. I wouldn't have more than one at the start, but later on it may be well to have more. I have a catalogue up at my house of the various makes and prices, and if you'll run up there any time I'll give it to you. At the same time I'll show you just how it's got to be inserted and attached. Maybe also I'll be able to help you in the making of the horn. I'll have to go now," he added, looking at his watch. "It's surprising how the time flies when we get on this subject. Good-bye, boys, and don't forget to drop in at the house whenever you can."
    The radio boys watched the minister's straight, alert figure as he went rapidly up the street.
    "Isn't he all to the good?" asked Bob admiringly.
    "You bet he is!" agreed Jimmy emphatically, the others nodding their assent.

CHAPTER  VII

BASEBALL  BY  WIRELESS

    FOR the next week the radio boys worked like beavers. They had pored over the catalogue that, according to his promise, Dr. Dale had lent them, and, acting on his advice, had picked out a tube of well-known make that could be bought for a moderate price. They had had to send to New York for it, because Dave Slocum did not have just that kind in stock, and they were feverish with impatience until it arrived. In the period of waiting they pitched in and helped Jimmy with the horn, and even Herb became sufficiently infected by the energy of the others to turn to and do his share of the work.
    The precious tube arrived on Saturday morning, and Bob, who had ordered it, was gloating over it when the other boys came over to the house.
    "It's come at last!" he cried exultantly, holding up the tube for their inspection.
    There were exclamations of satisfaction as the others gathered round Bob and examined it.
    "And it's come just in time to get a good christening," declared Joe. "That is, if we can have everything ready by three o'clock this afternoon."
    "What do you mean?" asked Bob.
    "Why, I just read in the morning paper that the broadcasting station is going to send out the big baseball game between the Giants and the Pittsburghs at the Polo Grounds this afternoon," replied Joe. "They say that they're going to send out the game play by play, every ball pitched, every strike, every hit, every base stolen, every run scored, so that you can follow the game from the time the first man goes to the bat till the last man goes out in the ninth inning. What do you think of that?"
    What they thought of it was evident from the chorus of jubilation that followed. All of them were ardent baseball fans, and in addition to that were good players themselves. Bob was pitcher and Joe first baseman on the High School nine, while Jimmy played a good game at short and Herb took care of the center field garden.
    Naturally, with this love of the game, they were keenly interested in the championship races of the big major league ball teams and, during the season, followed the ups and downs of their favorites with the closest attention. That spring the race had been especially hot between the Giants and the Pittsburghs. Both had started out well, and the Giants had cleaned up the majority of games in the East, while the Pittsburghs had been cutting a big swath in the West.
    Now the Pittsburghs were coming to New York on their first invasion of the year, and interest ran fever high in the Metropolis and the section round about. The newspapers were devoting columns of space to the teams, and it was certain that there would be a record attendance at the game that afternoon.
    "Bully!" cried Herb, as he danced a jig on the receipt of Joe's news.
    "It will be almost as good as sitting in the grandstand behind the home plate," exulted Jimmy.
    "Best thing I've heard since Sitting Bull sat down!" exclaimed Bob, as he clapped his friend on the shoulder.
    "First time we'll ever have seen a championship baseball game without paying for it," laughed Joe.
    "I wouldn't exactly call it seeing the game," said Bob. "But it's certainly the next thing to it. But now let's get busy so that we'll be sure to have everything ready by the time the game begins."
    They needed no urging and worked so fast and well that by dinner time they had the tube and horn arranged to their satisfaction. That left them time enough to go around among their friends and invite them to come in and enjoy the game with them. The invitation was accepted with alacrity, and some time before the hour set for the game to begin Bob's room was filled with expectant boys.
    Naturally, Bob, as host, was a little anxious and nervous as the moment approached when his improved set would be put to the test. It would have been a mortifying thing for him to fail.
    He felt sure that every attachment and connection had been properly made and that nothing essential had been overlooked. Still, it was with a certain feeling of apprehension that he turned the knob to tune in when his watch told him that it was three o'clock. The day was hot, and "static" was likely to be troublesome.
    There was a moment of hissing and whistling while he was getting perfectly tuned. Then he caught it just right, and into the room, clear and strong, came the announcement of the umpire, repeated by the man at the broadcasting station:
    "Ladies and gentlemen: The batteries for today's game are Blake and McCarthy for Pittsburgh, Hardy and Thompson for New York. Play ball!"
    There was a roar of delight from the boys in the crowded room and a clapping of hands that made Bob's face flush with pleasure. But he held up his hand for silence, and the excited boys settled back in their chairs, listening intently so as not to miss a feature of the game.
    Then followed, play by play, the story of the first inning with the Pittsburghs, as the visiting team, first at bat.
    The hum of conversation had ceased in the room, and the boys leaned forward intently, anxious not to lose a syllable.
Pages 71-72:

    There was a momentary pause.
    "Krug hits a terrific drive to the box," announced the voice. "Compton leaps into the air and spears it with his left hand. He throws to Albers and catches Wilson, who had left the bag. Albers hurls the ball to Menken and gets Ackerson, who was trying to scramble back to second. Triple play, three men out and the Giants win, three to two!"
    There was a moment of stupefaction in the crowded room. Then a roar broke out that brought Mrs. Layton up to the room in a hurry under the impression that something dreadful had happened.
    "It's all right, Mother," laughed Bob. "We're only excited over the baseball game. It came out so unexpectedly that it took us all off our feet."
    "You seem to be all on your feet, as far as I can judge," Mrs. Layton smiled back. "But you can make all the noise you want as long as you are happy," and with a wave of her hand she left them.
    "A triple play!" exclaimed Bob hilariously. "The thing that happens only once in a blue moon. Say, fellows, maybe we didn't pick out a corking game to christen our radio with!"
    "And almost as good as though we were right at the grounds," cried Joe. "I've seen many a game, and I never got more real excitement over one than I've had this afternoon. I could almost hear my heart beat while I was wondering what Krug was going to do."
    "And just think what it will be when the World's Series comes along in the fall!" chuckled Jimmy. "We'll take in every game without going out of Clintonia."
    "That is, if it's played in the East," put in Herb. "It may not be so easy if it's played in the West."
    "It doesn't matter where it's played," rejoined Jimmy. "By the time fall comes, we'll probably have improved our radio set so that we can listen in on Chicago just as easily as we have to-day on Newark. And, anyway, the results will be sent to the Newark station so that it can be broadcasted all over the East. We'll take them all in, never you fear, and we won't have to pay a fortune to speculators for the tickets either."
Pages 74-83:
CHAPTER  IX

THE  LOOP

    "DO YOU know, fellows," remarked Bob, as he was talking with his friends a few days later, "I've been thinking----"
    "Bob's been thinking!" cried Herb. "Fire the cannon, ring the bells, hang out the flags. Bob's been thinking!"
    "Are you sure it's that, or have you only been thinking that you've been thinking?" grinned Joe.
    "When did it attack you first?" asked Jimmy, with great solicitude. "And where does it hurt you worst? Are you taking anything for it? You don't want to let it go too long, Bob. I knew a fellow who had that same trouble and didn't think it was worth while to send for a doctor, and before he knew it----"
    Bob made a dive at him that Jimmy adroitly ducked, losing nothing but his hat in the process.
    "Listen to me, you boneheads," Bob commanded, "and I'll try to get down on the same level with your feeble intelligence. I've been thinking that perhaps we can better our set still more in the matter of aerials."
    "Alexander always looking for new worlds to conquer," murmured Joe. "We nearly got killed the last time we bettered our aerial. What's the matter with the umbrella type? I thought that was the ne plus ultra, the sine qua non, the----"
    "The e pluribus unum," Herb helped him out, "the hoc propter quod, the hic jacet, the requiescat in pace, the----"
    At this point his hat followed Jimmy's.
    "The umbrella kind is good, all right," admitted Bob; "and, for that matter, I'm not dead sure that it isn't the best. It certainly gave us fine results in the baseball game on Saturday. But there's nothing so good that there may not be something better, and I thought it might be well to rig up a loop some day and try it out. If it works as well or better than the umbrella, we may use it when we come to set up our radio at Ocean Point."
    "Is it a big job?" asked Herb, who as a rule was not on speaking terms with anything that looked like work.
    "No," answered Bob. "It's easy enough to make. We'll just get Jimmy here to make a frame for it down in his father's carpenter shop----
    "Jimmy!" repeated that individual, in an aggrieved tone. "We'll just get Jimmy to make the horn. Sure! We'll just get Jimmy to make a frame. Sure! I suppose if one of us was marked out to die, you'd say, 'We'll just let Jimmy do it.' Just as easy as that."
    "Stop right there, Jimmy," commanded Joe "You'll have me crying in a minute, and it's an awful thing to see a strong man weep."
    "After Jimmy has made the frame," continued Bob, not at all moved by the pathos of the situation, "all we'll have to do will be to wind it about eight times with copper wire. That will give us a lot of receiving area and capacity. The frame ought to be about four feet square. It'll have to be mounted on a pivot----"
    "Let Jimmy make the pivot," murmured Jimmy.
    "So that it can be swung end on in the direction of the broadcasting station," continued Bob, not deigning to notice the interruption. "It has to be pointed in that direction in order to get the message. If it were at right angles, for instance, we probably would hear only very little or perhaps nothing at all. You see, with that kind of aerial we don't have to put up anything on the roof at all. We could have it inside the room. It could be fastened to a hook in the ceiling, so that when we weren't using it we could hoist it up and get it out of the way. That kind is used a lot on ships and at ship stations on shore. They call it sometimes a 'radio compass.' You can see it must be pretty good or they wouldn't use it so widely."
    "It is good," broke in a bass voice behind them, and as they turned in surprise they were delighted to recognize in the owner of the voice Mr. Frank Brandon, the radio inspector, by whose aid they had been able to track down Dan Cassey, the rascal who had tried to defraud Nellie Berwick, an orphan girl, of her money.
    There was an exclamation of pleasure from all of the boys, with whom Mr. Brandon was a great favorite.
    "What good wind blew you down this way?" asked Bob, after the greetings and hand-shakings were over.
    "A little matter of business brought me down to a neighboring town, and while I was so near I thought I would run over to Clintonia and call on my old friend, Doctor Dale," replied Brandon. "He told me that you boys won the Ferberton prizes," he continued, addressing Bob and Joe, "and I congratulate you. I wasn't surprised, for I knew you'd been doing hard and intelligent work on your sets. And I can see from the conversation I overheard that you're just as much interested in it as ever."
    "More than ever," affirmed Bob, and the others agreed. "We're just crazy about it. We think it's just the greatest thing that ever happened."
    "There are lots more who think the same thing," said Brandon, with a smile. "And I guess they're about right. By the way, there's an interesting thing about that radio compass you were speaking about that isn't generally known. I was over on the other side when the thing happened, and I got some inside dope on it."
    "Tell us about it," urged Bob, and the others joined in.
    "It was just before the battle of Jutland," replied Brandon, "which, as of course you know, was the biggest naval battle fought during the World War. The German fleet had been tied up in their own home waters for nearly two years, and hadn't ventured out to try conclusions with the British fleet that was patrolling the North Seas. In fact, it began to be thought that they never would come out. But at last the German naval leaders determined to risk a battle. They made their preparations with the greatest secrecy, because, their vessels not being as numerous as those of the British, their only chance of success lay in catching a part of the British fleet unawares before the rest of the fleet could come to their rescue.
    "But the British naval authorities were on the alert. They had this radio compass you were talking about developed to a high point of efficiency and were able to listen in on the orders given by the German commanders to their vessels. The Germans hadn't any idea that they could be overheard and used their wireless signals freely. Now, you remember that the battle took place on May thirty-first."
    They did not remember at all, but they nodded their heads and tried to look as wise as possible. Jimmy especially had such an owlish expression that the others could hardly keep from laughing.
    "On the night of May thirtieth," resumed Brandon, "the German flagship wirelessed a lot of instructions that were heard at several places on the British coast. These were compared and it was possible to ascertain just where the flagship was stationed. The next morning the flagship sent another lot of orders, that were also heard by the British. It was then found that the flagship had moved seven miles down the river from the station where she had been the night before. That showed that the fleet was on the move. Instantly the British fleet was sent out to meet them. So when the Germans came out to surprise the British, they found that it was the other way around and it was they themselves that were surprised. Well, you know the result. The German ships had to retreat to their harbor, and they never came out again except to surrender after the war was over. That was one way that radio helped to win the war."
    "Just as it helped our aviators," put in Joe. "Precisely," assented Mr. Brandon. "The Germans are usually pretty well up in science, but we put it all over them in the matter of wireless while the war was on."

CHAPTER  X

OFF  FOR  THE  SEA  SHORE

    "BUT valuable as the radio was in war," Brandon went on, "I believe it is going to be still more valuable in the matter of maintaining peace. I think, in fact, that it may do away with war altogether."
    "I don't quite get you," said Bob, with a puzzled air.
    "In this way," explained Brandon. "It's going to make all the people of the world neighbors. And when people are neighbors they're usually more or less friends. They have to a large extent the same interests and they understand each other.
    "Now, most wars have been due to exclusiveness and misunderstandings. Each nation has dwelt in its own borders, behind its own mountains or its own rivers, and they've shut out of their minds and interests all people outside of themselves. They've grown to think that a stranger must necessarily be an enemy. Some little thing happens that makes them mad and they're ready to fight.
    "But the radio is going to break down all these barriers of exclusiveness and remove these misunderstandings. When people get to talking together each finds that the other one isn't such a bad fellow after all. When a man in Paris picks up his telephone and has a chat with one man in England and then another man in Spain and still another in Italy he finds that they are all human beings and very much like himself. If he had the Englishman, the Spaniard, the Italian in his office together, he'd probably invite them out to dinner and they'd all have a good time. When the time comes that in every country in South America men can tune in on the radio and listen to the inaugural address of the President of the United States coming from his own lips, they'll know that we have no unfriendly designs on their country and are only anxious to see them happy and prosperous. We'll hear the same speeches, we'll listen to the same concerts, and gradually we'll come to feel that we're all neighbors. That's why I say that the radio may in the course of time make all wars impossible, or at least very improbable."
    "It sounds reasonable," commented Bob. "I only hope that you're right."
    "I'm mighty glad that we happened to be in town when you dropped in to see the doctor," said Joe. "A few days later and we'd all have been down at Ocean Point for the summer."
    "Ocean Point!" exclaimed Mr. Brandon. "Is that where you boys are going?"
    "Yes," replied Joe. "Our folks have a little colony down there, and we go every summer. Why, do you know anything about the place?"
    "I should say I did!" replied Mr. Brandon. "I usually spend a week or two at Ocean Point myself, and I have a cousin there who has charge of the Ocean Point radio station. His name is Brandon Harvey. His first name you see is the same as my last name."
    "Why, that's fine!" exclaimed Bob.
    "Radio seems to run in your family," said Herb, with a smile.
    "We'll look him up and introduce ourselves, said Joe. "We're all radio fans, and that's a sort of freemasonry."
    "You'll find him a good fellow," said Brandon. "And I'm sure he'll be glad to meet you. If I happen to get down there about the same time that you do, I'll take you around and introduce you myself. You'll find that what he doesn't know about radio isn't worth knowing. He can run rings all around me."
    "He must be pretty good then," laughed Bob. "Though I don't believe it. But it will be dandy if you are able to spend part of the summer with us down there."
blistering job Pages 92-93:

    "If you fellows put as much energy into getting that aerial strung as you do in chinning with each other, we'd be receiving messages by now," said Bob, laughing. "Let's get busy and get things fixed up, and then we'll go down and see if there's any sign of that shark friend of Herb's."
    The radio boys all agreed to this, and without further delay took up the business of stringing the antenna. They had brought two masts with them, and these they proceeded to mount on the roofs of the two bungalows occupied by the Laytons and the Atwoods. These were so situated that the umbrella antenna ran directly over the community living room, thus giving an ideal condition for sending, as the boys intended to set up their apparatus in the big living room, so that everybody in the little colony could get the benefit of the nightly concerts and news bulletins sent out by the big broadcasting stations.
    As the radio boys had surmised, getting up the aerial was a blisteringly hot job, and before they had been at it many minutes the perspiration was running off them in streams. They kept doggedly at it, however, and at last the final turnbuckle had been tightened up, and everything looked taut and shipshape.
    "There!" exclaimed Bob, looking with satisfaction at the result of their labors. "I guess it will take a pretty strong gale to knock that outfit over."
    "A cyclone, you mean," said Joe. "I don't think anything short of that would even bother it."
Pages 100-101:

    In spite of his grumbling, he worked faithfully, and soon had the lids off a number of mysterious looking boxes, from which the boys got out much complicated looking apparatus. They had brought Bob's set, the one that had been awarded the big prize the previous spring, and Bob handled this lovingly.
    All the radio boys worked with a will, and the way in which the various apparently unrelated parts became connected up into a compact and highly efficient receiving station was surprising. After two hours of steady work they had the set in condition to test.
    "I don't think we've forgotten anything," said Bob, carefully going over the various connections. "Everything looks all right to me, so here goes to test it out."
    And sure enough, it was not long before they heard the familiar call of the big Newark broadcasting station and were listening to a big band perform in stirring style.
    "That sounds familiar," said Joe, as the band finished its selection with a flourish. "It doesn't seem to be any different than when we were in Clintonia, even though we're considerably further away from the sending station."
    "I guess a few miles don't make much difference to old man Electricity," said Herb.
Pages 147-150:
CHAPTER  XVIII

IN  THE  WIRELESS  ROOM

    "SAY, Bob," said Joe, as the four radio boys were walking briskly in the direction of the wireless station the following morning, "we must get Mr. Harvey to give us lessons in sending. That must be half the fun of radiophony, and we might as well do all there is to do. What do you say?"
    "I think you're dead right," said Bob heartily. "We'll speak to him about it to-day, and I guess he'll show us how all right. In fact, he offered to do that very thing the first time we were there, if you remember."
    "I know he did," said Joe. "And I'm going to remind him of it as soon as I get a chance."
    The chance was not long in coming, for that was one of the first things Mr. Harvey spoke of after their arrival at the station.
    "You fellows ought to practice up on receiving and sending," he said. "You can't really claim to be full-fledged radio fans until you can do that."
    "That's just what we were speaking of on our way here," said Bob. "If it wouldn't be asking too much of you, we'd like nothing better than to have you show us how."
    "Well, of course, it doesn't take very long to learn the international code, and after that it's chiefly a matter of practice," said the radio man. "I have a practice sending set here now, and if you like I'll give you your first lesson."
    The boys were only too glad to take advantage of this friendly offer. Harvey had a simple telegraph key, connected up to a buzzer and a couple of dry cells. The buzzer was tuned to give a sound very much like an actual buzz in an earphone. In addition he had a metal plate on which all the letters of the alphabet were represented by raised surfaces, a short surface for a dot, and a long one for a dash. The low spaces in between were insulated with enamel. In this way, if one wire was attached to the brass plate and the other brushed over the raised contact surfaces, each letter would be reproduced in the buzzer with the proper dots and dashes.
    The boys found this device a big help, as they could memorize the proper dots and dashes for each letter, and then by moving the wire along the plate could hear the letter in the buzzer just as it should sound.
    "But with this thing, it seems to me you don't need to take the trouble to memorize the code," said Herb. "Why, I could send a message with it right now."
    "You could, but it would be a mighty slow one," replied Brandon Harvey. "That thing is useful to a beginner, but it wouldn't work out very well for actual sending. It's too clumsy."
    "Yes, I suppose that's so," admitted Herb.
    "You fellows can take that along with you when you go," said the radio man. "You can dope out the code from that, but you'll need a key to practice with, too. If you like, I'll lend you this whole practice set until you get a chance to buy one yourselves."
    "You bet we'll take it, and many thanks!" exclaimed Bob. "We should have brought something of the kind down with us, but we didn't, so your set will be just the thing for us."
    "It's been some time since I've had any use for it," said Harvey. "But I came across it the other day, and it occurred to me that maybe you fellows could use it, as you told me the first time you were here that you intended to take up sending."
    "It was mighty nice of you to think of us," said Joe, his face beaming.
    "Oh, well, we radio fans have to stick together," returned Harvey, with a smile. "There's some extra head sets lying around here somewhere, and, if you like, you can listen in on some of the messages coming in. Things were pretty lively just before you fellows came in."
    The boys lost no time in taking advantage of this offer, and were soon absorbed in listening to the reports of shipping, weather conditions, and occasional snatches of conversation that came drifting in over the antenna. Harvey's pencil was busy as he jotted down reports and memoranda. The boys felt that they were in intimate touch with the whole wide world, and the morning flew by so fast that they were all astonished when Harvey announced that it was lunch time.
    "Say, but you certainly have an interesting job, Mr. Harvey," said Bob. "I only wish I were a regular radio man, too."
    "So do I," said Joe. "It's about the most fascinating work I can think of."
    "You might not like it so much if you were doing it every day," said Brandon Harvey. "But it's a big field, and getting bigger every day, so maybe a few years from now you may join the brotherhood. If you ever do, why, all the experience you're getting now will come in mighty handy."
Page 163-168

    "We've had a mighty fine evening, though, and I'm proud of the way our outfit showed up."
    The others felt the same way. They were just about to disperse when Mrs. Fennington entered the room.
    "This evening has been so successful," she said, "that I was wondering if we couldn't give a concert in aid of the new sanitarium that is being built here. They are greatly in need of money to carry the project on, and I'm sure you would be doing a wonderful thing if you could help it along."
    The boys were for the project at once, and said so.
    "But do you think people will pay to hear a radio concert?" asked Herbert.
    "Of course they will!" exclaimed his mother. "They pay to hear every other kind of a concert, don't they? And when they know it is to aid the new sanitarium they will be all the more anxious to come."
    "I'm sure we'll do our share," said Bob. "We'll be glad to give the concert, and if people shouldn't come to it, that wouldn't be our fault."
    "That will be excellent then," said Mrs. Fennington. "I'll speak to some of the other ladies about it, and we'll set a date and make all the arrangements."
    "That plan of mother's reminds me of something I was reading about the other day," Said Herb, after Mrs. Fennington had left the room. "It was in connection with that drive they were making for the disabled war veterans. Do you remember the 'flying parson' that won the transcontinental air race a couple of years ago? Well, he has a radio attached to his airplane and he arranged to have an opera singer give a concert over it. She sat in the plane and sang, and her voice was heard over a radius of five hundred miles. Then the parson gave a short, red-hot talk in behalf of the soldiers, and thousands of people heard about the drive that wouldn't have known of it otherwise. They say that money poured into headquarters by mail during the next few days."
    "Good stuff!" exclaimed Bob. "Our work will be on a smaller scale, but the spirit will be there just the same, and I bet our old radio will rake in a heap of coin for the sanitarium."

CHAPTER  XX

THE  RADIO  CONCERT

    "WHEN do we give the concert, Herb?" asked Bob at breakfast the next morning.
    "Mother isn't quite sure yet," replied Herb to Bob's question. "Not until she consults with some of the others, anyway. But she thinks that a week from to-night will be all right. Guess one night's the same as another as far as we are concerned."
    As a matter of fact, the projected concert was scheduled several days sooner than Herb had predicted, being set for the ensuing Saturday night, so as to get as many of the week-end visitors as possible. Tickets to the affair sold well, and from the first it became evident that there would be a large attendance. People were only too glad to come, both for the sake of hearing good music and to know that they were contributing to a worthy charity. The boys, as the volume of sales increased, realized that it was up to them to see that the visitors should have the worth of their money and they went over the set with a "fine-tooth comb," to use Herb's expression, in order to make sure that every part of it was in fine working order.
    "We'll have to test everything out pretty thoroughly," remarked Bob, that Saturday morning. "We'd never hear the last of it if anything went wrong to-night."
    "You bet!" said Joe. "We've got to have everything in apple-pie order."
    The audience began to arrive early. A large space had been roped off in front of the central bungalow and furnished with rows of campchairs. The boys had set up the loud-speaking horn on a small table on the porch, running leads from it to their apparatus in the living room. This enabled them to operate the set out of sight of the audience.
    By eight o'clock almost everybody was in his place, waiting expectantly, and in some cases somewhat sceptically, for the music to begin.
    But they had not long to wait. Inside the bungalow the boys, excited and tense, heard the familiar voice of the announcer at WJZ, the big Newark broadcasting station. While he was speaking the boys had the horn outside disconnected, but with their head phones they tuned until the announcer's voice was distinct and clear and all other sounds had been tuned out. Then, as the announcer ceased speaking, and in the brief pause that ensued before the first selection on the program started, the boys connected in the loudspeaker on the porch.
    The concert commenced. Violin solos, vocal selections, and orchestral numbers followed each other in quick succession, every note and shade of tone being reproduced faithfully by the radio boys' set.
    The audience sat in absorbed silence, listening spellbound to this miracle of modern science. At intervals they could not resist applauding, although the artists producing the music were many miles away. When the concert was over at last there was a regular storm of handclapping and calls for the boys, who at length had to appear on the porch, looking, it must be confessed, as though they would rather have been almost anywhere else.
    Cries of "Speech! Speech!" came from the audience, and at last Bob stepped forward.
    "We're mighty glad if all you folks enjoyed the concert," he said. "We boys are all very much interested in radio, and we want to have everybody know what it is like. Maybe before the sanitarium gets finished you'll have to listen to another concert," he added, with a grin.
    Cries of "we hope so" and "make it soon" came from the audience, which then dispersed with many expressions of commendation for the evening's entertainment.
    When the receipts for the evening were counted it was found that they had taken in over four hundred dollars, which was soon turned over to the trustees of the sanitarium.
    The concert was the chief topic of conversation in the neighborhood for the next few days, and the radio boys were deluged with requests for information concerning radio and radio equipment. They were somewhat surprised at the furor caused by their concert, but that was probably the first time that most of those present had ever heard radio music or had reason to give more than passing thought to the subject.