So engrossed were the boys in the problem of the magnet and vacuum tube that they forgot all about Herb and his experiments. So what happened took them completely off their guard.

There was a sudden cry from Herb, followed closely by an explosion that knocked them off their feet. For a moment they lay there, a bit dazed by the shock. Then they scrambled to their feet and looked about them. Herb, being the nearest to the explosion, had got the worst of it. His face and hands were black and he was shaking a little from the shock. He gazed at the boys sheepishly.

"Wh-what happened?" asked Jimmy dazedly.

"An earthquake, I guess," replied Bob, as he looked about him to see what damage had been done.

Some doughnuts, which their namesake had recently fetched from the store, lay scattered upon the floor, together with some rather dilapidated-looking pieces of candy, but aside from this, nothing seemed to have been damaged seriously.

Jimmy's followed Bob's gaze, and, finding his precious sweets upon the floor, began gathering them up hastily, stuffing a doughnut in his mouth to help him hurry. What mattered it to Jimmy that the floor was none too clean?

"Say, what's the big idea, anyway," Joe demanded of the blackened Herb. "Trying to start a Fourth of July celebration, or something?"

"I was just mixing some chemicals, and the result was a flare-up," explained Herb sulkily. "Now, stop rubbing it into a fellow, will you? You might know I didn't do it on purpose."

Bob began to laugh.

"Better get in connection with some soap and water, Herb," he said. "Just now you look like the lead for a minstrel show."

"Never mind, Herb," Joe flung after the disconsolate scientist as he made for the door. "As long as you don't hurt anything but Jimmy's doughnuts, we don't care. You can have as many explosions as you like."

"Humph, that's all right for you," retorted Jimmy. "But I'll have you know I spent my last nickel for those doughnuts."

"Just the same," said Bob soberly, as they returned to the problem of the vacuum tube, "we're mighty lucky to have come off with so little damage. Mixing chemicals is a pretty dangerous business unless you know just what you're doing."

"And even then it is," added Joe.



CHAPTER IX

A HAPPY INSPIRATION

The days passed by, the boys becoming more and more engrossed in the fascination of radio all the time. They continued to work on their sets, sometimes with the most gratifying results, at others seeming to make little headway.

But in spite of occasional discouragements they worked on, cheered by the knowledge that they were making steady, if sometimes slow, progress.

There were so many really worth-while improvements being perfected each day that they really found it difficult to keep up with them all.

"Wish we could hear Cassey's voice again," said Herb, one day when they had tuned in on several more or less interesting personal messages.

"I don't know what good it would do us," grumbled Joe. "If he speaks always in code he could keep us guessing till doomsday."

"He's up to some sort of mischief, anyway," said Bob; "and I, for one, would enjoy catching him at it again."

"We would be more comfortable to have Dan Cassey in jail, where he belongs," observed Jimmy.

But just at present the trailing of that stuttering voice seemed an impossible feat even for the radio boys. If they could only get some tangible clue to work on!

They saw nothing of Buck Looker or his cronies about town, and concluded that they were still at the lumber camp.

"Can't stay away too long to suit me," Bob said cheerfully.

It was about that time that Bob found out about Adam McNulty. Adam McNulty was the blind father of the washerwoman who served the four families of the boys.

Bob went to the McNulty cabin, buried in the most squalid district of the town, bearing a message from his mother. When he got there he found that Mr. McNulty was the only one at home.

The old fellow, smoking a black pipe in the bare kitchen of the house, seemed so pathetically glad to see some one—or, rather, to hear some one—that Bob yielded to his invitation to sit down and talk to him.

And, someway, even after Bob reached home, he could not shake off the memory of the lonesome old blind man with nothing to do all day long but sit in a chair smoking his pipe, waiting for some chance word from a passer-by.

It did not seem fair that he, Bob, should have all the good things of life while that old man should have nothing—nothing, at all.

He spoke to his chums about it, but, though they were sympathetic, they did not see anything they could do.

"We can't give him back his eyesight, you know," said Joe absently, already deep in a new scheme of improvement for the set.

"No," said Bob. "But we might give him something that would do nearly as well."

"What do you mean?" they asked, puzzled.

"Radio," said Bob, and laid his hand lovingly on the apparatus. "If it means a lot to us, just think how much more it would mean to some one who hasn't a thing to do all day but sit and think. Why, I don't suppose any of us who can see can begin to realize what it would mean not to be able even to read the daily newspaper."

The others stared at Bob, and slowly his meaning sank home.

"I get you," said Joe slowly. "And say, let me tell you, it's a great idea, Bob. It wouldn't be so bad to be blind if you could have the daily news read to you every day——"

"And listen to the latest on crops," added Jimmy.

"To say nothing of the latest jazz," finished Herb, with a grin.

"Well, why doesn't this blind man get himself a set?" asked Jimmy practically. "I should think every blind person in the country would want to own one."

"I suppose every one of them does," said Bob. "And Doctor Dale said the other day that he thought the time would come when charities for the blind would install radio as a matter of humanity, and that prices of individual sets would be so low that all the blind could afford them. The blind are many of them old, you know, and pretty poor."

"You mean," said Herb slowly, "that most of the blind folks who really need radio more than anybody else can't afford it? Say, that doesn't seem fair, does it?"

"It isn't fair!" cried Bob, adding, eagerly: "I tell you what I thought we could do. There's that old set of mine! It doesn't seem much to us now, beside our big one, but I bet that McNulty would think it was a gold mine."

"Hooray for Bob!" cried Herb irrepressibly. "Once in a while he really does get a good idea in his head. When do we start installing this set in the McNulty mansion, boys?"

"As soon as you like," answered Bob. "Tomorrow's Saturday, so we could start early in the morning. It will probably take us some time to rig up the antenna."

The boys were enthusiastic about the idea, and they wasted no time putting it into execution. That very night they looked up the old set, examining it to make sure it was in working order.

When they told their families what they proposed to do, their parents were greatly pleased.

"It does my heart good," said Mr. Layton to his wife, after Bob had gone up to bed, "to see that those boys are interested in making some one besides themselves happy."

"They're going to make fine men, some day," answered Mrs. Layton softly.

The boys arrived at the McNulty cottage so early the next morning that they met Maggie McNulty on her way to collect the day's wash.

When they told her what they were going to do she was at first too astonished to speak and then threatened to fall upon their necks in her gratitude.

"Shure, if ye can bring some sunshine into my poor old father's dark life," she told them in her rich brogue, tears in her eyes, "then ye'll shure win the undyin' gratitude uv Maggie McNulty."

It was a whole day's job, and the boys worked steadily, only stopping long enough to rush home for a bit of lunch.

They had tried to explain what they were doing to Adam McNulty, but the old man seemed almost childishly mystified. It was with a feeling of dismay that the boys realized that, in all probability, this was the first time the blind man had ever heard the word radio. It seemed incredible to them that there could be anybody in the world who did not know about radio.

However, if Adam McNulty was mystified, he was also delightedly, pitifully excited. He followed the boys out to the cluttered back yard where they were rigging up the aerial, listening eagerly to their chatter and putting in a funny word now and then that made them roar with laughter.

Bob brought him an empty soap box for a seat and there the old man sat hour after hour, despite the fact that there was a chill in the air, blissfully happy in their companionship. He had been made to understand that something pleasant was being done for him, but it is doubtful if he could have asked for any greater happiness than just to sit there with somebody to talk to and crack his jokes with.

They were good jokes too, full of real Irish wit, and long before the set was ready for action the boys had become fond of the old fellow.

"He's a dead game sport," Joe said to Bob, in that brief interval when they had raced home for lunch. "I bet I'd be a regular old crab, blind like that."

Mrs. Layton put up an appetizing lunch for the blind man, topping it off with a delicious homemade lemon pie and a thermos bottle full of steaming coffee.

The way the old man ate that food was amazing even to Jimmy. Maggie was too busy earning enough to keep them alive to bother much with dainties. At any rate, Adam ate the entire lemon pie, not leaving so much as a crumb.

"I thought I was pretty good on feeding," whispered Joe, in a delighted aside, "but I never could go that old bird. He's got me beat a mile."

"Well," said Jimmy complacently, "I bet I'd tie with him."

If the boys had wanted any reward for that day of strenuous work, they would have had it when, placing the earphones upon his white head, they watched the expression of McNulty's face change from mystification to wonder, then to beatific enjoyment.

He listened motionless while the exquisite music flooded his starved old soul. Toward the end he closed his eyes and tears trickled from beneath the lids down his wrinkled face. He brushed them off impatiently and the boys noticed that his hand was trembling.

It was a long, long time before he seemed to be aware that there was any one in the room with him. He seemed to have completely forgotten the boys who had bestowed this rare gift upon him.

After a while, coming out of his dream, the old man began fumbling with the headphones as if he wanted to take them off, and Bob helped him. The man tried to speak, but made hard work of it. Emotion choked him.

"Shure, an' I don't know what to make of it at all, at all," he said at last, in a quivering voice. "Shure an' I thought the age of miracles was passed. I'm only an ignorant old man, with no eyes at all; but you lads have given me something that's near as good. Shure an' it's an old sinner I am, for shure. Many's the day I've sat here, prayin' the Lord would give me wan more minute o' sight before I died, an' it was unanswered my prayers wuz, I thought. It's grateful I am to yez, lads. It's old Adam McNulty's blessin' ye'll always have. An' now will yez put them things in my ears? It's heaven's own angels I'd like to be hearin' agin. That's the lad—ah!"

And while the beatific expression stole once more over his blind old face the boys stole silently out.



CHAPTER X

THE ESCAPED CONVICT

The boys saw a good deal of Adam McNulty in the days that followed, and the change in the old man was nothing short of miraculous.

He no longer sat in the bare kitchen rocking and smoking his pipe, dependent upon some passer-by for his sole amusement. He had radio now, and under the instruction of the boys he had become quite expert in managing the apparatus. Although he had no eyes, his fingers were extraordinarily sensitive and they soon learned to handle the set intelligently.

His daughter Maggie, whose gratitude to the boys knew no bounds, looked up the radio program in the paper each day and carefully instructed her father as to just when the news reports were given out, the story reading, concerts, and so forth.

And so the old blind man lived in a new world—or rather, the old world which he had ceased to live in when he became blind—and he seemed actually to grow younger day by day. For radio had become his eyes.

Doctor Dale heard of this act of kindness on the part of the boys and he was warm in his praise.

"Radio," he told the boys one day when he met them on the street, "is a wonderful thing for those of us that can see, but for the blind it is a miracle. You boys have done an admirable thing in your kindness to Adam McNulty, and I hope that, not only individuals, but the government itself will see the possibilities of so great a charity and follow your example."

The boys glowed with pride at the doctor's praise, and then and there made the resolve that whenever they came across a blind person that person should immediately possess a radio set if it lay within their power to give it to him.

On this particular day when so many things happened the boys were walking down Main Street, talking as usual of their sets and the marvelous progress of radio.

Although it was still early spring, the air was as warm almost as it would be two months later. There was a smell of damp earth and pushing grass in the air, and the boys, sniffing hungrily, longed suddenly for the freedom of the open country.

"Buck and his bunch have it all their own way," said Herb discontentedly. "I wouldn't mind being up in a lumber camp myself just now."

"Too early for the country yet," said Jimmy philosophically. "Probably be below zero to-morrow."

"What you thinking about, Bob?" asked Joe, noticing that his chum had been quiet for some time.

"I was thinking," said Bob, coming out of his reverie, "of the difference there has been in generators since the early days of Marconi's spark coil. First we had the spark transmitters and then we graduated to transformers——"

"And they still gave us the spark," added Joe, taking up the theme. "Then came the rotary spark gap and later the Goldsmith generator——"

"And then," Jimmy continued cheerfully, "the Goldsmith generator was knocked into a cocked hat by the Alexanderson generator."

"They'll have an improvement on that before long, too," prophesied Herb.

"They have already," Bob took him up quickly. "Don't you remember what Doctor Dale told us of the new power vacuum tube where one tube can take care of fifty K. W.?"

"Gee," breathed Herb admiringly, "I'll say that's some energy."

"Those same vacuum tubes are being built right now," went on Bob enthusiastically. "They are made of quartz and are much cheaper than the alternators we're using now."

"They are small too, compared to our present-day generators," added Joe.

"You bet!" agreed Bob, adding, as his eyes narrowed dreamily: "All the apparatus seems to be growing smaller these days, anyway. I bet before we fellows are twenty years older, engineers will have done away altogether with large power plants and cumbersome machinery."

"I read the other day," said Joe, "that before long all the apparatus needed, even for transatlantic stations, can be contained in a small room about twenty-five feet by twenty-five."

"But what shall we do for power?" protested Herb. "We'll always have to have generators."

"There isn't any such word as 'always' in radio," returned Bob. "I shouldn't wonder if in the next twenty or thirty years we shall be able, by means of appliances like this new power vacuum tube, to get our power from the ordinary lighting circuit."

"And that would do away entirely with generators," added Joe triumphantly.

"Well, I wouldn't say anything was impossible," said Herb doubtfully. "But that seems to me like a pretty large order."

"It is a large order," agreed Bob, adding with conviction: "But it isn't too large for radio to fill."

"Speaking of lodging all apparatus in one fair-sized room," Joe went on. "I don't see why that can't really be done in a few years. Why, they say that this new power vacuum tube which handles fifty K. W. is not any larger than a desk drawer."

"I see the day of the vest-pocket radio set coming nearer and nearer, according to you fellows," announced Herb. "Pretty soon we'll be getting our apparatus so small we'll need a microscope to see it."

"Laugh if you want to," said Bob. "But I bet in the next few years we're going to see greater things done in radio than have been accomplished yet."

"And that's saying something!" exclaimed Joe, with a laugh.

"I guess," said Jimmy thoughtfully, "that there have been more changes in a short time in radio than in any other science."

"I should say so!" Herb took him up. "Look at telephone and telegraph and electric lighting systems. There have been changes in them, of course, but beside the rapid-fire changes of radio, they seem to have been standing still."

"There haven't been any changes to speak of in the electric lighting systems for the last fifteen years or more," said Bob. "And the telephone has stayed just about the same, too."

"There's no doubt about it," said Joe. "Radio has got 'em all beat as far as a field for experiment is concerned. Say," he added fervently, "aren't you glad you weren't born a hundred years ago?"

The boys stopped in at Adam McNulty's cabin to see how the old fellow was getting along. They found him in the best of spirits and, after "listening in" with him for a while and laughing at some of his Irish jokes, they started toward home.

"I wish," said Bob, "that we could have gotten a line on Dan Cassey. It seems strange that we haven't been able to pick up some real clue in all this time."

For, although the boys had caught several other mysterious messages uttered in the stuttering voice of Dan Cassey, they had not been able to make head nor tail of them. The lads liked mysteries, but they liked them chiefly for the fun of solving them. And they seemed no nearer to solving this one than they had been in the beginning.

"I know it's a fool idea," said Herb sheepishly. "But since we were the ones that got Cassey his jail sentence before, I kind of feel as if we were responsible for him."

"It's pretty lucky for us we're not," remarked Joe. "We certainly would be up against it."

On and on the boys went. Presently Joe began to whistle and all joined in until suddenly Jimmy uttered a cry and went down on his face.

"Hello, what's wrong?" questioned Bob, leaping to his chum's side.

"Tripped on a tree root," growled Doughnuts, rising slowly. "Gosh! what a spill I had."

"Better look where you are going," suggested Herb.

"I don't see why they can't chop off some of these roots, so it's better walking."

"All right—you come down and do the chopping," returned Joe, lightly.

"Not much! The folks that own the woods can do that."

"Don't find fault, Jimmy. Remember, some of these very roots have furnished us with shinny sticks."

"Well, not the one I tripped over."

It was some time later that the boys noticed that they had tramped further than they had intended. They were on the very outskirts of the town, and before them the heavily-wooded region stretched invitingly.

Jimmy, who, on account of his plumpness, was not as good a hiker as the other boys, was for turning back, but the other three wanted to go on. And, being three against one, Jimmy had not the shadow of a chance of getting his own way.

It was cool in the shadows of the woods, and the boys were reminded that it was still early in the season. It was good to be in the woods, just the same, and they tramped on for a long way before they finally decided it was time to turn back.

They were just about to turn around when voices on the path ahead of them made them hesitate. As they paused three men came into full view, and the boys stood, staring.

Two of the men they had never seen before, but the other they knew well. It was the man whose voice they had been trailing all these weeks—Dan Cassey, the stutterer!



CHAPTER XI

DOWN THE TRAP DOOR

It seemed that in the semi-darkness of the woods Cassey did not at once recognize the radio boys. He was talking excitedly to his companions in his stuttering tongue and he was almost upon the boys before he realized who they were.

He stopped still, eyes and mouth wide open. Then, with a stuttered imprecation, he turned and fled. The men with him stayed not to question, but darted furtively into the woods.

"Come on, fellows!" cried Bob, with a whoop of delight. "Here's where we nail Dan Cassey, sure."

The boys, except poor Jimmy, were unusually fleet, and they soon overtook Cassey. Bob's hand was almost upon him when the man doubled suddenly in his tracks and darted off into the thick underbrush.

Bob, with Herb and Joe close at his heels, was after him in a minute. He reached a clearing just in time to see Cassey dash into an old barn which had been hidden by the trees.

The boys plunged into the barn with Jimmy pantingly bringing up the rear. In Bob's heart was a wild exultation. They had Cassey cornered. Once more they would bring this criminal to justice.

"You guard the door," he called in a low tone to Joe. "See that Cassey doesn't get out that way, and Herb and I will get after him in here."

The barn was so dark that they could hardly see to move around. There was a window high up in the side wall, but this was so covered with dirt and cobwebs that it was almost as though there was none.

However, Cassey must be lurking in one of those dark corners, and if they moved carefully they were sure to capture him!

There was a loft to the barn, but if there had been a ladder leading up to it it had long since rotted and dropped away, so that Bob was reasonably sure the man could not be up there.

It was eery business, groping about in the musty darkness of the old barn for a man who would go to almost any lengths of villainy to keep from being caught.

Suddenly Bob saw something move, and, with an exultant yell, jumped toward it. Once more he almost had his hand upon Cassey when—something happened.

The floor of the barn seemed to open and let him through, and his chums with him. As he fell through the hole into blackness he had confused thoughts of an earthquake. Then he struck bottom with a solid thump that almost made him see stars.

He heard similar thumps about him and realized that Herb and Jimmy had followed him. Whatever it was they had shot through had evidently magically closed up again, for they were in absolute darkness.

"Well," came in a voice which Bob recognized as Jimmy's, "I must say, this is a nice note!"

"We've been pushed off the end of the world, I guess," said Herb, with a sorry attempt at humor. "Who all's in this party anyway? Are we all here?"

"I guess so," said Joe, and at the sound of his voice Bob jumped.

"What are you doing here?" he asked. "I thought you were going to guard the door."

"That's what I should have done, but I played the big idiot," retorted Joe bitterly. "I couldn't resist coming after you fellows to be in on the big fight. I suppose while I was trailing you boys somebody sneaked in the door and signed our finish."

"Looks like it," said Bob, feeling himself to make sure there were no bones broken. "And now, instead of delivering Cassey to justice we're prisoners ourselves. Say, I bet the old boy isn't laughing at us or anything just now."

"I'm awful sorry, Bob," said Joe penitently. "I thought if I kept my eye on the door——"

"Oh, it's all right," said Bob generously. "Accidents will happen and there's no use crying over spilled milk. I suppose the most sensible thing for us to do right now is to hustle around and find a way out of this place."

"Maybe there isn't any," said Jimmy dolefully. "Then what'll we do?"

"Stay here and let the rats eat us, I guess," said Herb cheerfully, and Jimmy groaned.

"Gosh, don't talk about eating, old boy," he pleaded. "I'm just about starved this minute."

"You'll probably stay starved for some little time longer," said Bob unfeelingly. He had risen cautiously to his feet, and finding that their prison was at least high enough for them to stand up in, reached his hands tentatively above his head.

As, even by standing on tiptoe, his fingers encountered nothing but air, he decided that they must have dropped further than he had thought at the time.

A hand reached out and took hold of him and he realized that Joe was standing beside him.

"Must have been some sort of trap door opening inward, I guess," said the latter. "You didn't see anything, did you, Bob?"

"No. It happened too suddenly. One minute I was reaching forward to grab hold of Cassey and the next moment I found myself flying through space."

"Humph," grunted Joe. "It was lucky for Cassey that we all happened to be in a bunch," he said. "He couldn't have gotten rid of us so quickly if we'd been scattered about——"

"As we should have been," added Bob. "Just the same," he added, after a minute, "I don't suppose it would have done any good if one of us had been left up there. It must have been the men who were with Cassey who sprang the trap on us; and if that's so, the fight would have been three to one."

"I'd like to have tried it just the same," said Joe belligerently. "I bet Cassey would have got a black eye out of it, anyway."

For some time they groped around the black hole of their prison, hoping to find some way of escape, but without success. They were beginning to get tired and discouraged, and they sat down on the floor to talk the situation over.

The queer thing about this hole in the ground was that it possessed a flooring where one would have expected to find merely packed-down dirt. The flooring consisted of rough boards laid side by side, and when the boys moved upon it it sounded like the rattling of some rickety old bridge.

"There's some mystery about this place," said Bob. "I bet this is a regular meeting place for Cassey and whoever his confederates may be. In case of pursuit all they would have to do would be to hide in this hole and they'd be practically safe from discovery."

"I wonder," said Herb, "why Cassey didn't do that now."

"Probably didn't have time," said Bob. "I was right on his heels, you know, and probably he didn't dare stop for anything."

"And so they turned the trick on us," said Joe. "And it sure was a neat job."

"Too neat, if we don't get out of here soon," groaned Jimmy. "I bet they've just left us here to starve!"

"I wouldn't put it beyond Cassey," said Herb gloomily. "It would be just the kind of thing he'd love to do. He's got a grudge against us, anyway, for doing him out of Miss Berwick's money and landing him in jail, and this would be a fine way to get even."

"Well, if that's his game, he's got another guess coming," said Bob, adding excitedly: "Say, fellows, if that was a trap door that let us down into this hole, and it must have been something of that sort, we'll probably be able to get out the same way."

"But it's above our heads," protested Herb.

"What difference does that make?" returned Bob impatiently. "One of us can stand on the other's back, and we can haul the last fellow out by his hands."

"Simple when you say it quick," said Joe gloomily. "But I bet that trap door is bolted on the outside. You don't think Cassey's going to let us off that easy, do you?"

"Well, we could see anyway," returned Bob. "Anything's better than just sitting here. Come on, let's find that trap door."

This feat, in itself, was no easy one. They had wandered about in the dark so much that they had become completely confused.

Since Herb was the slightest, he was hoisted up on Bob's shoulders and they began the stumbling tour of their prison. It seemed ages before Herb's glad cry announced a discovery of some sort.

"I've found a handle," he said. "Steady there, Bob, till I give it a pull."



CHAPTER XII

GROPING IN DARKNESS

Herb tugged gently and gave another yell of delight when whatever was attached to the handle yielded grudgingly to the pull.

"It's the trap door, fellows!" he cried. "Move over a bit, Bob, till I pull the thing down."

Bob, who, about this time, was finding Herb's weight not any too comfortable, moved over, and, in doing so, stumbled, nearly pitching himself and Herb to the floor.

As it was, Herb lost his balance and leaped wildly. He landed on his feet and reached out a hand to find Bob.

"Of all the tough luck," he groaned. "There I had the thing in my hand and now we've gone and lost it again."

"Sorry. But stop your groaning and get busy," Bob commanded him. "I haven't moved from this spot, so if you get up on my shoulders again you ought to be able to get hold of the handle easily enough."

So, hoisted and pushed by Joe and Jimmy, Herb finally regained his perch and felt for the handle. He found it, and this time pulled the door so far open that the boys could see through the opening in the barn floor.

"If somebody can hold that door," panted Herb, "I think I can get through this hole. Grab hold, boy. It sure is heavy."

So Joe caught the door as it swung downward and Herb scrambled through the aperture. Bob gave a grunt of relief as the weight was taken from his shoulders.

"You're next, Joe," Bob was saying when Jimmy came stumbling up, carrying something that banged against Bob's legs.

"I've got it," he panted. "Had an idea I might find something like it. Trust your Uncle Jimmy——"

"For the love of butter, what are you raving about?" interrupted Joe, and Jimmy proudly exhibited his prize.

"A soap box," he said. "And a good big one, too. If we stand on that we can reach the opening easily."

"Good for you, Doughnuts," cried Bob, joyfully seizing upon the soap box. "This beats playing the human footstool all hollow. Jump up on it, Jimmy, and see how quick you can get out of here."

Jimmy needed no second invitation. He scrambled up on the tall box, and by stretching up on tip toe could just manage to get his fingers over the edge of the flooring above.

"Give me a boost, some one," he commanded, and Bob obligingly administered the boost.

Joe was next. Bob went last, holding the trap door with his foot to keep it from closing too quickly. Once upon the floor of the barn he took his foot away and the door banged to with a snap, being balanced by a rope and weight above.

"Well, there's that!" exclaimed Bob, eyeing the closed door with satisfaction. "If Cassey thought he was going to fool us long, he sure was mistaken."

"Maybe he's hiding around here somewhere," suggested Herb, lowering his voice to a whisper.

"No such luck," replied Bob. "I'd be willing to wager that the moment we struck bottom there, Cassey and his friends beat it away from here as fast as their legs could take them."

"Don't you think we'd better look around a little bit, anyway?" suggested Joe.

"It wouldn't do any harm," agreed Bob. "But first let's have a look outside. We don't want to overlook any clues."

The boys thrashed around the bushes about the barn until they were satisfied no one was hiding there and then returned to the barn. They were curious to find out just how they had been shot through that trap door.

They thought at first that it was perhaps worked by some sort of apparatus, but they found that this was not the case. They found by experimenting that the trap door yielded easily to their weight, and decided that it had been their combined rush upon Cassey that had done the trick. The weight of the four of them upon it had shot the door down so rapidly that they had not had time even to know what was happening to them, much less scramble to safety. Then it had shut on them.

"It couldn't have worked better for them," said Herb, as they turned toward the door of the barn. "I bet they're laughing yet at the way they put things over."

"Let 'em laugh," said Bob, adding fiercely: "But I bet you anything that the last laugh will be ours!"

"I wonder what Cassey was doing here, anyway," said Jimmy, as they walked slowly homeward. "It was lucky, wasn't it, that we happened along when we did?"

"I don't see where it's so lucky," grumbled Joe. "We're no nearer catching him now than we ever were."

"Except that we know he's around this locality," put in Bob. "I guess the police will be glad to know that."

"Oh! are you going to tell the police?" asked Jimmy, whose thoughts had been upon what he was going to get for dinner.

"Of course," said Bob. "He's an escaped criminal, and it's up to us to tell the police all we know about him."

"I only wish we knew more to tell," said Joe disconsolately.

Since they had been flung through the trap door, Joe had called himself every unpleasant name he could think of for his carelessness. If he had stayed at the door where he belonged, there would have been one of them left to grapple with Dan Cassey. Probably the two men who had been with Cassey when they had surprised him had not been anywhere around. They belonged to the type of criminal that always thinks of its own safety first. Probably they had not been anywhere near the barn. And if it had been only Dan Cassey and himself, well, he, Joe, could at least have given the scoundrel a black eye—maybe captured him.

He said something of this to his chums, but they laughed at him.

"Stop your grouching," said Bob. "Haven't we already agreed that there's no use crying over spilled milk? And, anyway, you just watch out. We'll get Cassey yet."

As soon as the boys reached town they went straight to the police station and told the story of their encounter with Cassey to the grizzled old chief, who nodded his head grimly and thanked them for the information.

"I'll send some men out right away," he told them. "If there's a criminal in those woods, they're sure to get him before dark. It's too bad you lads couldn't have got him yourselves. It would sure have been a feather in your caps!"

"Why doesn't he rub it in?" grumbled Joe, as they turned at last toward home and dinner. "He ought to know we feel mad enough about it."

"Well," said Bob, "if the police round him up, because of our information, it will be almost as good as though we'd caught him ourselves. I wouldn't," he added, with a glint in his eye, "exactly like to be in Cassey's shoes, now."



CHAPTER XIII

CUNNING SCOUNDRELS

But, contrary to the expectations of the radio boys, the police were not able to locate Cassey nor any of the rest of the gang. They searched the woods for miles around the old barn about which the boys had told them, even carrying their search into the neighboring townships, but without any result. It seemed as though the earth had opened and swallowed up Cassey together with his rascally companions. If such a thing had actually happened, their disappearance could not have been more complete.

"They must be experts in the art of hiding," grumbled Bob, upon returning from a visit to the chief of police. "I was certain they would be rounded up before this."

"Guess they must have made a break for the tall timber," said Joe.

"Decided, maybe, it isn't just healthy around here," added Herb, with a grin.

And then, just when they had decided that Cassey and his gang had made a masterly getaway, the radio boys got on their trail once again.

That very evening, when tuning in for the concert, they caught another of those mysterious, stuttering messages in the unmistakable voice of Dan Cassey!

"Rice, rats, make hay," was the substance of this message, and the boys would have laughed if they had not been so dumbfounded.

"What do you know about that?" gasped Jimmy. "That old boy sure has his nerve with him."

"They're still hanging around here somewhere!" cried Bob excitedly. "They've probably got a hiding place that even the police can't find."

"Oh, if we could only make sense of this!" exclaimed Herb, staring at the apparently senseless message which he had written down. "If we only had their code the whole thing would be simple."

"Oh, yes, if we only had a million dollars, we'd be millionaires!" retorted Jimmy scornfully. "Where do you get that stuff, anyway?"

"Well," said Bob, temporarily giving up the problem, "as far as I can see, all there is for us to do is to keep our eyes and ears open and trust to luck. Now what do you say we listen in on the concert for a little while?"

In the days that followed Cassey's voice came to them several times out of the ether, and always in that same cryptic form that, try as they would, they could not make out.

It was exasperating, that familiar voice coming to them out of the air day after day without giving them the slightest clue to the whereabouts of the speaker.

And then, while they were in town one day, they quite unexpectedly ran into their old friend, Frank Brandon, the wireless inspector, whose work for some time had taken him into another district.

However, he was to stay in Clintonia for a few days on business now, and since he had nothing particular to do that day, Bob enthusiastically invited him up to his home for a visit.

"Maybe you can give us some tips on our set," Bob added, as Mr. Brandon readily accepted the invitation. "We're not altogether satisfied with our batteries. For some reason or other they burn out too quickly."

"Yes, I'll take a look at it," agreed Mr. Brandon good-naturedly. "Although I imagine you boys are such experts by this time I can't tell you very much. What have you been doing with yourselves since we last met?"

The boys told him something of their experiences, in which he showed intense interest, and in return he told them some interesting things that had happened to him.

And when he spoke of catching mysterious messages in the stuttering voice of Dan Cassey, Bob broke in upon him eagerly.

"We've caught a good many such messages too," he said. "Have you managed to make anything of them?"

"Not a thing," said Mr. Brandon, shaking his head. "If it is a criminal code, and I am about assured that it is, then it is a remarkably clever one and one that it is almost impossible to decipher without a key. I've just about given up trying."

Then the boys told of their encounter with Cassey in the woods and their adventure in the old barn, and Frank Brandon was immensely excited.

"By Jove," he said, "the man is up to his old tricks again! I'd like to get hold of him before he does any serious harm. That sort of criminal is a menace to the community.

"The funny part of it," he continued, as they turned the corner into Bob's block, "is that these messages are not all in Cassey's voice. Have you noticed that?"

It was the boys' turn to be surprised.

"That's a new one on us," Bob confessed. "The only messages we have caught so far have been in Cassey's voice."

Frank Brandon slowly shook his head.

"No," he said, "I have caught a couple in a strange voice, a voice I never heard before."

"The same kind of message?" asked Herb eagerly.

"The same kind of message," Brandon affirmed. "I have taken it for granted that the owner of the strange voice is a confederate of Cassey's."

"Maybe one of the fellows who was with him in the woods," said Jimmy, and Mr. Brandon nodded gravely.

"It's possible," he said. "I don't know, of course, but I imagine that there are several in Cassey's gang."

By this time they had reached Bob's home, and as it was nearly lunch time, Mrs. Layton insisted that they all stay to lunch. The boys, not liking to make her trouble, said they would go home and come back later, but the lady of the house would have none of it.

"Sit down, all of you," she commanded, in her cheerful, hospitable way. "I know you're starved—all but Jimmy—" this last with a smile, "and there's plenty to eat."

Frank Brandon was very entertaining all during the meal and kept them in gales of laughter. Mrs. Layton found him as amusing as did the boys.

At last the lunch came to an end and Mr. Brandon professed himself ready to talk shop.

He was enthusiastic over the radio set the boys showed him and declared that he could see very little improvement to suggest.

"You surely have kept up with the march," he said admiringly. "You have pretty nearly all the latest appliances, haven't you? Good work, boys. Keep it up and you'll be experts in earnest."

"If we could only find some way to lengthen the life of our storage batteries," said Bob, not without a pardonable touch of pride, "we wouldn't have much to complain about. But that battery does puzzle us."

"Keep your battery filled with water and see if it doesn't last you about twice as long," suggested the radio expert. "Don't add any acid to your battery, for it's only the water that evaporates."

"Will that really do the trick?" asked Joe, wondering. "I don't just see how——"

"It does just the same," Brandon interrupted confidently. "All you have to do is to try it to find out. Don't use ordinary water though. It needs to be distilled."

"That's a new one on me, all right," said Bob, adding gratefully: "But we're obliged for the information. If distilled water will lengthen the life of our battery, then distilled water it shall have."

"It seems queer," said Mr. Brandon reflectively, "how apparently simple things will work immense improvement. Marconi, for instance, by merely shortening his wave length, is discovering wonderful things. We cannot even begin to calculate what marvelous things are in store for us when we begin to send out radio waves of a few centimeters, perhaps less. We have not yet explored the low wave lengths, and when we do I believe we are in for some great surprises."

"Go on," said Joe, as he paused. "Tell us more about these low wave lengths."



CHAPTER XIV

A DARING HOLDUP

Frank Brandon shook his head and smiled.

"I'm afraid I don't know much more to tell," he said. "As I have said, what will happen when we materially decrease the wave length, is still in the land of conjecture. But I tell you," he added, with sudden enthusiasm, "I'm mighty glad to be living in this good old age. What we have already seen accomplished is nothing to what we are going to see. Why," he added, "some scientists, Steinmetz, for instance, are even beginning to claim that ether isn't the real medium for the propagation of radio waves."

"What do you mean by that?" asked Bob, with interest. "Is it some sort of joke?"

"Joke, nothing!" replied Frank Brandon. "As a matter of fact, I fully believe that electro-magnetic waves can as easily be hurled through a void as through ether."

The boys were silent for a moment, thinking this over. It sounded revolutionary, but they had great respect for Frank Brandon's judgment.

"There's the Rogers underground aerial," Bob suggested tentatively, and Brandon took him up quickly.

"Exactly!" he said. "That leans in the direction of what I say. Why, I believe the day is coming—and it isn't so very far in the future, either—when no aerial will be used.

"Why, I believe," he added, becoming more and more enthusiastic as he continued, "that ten years from now we shall simply attach our receiving outfits to the ground and shall be able to receive even more satisfactorily than we do to-day." He laughed and added lightly:

"But who am I to assume the role of prophet? Perhaps, like a good many prophets, I see too much in the future that never will come true."

"I don't believe it," said Bob. "I shouldn't wonder if all your prophesy will come true in a few years."

"Well," said Herb, with a grin, "it will be a relief not to get any more broken shins putting up aerials."

Mr. Brandon laughed.

"I'm with you," he said. "I've been there myself."

"Have you read about that radio-controlled tank?" Joe asked. "The one that was exhibited in Dayton, I mean?"

"I not only read about it, I saw it," Mr. Brandon answered, and the boys stared at him in surprise. "I happened to be there on business," he said; "and you can better believe I was on hand when they rolled that tank through the traffic."

"What did it look like?" asked Jimmy eagerly.

"The car was about eight feet long and three feet high," responded Brandon. "It was furnished with a motor and storage batteries, and I guess its speed was about five or six miles an hour."

"And was it really controlled by radio?" put in Herb, wishing that he had been on the spot.

"Absolutely," returned Brandon. "An automobile followed along behind it and controlled it entirely by wireless signals. The apparatus that does all the work is called the selector, and it's only about the size of a saucer. It decodes the dots and dashes and obeys the command in an inconceivably short time—about a quarter of a second."

"It can be controlled by an airplane, too, can't it?" asked Bob, and the radio inspector nodded.

"In case of war," he said slowly, "I imagine these airplane-controlled tanks could do considerable damage."

Their guest left soon after that, and, of course, the boys were sorry to have him go. His last words to them were about Cassey.

"Keep your eyes open for that scoundrel," he said, "and we'll find out what he's up to yet."

But in the next few days so many alarming things happened that the boys had little time to think about Dan Cassey. The alarming happenings consisted of a series of automobile robberies in neighboring towns, robberies committed so skillfully that no hint nor clue was given of the identity of the robbers.

And then the robberies came nearer home, even into Clintonia itself. The president of one of the banks left his machine outside the bank for half an hour, and when he came out again it was gone. No one could remember seeing any suspicious characters around.

Then Raymond Johnston, a prominent business man of the town, had his car taken in the same mysterious manner from in front of his home. As before, no one could give the slightest clue as to the identity of the thieves.

The entire community was aroused and the police were active, and yet the mystery remained as dark as ever.

Then, one day, Herb came dashing over to Bob's home in a state of wild excitement. Joe and Jimmy were already there, and Herb stopped not even for a greeting before he sprang his news.

"Say, fellows!" he cried, sprawling in a chair and panting after his run, "it's time somebody caught those auto thieves. They are getting a little too personal."

"What's up?" they demanded.

"One of dad's trucks has been held up!" gasped Herb. "In broad daylight, too!"

"Was anything taken?" asked Joe.

"Anything? Well, I should say! They looted the truck of everything. It's a wonder they didn't steal the machinery."

"That's a pretty big loss for your dad, isn't it?" said Bob gravely.

"It is!" replied Herb, running his fingers through his hair. "He's all cut up about it and vows he'll catch the ruffians. Though he'll have to be a pretty clever man if he does, I'll say."

"They do seem to be pretty slick," agreed Bob.

"I wonder if the same gang is responsible for all the robberies," put in Joe.

"It looks that way," said Jimmy. "It looks as if there were a crook at the head of the bunch who has pretty good brains."

"A regular master criminal, Doughnuts?" gibed Herb, then sobered again as he thought of his father's loss.

"It's bad enough," he said gloomily, "to hear of other people's property being stolen, but when it comes right down to your own family, it's getting a little too close for comfort."

"What is your dad going to do about it?" asked Bob.

Herb shrugged his shoulders in a helpless gesture.

"What can he do?" he asked. "Except what everybody else has done—inform the police and hope the rascals will be caught. And even if they are caught," he added, still more gloomily, "it won't do dad much good, except that he'll get revenge. The crooks will probably have disposed of all their stolen property before they're caught."

"Well, I don't know," said Bob hopefully. "Those fellows are getting a little bit too daring for their own good. Some day they'll go too far and get caught."

"I hope so. But crooks like that are pretty foxy," returned Herb, refusing to be cheered. "They're apt to get away with murder before they're caught."

The lads were silent for a moment, trying to think things out, and when Bob spoke he unconsciously put into words something of what his comrades were thinking.

"It seems as if radio ought to be able to help out in a case like this," he said, with a puzzled frown. "But I must say I don't see how it can."

"It can't," returned Herb. "If some one had been lucky enough to get a glimpse of one of the thieves, then good old radio would have its chance. We could wireless the description all over the country and before long somebody would make a capture."

Bob nodded.

"That's where the cunning of these rascals comes in," he said. "Either nobody sees them at all, or when they do the thieves are so well disguised by masks that a useful description isn't possible."

"Were the fellows who held up your father's truck masked?" asked Jimmy with interest.

Herb nodded.

"From all I can hear," he said. "It was a regular highway robbery affair—masks, guns, and all complete. The driver of the truck said there were only two of them, but since they had guns and he was unarmed, there wasn't anything he could do.

"They made him get down off the truck, and then they bound his hands behind him and hid him behind some bushes that bordered the road. He would probably be there yet if he hadn't managed to get the gag out of his mouth and hail some people passing in an automobile. Poor fellow!" he added. "Any one might have thought he had robbed the truck from the way he looked. He was afraid to face dad."

"Well, it wasn't his fault," said Joe. "No man without a weapon is a match for two armed rascals."

"Didn't he say what the robbers looked like?" insisted Jimmy. "He must have known whether they were short or tall or fat or skinny."

"He said they were about medium height, both of them," returned Herb. "He said they were both about the same build—rather thin, if anything. But their faces were so well covered—the upper part by a mask and the lower by bandana handkerchiefs—that he couldn't give any description of them at all."

"I bet," Bob spoke up suddenly, "that whoever is at the head of that rascally gang knows the danger of radio to him and his plans. That's why his men are so careful to escape recognition."

The boys stared at him for a minute and then suddenly the full force of what he intimated struck them.

At the same instant the name of the same man came into their minds—the name of a man who used radio for the exchange of criminal codes, a man who stuttered painfully.

"Cassey!" they said together, and Herb added, thoughtfully:

"I wonder!"



CHAPTER XV

OFF TO THE WOODS

For days the town hummed with the excitement that followed the daring robbery of the truck belonging to Mr. Fennington, but as time passed and there seemed little prospect of bringing the robbers to justice, interest died down. But the radio boys never abated their resolve to do all in their power to recover the stolen merchandise, although at that time they were kept so busy in high school, preparing for a stiff examination, that they had little time for anything else.

"It's getting so bad lately that I don't even get time to enjoy my meals," grumbled Jimmy, one sunny spring afternoon. "Swinging an oar a la Ben Hur would be just a little restful exercise after the way we've been drilling the last week."

"Get out!" exclaimed Joe. "Why, you wouldn't last two hours in one of those galleys, Doughnuts. They'd heave you over the side as excess baggage once they got wise to you."

"After two hours of rowing in one of those old galleys, he'd be glad to get heaved overboard, I'll bet," put in Herb, grinning. "I think Jimmy would rather drown any day than work that hard."

"Huh! I don't see where you fellows get off to criticize," retorted the harassed youth. "I never saw any of you win gold medals for hard and earnest work."

"Lots of people deserve medals who never get them," Bob pointed out.

"Yes. But, likewise, lots of people don't deserve 'em who don't get 'em," retorted Jimmy, and for once appeared to have won an argument.

"I guess you're right at that," conceded Bob. "But, anyway, I'm going to pass those examinations no matter how hard I have to work. It will pretty near break my heart, but it can't be helped."

The others were equally determined, and they dug into the mysteries of Horace and Euclid to such good effect that they all passed the examinations with flying colors. After that came a breathing space, and just at that time a golden opportunity presented itself.

Mr. Fennington, Herbert's father, had become interested, together with several other business men of Clintonia, in a timber deal comprising many acres of almost virgin forest in the northern part of the state. He was going to look over the ground personally, and when Herb learned of this, he urged his father to take him and the other radio boys along for a brief outing over the Easter holiday. When his father seemed extremely dubious over this plan, Herb reminded him that Mr. Layton had taken them all to Mountain Pass the previous autumn, and that it would be only fair to reciprocate.

"But the Lookers are up in that part of the country, too," said Mr. Fennington. "Aren't you fellows scared to go where Buck Looker is?" he added, with a smile lurking about his mouth.

"Oh, yes, we're terribly afraid of that!" answered Herb sarcastically. "We'll take our chances, though, if you'll only let us go with you."

"Well, well, I'll see," said his father, and Herb knew that this was practically equivalent to surrender. Accordingly he hunted up his chums and broached the project to them.

"Herb, your words are as welcome as the flowers in May," Bob told him, with a hearty slap on the back. "If this trip actually works out, we'll forgive you all last winter's jokes, won't we, fellows?"

"It's an awful lot to ask of a fellow, but I suppose we can manage it," said Joe, and Jimmy, after pretending to think the matter over very seriously, finally said the same.

They were all overjoyed at the prospect of such a trip, and had little difficulty in getting the consent of their parents. Mr. Fennington eventually consented to take the radio boys with him, and there ensued several days of bustle and excited packing. At length all was ready, and they found themselves, one bright spring morning, installed in a big seven-passenger touring car en route for Braxton Woods, as the strip of timberland was called.

"This is the life!" chortled Jimmy, as the miles rolled away behind. "Fresh air, bright sun, the song of birds, and—doughnuts!" and he produced a bulging paper bag full of his favorite dainty.

"How do you get that way?" asked Joe severely, although he eyed the bag hungrily. "The 'song of doughnuts!' You're the only Doughnut that I ever heard of that could sing, and you're no great shakes at it."

"Oh, you know what I meant!" exclaimed Jimmy. "At least, you're thicker than usual if you don't."

"Do you hear that, Joe?" laughed Bob. "The boy's telling you that you're thick. Are you going to stand for that?"

"He knows it's true. And, anyway, he doesn't dare talk back for fear I won't give him one of these delicious little morsels," said Jimmy placidly. "How about it, Joe?"

"That's taking mean advantage of a poor fellow who's practically dying of starvation," said Joe. "Give me a doughnut, and I won't talk back—until after I've eaten it, anyway."

"That's all right then," said his plump friend. "After you've eaten one, you'll feel so grateful to me that you'll regret all the low-down things you've ever said about me."

"Oh, you're the finest pal any fellow ever had," declared Joe. "How many doughnuts have you left, Jimmy?"

"Something tells me that you don't mean all you say," said Jimmy suspiciously. "Just the same, I'll take a chance and give you another one. They won't last long at the rate they're going; I can tell that without half trying."

"Well, a short life but a merry one," said Bob. "Come across with another, Jimmy, will you?"

"You know I love you too much to refuse you anything, Bob," said Jimmy. "Just the same, I'm going to hold out another for myself, and then you big panhandlers can finish them up. I've just had four, but I suppose those will have to last me for the present."

"Say, that's tough—only four!" exclaimed Herb, in mock sympathy. "What will you ever do until lunch time, I wonder?"

"I'm wondering the same thing myself; but I'm used to suffering whenever I'm with you fellows, so I suppose I'll have to grin and bear it somehow."

"I don't see why you didn't bring some more, while you were about it," complained Bob. "You might have known that wouldn't be half enough."

"It will be a long time before I buy any more for you Indians, you can bet your last dollar on that," said Jimmy, in an aggrieved voice. "You've been going to school a number of years, now, but you still don't know what 'gratitude' means."

"The only one that should be grateful is yourself, Doughnuts," Joe assured him. "You know if you had eaten that whole bag full of doughnuts that you'd have been heading a funeral to-morrow or next day. It's lucky you have us around to save you from yourself."

While Jimmy was still framing an indignant reply to this there was a loud report, and the driver quickly brought the big car to a halt.

"Blowout," he remarked laconically, walking around to view a shoe that was flat beyond the possibility of doubt. It was not an unmixed evil to the boys, however, for they welcomed the chance to get out and stretch their cramped muscles. They helped the driver jack up the wheel and change shoes, and in a short time they were ready to proceed.

Back they climbed into their places, and with a rasp of changing gears they were on their way once more.

Braxton Woods lay something over a hundred miles from Clintonia, but the roads were good most of the way, and they had planned to reach their destination that evening. When they had covered sixty miles of the distance, Mr. Fennington consented to stop for the lunch for which the boys had been clamoring for some time. They took their time over the meal, building a fire and cooking steak and frying potatoes.

"Gee, this was a feast fit for a king!" exclaimed Jimmy, when it was over.

The boys lay down on the newly sprouted grass, but had hardly got settled when the driver, who appeared restless, summoned them to proceed.

"We've got a long way to go yet," he said, "and the last fifteen miles are worse than all the rest of the trip put together. The road is mostly clay and rocks, and at this time of year it's apt to be pretty wet. I don't want to have to drive it after dark."

Mr. Fennington was also anxious to get on, so their rest was a brief one, and they were soon on their way again.

The radio boys laughed and sang, cracked jokes, and waved to passing cars, while the mileage record on the speedometer mounted steadily up. The sun was still quite a way above the western horizon when they reached the place where the forest road branched off from the main highway. The driver tackled this road cautiously, and they soon found that his description of it had not been overdrawn. It was a narrow trail, in most places not wide enough for two cars to pass, and they wondered what would happen should they meet another car going in the opposite direction. But in the whole fifteen miles they met only one other motor, and fortunately that was at a wide place in the road.

The scent of spring and growing things was strong in the air, and compensated somewhat for the atrocious road. The boys were often tossed high in the air as the car bumped over logs and stones, or came up with a lurch out of some deep hole. But they hung on to each other, or whatever else was most convenient, and little minded the rough going.

After one particularly vicious lunge, however, the heavy car came down with a slam, and there was a sharp noise of snapping steel. With a muttered exclamation the driver brought his car to a halt and climbed out.

"Just as I thought!" he exclaimed. "A spring busted, and the nearest garage twenty miles away. Now we're up against it for fair!"

"Do you mean that we can't go on?" asked Mr. Fennington anxiously. "It will be dark in another hour."

"I know it will," replied the chauffeur. "But what can we do about it?"

"Can't we make a temporary repair?" suggested Bob. "We can't have much further to go now."

"Well, I'm open to suggestions, young fellow," growled the driver. "If you can tell me how to fix this boiler up, go to it. It's more than I can do."

Bob and the others made a thorough examination of the damage, and they were not long in concocting a plan. Bob had brought with him a small but very keen-edged ax, and it was the work of only a few minutes to cut a stout limb about six inches in diameter from a tree.

With this, and a coil of heavy rope that was carried in the car for emergencies, they proceeded to make the temporary repair.



CHAPTER XVI

PUT TO THE TEST

First of all the boys trimmed the branch to a length slightly greater than the distance between axle and axle of the car. Then, near each end, they cut a notch about two inches deep, one to fit over the front and one over the rear axle. Next they placed the branch in position, and with the heavy rope lashed it securely into position. Thus the front and rear axles were kept at the proper distance from each other, and, moreover, the side of the car that was over the broken spring could rest on the stout pole.

The driver, who at first had watched their efforts with a derisive grin, took their plan more seriously as he realized the scheme, and now he examined the completed job with an air of surprised respect.

"I've got to admit that that looks as though it might do the trick," he admitted, at length. "I've seen a lot of roadside repairs in my time, but blest if that hasn't got 'em all beat. I'll take it at slow speed the rest of the way, and we'll see if it will stand up long enough to get us in."

And get them in it did, in spite of much creaking and groaning and bumping.

The automobile drew up before a long one-story building, constructed roughly but substantially of unpainted boards. Supper was being served, and they were just in time to partake of a typical lumber camp meal. The big table was laden with huge joints of meat, platters of biscuits and vegetables, while strong, black coffee was served in abundance. After this plates of doughnuts were passed around, greatly to Jimmy's delight, and for once he could eat all he wanted with nobody to criticize, for the lumbermen were no tyros at this sort of thing, and packed away food in quantities and at a speed that made the boys gape.

"Gee!" exclaimed Bob, after they had emerged into the balmy spring air outside, "I used to think that Jimmy could eat; but he can't even make the qualifying heats with this crowd. You're outclassed, Doughnuts, beyond the chance of argument."

"I don't see but what I'll have to admit it," sighed his rotund friend. "But I don't care. It seems like Heaven to be in a place where they serve doughnuts like that. There's none of this 'do-have-a-doughnut' business. Some big husky passes you a platter with about a hundred on it and says, 'dig in, young feller.' Those are what I call sweet sounding words."

"And you dug, all right," remarked Joe, grinning. "I saw you clean one platter off all by your lonesome—at least, you came pretty near it," he qualified, with some last lingering regard for the truth.

"I didn't anything of the kind! But I only wish I could," lamented Jimmy.

"Never mind, Doughnuts, nobody can deny that you did your best," laughed Herb. "After you've had a little practice with this crowd, I'll back you against their champion eater any day."

"So would I," said Bob. "We've often talked about entering Jimmy in a pie-eating contest, but I never before thought we could find anybody who would even stand a chance with him. Up here, though, there's some likely-looking material. Judging from some of those huskies we saw to-night, they might crowd our champion pretty hard."

"You can enter me any time you want to," said Jimmy. "Even if I didn't win, I'd have a lot of fun trying. I never really got enough pie at one time yet, and that would be the chance of a lifetime."

At first the boys were more than half joking, but after they had been at the camp a few days and had begun to get acquainted, they let drop hints regarding Jimmy's prowess that aroused the interest of the lumbermen. He was covertly watched at meal times, and as the bracing woodland air and long hikes combined to give an added edge to his appetite, his ability began to command attention. There were several among the woodsmen who had a reputation for large capacity, but it was soon evident that Jimmy was not to be easily outdistanced in his own particular department.

At length interest became so keen that it was decided to stage a real old-fashioned pie-eating contest, to determine whether the champions of the camp were to be outdistanced by a visitor from the city. The cook was approached, and agreed to make all the pies that, in all human probability, would be needed.

"Jimmy, you're in for it now!" exclaimed Herb, dancing ecstatically about his plump friend. "Here's your chance to make good on all the claims we've ever advanced for you. You're up against a strong field, but my confidence in you is unshaken."

"It simply isn't possible that our own Jimmy could lose," grinned Bob. "I've seen him wade into pies before this, and I know what he can do."

"I appreciate your confidence, believe me," said Jimmy. "But I don't care much whether I win or not. I know I'll get enough pie for once in my life, and that's the main thing."

The time for the contest was set for the following evening, the third of their stay. Five lumbermen had been put forward to uphold the reputation of the camp, and they and Jimmy ate no supper that night, waiting until the others had finished. Then the board was cleared, and the cook and his helper entered, bringing in several dozen big pies of all varieties. One of these was placed before each of the contestants, and they could help themselves to as many more as their capacity would admit.

The cook, as having the best knowledge of matters culinary, was appointed judge, and was provided with a pad and pencil to check up each contestant. A time limit of two hours was set, the one having consumed the greatest amount of pie in that time to be declared the winner.

The cook gave the signal to start, and the contest was on.

The lumbermen started off at high speed, and at first wrought tremendous havoc among the pies, while Jimmy ate in his usual calm and placid manner, evidently enjoying himself immensely. Each of the lumbermen had his following, who cheered him on and urged him to fresh endeavors. Bob and Joe and Herb said little, for they had observed Jimmy's prowess over a period of several years, and knew his staying qualities.

At the end of the first half hour their friend was badly outdistanced, but the other contestants had slowed up noticeably, while Jimmy still ate calmly on, no faster and no slower than when he had started. He was only starting on his second pie when all the others were finishing theirs, but the confidence of his three comrades remained unshaken. They observed that the lumbermen chose their third pies very carefully, and started to eat them in a languid way. They were only about half through when Jimmy disposed of his second one, and started on a third.

"How do you feel, Jimmy?" asked Herb, with a grin. "Are you still hungry?"

"No, not exactly hungry, but it still tastes good," replied Jimmy calmly. "You sure can make good pies, Cook."

The other contestants essayed feeble grins, but it was easy to see that their pies no longer tasted good to them. More and more slowly they ate, while Jimmy kept placidly on, his original gait hardly slackened. He finished the third pie and started nonchalantly on a fourth. At sight of this, and his confident bearing, two of the other contestants threw up their hands and admitted themselves beaten.

"I used to like pie," groaned one, "but now I hope never to see one again. That youngster must be made of rubber."

"I've often said the same thing myself," chortled Bob. "Just look at him! I believe he's good for a couple more yet."

Excitement ran high when two of the remaining lumbermen were forced out toward the middle of their fourth pie, leaving only Jimmy and a jolly man of large girth, who before the start had been picked by his companions as the undoubted winner.

"Go to it, Jack!" the lumbermen shouted now. "Don't let the youngster beat you out. He's pretty near his limit now."

It was true that flaky pie crust and luscious filling had lost their charm for Jimmy, but his opponent was in even worse plight. He managed to finish his fourth pie, but when the cook handed him a fifth, the task proved to be beyond him.

"I've reached my limit, fellers," he declared. "If the youngster can go pie number five, he'll be champion of the camp."

Excitement ran high as Jimmy slowly finished the last crumbs of his fourth pie, and the cook handed him a fifth. Would he take it, or would the contest prove to be a draw?



CHAPTER XVII

THE BULLY GETS A DUCKING

"Our man doesn't have to eat another whole pie," protested Bob. "If he just eats some of it he'll win, Mr. Judge."

"That's right," nodded the cook. "How about you, young feller? Are you able to tackle it?"

"Sure thing," responded Jimmy. "Hand it over."

He forced himself to cut and eat a small piece, and when he had finished, pandemonium broke loose. The judge declared him undisputed champion of the camp, and he was caught up and elevated to broad shoulders while an impromptu triumphal procession was organized that circled the camp with much laughter and many jokes at the expense of the defeated aspirants for the title.

After this was over, the boys held a little private jubilation of their own in the little cabin where they were quartered with Mr. Fennington. He had been away during the contest, but he returned shortly afterward, and laughingly congratulated Jimmy on his newly won honors.

"How do you feel?" he inquired. "Do you think you could manage another piece of pie? I'll see that you have a large piece if you think you can."

"No, sir! I've had enough pie to last me for a good while to come," declared Jimmy positively. "I'll be ashamed to look a pie in the face. For the next week or so I'll have to stick to my favorite doughnuts for dessert."

"Well, you did nobly, Doughnuts, and I love you more than ever," declared Bob. "You were up against a field that anybody might be proud to beat."

"And the best part of it, to me, is the feeling that our confidence in Jimmy's eating powers was justified," declared Joe. "After all the wonderful exhibitions he's given in the past, it would have been terrible if he hadn't come up to scratch to-night."

"The way that fellow they call Jack started off, I never thought you had a chance, Jimmy," confessed Herb.

"If he could have held that pace, I wouldn't have had a look-in," admitted Jimmy. "I figured he'd have to slow down pretty soon, though. 'Slow but sure' is my motto."

"How would you like to take a nice three-mile sprint now?" asked Herb mischievously.

"Three mile nothing!" exclaimed Jimmy scornfully. "I couldn't run three yards right now. I think I'll lie down and give my digestion a chance," and in a few minutes he was peacefully snoring.

The next morning he showed no ill effects from the prodigious feast, but ate his usual hearty breakfast. The others were forced to the conclusion that his table ability was even greater than they had suspected, and from that time on they firmly believed him to be invincible in his particular department.

By this time they were thoroughly familiar with the camp, and decided to make an excursion into the woods the following day, taking lunch with them and making it a day's outing. The cook so far departed from his usual iron-clad rules as to make them up a fine lunch, making due allowance for Jimmy's proven capacity.

They started out immediately after breakfast. Not being particular as to direction, they followed the first old logging road that they came to. It led them deeper and deeper into the forest that was alive with the sounds and scents of spring. Last year's fallen leaves made a springy carpet underfoot, while robins sang their spring song in the budding branches overhead.

For some time the boys tramped in silence, breathing deeply of the exhilarating pine and balsam atmosphere and at peace with all the world. Soon there was a glint of water through the trees, and the boys, with one accord, diverged from the faint trail that they had been following and were a few minutes later standing at the water's edge.

They found themselves on the shore of a large lake. It was ringed about with big trees, many of which leaned far out over it as though to gaze at their reflections in the water. The ripples lapped gently on a sloping sandy beach, and the invitation to swim proved irresistible to all but Jimmy.

"I know what lake water is like at this time of year," he said. "You fellows can go in and freeze yourselves all you like, but I'll stay right here and look after the things. Just dive right in and enjoy yourselves."

"Well, we won't coax you," said Bob. "But that water looks too good to miss. It is pretty cold, but I guess that won't kill us."

Off came their clothes, and with shouts and laughter they splashed through the shallow water and struck out manfully. The icy water made them gasp at first, but soon the reaction came, and they thoroughly enjoyed their swim. They tried to coax Jimmy in, but he lay flat on his back under a tree and was adamant to all their pleadings.

The others did not stay in very long, but emerged glowing from the effects of exercise and the cold water. As they were getting into their clothes they heard voices coming toward them, and they had hardly finished dressing when the voices' owners came crashing through the underbrush close to where the boys were standing.

The two groups stared in astonishment for a few moments, for the newcomers were none other than Carl Lutz, Buck Looker, Terry Mooney, and another older fellow, who was a stranger to the radio boys.

Buck's expression of surprise quickly gave place to an ugly sneer, and he turned to his friends.

"Look who's here!" he cried, in a nasty tone. "I wonder what they're up to now, Carl?"

"We're not hiding from the cops because we broke a plate glass window and were afraid to own up to it," Bob told him.

"Who broke a window?" demanded Buck. "You can't prove that it wasn't a snowball that one of your own bunch threw that broke that window."

"We don't throw that kind of snowballs," said Joe.

"What do you mean by that?" asked Buck.

"Are you trying to say that we put stones in our snowballs?"

"I don't have to say it," retorted Joe. "You just said it yourself."

Too late Buck realized his mistake, and his coarse red face grew purple as Herb and Jimmy grinned at him in maddening fashion.

"Don't you laugh at me, Jimmy Plummer!" he exclaimed, picking on Jimmy as being the least warlike of the radio boys. "I'll make you laugh out of the other side of your mouth in a minute," and he started to dash past Bob to reach his victim.

But to do so he had to pass between Bob and the bank of the lake, which just at this point was a foot or so above the water.

As he rushed past, Bob adroitly shot out a muscular arm and his elbow caught the bully fair in the side. Buck staggered, made a wild effort to regain his balance, and with a prodigious splash disappeared in the icy waters of the lake.

For a few seconds friend and enemy gazed anxiously at the spot where he had gone under, but he soon came to the surface, and, sputtering and fuming, struck out for the shore and dragged himself out on to dry land.

He made such a ludicrous figure that even his cronies could not forbear laughing, but he turned on them furiously and their laughter suddenly ceased. Then he turned to Bob.

"If I didn't have these wet clothes on, I'd make you pay for that right now, Bob Layton," he sputtered. "I'll make you sorry for that before you're much older."

"Why not settle it right now?" offered Bob. "Your clothes will dry soon enough, don't worry about that."

"Yes, I know you'd like nothing better than to see me get pneumonia," said Buck. "You wait here till I go home and get dry clothes on, and I'll come and give you the licking that you deserve."

"That's only a bluff, and you know it," said Bob contemptuously. "But if any of your friends would like to take your place, why, here I am. How about you, Lutz?"

But Carl muttered something unintelligible, and backed away. The others likewise seemed discouraged by the mischance to their leader, for they turned and followed his retreating form without another word.

"Some sports!" commented Joe.

"Game as a mouse," supplemented Herb.

"That was a swell ducking you gave Buck," chuckled Jimmy. "Just when he was going to pick on me, too. I owe you something for that, Bob."

"Pay me when you get rich and famous," laughed his friend. "You don't owe me anything, anyway. It was a pleasure to shove Buck into the lake. I'm perfectly willing to do it again any time I get the chance."

"Oh, it's my turn next time," said Joe. "I can't let you hog all the fun, Bob."

"All right," replied his friend. "If we run into him again, I'll leave him to your tender mercies. But I don't imagine he or his friends will bother us any more to-day, so why not have lunch?"

"I was thinking the same thing," remarked Jimmy, and they forthwith set to work to prepare what Jimmy termed a "bang-up lunch."



CHAPTER XVIII

A STARTLING DISCOVERY

The cook had supplied the radio boys with a lavish hand, but their long walk and the swim had given them ravenous appetites, and by the time they finished there was little left of the lunch. Even this little was soon disposed of by the bright-eyed birds that ventured close in pursuit of the tempting bits. By sitting as still as statues the boys succeeded in enticing the little fellows almost within arm's length, and derived no little amusement at the evident struggle between greed and caution.

But soon the last crumb was gone, and after a short rest the lads began to think of returning to camp. They did not want to go back by the same road over which they had come, however, so decided to follow the shores of the lake until they should find some other path. This was, of course, a roundabout way of getting home, but they had the better part of the afternoon before them, and were in no particular hurry.

"Come on over to the north," suggested Joe. "I think there is another trail in that direction."

"Yes, and I imagine the walking is better," put in Herb.

"Say, you don't want to go too far out of the way," came hastily from Jimmy. "We've got to walk back remember."

"Forward it is!" cried Bob. "Come on, Jimmy, you've got to walk off that big lunch you stowed away."

"Gee, if I walk too far I'll be hungry again before I get home," sighed the stout youth.

"Wow! hear Jimmy complain," burst out Joe. "He hardly has one meal down than he's thinking of another."

To find another trail was not as simple a matter as it had seemed, and they must have traveled over two miles before Bob's keen eyes detected a slight break in the dry underbrush that might denote a path such as they sought. They found a dim trail leading in the general direction in which they wished to go, and set out at a brisk pace, even Jimmy being willing to hurry as visions of the loaded supper table floated before him.

Gradually the path widened out, as others ran into it, until it became a fairly well-defined woods road. It was thickly strewn with last year's soft and rotting leaves, and the boys made little sound in spite of the rapidity of their pace. Bob and Joe and Herb were striding along in a group, Jimmy having dropped behind while he fixed a refractory shoe lace, when suddenly Bob halted abruptly and held up a warning hand. The others, scenting something amiss, stopped likewise, looking inquiringly at Bob.

Silently he pointed to a spot slightly ahead of them and several paces off the road. Even as the others gazed wonderingly, Bob beckoned them to follow and slipped silently into the brush that lined the road.

On the other side stood a big tree, its trunk and branches sharply outlined against the clear sky. At the base of this tree, with his back toward them, stood a man. Now, the surprising part of it all, and that which had caused the boys to proceed so cautiously, was the fact that the man wore headphones and was evidently receiving a message of some kind. Fastened to the tree was a box, which evidently contained telephonic apparatus. At first the boys thought he must be listening at an ordinary telephone, but the fact that he had no transmitter indicated that he was listening in on a radio receiving set.

The boys had hardly reached their place of concealment when the man turned sharply about, darting furtive glances here and there, evidently in search of possible intruders. The boys crouched lower behind the bushes and prayed fervently that Jimmy would not arrive before the man had gone. The fellow was of fair size, with a deeply tanned face, and wore a moustache. Fortunately, after they had been watching him a few minutes, he removed the earphones, placed them in the box, and, after locking it, started into the woods, following a dimly marked footpath.

It was well that he left when he did, for not two minutes later Jimmy came puffing along, looking anxiously for the others. He stopped in amazement when he saw his friends emerge from the bushes, and was about to raise his voice in vehement questionings when Bob leaped at him and clapped a hand over his mouth.

"Be quiet!" he hissed into his ear. "There's some funny work going on here, and we want to find out what it is."

Thus admonished, Jimmy was released, and in low tones the others told him of what they had seen and showed him the box fastened to the tree. While they were about it, they made a hasty search for the antenna, and found it strung close to the trunk of the tree, extending from the top almost to the roots. After this discovery they hurried after the man with the moustache, fearful lest they should lose his trail.

It was no easy matter to follow the dimly marked path, for it passed at times over stony ground and big boulders, where often it took much searching here and there before they picked up its continuation.

"We may be taking all this trouble for nothing," said Bob, after one of these searches. "Maybe he's just a lumberman receiving instruction by wireless from his employers. Big business firms are using radio more and more for such purposes."

"I didn't like the way he kept looking about him, as though he had something to conceal," objected Joe. "It can't do any harm to see where he goes, anyway. We may find out something important."

"His hands weren't those of a lumberman," observed Herb. "Those hands never saw rough work nor, judging from the man's face and manner, honest work. Come on, fellows."

Accordingly the boys followed the difficult trail with untiring patience, and at last their perseverance was rewarded. The path widened out into a little clearing, and at the further side of this was a rough log cabin. The little shack had two small windows, and with infinite caution the boys approached until they could see into the nearest one.

The interior was rudely furnished with a heavy table and two crudely fashioned chairs, while in the corner furthest from them two bunks had been built, one above the other. In another corner was a compact radio transmitting set.

At the table was seated the man with the moustache, intently studying a notebook propped up before him. From this he made notes on a sheet of paper, scowling at times like one engaged in a difficult task. At length he shoved back his chair, rose to his feet, and, striding across the little shack, carefully placed the notebook under a board on a shelf. Luckily he was so absorbed in what he was doing that he did not even glance toward the window where the radio boys were observing his every motion.

But Bob now judged that they had seen enough, and he wished to run no unnecessary risk of detection. At a signal from him they made for the underbrush at the edge of the clearing, where they could command a view of the door, and waited to see if the mysterious stranger would emerge.

In a few minutes the door opened and the man stepped out, stopping to fasten it securely behind him. Then, with a quick glance about the little clearing, he made for the path leading to the main road and in a short time the sound of his going died away.

The boys waited a few minutes, thinking that possibly he might return for something forgotten, but no further sound came from the path. At length they ventured to approach the deserted cabin.

The door had been fastened with a heavy padlock, but this was not sufficient to deter the radio boys. Searching through their pockets for some implement with which they could undo the lock, Jimmy discovered a stout fish-hook, and after they had ground off the barbs against a flat stone this made an ideal tool. With it Bob probed about in the interior of the padlock, and at length, with a sharp click, it sprung open. Ordinarily he would not have done this, but he had every reason to believe that he was dealing with a criminal and that he was justified in the interest of law and order in taking steps that would prevent any further depredations against society.

"More ways than one of killing a cat," remarked Bob, as he pushed open the heavy door and entered the cabin. "We've got to know what's in that notebook before we leave this place. Let's have a look."

The boys quickly brought the book from its place of concealment and carried it to the table, where they bent eagerly over it as Bob turned the pages.

"It doesn't look like sense to me," complained Jimmy. "I never saw such a lot of fool words jumbled together."

"Yes, but something tells me there's method in this madness," said Bob, his brows knit as he concentrated on the problem before him. "Say, fellows!" he exclaimed, as sudden excitement gripped him, "do you remember those nights we were listening to our big set and we heard the mysterious messages? They were just a lot of words, and we couldn't make anything out of them at the time."

"You bet I remember!" exclaimed Joe. "I think I could even tell you most of the words. Why, there's some of them in that book, right now!"

"Exactly," replied Bob, nodding. "I remember them, too, and this must be the key to the code. My stars, what luck! Let's see how close we can recall the words we caught, and then we'll see if we can make sense of them with the help of this key."

"I'll tell you the words as I remember them, and you check me up," suggested Joe, and this they accordingly did.

Between them they managed to get it straight, just as they had heard it, "Corn-hay-six-paint-water-slow-sick-jelly."

"I think that's right," said Bob. "Anyway, we'll see if it comes right with the key. You read the words, Joe, and I'll find them in this notebook and you can write them down. Shoot the first one."

"Corn," said Joe.

Bob hunted rapidly down the columns of code words and their equivalents, and soon found the one he was after.

"Motor truck," he read out.

"That sounds promising!" exclaimed Joe. "The next word I've got is 'hay.' What's the answer to that?"

"Silk," said Bob, after a shorter search this time.

"Six," read Joe.

"Castleton Road!" exclaimed Bob, his voice shaking with excitement as he traced down the columns of words. Herb and Jimmy were also excited; especially the former, as he realized better than the others how serious a loss the theft of his father's truckload of silk had been and now thought he saw some clue in this message that might throw light on the whereabouts of the stolen goods.



CHAPTER XIX

THE ROBBERS' CODE

"The next word is 'paint,'" said Joe. "What does that stand for, Bob?"

"Just a minute, till I find it," replied his friend, and after turning over several pages found the word he sought.

"It means 'to-night,'" he said. "Read what we've got so far."

"Motor truck—silk—Castleton Road—to-night," read Joe. "That's clear enough so far. The next code word is water."

"'No guards,'" said Bob. And so they went, until the completed message read as follows:

"Motor truck—silk—Castleton Road—to-night—no guards—hold up—take everything to usual place—notify when job is done."

"That's the message that caused the theft of my father's merchandise!" exclaimed Herb, jumping to his feet. "If we had only had the key then, when there was still time, we could have prevented the hold-up."

"Very likely we could," agreed Bob soberly. "But we may be able to do the next best thing, Herb—get the stuff back again. If we make a copy of this key and then leave the book just where we found it, the thieves will never dream that anybody knows their secret, and they'll keep right on using the same code."

"I see," said Herb slowly. "And then if we hear any more code messages we can translate them with this key, and likely get on the trail of the crooks."

"Exactly!" replied Bob. "Now, I have a notebook here, and if one of you fellows will dictate that code, I'll copy it down and we'll get out of here while the getting's good. There's no telling what minute some of the gang will show up."

"I'll dictate," volunteered Joe. "But while you and I are doing that, Bob, why can't Jimmy and Herb act as lookouts? Then if any of the gang comes along they can give us warning and we'll clear out."

"That's good advice," agreed Bob, and Herb and Jimmy went outside and up the path a short distance, where they crouched, listening, with every muscle tense to warn their comrades if danger threatened.

Meanwhile, in the cabin, Bob's pencil flew at furious speed as Joe dictated. The code was very complete, and consisted of over two hundred words, each word, in some cases, standing for a whole phrase. Bob wrote as he had never written before, but in spite of his utmost efforts it took over an hour to copy the entire list. He and Joe expected every minute to hear Herb or Jimmy give the alarm, but the woods remained calm and peaceful, and they finished their task without interruption.

"There's the last word, Bob!" exclaimed Joe, with a sigh of relief. "Let's put that little book back on the shelf where we found it, and make a quick getaway."

"Yes, we've got to make tracks," agreed Bob. "It will be away after dark now when we get back to the camp. If we don't hurry they will be organizing searching parties for us."

With great care he placed the notebook back on the shelf, under the board, and then gazed searchingly around the cabin to make sure that no signs of their visit were left behind to warn the thieves. After assuring himself that everything was exactly as they had found it, he and Joe left the rude habitation, snapping the big padlock through the hasp.