"We'll have to put up a radio station here then," said Cub.

"Oh, sure, we can't do without that wherever we go now-a-days," his father replied.

They skirted the entire shore of the island and found Bud's suggestion regarding high, steep banks to be true in every quarter. Not another practical landing place, except with derrick or rope ladder, was discovered. They estimated the island to be about five acres in extent.

"Well, we haven't found much evidence yet, indicating that this is the place we were looking for," Cub remarked as they arrived back at the starting point of their exploration.

"I suppose the next thing for us to do is to explore the interior of the island, and then perhaps we'll be in a position to form some sort of conclusion," said Mr. Perry.

"All right, let's finish this job as soon as possible," Bud proposed, as he started toward a thicket of bushes and small trees a few yards from the landing place.

All being in harmony with this plan, there was a general move toward the interior. The thicket, however, proved to be only about twenty feet in depth, and beyond this was a clear area a quarter of an acre in extent.

"Somebody's had a camp here not many days ago," Cub announced, as he pressed forward eagerly toward the center of the open area.

"Yes, and a tent has stood right here," said Mr. Perry, indicating several guy-rope stakes driven in the ground.

"Whoever it was didn't leave more than a day or two ago," Hal declared. "See how the grass is tramped down around here?"

"What's this?" exclaimed Bud as he ran back toward the thicket through which they had passed and picked up a pole about ten feet long and two inches thick.

Mr. Perry and the other two boys rushed forward and made an eager examination of Bud's discovery.

"This looks interesting," said Bud significantly as he called attention to several worn places at both ends and the middle of the pole, as if with iron rings or wire held close around it under a strain.

"There's another just like this one over there," cried Hal, suddenly darting forward toward a slender pine tree about a hundred feet away and standing a short distance out from the thicket border of the open area.

Mr. Perry, Cub, and Bud rushed after Hal, who picked up, under the pine tree, a pole almost the exact duplicate of the one found by Bud. After a careful examination of them both, Mr. Perry announced:

"It looks to me, boys, as if you had discovered the spreaders of a demolished aerial."

"No doubt of it," Hal agreed. "Somebody used this tree and that one over there as masts of an aerial."

"But trees are not supposed to be good for aerial masts," Bud objected.

"They're all right if you have your insulation well out beyond the branches," said Cub.

"Yes, that's true," Bud admitted. "And look up there—see that wire? The fellow who took down this aerial didn't do his work very well."

All looked up in the tree and saw a wire hanging down among the branches and appearing to be attached at the farther end near the top of the pine.

"It was probably done in a hurry," Mr. Perry observed.

"And that is one more point to the argument that this is the island we were looking for," said Bud.

"Yes, but the fellow we came to rescue is gone and left no trace where he's gone to," added Cub.

"Still, don't you think the search has been worth while?" the latter's father inquired.

"I do," put in Hal, who had been noticeably quiet and meditative since the last very important discovery. "This makes it look as if that last distress message we got from the island was no fake affair?"

"Why?" asked Bud.

"Why!" flashed Hal. "It's plain enough to me. Those four fellows, he said were coming to attack him, probably overpowered him and swept away his camp, radio outfit, and all."

"And what did they do with him?" demanded Cub, eager for the last chapter of the plot.

Hal seemed about to make answer to this question, but something of the nature of a "lump in his throat" checked his utterance. His friends read his mind without difficulty.

"Never mind, Hal," said Cub with his bravest effort at consolation; "if the prisoner on this island was your cousin, we'll follow those enemies of his to the end of the world and make them give him up, won't we, dad?"

"Don't you worry too much over this affair, Hal," urged Mr. Perry by way of response to his son's extravagant assurance. "If the person you got those messages from was your cousin, I don't believe the fellows who were after him had reason to do him any serious harm. But you may be sure that we will not leave a stone unturned in an effort to solve this—this—"

"Mystery," suggested Cub mischievously grasping at the opportunity to give his father a good-natured dig.

"Call it what you wish," smiled Mr. Perry. "But under any name you may be pleased to style this problem, we are going to go after it with some more mathematics—"

"And geography," interposed Cub.

"Yes, and geography, and you boys know what success we have had with mathematics and geography in this search of ours thus far. Now, meanwhile, I'm going to make a new suggestion which I hope you boys will look upon with favor. Let's establish a camp of our own right here on the spot where the Canadian Crusoe had his camp."



CHAPTER XII

Hal's Discovery

The boys were delighted with the suggestion of Mr. Perry that they establish a camp on the island and needed no urging to begin work on the project. With true outing instinct they had come prepared for just such an emergency as this. They had brought with them a tent large enough for four and a complete set of camp tools, including spade, shovel, axe, pickaxe, hatchet, saw, hammer, and nails.

Returning to the Catwhisker, they hauled all these supplies out on deck preparatory to taking them ashore.

"Let's make a better ascent up this steep bank before we carry these things up," Mr. Perry proposed. "It's quite a climb, as it is, without a load in our arms to hamper us."

"Only one person can work at a time to any advantage," Bud suggested.

"That's true," replied the director of the expedition. "But we can work in rapid shifts and finish this job quickly. I'll take the first trick and make things fly for about fifteen minutes, and then one of you can take my place."

With these words, he stripped off his coat, seized the pickaxe and shovel and stepped over the side of the boat onto the landing ledge. Then he began a vigorous attack on the steep incline between the ledge and the land level above.

The task consumed a little more than an hour of speed labor, and by that time it was after one o'clock and each of the hillside stairway builders had worked up a very healthy appetite. So they prepared and ate luncheon on board the yacht, and then began the work of moving tent and other supplies to the site selected for their camp. By the time this was done and the tent pitched, it was 3 o'clock.

"Now, what next?" asked Cub as he sat down on a camp chair after the last guy rope had been drawn taut and fastened securely to its peg. "It seems to me that it's about time for another pow-wow of the Catwhiskerites."

"I agree with you, Bob," said his father, also unfolding a camp chair and sitting down, followed by similar action on the part of the other two boys.

"Well, what's the question?" asked Bud.

"I'll offer a question if somebody'll take the chair and preside," Hal volunteered.

"All right," Bud agreed. "You act as chairman, Mr. Perry."

"I am elected by Bud, there being no opposition," announced the owner of the Catwhisker. "Now, what is the question, Hal?"

"I'll put it this way," the latter replied: "Resolved, that mathematics is more useful to a detective than a flashlight or a skeleton key."

"That isn't half-bad at all," declared Cub in the midst of general laughter and applause. "The main trouble is that we can't find anybody on this island to take the other side of the question."

"Very well," ruled the chair; "this question being decided in favor of the affirmative, we will now proceed to the next."

"Which is as follows," Bud announced; "to-wit, why have we established our camp on this island, how long are we going to remain here, and what shall we do while here?"

"Now, we're getting down to business," said Cub. "But that's a composite question. First, why are we here?"

"We're here because we're here," Hal replied solemnly.

"The chair is willing to accept that as a good and valid reason provided other collateral questions are answered satisfactorily," Mr. Perry announced.

"Next question, how long are we going to stay here?" Cub continued.

"I should say we will stay here until we find a reason for moving on to the next place," said Bud.

"Another excellent answer and fully supporting answer number one," Mr. Perry announced. "Now, for an answer to question number three—What shall we do while here?"

"I'll answer that," said Cub; "well fish, cook, eat, sleep, explore and keep our eyes peeled."

"Peeled for what?" asked Hal.

"More mathematical evidence."

"Good!" exclaimed Bud. "We mustn't lose sight of the purpose of this expedition. If our radio Crusoe is really Hal's cousin, we're bound by the ties of friendship to stick to our task till it's finished."

"Very well," said the chair. "Having settled the question of general policy, let's get down to some more detail. What shall we do next?"

"Complete our exploration of the islands," said Cub. "There's no telling what we may find."

"Now, you're beginning to look at things the way your father does," put in Hal shrewdly.

"How's that?" Cub inquired.

"Why you're willing to look for a trail. I'm not saying you were any worse than Bud and I were before we got started on this hunt. We just stumbled on a trail to begin with, but when we lost it we didn't know what to do next until your father told us it was up to us to scout around and find it again."

"Yes, that's right," Cub admitted. "We scouted around in the air and found the trail that brought us here."

"Moral: Whenever at a loss, do some broadcasting," suggested Mr. Perry.

"Right," declared Bud; "Now the thing for us to do is some physical broadcasting on this island."

"In other words, we'll all go in different directions and examine every square foot of this island," Cub inferred.

"Exactly," assented Mr. Perry. "It ought not to take very long. There are only about five acres here, although the place is pretty well covered with bushes and trees."

Without further ado they separated toward different points of the compass. It was indeed a random exploration, well characterized as something of a "broadcast," but the task was well executed by all. They had no definite expectation in view, and hence they had to content themselves with examining every physical feature as a naturalist or a topographer, perchance, would look for the feature demands of his specialty, and in about half an hour reconvened in front of their tent. Hal was the only person present with a look of excitement or eagerness on his face, and consequently the general interest of the others was directed toward him.

"You've found something, I know, Hal," Bud declared. "You came running through the bushes as if you were chased by a catamount or else you had something on your mind that threatened to burst your cranium."

"I didn't meet a catamount," replied the boy to whom these remarks were addressed; "but I did find something that excited me very much. I've learned two important things."

"What are they?" Cub demanded.

"I've learned the name of this island and made sure of the name of the person we came here to find."

"You don't say!" Cub exclaimed. "I don't see how the name of this island can mean anything to us, but we should be very glad to know who the fellow is that we came here to find."

"Well, the name of this island is important, or at least interesting," Hal returned; "and I am going to give you that first. It is Friday Island and was given that name by the Robinson Crusoe who was marooned here because he landed here last Friday. Now, I'll tell you the other important item. The fellow who was marooned with a wireless outfit was no other person than my cousin as I suspected. And I have learned why he was marooned here."

"Why?" demanded Hal's three companions in chorus.

"Because he was a college freshman and some of the upper classmen had it in for him and they simply strong-armed him, captured him, and brought him here to haze him."

Every one of Hal's three companions gasped with astonishment. The possibilities of such an explanation of this strange "radio-island affair" had never occurred to one of them.



CHAPTER XIII

"Robinson Crusoe's" Diary

"How in the world did you find that out?"

"Who told you all o' that?"

"Where is your cousin now?"

These questions and others of like character were fired at Hal in rapid succession, indicating the eagerness of all the members of his audience for more light on the subject. As for Hal, he was moved by conflicting emotions, which puzzled his friends considerably at first. He did not burst forth with a storm of replies, a thing that he might well have done consistently with boy nature. He seemed to be meditating how to begin, as if there was so much on his mind he did not know what to say first.

In reality, although this confusion of ideas probably had something to do with his momentary silence following the storm of questions rained at him, Hal was much elated with the good fortune that had thrown some remarkable information into his possession; still, he was deeply concerned over the possible fate of his cousin. It was the latter concern, no doubt, that tempered and held in check his jubilation over his discovery.

"I think, Mr. Perry, you will admit now that there is such a thing as a mystery," he said.

"Why?" inquired the individual at whom this remark was directed.

"No, I am merely very curious," replied Mr. Perry, with a smile.

"Oh, hurry up, Hal, and tell us what this means," urged Cub impatiently. "What's the use o' keepin' us guessing all this time. Bud and I'll admit we're mystified."

"Yes," grinned Mr. Perry; "you'd better hurry up and enlighten us, or I'll have to drag the secret out of you with mathematics."

"Addition or subtraction," asked Hal.

"Extraction," replied "the man who couldn't be mystified" with significant emphasis on the "ex".

Laughter followed this quip, the levity of which caused Hal to feel more like "loosening up".

"Well," said the latter, producing a small leather-back notebook from one of his pockets; "here is the secret of my information."

"Where did you get that?" Cub demanded.

"I found it."

"Where—not here?"

"Yes, on this island. It's a diary of my cousin, beginning with the time he was left here by a bunch of college hazers."

"Does it give any hint where he is now, Hal?" inquired Mr. Perry.

"I don't think so," replied the boy with the notebook. "I ran my eye through it hurriedly, but didn't have time to read it all. If you'll sit down and listen, I'll read it to you from the beginning."

All being agreeable to this proposition, they seated themselves on camp chairs in front of the tent and Hal began as follows:

"First, I'll begin by telling you where I found this book. I'll take you back to the spot after I've finished reading. Before I found this book, I discovered a sign, or notice, written on a piece of paper and pinned to the trunk of a tree about four feet from the ground. On that paper was written with lead pencil these words under date of last Friday:

"'I Alvin Baker, a student at Edwards College, hereby name this island Friday island, because I was marooned here alone, like Robinson Crusoe, on Friday, June 9, 1922.'"

"I'd like to make the acquaintance of that boy," said Mr. Perry warmly. "He has both imagination and a sense of humor in the midst of adversity."

"Naturally I began to look about me for some trace of the person who had pinned the notice on the tree," Hal continued. "I was standing in an open space about thirty feet in diameter. The tree on which this notice was pinned is at the edge of that space. There are a few small bushes here and there in the open, but the ground there is covered with long coarse grass. The first thing that attracted my attention, as I began to look about me was the fact that the grass was trampled down over a considerable area. I examined it carefully and while doing so found this notebook in the grass. It didn't take me long after that to reach the conclusion that Cousin Alvin had been attacked by somebody and in the struggle lost this notebook out of his pocket."

"It was probably the four ugly looking men he said were coming ashore when he sent his last distress message to us," Cub inferred.

"I wonder why he didn't tell us the truth," Bud put in. "Why didn't he tell us he was being hazed by some college boys?"

"He explains that in his diary," Hal replied. "Now listen and I'll read the first entry."

Hal's injunction being met with quiet, eager attention, he read as follows:

"Friday, June 9, 1922. Last night while I was walking through the grove of trees near the campus of Edwards College, I was attacked and overpowered by several sophomores, who slipped a bag over my head and carried me to a motor-boat moored a short distance away. They tried to conceal their identity, but I recognized the voices of Jerry Kerry and Buck Hardmaster. They kept me a helpless prisoner, with arms and legs bound and eyes bandaged, in the cabin for several hours, during which I could feel the boat constantly on the move. About 3 o'clock in the morning I was carried ashore on this island. My hands were untied, and then I could hear my captors hurrying away. I removed the bandage from my eyes and with my pocket-knife cut the rope around my ankles. It was too dark yet to see anything distinctly, so I had to wait for break of day before doing anything. An hour later I discovered near the landing place a considerable layout of supplies and equipment most of which I recognized as my own property. Then I recalled that one of my captors had thrust something into one of my pockets just before they took me ashore and I put my hand into that pocket and drew out an envelope that I knew I had not put there. In the envelope I found a typewritten note, which read as follows:

"'Alvin Baker, you have succeeded during all of your freshman year to date in frustrating every attempt to haze you and have boasted that there was no "gang" of boys at Edwards smart enough to do the trick. We are now performing the trick in a manner that ought to convince you that such a boast is the freshest of freshman folly. We raided your room and took therefrom your radio sending and receiving outfit, and have added thereto necessary equipment for erecting an aerial. This we leave with you in order that you may summon help through the atmosphere. Meanwhile, you may comfort yourself with the distinction of being the first college freshman ever given a radio hazing. Now, put up your aerial and send out a message for help. Radio is your only hope. Nobody ever stops at this island and it is impossible for passing vessels to see any signal of distress you may devise. If you are too proud to admit defeat and refuse to send out a broadcast for help, you must remain here two weeks, at the end of which time you will be captured again after dark, bound and blindfolded, and taken back to the mainland and released. The identity of the persons responsible for your defeat you will never be able to discover. Enough canned food has been left with you to keep body and soul together a week. At the end of that time, if you have failed to effect your own rescue by radio, more canned food will be left here for you. We are leaving also a tent, a few camp utensils, matches, and fishing tackle. You must drink river water. Now prove yourself as big as your boast.'

"I decided to defeat those fellows, if possible, by getting away from the island without broadcasting an admission that I had been marooned by sophomore hazers. So I pitched the tent and then constructed an aerial out of material supplied by them and began to broadcast messages of distress, saying that I had been marooned by river thieves who had stolen my boat. But soon I found that there was someone 'in the air' who was determined to defeat this purpose. It is now 11 p.m., and he seems to have been successful in his attempts to make it appear that I am a faker. Nobody has offered to come to my rescue."

Saturday's entry in the diary opened as follows:

"Last night, between 2 and 3 a.m., I was awakened by a slight noise outside near the tent. I stole cautiously to the entrance and peered out. It was a bright moonlight night and in front of the tent I saw two men apparently examining the camp with much curiosity or evil intent, perhaps both. Evidently they saw me watching them, for they suddenly turned and fled. I followed them cautiously and saw them get into a power boat and motor away. I called to them, explaining my situation and offering to pay them if they would take me away from the island, but they gave me no answer. Probably they were river thieves and the boat they had was stolen."



CHAPTER XIV

More Light and More Mystery

The next two days, Saturday and Sunday, were devoted by the island prisoner to the sending out of further calls, for help, and these calls were met by a campaign of ridicule, similar to that begun by his nemesis on the first day of his imprisonment, according to the diary read by Hal to his companions. A few listeners-in indicated a willingness to come to his rescue, in spite of the plausible ridicule from anonymous source, but when asked where he was imprisoned, ignorance on that subject frustrated all good intentions along that line until his S O S reached Cub at the latter's home on the following Monday.

"I tried to make this mysterious enemy of mine identify himself," wrote the diarist under Saturday date; "but he professed to have a wager posted against me which bound us both to secrecy. This caught me in the solar plexus of my conscience, for I was broadcasting my appeals for help under a false identity. Two or three amateurs looked me up under the name, call, and address that I gave and then broadcast a denunciation of me. It begins to look as if my hazers are going to win a full revenge for the way I laughed at them at college. This day's experience has convinced me that I am in bad throughout the radio atmosphere. It begins to look as if I am up against it and will have to stay here the full two weeks to which those hazing kidnappers of mine sentenced one. I wonder if they will make the term longer because I resorted to the method I have pursued thus far in order to avoid admitting that I had been hazed. Well, I have this consolation, anyway, that they have to pay for my food as long as I am here. They had to furnish me a tent also."

"Caught half a dozen fish today and named this place Friday island because of the day, or night, I was brought here and my subsequent Robinson Crusoe experiences," began the entry for Monday.

Then followed a gleeful memorandum of his apparent success in interesting Cub Perry with an account of his predicament, in spite of the efforts of his radio nemesis to prove him a trifler with the truth. Tuesday's entry closed with a notation of the announcement from Cub that the Catwhisker was about to start on a rescue trip from Oswego to the Lake of the Thousand Islands and would endeavor to find him by radio compass.

"The situation is cleared up very much," Mr. Perry remarked after Hal had finished reading the diary. "The chief problem now remaining to be solved is, what became of your cousin?"

"In other words, that's the mystery before us," said Bud, with a twinkle of fun in his eyes.

"Call it what you will," smiled Mr. Perry. "But it doesn't strike me as in the least mysterious. Evidently he was taken away from this island by the fellows who put him here."

"And what did they do with him?" was the query with which Cub supplemented his father's observation.

"That, of course, we don't know," the latter replied. "They may have taken him over to the Canadian shore and released him for reasons of their own."

"Then it's up to us to find out," Cub inferred.

"Surely. We've had remarkable success thus far. It would be a pity for us to meet with failure. That would spoil our story."

"Story!" exclaimed Bud. "What story?"

"Our story—the one we've been enacting thus far. Look back over our experiences in the last two days and see if you can make anything but a very fascinating yarn out of them."

"It's a radio-college story, isn't it?" Hal suggested.

"Yes," Mr. Perry agreed; "that would be one good way to put it."

"If it didn't involve my cousin in a critical situation, I'd hope the story wouldn't end yet," said Hal. "I'd like to see it run thirty or forty chapters."

"How many chapters do you figure it would make thus far?" asked the director-general of the expedition with a look of keen interest.

"Oh, about ten or fifteen," Hal replied.

"Then, to suit your taste, it ought to be only about half finished."

"Yes, but for my cousin's sake, I wish it were finished right now and Alvin were safe with us or at home."

"But wishes won't produce results nor cut off chapters," Cub philosophised.

"No, the denouement will work itself out along natural lines under natural laws," Mr. Perry predicted.

"I don't think this story is going to amount to anything as a yarn," Cub announced with a look of superior wisdom.

"Why not?" asked his father.

"Because there's no villain in it. I never did like a story with a tame ending, and the worst kind of a story on earth is one that starts with a thrill and ends with a nap in a sunparlor."

Laughter greeted this grotesque contrast.

"I don't think you need expect any such up-shot in this affair," Mr. Perry advised.

"Do you expect a villain to show his hand?" Bud inquired.

"It seems to me that we have some villains in the plot already."

"Who are they?" asked Hal.

"How about those sophomores who kidnapped your cousin and marooned him here?"

"Oh, they're only play villains," Cub put in disdainfully.

"How do you know they wouldn't do something worse than haze freshmen?"

"I don't; but until they do they're just play villains, and that doesn't interest me."

"I see," Mr. Perry observed; "you want people to be either very good or very bad."

"No," Cub returned slowly. "I wouldn't put it that way; I don't want anybody to be bad at all; but the fact of the matter is there are lots of good people in the world and a good many bad."

"And to make a good story you think it is necessary to bring good people and bad people together, eh?"

"Well, that's what makes fireworks, isn't it?"

"Oh, ho, I get you now," said Mr. Perry. "You're fond of spectacular things."

"No, I wouldn't put it that way," Cub replied; "but I don't like to see anybody make a bluff at anything and not make good. Now, we've started out with a glorious bluff at some very clever rascality, and it looks as if it's going to prove to be just an ordinary hazing affair."

"It looks to me like a very extraordinary affair, whether it was hazing or not," returned his father.

"And you think we'll find a villain if we investigate it to the end?"

"Why, sure," Mr. Perry smiled. "I shouldn't be surprised if we'd find Captain Kidd's treasure buried on this island."

"Now you're joking," Bud put in.

"What kind of mathematics would you use to locate that treasure?" Hal inquired with a kind of jovial challenge.

"Cube root," was the reply.

"That means dig at the roots of a four-cornered tree and you'll find a box of pieces of eight shaped like a gambler's dice," Cub inferred.

"That's pretty good imagination, and, I think ought to put us in a frame of mind well suited for further investigation," said Mr. Perry. "Now let's go to the spot where Hal found that diary of his cousin and see if we can't discover something more of significant interest."



CHAPTER XV

The Hook-Up on Shore

Arrived at the open area where Hal had found his cousin's "Crusoe diary", the three boys and Mr. Perry began a careful examination of the surroundings for further evidence that might throw light on the strange affair, which, for the time at least, appeared to defy the mystery scoffer's "mathematics".

First they scrutinized every foot of ground where the grass had been trampled so violently, it seemed, as to suggest a physical combat. But they were not sufficiently skilled in the arts and subtleties of the aborigines to work out the "code" of footprints and twists, tears, and breaks in the grass, twigs and foliage. So the result of the inspection of an apparently recent battle ground was nil.

"I believe we've exhausted every possibility of a clew to the mystery in this spot," declared Cub at the end of half an hour's search. "Let's not waste any more time here."

"What'll we do next, then?" asked Bud.

"Go fishin'" Cub replied.

"I think that's a good suggestion," said Mr. Perry. "We've concentrated our minds and efforts on this problem all day thus far, and a little relaxation probably will do us good."

"Where's the best place to fish?" Hal inquired.

"I think I know," Bud replied. "I found a place where we can climb down the bank to a dandy little beach while I was looking over my section of the island. A little spur of land runs out at that point, so as to form a small bay, and the water there is quiet and looks deep."

They returned to the camp and got their fishing tackle and soon were casting baited hooks into the bay. Bud's prediction as to the hopeful appearance of this place, from an angler's point of view, proved well founded. In less than an hour they caught more fish than they could eat at supper and breakfast.

After supper they formed a campfire circle in front of the tent—without a fire, however, for the normal heat of the atmosphere was all that comfort could demand—and held a further discussion of the situation and the problem with which they were confronted.

"I don't know, boys, but we ought to make a trip somewhere in the Catwhisker and get police help to solve this problem," Mr. Perry remarked with a reflection of years and judgment in his countenance. "Hal's cousin may be in serious trouble, for all we know, and it's our duty to enlist every agency at our command to aid him."

"But while we're gone something might develop here that would throw light on the mystery," said Bud. "Excuse me, Mr. Perry, for insisting on calling it a mystery. I can't think of it as anything else."

"Oh, goodness me!" returned the one thus addressed. "I'm afraid you boys failed to get what I was driving at. I didn't mean there was no such thing as mystery. That depends on your point of view. It is only people who are easily startled or confused by unusual things who are easily mystified. I don't mean to say that it would be impossible to mystify me under any circumstances. For instance, if the man in the moon should suddenly jump down on the earth and give me a brick of green cheese, and then jump back again before I could say 'thank you' I presume I'd be greatly mystified."

"Your illustration won't stand a test of reason, dad," Cub objected. "To test whether it is possible for you to be mystified you must offer a test that is possible."

"That's precisely why I offered that impossible illustration," Mr. Perry smiled. "I wanted to see if any of you boys would catch the inconsistency. You just call this affair a mystery as long as you think it is one, but after it is cleared up, I fancy you'll have difficulty in looking back and picturing it as a mystery in your minds. But I didn't intend to take us off our subject. I was going to answer Bud's argument that something of importance might develop while we were gone. Yes, that is true, but it wouldn't be necessary for all of us to go. Two of us might make the trip and the other two remain here."

"That's a good idea," declared Hal. "Suppose you and Cub go and leave Bud and me here to look after the camp and watch for developments?"

Mr. Perry did not reply at once. Something new seemed to have slipped into his mind and appeared to be giving him some concern.

"On second thought," he said after a few moments of silence; "I'm inclined to withdraw my suggestion."

"What's up now, dad?" Cub inquired.

"I was just recalling a portion of Hal's cousin's diary," his father replied. "According to that, it seems that rough characters visit this place sometimes."

"Oh, we're not afraid," Hal protested. "Besides, you could make the trip there and back in a few hours."

"Well, we'll think it over and decide in the morning what we'll do," said Mr. Perry.

"Meanwhile, I tell you what we ought to do," Bud proposed. "It's an hour before dark and we'd have time to bring Hal's wireless outfit up here and hook it up before the sun sets."

"That's a peach of an idea," declared Cub, jumping to his feet in his eagerness. "I've got two hundred and fifty feet of extra wire and some insulators on the boat and we can put up an aerial here without taking down the one on the Catwhisker. Then we can shift the radio outfit back and forth to the island and to the boat as we please."

"Good!" exclaimed Hal. "I'm with you on that. Let's get busy and not waste a minute of daylight."

They worked rapidly, and as they were well supplied with material and tools the progress made by them measured up to expectations. They fashioned a two-wire antenna with the spreaders left on the island by Hal's cousin; connected a lead-in to this, and then Cub and Bud climbed the two trees and, with the aid of ropes tied around their waists and the guiding assistance of their companions below, drew the "ether-wave feeler" up to a lofty elevation and fastened it as nearly taut as they could stretch and hold it. In this work they took due consideration of the professional objection to tree entanglements in aerials so that the insulators were well beyond the reach of the longest limbs.

"It's a simple matter now to bring the outfit ashore and hook it up with the aerial," said Hal. "Let's do it."

Enthused by the novelty of their enterprise, they continued the work, even though dusk was rapidly gathering. Several electric-battery flash-lights were produced, so that the twilight did not seriously hinder them. By the time the stars had become a billion glittering gems in the sky, the hook-up had been completed with Hal's sending and receiving set on a table that had been transported from the yacht to a convenient position directly under the aerial and near the opening of the tent.

"Now, let's see what's going on in the air," said Cub. "Hal, you take the first whirl through the atmosphere."

Hal sat down by the table and put a pair of phones to his ears. Then he began to tune. First there came to him a discordant confusion of static and other noises, including an admixture of "ham impudence".

"W H Q's on," announced Hal presently, pushing over the horn switch, whereupon the clear tones of a quartet from the Rochester station was thrown with amplified resonance out upon the reamplifying atmosphere of a land-and-water wilderness.

They "sat through" the program with a degree of enjoyment never before experienced by them under a radio spell. They could almost imagine themselves on an enchanted isle with a band of fairy songsters teasing harmonious echoes out of their surroundings.

"My! I didn't suppose such weird beauty of sound could be produced under any possible conditions," exclaimed Mr. Perry at the close of the last number on the program.

"Now the air will be free for all for a short time," said Hal, putting on the phones and throwing back the horn switch, while the other boys also donned their phones. "I'm going to see if I can get any of those fellows we talked with on the way up here."

"Get that amateur with the radio compass who proved Mr. Perry's mathematical theory," suggested Bud.

"All right I remember his call and wave length; so here goes."

Hal tuned for several moments and sent the call of the Canadian amateur in question. Then suddenly he gave a little gasp of surprise. Only Mr. Perry felt a curiosity as to what it meant, for the other two boys knew as soon did the boy at the transmitting key. Someone was calling them and the call he gave as his own was the Canadian V A X. Then came the following message:

"Have you not given it up yet, boys? I did not mean to carry the joke so far. Better go back home."

Mr. Perry was waiting patiently for an explanation of the tense interest manifest in the attitudes of the three boys. Presently Cub gave it to him, thus:

"We're on the trail again, dad. This fellow we've got is posing as Hal's cousin and he's advising us to go back home."



CHAPTER XVI

Running Down a Radio Fake

"You say you are V A X?" dot-and-dashed Hal to the amateur who had thus represented himself.

"Yes," was the reply.

"What is your name?"

"Alvin Baker."

"Where do you live?"

"At Port Hope."

"Where are you now?"

"On the river with some friends."

"Have you any relatives in the United States?"

"Yes."

"Where do they live?"

"In New York."

"New York City?"

"No—State."

"What city?"

"I have forgotten."

"Is it Rochester?"

"I do not know."

"Is it Oswego?"

"I am not certain."

"Have you a cousin named Hal?"

"Yes."

"What is his last name?"

"Baker."

"Have you any relatives named Stone?"

"I think so."

"Is the name Hal Stone familiar to you?"

"Never met the gentleman."

"Then your name is not Alvin Baker?"

"Maybe you know my name better than I do."

"No, but I know just as well as you do that you are not Alvin Baker."

"How do you know that?"

"Because Alvin Baker is my cousin. I am Hal Stone, and I live in Oswego, New York."

"I do not believe you. You are an impostor."

"Let me tell you a secret. I have penetrated your plot. You are an enemy of my cousin. There was no wager between him and you, but you don't want us to find him. You had better keep out of the atmosphere or I will have you arrested on a charge of disorderly conduct in the air."

No answer.

"V A X, V A X, V A X," called Hal.

Still no reply.

"I cornered him, proved he was an impostor, and now he won't talk to me any more," said Hal, addressing his companions. Then he translated the code conversation, just completed, for the benefit of Mr. Perry.

"Well, that disposes of him for the time being, at least," was the latter's comment.

"But leaves a mystery as to his identity," put in Bud with a "mystery smile".

"No, I don't think there's any question as to his identity."

"Have you worked it out by mathematics, dad?" Cub inquired.

"Yes, by sines and cosines."

"What are sines and cosines?" asked Hal.

"You'll find out when you go to college and study trigonometry," Mr. Perry replied.

"Oh, I've seen those words," Cub answered, with some of his alleged characteristic "highbrow eagerness". "You spell sine, s-i-n-e, and cosine, c-o-s-i-n-e."

"Exactly," smiled Mr. Perry. "Those are terms used in higher mathematics. But, in order that you youthful minds may not work too hard over my trick, I'll admit that in my mind I spelled sine s-i-g-n, and cosine, c-o-s-i-g-n."

"No use to try to get ahead of my father," Cub declared, shaking his head. "He could prove that water runs uphill by mathematics. He means the signs and cosigns indicate that—. What do they indicate, dad? We got off the question just because you wanted to carry your point with a pun."

"I meant to say that this fellow whom you cornered and chased out of the air is one of the fellows who hazed Hal's cousin by marooning him on this island," Mr. Perry answered.

"Gee! that never occurred to me," exclaimed Cub, swinging his long arm with a snap of his finger like the crack of a whip. "I bet anything you're right."

"We get one step nearer every time we make a move," said Bud eagerly.

"Yes, but the question is, how many steps do we have to take before we settle this—this—mystery?" Cub demanded.

"Don't look ahead so far," Mr. Perry warned. "Here's a rule in such matters that applies to all men—and boys—of small or large capability. Be careful never to look ahead so far you can't see the step you are in the act of taking."

"All right," Cub assented. "What is the next step for us to take?"

"Find out who the fellows are that hazed Hal's cousin." Bud replied.

"Yes, that's a good suggestion, though it'll probably require several steps to gain that information. Still, you're not looking so far ahead, when you propose that move, as to be unable to see your first step."

"Why not try to get in touch with some amateur in Cousin Alvin's home town by wireless?" Hal suggested.

"That's the very thing I was in hope one of you would propose," Mr. Perry replied. "You boys haven't by any means exhausted the possibilities of your radio outfit."

"We have no Canadian call book," said Hal, "but perhaps I can induce one of the amateurs we've been talking with to look up the call of one or more amateurs in Port Hope and give them to me."

Without more ado, he swung the switch into sending position and began to call the amateur who had given them the information that had enabled them to locate Friday Island. Success rewarded his efforts almost immediately. The curiosity of the Rockport amateur, however, had to be satisfied before further service could be had from him. This Hal did with due patience and speed, reciting their experiences since their arrival at the island. Meanwhile the Canadian consulted his call book, and was ready with the desired information by the time his very excusable curiosity had been satisfied. He supplied Hal with two Port Hope calls, together with their wave lengths.

Then began the task of getting into communication with the Port Hope amateurs. Hal sent the call of each of them a score or more of times, but got no answer from either. At last, however, another Port Hope amateur, who chanced to be listening in, answered for them. He informed Hal that the sending outfit of one of these Port Hope boys was out of working order and the other amateur was out of town. Then the operator on Friday Island put the following questions to him:

"Do you know Alvin Baker?"

"Yes," was the reply.

"Is he at home?" Hal continued.

"I think not. He is at college."

"I am his cousin, Hal Stone, from Oswego, New York. I am with some friends on an island in the St. Lawrence River. I have learned that Alvin is in trouble. He was hazed by some sophomores, who left him alone on an island in the river. We found the island, but Alvin had been spirited away and is probably being held prisoner by them. This hazing gang seems to consist of some pretty rough characters. I want to get in touch with my uncle, Alvin's father."

"I will call your uncle on the telephone and tell him what you say," the Port Hope amateur dot-and-dashed in reply.

"Ask him to come over to your house, and tell him I will explain everything to him through you, and then perhaps he can form a plan for his son's rescue."

These and subsequent proceedings, in furtherance of the plan outlined "over the wireless" by Hal, took considerable time, but at last the situation was made clear to Mr. Baker, who announced his intention to start on a search for his son at once. Meanwhile Bud and Cub listened-in eagerly and translated the code messages for Mr. Perry.

"I tell you what we'll do," the latter said after the communication of events had been completed for the benefit of Mr. Baker. "Tell him to take a train to some river port, the nearest possible to this island, and we'll meet him with the motor boat."

Hal did as requested, and presently Mr. Baker caused this message to be sent:

"I will meet you at Rockport about noon to-morrow."

"Step number one proved to be well worth while," observed Mr. Perry. "Now let's go to bed and in the morning we'll take step number two."



CHAPTER XVII

Bud's Discovery

Next morning the day's program was discussed at the breakfast table, the latter being a light collapsible affair carried as an item of equipment of the Catwhisker. Hal introduced the subject by saying:

"Mr. Perry, don't you think two of us ought to stay here while the other two of us make the trip to bring Uncle John over here?"

"What's the use?" Mr. Perry returned. "Nobody's going to run away with the island."

"No, but we've established a camp here, pitched a tent, and brought ashore a lot of camp material and supplies. If we all go we'll have to strike the tent and take all these things back on the boat."

"Well, I don't know that it makes any particular difference to me," the owner of the yacht replied. "It'll be broad daylight and we'll be gone only a few hours. It isn't at all likely that anything will happen during that time."

"I'll stay here with Hal, if he wants to stay," Bud volunteered.

"That would be about the only way to arrange it," said Mr. Perry. "I don't like to have any of you boys make the trip without my being along, and as Cub knows the engine of the Catwhisker better than any other member of our party, I think I'd better take him with me."

"That's the best arrangement," said Hal. "And while you're gone, Bud and I'll play Robinson Crusoe and Friday."

"Who'll be Crusoe and who'll be Friday?" Cub inquired.

"Oh, we won't quarrel about that," Bud replied. "Hal may have his choice and I'll take what's left."

"This plan will simplify matters, to say the least," Mr. Perry announced. "About all we'll have to do when we decide to start is start."

"You don't need to wash any dishes before you go," said Bud. "Friday'll do that."

"There you go already," laughed Mr. Perry. "I predict a revolution on this island before we return."

"No, nothing of the kind," Bud returned. "I was assuming that the lot of Friday would fall to me. In other words, I volunteer to wash the dishes."

"I think you'll both have to be Fridays," Cub advised. "The real Crusoe of this place has disappeared and we don't want anybody usurping his honors in his absence. It is our duty to find him, reinstate him here, and then rescue him."

"And make prisoners of the buccaneers who marooned him," suggested Mr. Perry.

"Yes, and make them walk the plank," added Bud.

"We're not exactly right in calling Hal's cousin a Robinson Crusoe, are we?" asked Cub reflectively. "You know Crusoe wasn't marooned; he was shipwrecked on his island."

"Yes, but Crusoe was just a hero in fiction, you know," Mr. Perry replied. "Alexander Selkirk, the real Crusoe, was marooned on an island in the south Pacific."

"Too bad he didn't have a wireless outfit," said Hal.

"Well, boys, my portion of the breakfast is stowed away, and I must remind you that the moments are fleeting rapidly," announced the director of the expedition presently. "Cub, are you ready to start?"

"All ready," the latter replied, rising from his chair and turning the "finish" of a cup of coffee down his throat.

"I would suggest that you boys try to raise some amateur over in Rockport and probably you can stir up some local interest there in this affair," Mr. Perry suggested. "I'm always in favor of all the publicity that can be had in cases of rascality, and this looks to me like something more than a mere hazing."

"Why, dad, I haven't heard you say anything like that before," said Cub, with a curiously inquiring look at his father. "What do you mean by that?"

"I don't know," was the reply. "Maybe it's our remarks about Crusoe, buccaneers, marooning, and walking the plank that worked on my mind and set me to thinking about outlaws. I've just got a feeling that this affair isn't going to be explained along any play lines."

"But Hal's cousin didn't have any suspicion that it was anything more than a hazing affair, according to his diary," Cub reminded.

"I'm not so sure about that, either. You know he explained his distress messages by saying that he had been marooned by some river thieves or bandits."

"But he said in his diary he didn't want to tell the truth," said Hal.

"True, but he may have had a suspicion, nevertheless, that he felt was not tangible enough to incorporate in his diary. However, that will all be explained in due time, let us hope. Now, let's hurry. Good-bye, Hal, Bud. We'll be back as soon as possible."

A few minutes later that Catwhisker was backing out of the narrow harbor with Cub and his father aboard and Bud and Hal on shore watching their departure. Presently the yacht was out of sight from their hemmed-in position, the view being obstructed by trees and tall bushes on an intervening isle, which constituted a link of the insular chain that surrounded Friday Island.

"Now, let's wash the dishes," said Bud, turning back toward the camp.

"I thought Friday was going to do that work," Hal reminded with a broad grin on his face.

"Wasn't it ordered that both of us should be Fridays?" Bud demanded smartly.

"You win," laughed Hal. "But here's a better way to handle the subject in view of another duty before us. You know we're supposed to try to get in touch with somebody by radio at Rockport and we haven't much time to spare before the Catwhisker arrives there. You get busy on the job and I'll take care of the dishes."

"Not on your lightning switch," returned Bud emphatically. "I volunteered to be Friday, and I'm not going to slip out of my promise through your generosity. You get busy with the key and the phones and I'll get busy with the dishrag."

As no reasonable argument could be adduced to defeat this proposition, the two boys were soon busy as prescribed by the last speaker. Bud's task required only about fifteen minutes, and after it was finished he rejoined his companion at the radio table.

"Well, what luck?" he inquired.

"Nothing doing," Hal replied. "I've managed to get the calls and waves of two amateurs at Rockport, but neither of them answers."

"Keep it up anyway," Bud urged, "and I'll take a tackle and go over to the place where we took in our haul of fish yesterday, and see what I can do this morning. Call me if you get anything interesting."

Hal promised to do as requested and then Bud hurried away. The former continued his efforts unsuccessfully with the sending key for nearly half an hour, hearing no sound from his friend in the meantime. Then he was about to take the receivers from his ears and go in search of the fisher-boy to find out what success he had had, when the latter appeared on the scene with a look in his face that startled the youth at the radio table.

"What's the matter, Bud?" Hal inquired, as he literally tore the phones from his ears. "Has anything happened?"

"Not exactly," the other replied. "But I've made a discovery that may mean trouble for us. At least, we'll have to be on the lookout from now on."

"Why—what do you mean? Hurry up; don't keep me in suspense. What kind of discovery have you made?"

"I've discovered that we're not the only persons on this island," was Bud's chilling response.



CHAPTER XVIII

Unwelcome Visitors

"Why, Bud, what do you mean?" Hal demanded, in astonishment. "Who else is on this island?"

"Some men. I don't know how many," Bud replied in cautious tone. "I heard them talking about us. But keep your voice low, for this island is small and they may hear you."

"I was going to remark that this is a small island to contain much of a hiding place for anybody."

"Yes, but it's wild with bushes. And these men are bad fellows, I could tell from the way they talked about us. They're as mad as hops 'cause we're here. They're studying how to get rid of us without making more trouble for themselves."

"That's funny," Hal remarked. "Why should they care if we're here? Do they claim they own this island?"

"I don't know whether they do or not. I didn't hear them say anything about that."

"Where are they now?"

"Over near our fishing place, if they haven't left. They were hidden in some bushes, and I might 'ave run right into them if it hadn't been for their voices. After I heard them I kept myself under cover and crept closer till I could get what they said."

"Were you listening to them all the time you were gone?"

"Just about."

"And didn't you find out anything more specific than what you've told me?"

"No, I don't think I did."

"Why did you leave them?"

"They seemed to 've talked the subject dry and turned to other matters, and I thought I'd better come and tell you about it."

"And they're there yet?"

"So far as I know."

"After they'd talked their subject dry, what did they find to discuss?" asked Hal.

"Something wet," Bud answered with a grin.

"I get you; you mean they had some moonshine with them."

"Or some Canadian whisky."

"Probably that. But this makes the situation look a little better for us. If they're just a bunch of fellows out for a liquor outing, maybe we don't need to be much concerned about them if we keep shy of them."

"I don't think that's all there is to it," Bud replied, with a note of warning in his voice. "I heard one of them say we were likely to make trouble for them and we ought to be chased away and scared so badly we'd never come around here again, and the others seemed to agree with him."

"That sounds like a mystery," said Hal.

"I don't believe Mr. Perry would talk mathematics to explain such conversation," Bud declared.

"If he did, he'd probably make another pun about sines and cosines. But, say, don't you think we'd better make further investigation?"

"I don't know what we could do unless we did some more eavesdropping, and that might cause them to get ugly if they caught us in the act," Bud reasoned.

"Yes," Hal agreed; "I suppose we'd better wait as quietly as we can till Mr. Perry and Cub get back; then we can decide better what to do."

"I don't see that there's anything for us to do but get away from here as soon as possible," said Bud. "Mr. Perry won't want to get into trouble with four men."

"He'll probably have a talk with them to find out what's on their minds," was Hal's conclusion.

"And then get out rather than have a fight," Bud added.

"Oh, I hope there won't be anything as bad as that."

"Why not, if we insist on staying? If these fellows are the rough characters we suspect them of being, that's the very sort of thing they'd resort to, provided, of course, that they thought they could get the best of us."

"Here they come now!" suddenly gasped Hal, indicating, with his gaze, the direction from which "they" were approaching.

Bud turned quickly and saw four men emerge from the thicket some fifteen feet to the rear of the tent. They did not look like rowdies, for they were fairly well dressed, but there was nothing reassuring in the countenance of any of them. One was tall and angular, another was heavy and of medium height, another was very broad-shouldered and deep-chested and had long arms and short legs, a sort of powerful monstrosity, he seemed, and the fourth was fairly well proportioned, but small. There was not a reassuring cast of countenance among them.

"We'll just have to stand our ground and hear what they have to say," Hal whispered: "Maybe they'll be reasonable if we don't provoke them. Be careful and don't say anything sassy."

"I won't," was the other's reassurance.

The four men approached to a point a few feet from the radio table and halted, and the tall angular man, assuming the role of spokesman, demanded in deep tones:

"What're you kids doin' here?"

"We're just waiting for some of our friends to come back," Hal replied.

"Where'd your friends go?" continued the spokesman with a leer that caused the two boys to shrink back a step or two.

"They just took a trip in the motor boat," replied Hal cautiously. "They'll be back soon."

"Oh, they will, eh," leered the man as if he penetrated the weakness of the warning in the boy's answer. "How many are they of your friends?"

"More than we are," replied Hal, having reference to physical size of Mr. Perry and Cub.

"Oh, come now, kids, tell us the truth," ordered the leering spokesman, advancing a pace nearer. "Tell us how many went away in your boat and how soon they'll be back."

"There was a large man and a big boy," Bud interposed with more assurance that he felt.

Sly grins crept over the countenances of the four men.

"Oh," grunted the spokesman; "you hope by that kind o' talk to scare us away. Well, nothin' doing along that line. This here island belongs to us, and we don't allow no trespassin."

"Is the island for sale?" inquired Hal, who thought he saw an opening through which he might work up the interest of the three men without arousing their antagonism.

"Fer sale?" repeated the spokesman of the quartet, all four of whom seemed to exchange among themselves a round of sinister glances. "Well, I guess nit. They ain't enough money this side o' the United States treasury to buy this island from us."

"We might be able to scrape up a handsome sum, if necessary," Hal reasoned.

A suggestion of covetous greed shone in the eyes of all four men, but the spokesman belied his own looks by saying:

"Nothin' doing. We want you guys to git out o' here. This is our summer resort, eh, Spike"—turning to the long-armed, deep chested man.

"Spike" nodded grimly and replied:

"You bet it is, cap'n. We're gen'lemen of leisure an' don't care fer money. All we want is our own, and they's sure to be trouble if anybody tries to take it away from us."

"Well, we don't want anything that doesn't belong to us," was Bud's reassuring answer; "and if this island is yours, we surely don't want to stay here. But we thought that maybe you'd be glad to sell, for a member of our party said he'd like to buy all of the islands of this group if he could find the owner."

"Who is he?" asked the quartet's spokesman.

"His name is Perry and he lives at Oswego, New York," Bud replied.

"Well, you all go somewheres else to talk that matter over and then take it up with my real estate agent. Meanwhile I don't allow no trespassers on this ground."

"But we can't go until our friends come back with their boat," said Hal. "They promised to return soon."

"Where did they go?"

"To the Canadian Coast."

"What fer?"

"To get another friend who will join us."

"Well, they'd better hurry up or they won't find you when they get back."

"What's that you got there?" asked the man who had been addressed as "Spike", indicating the radio table and outfit thereon.

"That's a wireless outfit, you goof," replied the tall, angular spokesman.

"I tell you what we'll do," Hal announced, taking inspiration from the attention thus called to his radio apparatus. "We'll call our friends by wireless and have them return at once and take us away. How's that?"

"All right," was the assenting response. "Go ahead, but be careful, no tricks, or our revenge will be speedy, and that's no name fer it."

With this warning the four men walked away and Hall got busy with a diligence inspired by a sense of danger and, at the same time, a sense of the opportunity afforded by the possibilities of the world's latest great invention, radio.



CHAPTER XIX

"S O S" from Friday Island

Max Handy, the Canadian youth at Rockport, who gave the crew of the Catwhisker, by wireless, directions whereby the latter were able to locate "mathematically" the whereabouts of the "Canadian Crusoe's Friday Island" listened in much of the time thereafter, in the hope of being able to keep in touch with developments to the end of this interesting radio affair.

And this hope was realized in a degree that could hardly have been expected with moderation. But he was well equipped, and, being mechanically inclined, and industrious, he was able to get a maximum of results with his sending and receiving outfit.

He had traced the rescue yacht all the way from Oswego to Friday Island, and the last message he had picked up from the three young radio Americans was the one that completed the agreement under which the yacht was to proceed to Rockport next day and meet the father of the "missing Crusoe". Then he attempted to get in communication with the island operator, but Mr. Perry had just announced that the next number on the program would be "everybody to bed at once", and there was no more listening-in before the next morning.

Max stayed up late that night, with phones to his ears, eager to get another message from the island, and he was a very much disappointed enthusiast when at last he gave up his efforts, convinced that they were useless. He slept late next morning and consequently lost an opportunity to respond to Hal's first call to enlist the aid of the Rockport amateurs in the campaign to rescue the missing "Crusoe".

But at last he caught a message from the island, and the conversation, translated from code, that took place between him and Hal, following a few introductory inconsequentials, was as follows:

"I listened-in last night and heard your arrangements for today," the Canadian dot-and-dashed. "When are you coming to Rockport?"

"Two of us are on the way," Hal replied. "They ought to be there by this time."

"Is there anything I can do to help you?"

"Yes. Can you go to the dock and ask them to hurry back? There are four ugly acting men here on the island, who have ordered us off. They threatened to make trouble for us if we do not go soon."

"Don't your friends know those men are there?"

"No; we discovered them after the boat left."

"All right, I will run down to the dock and tell them."

Max literally kept his promise relative to his manner of travel. He ran all the way to the dock, half a mile. The Catwhisker was there, tied fast with cables, but nobody was on board.

"They've gone to the depot," he concluded; then he turned his steps toward the railroad station.

He ran and walked alternately, with a dozen changes of speed, and arrived just as the train from the west was pulling in. He had no difficulty in identifying Mr. Perry and Cub when they introduced themselves to Mr. Baker, as the latter stepped from a coach, and a moment later he was addressing the owner of the Catwhisker thus:

"Is this Mr. Perry of Oswego, New York?"

The latter turned quickly and beheld a youth about the age of his own son, but of considerably shorter stature.

"It is," he replied somewhat apprehensively, in view of recent stirring events and the logical probability of more of the same sort.

"Well, I have something important to tell you," Max continued. "I'm the boy who gave you the radio compass information that made it possible for you to find Friday Island."

"Gee! I'm glad to meet you," exclaimed Cub, seizing the Canadian youth by the hand and forgetting, in his eagerness, the announcement from the "radio compass detective" that he had "something important" to communicate.

But the latter, although equally pleased to meet the young amateur from the States, was on his guard against a delay of this sort and soon broke through the effusion of cordiality with which Cub greeted him and continued his communication thus:

"I was just telegraphing with one of the boys on the island, and he told me to tell you to hurry back. There are four men on the island who ordered them away and threatened to make trouble for them if they didn't get away soon."

"What's that!" exclaimed Mr. Perry, seizing the youth by the arms. "You say you got that kind of message from those boys?"

"Sure I did," the boy replied; "and they want you to hurry back."

"What kind of men are they—rough characters, bad men?"

"That's what I understood him to mean."

"Come on, Mr. Baker, Bob; we must hustle along. Thank you, my boy; you'll hear from me again."

"I'll hurry back and tell the boys I found you and you're on your way," shouted Max as he ran down the street toward home.

Mr. Perry led the way toward the dock at a rapid pace. Presently they found themselves in front of a hardware store, and the owner of the Catwhisker stopped and said:

"I'm going in here a minute."

He entered, and Mr. Baker and Cub followed, wondering a little as to the motive of the boy's father. But they were not long left in doubt.

"Have you any fire-arms on sale here?" Mr. Perry asked, addressing the proprietor.

"Small or large?" the latter inquired.

"Small."

"Right this way."

He stepped behind a show case in which was a display of automatics and revolvers. Mr. Perry selected one of the former and a box of cartridges and took out his pocketbook to pay for them.

"I believe I'll take one, too," interposed Mr. Baker, also producing a purse.

The storekeeper looked somewhat curiously at the two men.

"I'm supposed to exercise care and judgment in selling these weapons," he remarked slowly.

"Of course, of course," returned Mr. Perry. "The situation is this: We belong to a yacht on the river and have run up against some bad characters. I am the owner of the yacht and have decided that we need protection."

"Sure, sure, that's perfectly satisfactory," said the hardware man. "You can buy out my whole arsenal on that explanation."

"We won't need it," Mr. Perry smiled. "These two guns are enough."

The purchase completed, the two men and the boy left the store and hastened on toward the municipal docks.

Meanwhile Max arrived at his home and went direct to his radio room. There the first thing he did was to don his phones, and the result was instantly startling.

He had left the instrument tuned to the Friday Island wave length and the aerial switch in receiving position.

"S O S, S O S, S O S," crashed into his ears in rapid, energetic, excited succession, it seemed to his susceptible imagination.

Quickly he threw over the switch, and called for an explanation. It came as follows:

"Those men have seized my friend, and now are coming after me. S O S, S O—"

That was all—not another dot or dash. Desperately Max appealed for further details, but it was like calling for life in a cemetery. The ether was dead, so far as Friday Island was concerned.



CHAPTER XX

Four Prisoners

When the Catwhisker arrived at Friday Island again, the place appeared to be deserted.

The camp was as they had left it, except that the breakfast dishes were washed and put away. "Friday" had performed his duty, but both boys had disappeared, and there seemed to be only one explanation of their disappearance, namely, the premonition of danger at the hands of the four strange men that the Rockport amateur, Max, had received from the boys on the island. No damage had been done to the tent or any of the camp paraphernalia, even the radio outfit being exactly as it had been when they left it in charge of Hal and Bud a few hours previously.

"This is getting pretty serious," Mr. Perry said, after they had made an unsatisfactory review of the situation. "I confess I don't know what to make of it."

Cub felt an impulse to brand this new affair as the most puzzling mystery that had yet confronted them, but he checked the utterance wisely enough as entirely too facetious for the occasion.

"We've got to get the authorities busy on this case," Mr. Perry added after a few moments' hesitation. "We may be sure now that it's more than a hazing affair. There must be a retreat of some bad men around here somewhere."

"What authorities shall we ask to help us?" Cub inquired.

His father seemed about to answer, but he hesitated a moment or two, with a puzzled look, first at his son, then at Mr. Baker.

"That's so," he said presently. "Where are we—in Canada or the United States?"

"I think we ought to apply for help in both New York and Ontario," said Mr. Baker, who was ordinarily a man of quiet demeanor, but now was worked up to a state of nervous worry over the fate of his son.

"It's going to take some time to make trips to both sides of the river and get the authorities of New York and Ontario busy," said Mr. Perry; "but I suppose that's the only thing to do, and every minute wasted is an opportunity lost. So let's go right away."

"Hold on, father," Cub interrupted; "you forget that we have a means of calling help right here."

"It won't do to depend on your radio messages" his father replied. "You know the experience Mr. Baker's son had trying to get help that way."

"Yes, but there were conditions that queered his calls," Cub replied. "Just remember the results we got by calling our new friend, Max, at Rockport, and what he did for us. Unless I'm badly mistaken, we can look for more help from him."

"Yes, you're right, Bob," Mr. Perry admitted. "But I don't like the idea of staying here and depending on a few boys to take care of so big a proposition. We need to arouse the whole country around here, including all people along the shores, on the islands and those boating up and down the river."

"In other words, there must be some real broadcasting," Cub interpreted.

"You bet you, and more than any amateur radio station in the country can do. Now, we've wasted too much time already. Come on; we've got to get started without any more delay."

"But let me stay and see what I can do while you're gone," Cub pleaded. "I bet I can have a police boat headed this way before you reach the mainland."

"No, nothing doing," his father ruled unwaveringly. "You'd disappear just the way the other boys did. We can't afford to run any more such risks."

"I'd be safe enough if you let me have that automatic o' yours, dad," Cub argued,

"No, sir-ree; I'm not going to leave you here alone to fight any gun battle with a band of bandits."

But the boy was still undismayed by his father's resoluteness. He had one more proposal to offer, and he presented it thus:

"You don't need to leave me here alone, dad. Mr. Baker may stay; you can run the Catwhisker alone."

Both men had started toward the landing place, expecting the boy to follow, but they stopped suddenly and faced about on hearing this new proposition. Mr. Baker looked almost eagerly at Mr. Perry, it seemed, and, observing that the latter's unyielding attitude had softened somewhat, he said:

"That's agreeable to me if it is to you."

"Well," returned Mr. Perry with slow deliberation, "that sounds pretty good. If it suits you both, it suits me. I don't think you'll have to use the guns, even if any bad actors do happen around. If you show them, that'll probably be enough. Do you know how to handle an automatic, Bob?"

"Sure I do," the latter replied. "All you have to do is keep the nose pointed away from you and toward the target you want to hit. To shoot, you just keep pulling the trigger, and when it's empty you're safe from accident until you fill the chamber again."

"That's a simple statement of facts," Mr. Perry smiled; "but you left out the most important of all, and until you tell me what that is, I'm not going to let you have it."

"Oh, I know what it is; you've told it to me lots of times," Cub replied with eager alertness. "You know, dad, I always remembered what you told me, and I didn't forget that advice of yours about fire-arms. It is, 'always handle an unloaded gun as if you know it's loaded.' I promise you, dad, I'll not forget it this time."

"I guess it's safe to let you have it," said Mr. Perry, handing over the weapon. "All right, now that everything's settled, I'll be gone and you two see what you can do through the air."

That ended the discussion, and a few minutes later the owner of the Catwhisker was putting all the speed he could put into the power boat toward the Canadian shore, while Cub devoted all his energy and skill to the task of summoning as much aid as possible by wireless, Mr. Baker standing by and waiting eagerly for results.

And results were not long coming. The yacht was scarcely out of sight beyond the outer rim of islands, when Cub recognized the call of Max Handy, the Canadian amateur at Rockport. He acknowledged the call, and then telegraphed the following:

"I am the boy whom you met at the depot a few hours ago. When we got back, we found the two boys we left here were gone."

"I knew something had happened," Max replied. "After I left you I got their S O S. Then one of them telegraphed that some men had seized his friend and were coming after him. His last message was broken off in the midst of a new S O S. I couldn't get him again, I called up the police and they said they would see it got to the proper authorities for investigation."

Cub translated this message for the benefit of Mr. Baker and was about to continue the telegraphic conversation when four men, armed with clubs, and with anything but friendly demeanor, appeared on the scene. Mr. Baker saw them first and sounded the alarm.

"Here they come," he said in low tone, the accents of which caused Cub to start to his feet and reach for his father's pistol which he had laid on the radio table. "Be careful," the man continued. "Don't shoot unless I do. Maybe we can get some information from those fellows. Put your gun in your pocket and don't draw it unless they attack us or you see me draw mine."

The movement of Cub, transferring the automatic from the table to the right pocket of his coat, did not escape the notice of the visitors, who appeared to have come from the wooded depths of the island. But evidently their uncertain vision left their minds in a condition of doubt as to the significance of the act, for they continued to advance, however, with some appearance of caution.

"I'll go forward a few steps to meet them," said Mr. Baker, in a low voice to Cub. "You stay back here and be careful with your gun. Don't use it unless you see me use mine; then keep your head. I think we'll be able to handle this situation without any violence."

He advanced half a dozen paces, then stopped and addressed the unwelcome visitors, who were now distant from him only about fifteen feet.

"Halt where you are, gentlemen," he said. "We are armed, and any further advance on your part will be met with the use of our weapons."

The "gentlemen" stopped with due consideration for the warning, but with scowls that indicated the poor grace of their obedience. A description of them would mark them as the ones who are heretofore recorded as having made an unfriendly call on Hal and Bud at the island camp earlier in the day. The tall, angular man again was spokesman for them.

"What're you fellers doin' on our island?" he demanded, with a deepening of his scowl.

"I didn't know the island belonged to you," Mr. Baker returned quietly. "You don't happen to carry a deed to it in your pocket, do you?"

"No, but it's ours, or it belongs to one of us," the angry spokesman replied. "And we don't intend to allow any trespassing."

"We have no desire to do any trespassing," was the response to this veiled threat. "But I want to answer you with a clear statement of our position. We are here with a purpose and we don't intend to be turned aside from that purpose. To get down to brass tacks, three boys, one of them my son, have disappeared under remarkable circumstances from this island, and the indications point directly toward you men as responsible for their disappearance. What your motive is I have no idea, but you may be sure that it will be fathomed, and now that we have you in our power, we don't intend to let you get away from us. We are armed with automatic pistols that shoot like machine guns and one move either toward or from us, contrary to order, will start them barking. Now, my instruction to you is that you drop those clubs and come forward, one at a time, and allow my companion to search you for weapons."

As he spoke, Mr. Baker drew his pistol from one of his trouser pockets, and Cub did likewise. Instantly the scowls disappeared from the faces of the four men and were succeeded by looks suggestive of panic.

"There's no need of any such action by you," said the leader of the invaders with plaintive whine. "We ain't done nothin' out o' the way. We did drive those kids off o' the island, but we didn't hurt 'em. They're all right, and we c'n take you to 'em any time you want to go."

"How could you drive them off of here when they had no boat to go in?" Mr. Baker demanded.

"Oh, we took 'em in our boat and put 'em on another island. If you'll agree to go away from here we'll produce those boys and land you anywhere you want to go."

"Why is it you're so anxious to have us go?" demanded Mr. Baker. "Is there something going on here that you don't want the authorities to know anything about?"

This shot seemed to throw confusion into the ranks of the visitors, judging from the expressions of their countenances. But their spokesman attempted to brush the inference aside as of no consequence to them by answering:

"That's foolish. If you think there's anything bad going on here, just bring on the police and investigate; but we don't intend to have anybody on these islands who hasn't any right here."

"Very well, we'll make a test of the question of rights so there won't be any dispute about it hereafter," said Mr. Baker. "Robert, will you call your friend at Rockport and tell him to send some officers here for four prisoners, but keep your weather eye on these fellows meanwhile and your pistol beside you ready for instant use."

Cub did as directed and soon was dot-and-dashing a thrilling message to Max Handy, who had been waiting apprehensively all this time for an explanation of the island operator's protracted silence.



CHAPTER XXI

The Hostage

Meanwhile the four prisoners held a furtive conference among themselves, and after Cub had finished his telegraphic conversation with the Canadian amateur, the leader of the worthy quartet addressed Mr. Baker as follows:

"Looky here, Mister man, we've decided that we're not going to stay here any longer. You ain't got nothin' on us, and you haven't got any reason to hold us up with those guns. We haven't done nothin' criminal, and we don't intend to be held for crim'nals. We'll tell you where your kids are and ev'rything'll be all right if you keep off o' our islands. We own all these islands here, and we're not goin' to 'low no trespassin'."

"The main trouble with your proposition is that we have no way of knowing whether you're telling the truth," answered Mr. Baker. "Can you tell us where the boys are and then prove that they're there before we let you go?"

"We c'n tell you where they are and you must take our word fer it," was the fellow's reply. "They're over on the first island in that direction, pointing to the southwest. You can't miss it. It's an island about the same size as this one, all by itself. You'll find 'em there if somebody hasn't taken 'em off."

"No, that won't do," replied Mr. Baker. "We can't afford to let you go."

"All right, then, let me tell you something more," said the spokesman of the strange quartet, whose self-confidence and courage seemed to be on the increase. "Do you see that stake there?"—indicating the visible end of a piece of wood similar to a guy-rope stake, that had been driven into the ground at a point midway between the two hostile conferees.

"I see it very plainly," Mr. Baker replied.

"Do you know what it means?"

"I must confess my ignorance."

"Well, I have a surprise for you. There are other stakes driven about a hundred feet apart clear across this island east and west. That is the dividing line between the United States and Canada. You are a Canadian, ain't you?"

"I am."

"Well, that line there means that you are now in Canada and we are in the United States. If you come over here to take us you are invading the United States. If you shoot at us, you are shooting across the border line at citizens of the United States. I defy you to commit any such act."

Mr. Baker was "almost taken off his feet" by the shrewdness of this argument, and for several moments he was unable to make any intelligent reply. Cub also was nonplused at the "international situation". However, the ludicrous element of the affair did not escape them, and presently Mr. Baker was hurling the following heated rejoinder at the spokesman of the unfriendly four:

"Now, see here, my fine fellow, I'm not going to listen to this nonsense any longer. My son has been kidnapped by you scoundrels, and I am a desperate man right now. I am in a mood at this moment to snap my fingers at international lines, if what you say is the truth. I don't care to dispute your word on so flimsy a subject. But here is the only compromise I am willing to make with you. One of you has got to stay here a prisoner until those boys are returned to us. I'm in dead earnest, believe me. If you try to escape, I'll shoot, and if necessary, I'll shoot to kill. Now you come right over here into Canada as quick as ever you know how, for if you don't, in a very few seconds I'm going to begin to shoot. I'm a good shot and my bullets will hit your feet first. Your companions may go and as soon as they bring back those three missing boys you may go, too. Now, come along into Canada. Hurry up, I'm going to count ten, and if you're still over there in the United States contaminating the soil and atmosphere of Uncle Sam with your impudence after I've stopped counting, I'm going to begin to shoot. If I have to bring you over into Canada, you'll come on a stretcher—see? Now I'll begin to count—one, two, three, four, five, six, seven, eight—"

The brave spokesman of the unwelcome visitors collapsed at Number 8 and shuffled rapidly toward the counter with the automatic pistol. His three companions, inspired, no doubt, with an eagerness commensurate with his panic, broke into a run and soon disappeared in the thicket at the rear of the camp.

"You'd better call after your friends and remind them that it's up to them to bring those boys back or your fate hangs by a thread," Mr. Baker advised as he proceeded to examine the fellow's pockets for dangerous weapons.

But the prisoner was either too sullen or too much frightened to respond to any suggestion requiring the exercise of wits. He merely obeyed clear-cut orders and turned a deaf ear to all other utterances on the part of his captors.

"We'd better secure him so that there'll be no chance of his getting away," Cub suggested. "There are some pieces of guy-rope in the tent. I'll get them and we'll fix him in a condition of safety."

Accordingly he went into the tent and a moment later reappeared with two pieces of rope, the strands of which he unplaited and knotted together, end to end, and then tested the knots by straining them across his knee.

"Now, we're ready," he said, addressing the prisoner. "Turn around and put your hands together behind you. There, that's right. I'll try not to be too cruel, but I must tie this rope pretty tight. Holler if it tortures you, but I must be the judge as to whether you can stand it. There, you won't be able to do any mischief with your hands. Now, come on; well go into the tent and take care of your lower extremities, as you know we couldn't afford to let you walk away. We have to hold you for ransom, you know, and the ransom is three healthy, uninjured boys."

The prisoner obeyed without a word, and a few moments later he was tied on the ground in the tent with legs also securely bound.

"Now, I'll proceed to report developments to our radio friend at Rockport," Cub announced as he and Mr. Baker came out in the open again.

With these words he sat down at the table, donned the phone headpiece and began to work the key. He had no difficulty in getting into communication with the Canadian amateur again, and gave him a detailed account of what had taken place since his last report of earlier developments.

"My father is on the way alone in the Catwhisker, bound for Rockport," the boy added after finishing his account of the dispute with the professed owners of the island. "Can you get word to him of what has happened? Tell him to come back with a few armed men as soon as possible."

"I will run down to the docks and meet him," returned Max. "Maybe I will come along."

That ended their code conversation for the time being, and Max started at a brisk pace for the municipal docks.

Meanwhile, Mr. Baker and Cub kept an alert watch over their prisoner and the camp in general to guard against a surprise, for they were not unmindful of the danger of an attempt on the part of the three departed visitors to overthrow the advantage the man and the boy had gained through the instrumentality of two dangerous weapons. But soon they found time dragging heavily on their hands, so that it is no wonder that before long they began to cast about them for something to do that would add to the small degree of hopefulness of their situation.

"Let's bring that fellow out here and see what we can get out of him," Cub proposed at last. "Maybe we can induce him to tell us something,"

"All right," Mr. Baker replied; "but we must not forget to keep a sharp lookout while we're quizzing him."

"You go in and bring him out, and I'll keep watch to prevent a surprise," Cub proposed.

This being agreeable to Mr. Baker, the plan was soon put into effect. The rope strands around the prisoner's ankles were removed and he was led out into the open. True to his resolve not to be caught napping, Cub now kept on the move and on the alert, describing a small circle around the position of the two men who were seated on camp chairs about twenty feet from the tent.

"I've brought you out here for a sociable chat," Mr. Baker explained, while Cub gave close attention in order that he might not lose a word. "I hope you'll be as sociable as I shall try to be, for if you're not, I shall have to take you back into the tent and shackle your feet again."

The fellow did not reply, although his silence could hardly be attributed to a spirit of sullenness.

"Maybe you'll tell me a little more than you were willing to tell me in the presence of your friends," Mr. Baker continued. "I'd like to know something about the business and associations of you and your friends, so that we may know how to treat your demands. Now, rest assured that none of us has any desire to do any illegal trespassing, and as soon as you've proved to us that you own this island and that we are unwelcome on these premises, we'll get off and beg your pardon for our intrusion. But you don't seem to have established any camp here and you don't seem to be able to produce as much evidence of ownership as we can."

Mr. Baker now waited a few moments for a response to his introductory statement, but none came. The fellow seemed to be almost embarrassed by the straightforward and well connected ideas of the man who addressed him.

"Well, let's see," Mr. Baker continued. "How can I present the matter so as to start you out right? Perhaps you will be willing to tell me who you are and what your business is. But first. I'll be fair and introduce myself. My Name is James C. Baker. I live in Port Hope, and my business is that of hay, grain and feed merchant. Now, will you tell me your name? One of your friends called you Captain. Do you run a boat on the river?"

Whether the fellow was about to reply or would continue in stubborn silence may not be known, for the thus-far-one-sided conversation was suddenly interrupted by a shout of eager joy from the pacing boy sentinel.

"Oh, there they come, there they come," the latter shouted. "There are Hal and Bud."

Sure enough, two boys had just emerged from the narrow belt of bushes between the camp area and the only practical landing place of the island.