As the Sleuth drew nearer, the boys made out the masts and hull of a trim-looking schooner,

  anchored for the night off one of the islets.

  "Nice lines," commented Joe. "Pass close to her, will you, Frank?"

  Quietly, with her engine throttled down, the motorboat drew abreast of the larger vessel. It

  was now dusk and a light shone in her cabin from which came the sound of activity. Frank

  gazed in admiration at the tall masts and shipshape rigging-Suddenly Joe's fingers clutched his brother's shoulder. "Look! On the deck!"

  As the Sleuth passed the schooner, Frank caught a quick glimpse of the figure of a boy leaning over the rail.

  Joe cried out, "That was Chet!"

  CHAPTER X

  A Narrow Escape

  "IT'S either Chet or his double!" Joe exclaimed. "But I'm sure my eyes weren't playing tricks."

  "Do you suppose he's a prisoner on that schooner?" Frank asked. "Well, we'll soon find out!"

  He turned the wheel sharply and the Sleuth swung about. It circled close to the anchored

  vessel.

  "Chet!" cried Joe, making a trumpet of his hands. "Chet Morton! It's Frank and Joe! Are you all right?"

  "Che-e-t!" both boys yelled together. "Che-e-t Mo-or-ton!"

  A momentary hush followed, as the Hardys paused for breath. All sounds of activity aboard the

  schooner ceased. Abruptly a burly sailor in white duck trousers appeared on deck.

  "What's all the holler?" he barked. "Clear out of here, or you'll get in plenty of trouble!"

  As Joe stood up to retort, Frank yanked him down again. "We should go!" he whispered. "Let him think he scared us off."

  The Sleuth's engine roared louder, and the boat moved along the shore of the island until the

  white sails were out of sight.

  "It'll be black night out here in half an hour," Frank explained. "Then we'll go back and see what's up."

  Daylight faded away, leaving in its place broadly sprinkled stars. A calm ocean swayed their

  boat gently.

  Rocks along the shore humped up, massive shapes in the darkness.

  "Now!" Frank said softly.

  Joe took the wheel and throttled the smooth-running engine so low that its sound was only a

  faint hum.

  Keeping as close to shore as possible, the Sleuth crept toward the anchored schooner.

  When the vessel loomed just ahead, Joe cut the throttle completely and the motorboat glided

  noiselessly under her stern. Frank, holding out his hands to ward off the hull, suddenly felt

  rough fibers.

  "A rope ladder!" he whispered. "I'm going up!"

  "I'll follow," said Joe.

  After securing their own boat with a loose hitch, Frank cautiously drew his body upward, rung

  by rung.

  Joe was right behind him. Frank slipped underneath the rail and crawled along the empty deck.

  Joe reached the top of the ladder and stepped forward. Suddenly, from out of the darkness,

  two powerful arms seized him in a viselike grip, and a man's sandpaper voice called out: "Here!

  I caught one of them!"

  Joe tensed in surprise, then spun around, breaking the grip. He ducked. With all his strength he drove upward, his head hitting the midsection of his attacker like a battering ram.

  As the man fell back, gasping, Joe leaped to his feet. "Frank!" he cried hoarsely. There was no reply, but a wild clamor rose from the fore part of the deck.

  "Here he is!" someone cried out.

  "No, here!" another rasped.

  "That's me, you fool!"

  Someone began ringing the deck bell. There came the shuffle of running feet and the grunting

  of men short of breath.

  Then Frank's clear voice sang out, "No use, Joe! Overboard!"

  Both boys vaulted the rail. As Joe hit the water, another geyser of spray rose several feet from him. The Hardys popped to the surface, then disappeared under the dark water again.

  "Harbor thieves!" came shouts from the deck. "Get them!" The bell clanged on. There were two sudden bursts of light, accompanied by sharp explosions. Someone was shooting wildly!

  Frank and Joe surfaced near the rope ladder and quickly untied the Sleuth. Swimming with

  swift, silent

  strokes they pushed their craft away from the schooner into the protecting darkness.

  "Whew!" breathed Joe as he tumbled, panting, into the motorboat. "They must have been on deck, watching."

  "Anyhow, I found out what we wanted to know," Frank reported. "That wasn't Chet, but a boy who looks a lot like him."

  "How do you know?"

  "He tackled me. I said, 'Chet, it's Frank!' but he hung on tightly. That's when I yelled for you to go over the side."

  Joe started the motor and opened the throttle all the way. As the Sleuth gained power, the

  prow lifted and the boat leaped forward. Safely away from the yacht, Joe switched on the

  running lights. Along the shore, they could see a solitary light here and there. Presently the bright glow of beach fires told them they were passing Shantytown.

  "No more stops tonight," Frank said with a chuckle.

  The Sleuth crossed the quiet expanse of Bayport harbor and finally entered their boathouse.

  Twenty minutes later they reached the Hardy house. Their mother and aunt were anxiously

  waiting.

  "Goodness gracious!" scolded Aunt Gertrude. "Is this a time to come home-" She stopped and gasped.

  "Oh! Look at them! Soaking wet-like a pair of drowned rats!"

  "We're almost dry, Auntie," Joe replied with a laugh. "We fell in over an hour ago."

  "Fell in!" their mother exclaimed. "We can't wait to hear! But first you'd better go upstairs and change, then have some supper."

  Soon Frank and Joe, comfortable in fresh, dry clothes, were seated at the kitchen table before a late but steaming dinner.

  "Where's Dad?" Frank asked.

  "He left town this afternoon," Mrs. Hardy replied. "He's checking an out-of-state clue on the bank robbery. Now tell us what happened to you boys."

  "Well, we thought we saw Chet on a schooner," Frank began, as he cut into a generous slice of roast beef.

  "Only it wasn't Chet . . ." Joe said, and helped himself to a baked potato.

  "They thought we were thieves . . ." Frank tried again.

  "So we jumped overboard!" Joe added.

  "A very clear account," Aunt Gertrude commented tartly.

  As soon as the brothers finished eating they excused themselves, jumped up, and headed for

  the back door.

  "Oh, no!" cried Aunt Gertrude in alarm. "Where are you off to now?"

  "Just out to the laboratory, Auntie," Frank reassured her. "We found something today we must work on."

  The boys ran up the garage stairs and Joe unlocked the door at the top. Frank switched on the

  fluorescent light over a clean table. On it he laid the cheesecloth bundle of glass fragments

  from the Sleuth.

  "We'll need something to hold these together," he noted, unwrapping the green shards. As the brothers examined them, Frank reached for a container of putty. "This will be better than glue."

  Treating the fragments like pieces in a jigsaw puzzle, the young sleuths rebuilt a twelve-ounce, green-tinted pop bottle.

  "Fizzle," Joe read from the raised glass letters. "Fizzle-where-"

  "Harry's confectionery in Northport!" Frank broke in excitedly. "The owner said that the bald man bought several bottles of Fizzle!"

  "You mean he might have been the one who left the broken glass in the Sleuth?"

  "Yes! Not only that-he might have done it while helping to steal our boat."

  "Wait a minute!" Joe's thoughts raced as he followed his brother's line of deduction. "If that's true, he could be one of the bank robbers! They stole a car in Northport!"

  "And don't forget the postcard business, which may tie him in with the kidnaping of Chet and Biff!"

  Joe nodded. "Then there's Ben Stark, the pilot of the Black Cat, which by the way, came down from Northport the day of the bank robbery. Is he linked with both cases? And is his pal Sutton?

  And where do the fights at Shantytown fit in?"

  "That's for us to find out," Frank said determinedly. "Especially since the answer might lead us to Chet and Biff. We're pretty sure they were in Shantytown-since we found Chet's gorilla mask off the coast there, and his sleeve was picked up behind Sutton's shack."

  The excitement suddenly faded from Joe's face. "Maybe our hunches are on the wrong track.

  After all, Fizzle could be sold in other places besides Northport-and we have no proof the bald guy left the bottle in the Sleuth"

  "Don't be a pessimist," Frank begged. "Remember what Dad says: 'Persistence is just as important as cleverness in detective work.' "

  "Yes, and a little luck helps, too. Don't worry. It's just that we have so many mysteries to solve.

  Which one do we tackle next?" The ringing of (the telephone interrupted. Frank answered.

  "Glad to find you home," came Chief Collig's familiar voice. "Maybe you can help me. We have a man down here-been brought in for stealing. He seems to think you and Joe can clear him."

  "Joe and I?" repeated Frank, astonished. "Why . . . what's his name? What does he look like?"

  "He's a big, strong fellow-a stevedore. Calls himself Alt"

  CHAPTER XI

  Midnight Caller

  "ALF Lundborg a thief!" Frank exclaimed. "I can't believe it! We'll be right down, Chief Collig,"

  he promised.

  "I don't buy it," Joe said flatly as they started out. "What's the pitch?"

  Frank shrugged and hurried off to inform his mother of the errand, while Joe locked the

  laboratory. Then the brothers rushed downtown on their motorcycles to Chief Collig's office.

  "Where's Alf?" asked Joe, looking around as he entered.

  "We're holding him in a cell until I talk to you boys," the officer explained.

  "He's the man we told you about yesterday," Frank reminded the chief. "The one who helped us in Shantytown. If it hadn't been for him, Sutton would have cracked my skull with a

  blackjack."

  "I remember," the chief replied. "Sutton's the cause of his arrest." Before the surprised boys could speak, he added, "I'll let Lundborg tell you himself." Over his intercom he ordered the suspect brought in.

  "I don't believe Alf's a thief," Frank said.

  "But he does have a record for petty theft and disturbing the peace," Chief Collig said soberly.

  "That makes it look bad for him."

  "How long ago was that?" Joe asked.

  "Alf's last brush with the law was five years ago," Collig replied. "He claims he was just a wild kid at the time."

  The door opened and Alf stood on the threshold. His giant frame almost hid the sergeant

  behind him.

  When he saw the Hardys, his troubled face lighted up instantly.

  "I knew you fellows wouldn't let me down," he burst out. "Tell the chief I didn't take it!"

  "Take what, Alf?" said Frank.

  "The police found a transistor radio in my knapsack," the big man explained, "but I didn't put it there!"

  "Sutton reported it stolen," the officer said. "We sent out Lieutenant Daley to investigate, and he found it in Lundborg's bag."

  "Is Lieutenant Daley still here?" Frank asked. "Would you have him come in?" Collig nodded.

  A few minutes later a tall, thin-faced officer entered. He and the Hardys had known one

  another for years and exchanged greetings. "Lieutenant Daley," Frank said, "when you were hunting for the radio who suggested that you look in Alf's knapsack?"

  "Sutton," the officer answered.

  Frank nodded. "It looks like a plant, Chief."

  "Sure it is," Joe declared. "Alf scared Sutton off when he attacked Frank. He probably planted the radio to get even."

  "That's right! That's just what I told them!" Alf boomed. "Thanks a lot for sticking by me, fellows. I'll get Sutton!"

  "Hold on there!" commanded Chief Collig. "You'll be back here for assault if you try that. Since the Hardys back up your story, I'll let you go. But if Sutton prosecutes, we'll have to bring you in again."

  "Okay." Alf wrung the boys' hands, thanked them, and left.

  Frank pointed to a radio on Collig's desk and asked, "Is this the stolen property?"

  "That's it," Lieutenant Daley spoke up.

  "Take a look," the chief invited, and Frank picked up the compact, heavy little set.

  "Japanese make. Yokohama Super-X."

  "Let's see," Joe requested. He gave a low whistle as his brother passed it to him. "What a little beauty!

  Brand new, too. Look at that nickel-and-ivory case!"

  "It's an expensive, rare set," Lieutenant Daley commented. "Not many people can afford one."

  "That's true," Frank said. "Hank Sutton seems to be just a seedy-looking character who lives in Shantytown. But Joe and I have a hunch as to how he could afford a radio like this."

  "You mean he stole it?" Chief Collig asked.

  "We think he belongs to a ring of thieves," Frank told him. "If they fight among themselves, it would explain the trouble in Shantytown."

  Lieutenant Daley looked doubtful. "If Sutton stole the radio, why would he plant it on Alf? That would only call the attention of the police to himself."

  Frank grinned. "If you'd seen Sutton go after me, you'd know he acts first and thinks later."

  "Then he's probably regretting Lundborg's arrest right now," Lieutenant Daley returned.

  "That's not all he'll regret," Joe promised grimly, "if he's had anything to do with Chet and Biff's disappearance."

  "That reminds me," the chief said. "The boys' parents received postcards from Northport, too.

  We're looking for the bald, loud-voiced man you told me about, but that isn't much to go on."

  "No," Frank admitted, "but we're working on a new clue." He told of the discovery of the Fizzle soda bottle and the purchase of a similar one by the bald-headed man in Northport. "That's why we think he's connected with stealing the Sleuth as well as Chet and Biff's disappearance."

  "Then," Joe put in, "we learned that the dock manager up there owns the Black Cat and rented it the day of the bank robbery to the bald fellow and Ben Stark-the one we saw talking to Hank Sutton in Shantytown."

  Chief Collig looked at the boys keenly. "I see what you're driving at-that Sutton may be more than a petty thief-he and the other two might be involved in the robbery!"

  As Lieutenant Daley stared at the Hardys in amazement, Frank replied, "You're right, Chief. But we have no solid evidence yet to back up our hunch. Joe and I will check stores in town

  tomorrow to see where the radio came from."

  "Good. We'll do some checking of our own too. Thanks, Frank and Joe, for coming down."

  When the Hardys reached home, their house was dark. They let themselves in quietly, went to

  bed, and fell asleep at once.

  Some time later Joe was awakened by a noise. He sat up, listening. It came again-a soft

  knocking.

  "Frank!" he whispered, shaking his brother. "Someone's at the front door."

  Instantly Frank was awake. The boys hurried downstairs. As the gentle knocking began again,

  Frank switched on the porch light. Joe swung open the front door. Before them stood a tall,

  thin, worried-looking man.

  "Mr. French!" cried Joe in surprise.

  The costume dealer's mouth dropped open in astonishment. "You-you're not-you're here!" he stammered incoherently.

  "Yes, of course, we are," Frank responded. "Why are you so surprised to see us?"

  "Why-ah-I'm terribly sorry, boys!" Mr. French looked nervously over his shoulder. "I-I see I've come to the wrong street-looking for High Avenue, and this must be High Street. So sorry! Good night!"

  The tall man hurried down the steps to a car at the curb and drove away.

  Joe turned to his brother. "There isn't any High Avenue in Bayport. Mr. French must know that.

  He's been in business here for years."

  As Frank closed the door, they heard footsteps at the top of the stairs and their mother's voice asked softly, "What is it, Gertrude?"

  "Burglars!" hissed their aunt. "I heard them talking." She called down in a loud but shaky voice,

  "The police are coming! Go or I'll call my nephews! Frank! Joe!"

  "We're down here, Auntie!" Frank informed her, stifling a laugh. "There are no burglars."

  After a second's pause there came a weak "Well!" followed by "Humph! I might have known!"

  "What's the matter, boys?" Mrs. Hardy asked.

  "Someone here who said he had the wrong street," Joe told her, and switched off the porch light.

  The next morning the boys ate an early breakfast. Afterward, Frank suggested, "Let's try all the appliance stores to see if Sutton did buy the Super-X radio. We can see Mr. French later."

  Joe agreed and they set off. They went from shop to shop, but the story was always the same:

  The merchants did not stock the Yokohama Super-X radio-it was too costly to sell many sets. At last, however, a young clerk in a hi-fi equipment store said, "Yes, we have them. I'll be glad to show you

  one."

  "We're not here to buy," Frank said. "We just want to know if you've sold any recently."

  "No," the disappointed clerk admitted. "We don't sell many. We thought we would-despite the high price-because the Super-X transistor has so many extra features-FM, short wave-name it!"

  "Where do you get them?" Joe asked.

  "We import directly from the Yokohama Radio Company's distributors in Japan. The radios

  come in by ship and are unloaded on the Bayport docks."

  "Have you missed any from your stock lately?" Frank queried.

  The clerk looked surprised, but answered readily, "No, but we were short one crate on the last shipment.

  My boss wrote to the distributor in Japan about it, but there hasn't been time for a reply yet."

  The boys thanked the youth and returned to the street. They wondered about the clerk's