“Not much like last summer, is it, Jack?”

“Not much, Frank.”

“No Mexican bandits. No Chinese bad men. No dens in Chinatown. Say, Jack, remember how you felt when we were licked in our attempt to escape from that dive out in San Francisco? Boy, that was the time when things looked mighty blue. Jack?”

No answer.

“Jack?” In a louder tone.

Still no answer.

Frank turned around impatiently from where he lounged in the open doorway of the radio station, and faced his chum at the receiver.

“Oh, listening-in,” he exclaimed, and fell silent. Facing about, he gazed southward to where, less than a mile away, sparkled in the bright July sunshine the clear waters of the open Atlantic.

Frank Merrick was thinking of the adventures crowded into the lives of himself and his two chums, 4 Jack Hampton and Bob Temple, during their summer vacation the previous year. All three boys were sons of wealthy parents and lived on country estates at the far end of Long Island. Jack’s mother was dead. Frank who was an orphan, lived with the Temples. All had attended Harrington Hall Military Academy, but Jack, a year older and a class ahead of his chums, had graduated the previous spring and already had spent his Freshman year at Yale.

The previous year Jack had gone to New Mexico with his father, an engineer, who was then superintendent in charge of field operations of a syndicate of independent oil operators. Mr. Hampton had been captured by Mexican rebels, and rescued by the boys, for Frank and Bob with Mr. Temple had joined Jack after his father’s loss. Later Mr. Temple had taken the boys on to San Francisco with him, and there they had become involved in the plottings of a gang of Chinese and white men, smuggling coolies into the country in violation of the Exclusion Act.

It is not to be wondered at that Frank, dreaming of those adventurous days as he lounged in the doorway, felt a twinge of regret at what promised to be a dull vacation by comparison.

It was true, he thought, they had everything to 5 make them happy and keep them interested, however. Here was the powerful radio station built by Mr. Hampton under government license to use an 1,800 meter wave length, for purposes of trans-oceanic experiment. Then, too, Frank and Bob jointly owned a powerful all-metal plane, equipped with radio, and adapted for land or water flying. Besides, there was the new and powerful speed boat bought for the three of them this summer by Mr. Hampton and Mr. Temple.

And their homes were admirably located for vacationing, too. On the far end of Long Island, miles from another human habitation, with dense woods, miles of lonely beach, and the open sea—all at their command. Well, Frank thought, after all it might not be so exciting a summer as the last, yet the three of them ought to be able to have a pretty good time.

An exclamation of anger from Jack caused Frank to face about. His chum had taken the receiver from his head.

“That interference again?” asked Frank.

“Yes,” replied Jack, rising and joining his chum in the doorway. “Oh, there comes Bob,” he added, pointing to a tall, broad figure swinging over the top of a low sandhill from the beach.

Frank’s glance followed in the direction Jack indicated. Although Bob was still distant there was 6 a purposefulness about his stride and about the way he waved a response to their greetings that caught his chum’s attention.

“Bob’s got something on his mind,” he said, with conviction. “Wonder what it is?”

“Maybe, he found something, hiking along the beach.”

“Maybe, he did,” agreed Frank. “I didn’t feel like hitting it up with him this morning, felt kind of lazy, as if I had spring fever. It would be just my luck to have him make a discovery on the one morning I wasn’t along with him.”

Bob’s figure disappeared in a fold in the sandhills, and Frank remembering Jack’s disgust over interference in the radio receivers, began to question him about it while waiting for Bob to arrive.

“What was it like this time, Jack?” he asked.

“Just the same, only worse,” answered Jack. “Tune up to 1,375 meters for receiving and then comes that snarling, whining, shrieking sound. It’s steady, too. If it were dot and dash stuff, I might be able to make something out of it. But somebody somewhere is sending a continuous wave, at a meter length, too, that is practically never used. From 1,100 meters to 1,400 meters, you know, is reserved and unused wave territory.”

“I wonder what it can be,” said Frank. 7

Bob by now had approached within calling distance, and he was so excited that he began to run.

“What’s the matter?” called Frank.

“Somebody chasing you?” asked Jack, as the big fellow ploughed through the sand and halted before them.

Bob grinned tantalizingly.

“What would you give to know?”

“At him, boys. At him,” cried Jack, making a flying tackle.

His arms closed about Bob’s waist. At the same time, Frank who had been standing to one side, dived in. His grip tightened about Bob’s legs below the knees. All three lads rolled over in the sand in a laughing, struggling heap. Presently, Jack and Frank bestrode the form of their big chum and Frank, who sat on his chest, gripped Bob’s crisply curling hair.

“Now will you tell?” he demanded in mock ferocity. “If you don’t––”

“All right, you big bully,” answered Bob. “Why don’t you pick on a fellow your size?”

With which remark, he gave a mighty heave—as Frank afterwards described it “like a whale with a tummyache”—and Frank and Jack went sprawling. Then he stood upright, brushing the sand from his khaki walking clothes. 8

“Oh, is that you down there?” he asked. “Why, where did you come from?”

Then, as Frank made a clutch for his ankle, he brushed him aside and sat down on the sand:

“Say, listen, cut out the fooling. I’ve got something to tell you fellows.”

Bob was so plainly excited that his chums were impressed. Scrambling up they seated themselves beside him.

“Fire away,” said Jack.

“What would you say to my finding the tracks of a peg-legged man coming up out of the sea, crossing the sands of Starfish Cove and disappearing into the trees beyond there?”

The inlet which Bob thus referred to was some three miles distant, with a patch of timber some twenty yards back from the water and a ring of low sandhills behind the woods.

“A peg-legged man?” said Frank. “That certainly sounds piratical. Go on. Your imagination is working well to-day.”

“Did he arrive in a boat?” asked Jack.

Bob nodded.

“Yes. I found where the boat had been run up on the sand. But—he didn’t leave. The boat went away without him. He disappeared inland, and there were no tracks marking his return.” 9

Jack whistled.

“Whew. Did you follow?”

“Did I follow? Huh. You can just bet I did follow. And, say, fellows––”

“What?”

“I know now where that strange interference in our radio receivers comes from.”

“Is that so?” demanded Jack, excitedly. “It was cutting up didoes just a few minutes ago, just before you arrived. Had been for some time, too.”

“Well,” said Bob, “that’s not to be wondered at. For when I followed Peg Leg’s tracks through the trees I discovered a radio station tucked away in a hollow behind the timber, with sandhills hiding it on the landward side. I watched for a while from behind a tree, but couldn’t see anybody. Then I hustled here to tell you fellows about it.”

Puzzled, the trio regarded each other in silence. Presently Jack spoke.

“Look here, fellows. There’s something queer about this. A mysterious radio station, hidden away, that sends a continuous wave on a hitherto unused wave length. This has been going on for a week. What does it mean? Then there is this man, this Peg Leg, whom Bob discovers arriving from the sea.”

“Let’s go together and investigate,” cried Frank, jumping to his feet. 10

“I’m with you,” declared Bob, also arising. “I would have gone up to the station and done that very thing, by myself, but—I don’t know—there was something about it all—something sinister.”

“Wait a minute, you fellows,” said Jack, also springing upright. “We can’t go putting our heads into trouble recklessly. Bob’s good sense prompted him when he refrained from pushing up to that radio station by himself. There is something sinister about this. That place is isolated, there are no roads near it, nobody ever hikes along that beach except us. How did the station ever come to be built? Why, the material and supplies must have been brought by boat. They couldn’t have been transported overland very well.”

“What shall we do, though, Jack?” asked Frank, impatiently. “You can’t reasonably expect to have a thing like this rubbed under our noses without our going ahead and investigating.”

There was so much plaintiveness in his voice, as of a child from whom a toy was being withheld, that Bob and Jack both burst into laughter. Then Jack sobered.

“Tell you what I think,” he said. “It’s only mid-afternoon. Let’s get out your plane, and take a look at this place from the air.”

“I guess the old boat is working all right now,” 11 said Frank. “How about it, Bob? You know we haven’t been up for two or three weeks, Jack. Bob’s been tinkering with it. When I last saw him at work, he seemed to have the engine entirely dismantled. Looked to me as if he had enough parts for three planes. Did you get it together again, Bob?”

“Yes,” said Bob. “And she’ll fly now, boy, believe me. Well, come on,” he added, starting for the hangar, not far distant but out of sight behind the sandhills.

The others followed.