been talking, I’ll bet.”

Tom hesitated, but in a moment his mind was made up.

“I suppose we might just as well tell you,” he said at last. “But it’s a secret and you’ll have to promise not to tell any one else.”

Henry readily agreed and Tom and Frank told him all they knew and what they suspected.

“Whew!” ejaculated Henry. “I shouldn’t be surprised if you’re right. I couldn’t see any sense to all that talk about boats and the West Indies and numbers, but I can now. I’ll bet those numbers were places out at sea—fifteen seconds west—and ‘Azalia’ may be the name of the ship. Say, won’t it be bully if we can find out something—radio detectives—Gee, that’s great!”

“Well, go on and call up Fleming,” said Frank. “Tell him to come over here.”

“He’s on the way now,” Henry announced when he returned to the room. “Are you fellows going to let him in on the bootlegger stuff?”

“Better not,” advised Tom. “If he’s heard the fellow talking we can tell him we’re just anxious to locate him. We can make a mystery out of not hearing the person that was talking back, you know.”

“It’s a mystery all right enough,” put in Frank. “If that other chap can hear him, why can’t we? There’s something mighty queer about it.”

“Search me,” replied Tom laconically. “Maybe he talks on a different wave length.”

“I never thought of that,” admitted Frank. “Say, next time they’re talking one of us will listen while the other tunes to try and pick up the other man.”

“And perhaps he’s in a different direction,” suggested Henry. “If he is of course we wouldn’t hear him with our loops pointed towards this fellow.”

“Of course!” agreed Tom. “We have been boobs. Just as like as not the one we didn’t hear is over to the west or the north and we were all listening to the southeast. Say, you’ve got sense, old man. Next time we hear this chap we’ll nab the other one, I bet. Hello! There’s the bell.”

Henry hurried from the room and returned presently, accompanied by another boy whom he introduced as Jim Fleming. Jim was undersized and round-shouldered with damp, reddish hair and big blue eyes behind horn-rimmed glasses. He had a most disconcerting manner of staring at one and constantly blinking and gulping—like a dying fish Frank declared later—and his hands and wrists

seemed far too long for his sleeves. He was such a queer, gawky-looking chap that the boys could scarcely resist laughing, but before they had talked with him five minutes they had taken a great fancy to him and found he knew a lot about radio.

While the boys told him of their interest in the strange conversations, he stood listening, his long arms dangling at his sides, his big eyes blinking and his half-open mouth gulping spasmodically until Tom became absolutely fascinated watching him.

Mentally, Frank and Tom had dubbed him a “freak,” a “simp,” a “bookworm” and half a dozen far from complimentary names and they had expected to hear him speak “like a professor,” as Tom would have expressed it. Instead he uttered a yell like a wild Indian, danced an impromptu jig and to the boys’ amazement exclaimed:

“Hully Gee! So youse’s onto that boid too! Say, fellers, isn’t he the candy kid though? Spielin’ on that flapper wave an’ cannin’ his gab if youse ask his call. Say, that boid oughter be up to the flooey ward—he’s bughouse I’ll say, with all his ship talk and numbers jazzed up an’ chinnin’

to himself. Say, did youse ever hear a bloke talkin’ to him?”

“No, we never did,” replied Tom. “Did you?”

“Nix!” answered Jim. “That’s why I say he’s got rats in his garret—flooey I’ll say—” Then, suddenly dropping his slangy East Side expressions, he continued: “Say, he’s had me guessing, too. But I can tell you one thing. He’s west of my place—I’m over at Bellevue, you know—Dad’s stationed there—and that’ll bring him somewhere between East 27th St. and Gramercy Square.”

“But, how on earth do you know that?” queried Tom in surprise.

Jim grinned and blinked.

“Same way you found out he was east of here,” he replied. “You needn’t think you fellows have got any patent on a loop, I’ve been usin’ one for six months. Ed—he’s my brother—is ‘Sparks’ on a big liner and showed me about it. But honest, if that fellow isn’t crazy an’ talkin’ to himself, why don’t we get the other guy sometimes?”

“That’s the mystery to us,” said Frank. “We decided just before you came in that the other fellow must be sending on a different wave length

or else was in some other direction. We were just planning to pick him up by one of us tuning and turning the loop while the others listened to this fellow, but if you hear this man west of your place that knocks one of our theories out. If the other chap was west you’d get him, too.”

“Yep, and ’tisn’t because he’s on a different length,” declared Jim. “Hully Gee, I’ve tuned everywhere from 1500 meters down trying to get him, and nothin’ doin’.”

“Didn’t you ever hear a funny sound like talking through a comb with paper on it?” asked Henry.

“Sure, sometimes I do,” admitted Jim, “but you can’t bring it in as chatter—I put it down to induction or somethin’—but Gee, come to think of it, it always does come in just right between this looney’s sentences.”

“I’ll bet ’tis the other fellow,” declared Henry. “Only if ’tis he’s got an awful wheeze in his throat or his transmitter’s cracked.”

“Well, let’s drop that and plan how we can locate this fellow we do hear,” suggested Frank.

“Yes, now we know he’s between your place and

here we ought to find some place where we can set up a loop to the north and south,” said Tom.

“Sure, we can fix that,” declared Jim. “I’ve got a cousin that lives over on 23d St. and there’s a good scout named Lathrop over on 26th. We can take sets to their places and put ’em up. They haven’t anything but crystal sets, and most likely they’ll know other guys and by trying out at different places we can spot his hangout all right. But say, what are you fellows so keen about findin’ him for?”

“Oh, nothing except the fun of it,” replied Tom, trying to act and speak in a casual manner. “You see we’re just experimenting to find out what we can do with loop aërials—call ourselves radio detectives—and we picked on this fellow because his messages seemed sort of mysterious and are so easily recognized.”

“Yea, I understand,” said Jim. “Say that’s a lulu of an idea—radio detectives. Well, I’ll bet we can detect this bughousey guy O. K.”

It was soon arranged that Jim was to see his cousin and that one of the boys’ loops would be set up in his home the following evening and that,

while Jim and Frank listened there, Henry and Tom would be at their sets and would call out as soon as they heard the messages from the mysterious speaker. All was arranged, but to the boys’ intense chagrin not a sound came to any of them which remotely resembled the well-known voice and short wave lengths of the man they were striving to locate. But they were not discouraged, for they knew from past experience that they could not expect to hear him every night.

The following day was Saturday and the boys devoted their holiday to putting up a set in Lathrop’s home. They now had four loop aërial sets ready to receive and located within a comparatively small area. They were sure that the station they were trying to find was within the few blocks between 20th and 27th Sts., but they were not at all sure whether it would be found to the east or west of Third Avenue. Moreover, as Jim pointed