The Radio Detectives

awlins heard them, and the only means of determining if he had received all the words was to keep a record for comparison when he came up. They were busily engaged at this and

. "I just rang up to be sure you w

n, we're just testing it out for th

lled up, but the maid said you were out with Tom. Didn't she tell you

d is coming down," said Tom, "Won't he be interested

pted talk, or attempt to talk, with Rawlins until,

ything. Say, I was just crazy to get back when I got your letter telling about your experiments and everything. Where's the diver fell

to come up and tell. You see we haven't got an under-sea sending set rigged

ore of that mystery chap?" cried H

d," Tom as

rd him last night and I got him again to-day just before

funny!" exclaimed Fran

ingo that I couldn't make out, but I got one word. Bet you

tten their under-water companion until Henry uttered a half surprised excla

at a gurgling splash he glanced through the trapdoor and saw the di

lins was removing h

ed Tom the moment Rawl

deaf,-yelling like that. Did you think you had to shout loud enough to have your voice go through the water? And I'

ah! It works! It's a success! We've solved it!

awlins. "But what the deuce wer

led tone. "We weren't talking Dut

he asked. "I heard some one jabbering Dutch or some other foreign

y. "I'll bet 'twas. He was talking just before I rang up as I tol

ason why he shouldn't have been heard under water. We're using a tiny little wave leng

n, "but if I'd understood his lingo I could have told what he was talking ab

nry ungrammatically. "That's the n

no," declared Tom. "Now let's get busy and fix it

would be able to hear sounds or that he might even distinguish words under water, but they had not dared to hope that their very first efforts would result

e short five watt waves in this way, think what it would mean to a submarine with big amplified sets and getting messages

ds from the dock and it's shoal water. I'm anxious to try it down a hundred feet or so and a mile or two from the sender.

e other tubes, and we get a detector and amplifier all in one. Look here-it's the smallest bulb you ever saw-about the size of a peanut and we operate it on a flashlight battery with a special little dry cell for the filament. Of course they don't last long, but a fellow can't stay down more than an hour or two anyway and the batteries will run the

g Henry the set and pointing

f his normal wave length, or for longer waves he turns it to the right and gets twice his normal length. If he wants to go to long wave lengths-for example, if he was a spy or something and wanted to get the big sending stations-he'd turn the knob clear to the left and then back to

do for an a?rial

m his helmet, like a loop, but made of two grids set at right angles to each

et on to this radio a little bit. When you get that sending outfit rigged you'll have to go down and test it. I'd probably bungle something. I didn't even dare

oves we can tune out under water," declared Tom

usied himself devising the fittings for his suit to accommodate the sending apparatus and helped the boys tr

set were well worked out and, with high hopes and flushed with the success of their achi

d they had all their time to themselves. Rawlins was already there and before they left that night t

lf as soon as the instruments were perfected. He listened to the boys' glowing accounts of their work and thei

have to thank the Huns for that. We found one on a captured U-boat, but as far as I know the government never took it up seriously-don't know why unless it was because there was no particular need of it. We never did find out what the Germans used it for-for all we know

d, out of pure curiosity and never expecting to hear anything, Tom turned his loop a?rial to the southeast and tuned for the short wave lengths used

nk who was listening to a broadcasted spe

the man plainly his words were meaningless, for h

r a few minutes of this. "Who cares what he'

and forgot all about the incident in his interest as

chuckled Frank as the talk ceased and the boys laid aside their receivers. "Say, won't

ng set works isn't any proof the sending set will. And without being able to talk back a dive

sanguine expectations had led them to think possible. To be sure, their experiments came to an abrupt ending right in the midst

and Henry in the shop had also heard him, the boys knew that their plans and the principles of the outfi

ow how to accomplish their aims. "You say these wireless waves go through everything and we get them through the suit in the receivin

his plan of a new suit in which the sending set could

t's easy enough to make watertight fittings where the wires come out and there's no tuning to do, We can always use a special wave length

they wished to make a test to determine if two men under water could converse

," he remarked as he worked. "But I see where that's an advantage. One of your troubles has been t

ngs a leak?" queried Frank. "We'

s you can, they'd still go on working for some time before they got soaked. And if I can't make a little c

when, after a test in the workshop, everything seemed in perfect working order, Tom a

m spoke into his mouthpiece and Frank, listening at his instrum

had expected would sound muffled. "Keep your ear glued to the s

surface of the water, and little did he or the others dream how much truth was in h