“That’s the name he was using when I heard him.”
“Well, it just proves this new thing is a peacherino,” declared Tom. “Now let’s get busy and fix it up in good shape and make a sending set to try out.”
Now that the boys’ first experiment had been such a huge success they were more enthusiastic and excited than ever. They had been confident that the diver 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 in the sound being carried to the ears of the man beneath the water as clearly and loudly as though he had been present in the same room with the speaker.
“I’ll bet water carries electromagnetic waves better than air,” declared Tom. “Why, if this little set can respond to these short five watt waves in this way, think what it would mean to a submarine with big amplified sets and getting messages sent with hundreds of watts. Why a fellow could sit in Washington and talk to submarines and divers all over the Atlantic.”
“You’ve hit on a wonderful possibility,” Rawlins assured him. “Of course I was pretty close—I didn’t go over a hundred yards 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. We’ll do that after we get things right—go down to my hangout in the Bahamas and give it a real honest-to-goodness tryout.”
“It’s all in that new amplifying arrangement and that single control tuner Frank hit upon,” said Tom. “And we’re not really responsible for either. Mr. Henderson gave us the idea for the tuner and a friend of Dad’s invented the tube, but couldn’t get any one interested. You see, Henry, this tube is just about 400 times as much of an amplifier as the 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 set steadily for five hours. For under-sea work the cost don’t count. What
we’re up against now is to make the sending set to go with it. The receiver was easy. That fits in this special helmet all right and don’t have to be waterproof, but the sending set’ll have to be outside and it’ll be an awful job to keep the water from short circuiting it.”
As he talked, Tom was showing Henry the set and pointing out its many novel features.
“This single tuner is great,” he continued. “It’s fixed so it’s set at a certain spot for the normal wave lengths sent from the diver’s home station. See, here in the middle at zero. Then, if he wants to get a shorter wave he turns it to the left which gives him a range down to half 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 the right and around to opposite the zero point. Then he’d be on about 2500 meters and that being his utmost length he just has to tune slowly towards zero again. And the rheostat works automatically with it and so
does the variable condenser and it’s not very complicated either.”