“Well, if the fellow who had this sub before used those crystals then they had ’em hooked up differently or something. I wonder if their sets in their suits would work better.”
Acting on this idea Rawlins donned one of the suits they had taken from their captives in New York and again went down, but the results were no better. As Frank had said, there were sounds—buzzing noises which were intermittent and indicated that Rawlins was speaking, but nothing that in the least resembled human voice or words.
“We’ll have to think this out,” declared Tom. “We get the noises, but not the words so it must be we pick up the waves and it’s a question of modulation. Let’s see. Those crystals magnify sounds when they’re touched or vibrated or when there’s a vibration or jar to the thing they’re resting on. Gosh! I believe I know our trouble.”
“Well, what is it?” demanded Frank.
“Why, we’ve got this rigged up for a detector—the way they did for submarines—and we do get the noises which was what they wanted when locating a sub, but we don’t get the words. The trouble is we’ve got the cart before the horse. We’ve hooked this up so the crystals come before the phones. What we need is to transfer the sound waves in the phones to the crystals and let ’em amplify them. As ’tis now we’re amplifying electric waves not sound waves.”
“I guess you’re right,” agreed Frank. “Let’s try it the other way.”
It took some time to rearrange the set, but with Mr. Henderson to advise and Bancroft to help, it was done at last and once more Rawlins entered the air-lock.
Hardly had he had time to reach bottom the boys thought when, to their inexpressable delight, his voice came to their ears clearly.
“Hello!” he said. “Do you get me?”
“Hurrah it works!” cried Tom and instantly Rawlins’s voice responded: