“Got it!” he exclaimed. “Had a bit of trouble at first, but it’s all right now. Now see if you can get this.”
As he spoke his words ended in a high, shrill squeal, but an instant later, as Tom turned the knob on his tuner, the words suddenly returned in a most startling way, the squeal seeming to change magically into words.
“Hurrah, I got it!” cried Tom jubilantly. “Come on up, Frank, Henry wants a chance.”
“You’ve certainly struck a wonderful thing here,” declared Rawlins, when he and Henry came up and had removed their suits. “How far do you suppose it will work?”
“That’s something we’ll have to find out,” replied Tom. “But the sounds come so loudly I’ll bet it’s good for a long distance. Somehow or other we get sound a lot louder inside a helmet than outside. I don’t just get the reason, but I expect it’s either because the whole air vibrates to the diaphragm of the receivers inside the helmet and no sound waves are lost or else because the helmet itself acts like a sounding board or maybe there are some sort of amplified waves set up.”
“I guess it’s the air being inclosed,” said Rawlins. “When I used to wear a regular suit and used an ordinary phone under water it was the same way, but I never thought of it in connection with radio. The whole thing gets me, there’s millions in this if we can patent it. Let’s go down once more and give her a real tryout. We’ll take a hike down river a few hundred yards and see if the boys get us. If they don’t we’ll come back and keep trying and if they do we’ll go on down as far as we can. Then, if we find it’s O. K. we’ll try to get your folks to let you go down to Nassau and we’ll show the world, I’ll bet.”
“That’s a good idea,” agreed Tom. “You keep
listening and now and then talking, Frank, and as soon as we lose your voice we’ll send and then walk back until we get you again. That way we can find if we can hear farther than you can or whether it’s the other way about.”
Donning their suits, Tom and Rawlins once more descended the ladder and half-floating, half-walking turned downstream. Rawlins had already cautioned Tom to keep close to his side and to hold to his hand, for, with the mud stirred up by their feet and carried by the current with them, it was impossible to see more than a few feet and Rawlins knew the danger that lay in becoming separated.
Even with the radio connecting them with the boys on the surface Tom might easily get confused and hopelessly lost if he strayed or was carried from sight of Rawlins and while Tom knew that, by turning on more oxygen, he could bob to the surface, yet danger lurked in this as he might emerge in the path of some steamer or motor boat and be run down or torn to pieces with the propellers. As long as they kept close to shore, following the docks and piers, there was no danger, for the only vessels in the vicinity were canal