CHAPTER V
THE UNDER-SEA WIRELESS
As soon as Rawlins was out of sight the boys commenced to talk, Tomspeaking through the transmitter while Frank wrote down what he said,for of course they could not know if Rawlins heard them, and the onlymeans of determining if he had received all the words was to keep arecord for comparison when he came up. They were busily engaged at thisand tremendously interested and excited, when the telephone bell rang.Telling Rawlins to wait a moment, and explaining the reason, Tom ceasedspeaking while Frank answered the call.
"Hello, Frank," came Henry's voice. "I just rang up to be sure you werethere. How's everything going?"
"Fine!" replied Frank, "come on down, we're just testing it out for thefirst time. When did you get back?"
"Last evening--but didn't have a chance to run around to see you. Icalled up, but the maid said you were out with Tom. Didn't she tell you?I'll be right down, you bet. Say, I've some news for you. So long."
"I'm glad he's back from that trip with his father and is coming down,"said Tom, "Won't he be interested and surprised if this works? Wonderwhat the news is."
Then, turning to his set, he continued his interrupted talk, or attemptto talk, with Rawlins until, five minutes later, Henry was pounding atthe door.
"Gee, but you've a fine place here!" he cried as he glanced about thelittle laboratory, "and you've diving suits and helmets and everything.Say, I was just crazy to get back when I got your letter telling aboutyour experiments and everything. Where's the diver fellow? Oh say,you're not really talking to him under water! Crickety! Isn't thatwonderful to think he can hear you down under the river!"
Tom laughed. "Don't know if he can," he replied. "We'll have to wait forhim to come up and tell. You see we haven't got an under-sea sending setrigged up yet and the one he's got is just a sort of makeshift forexperimenting."
"Have you fellows heard anything more of that mystery chap?" criedHenry, suddenly changing the subject.
"Not a word," Tom assured him.
"Well, I have then," declared Henry triumphantly. "I heard him lastnight and I got him again to-day just before I called you fellows. Hewas in the same old place, too."
"Honest? Say, that _is_ funny!" exclaimed Frank. "What was he saying?"
"Don't know," replied Henry, "He was talking some foreign lingo that Icouldn't make out, but I got one word. Bet you couldn't guess what'twas--another flower--Oleander this time."
The boys were so interested in Henry's news that they had temporarilyforgotten their under-water companion until Henry uttered a halfsurprised exclamation and jumped away from the square opening in thefloor over the river.
"Gosh, there he comes!" he cried, as overcoming his first surprise at agurgling splash he glanced through the trapdoor and saw the diver'shelmet appearing. "Don't he look like a regular sea monster?"
A moment later, Rawlins was removing his suit and helmet.
"Did you hear us?" cried Tom the moment Rawlins' face was visible.
"Did I!" exclaimed the diver. "Did I! Let me tell you I wished I hadcotton stuffed in my ears. You must think I'm deaf,--yelling like that.Did you think you had to shout loud enough to have your voice go throughthe water? And I'll tell you I thought a tornado'd struck the place whenyour friend here arrived. I even heard the telephone bell."
Tom and Frank fairly danced with delight. "Hurrah! It works! It's asuccess! We've solved it! It's under-sea radio!" shouted the excitedboys.
"I'll say it works!" declared Rawlins. "But what the deuce were youtrying to talk Dutch for?"
"Talk Dutch?" cried Tom in a puzzled tone. "We weren't talking Dutch oranything but United States."
It was Rawlins' turn to be amazed. "Well, who in thunder was then?" heasked. "I heard some one jabbering Dutch or some other foreignlanguage--don't know what 'twas except it wasn't French or Spanish."
Henry gave a whoop. "It was that other fellow!" he cried excitedly."I'll bet 'twas. He was talking just before I rang up as I told you.Jehoshaphat! Mr. Rawlins must have heard him under water."
"I guess that's it," agreed Tom. "Funny it didn't occur to me. Of coursethere's no reason why he shouldn't have been heard under water. We'reusing a tiny little wave length and so's he, and he's close to here, youknow. Did you hear him loudly, Mr. Rawlins?"
"Well, not so as to deafen me the way you did," replied the diver with agrin, "but if I'd understood his lingo I could have told what he wastalking about. The only word that sounded like sense to me was somethinglike Oleander."
"Then 'twas him!" fairly yelled Henry ungrammatically. "That's the namehe 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 setto try out."
Now that the boys' first experiment had been such a huge success theywere more enthusiastic and excited than ever. They had been confidentthat the diver would be able to hear sounds or that he might evendistinguish words under water, but they had not dared to hope that theirvery first efforts would result in the sound being carried to the earsof the man beneath the water as clearly and loudly as though he had beenpresent in the same room with the speaker.
"I'll bet water carries electromagnetic waves better than air," declaredTom. "Why, if this little set can respond to these short five watt wavesin this way, think what it would mean to a submarine with big amplifiedsets and getting messages sent with hundreds of watts. Why a fellowcould sit in Washington and talk to submarines and divers all over theAtlantic."
"You've hit on a wonderful possibility," Rawlins assured him. "Of courseI was pretty close--I didn't go over a hundred yards from the dock andit's shoal water. I'm anxious to try it down a hundred feet or so and amile or two from the sender. We'll do that after we get things right--godown to my hangout in the Bahamas and give it a real honest-to-goodnesstryout."
"It's all in that new amplifying arrangement and that single controltuner Frank hit upon," said Tom. "And we're not really responsible foreither. Mr. Henderson gave us the idea for the tuner and a friend ofDad'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 theother tubes, and we get a detector and amplifier all in one. Lookhere--it's the smallest bulb you ever saw--about the size of a peanut andwe operate it on a flashlight battery with a special little dry cell forthe filament. Of course they don't last long, but a fellow can't staydown more than an hour or two anyway and the batteries will run the setsteadily for five hours. For under-sea work the cost don't count. Whatwe're up against now is to make the sending set to go with it. Thereceiver was easy. That fits in this special helmet all right and don'thave to be waterproof, but the sending set'll have to be outside andit'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 manynovel features.
"This single tuner is great," he continued. "It's fixed so it's set at acertain spot for the normal wave lengths sent from the diver's homestation. See, here in the middle at zero. Then, if he wants to get ashorter wave he turns it to the left which gives him a range down tohalf his normal wave length, or for longer waves he turns it to theright and gets twice his normal length. If he wants to go to long wavelengths--for example, if he was a spy or something and wanted to get thebig sending stations--he'd turn the knob clear to the left and then backto the right and around to opposite the zero point. Then he'd be onabout 2500 meters and that being his utmost length he just has to tuneslowly towards zero again. And the rheostat works automatically with itand so does the variable condenser and it's not very complicatedeither."
"But what does he do for an aerial?" queried Henry.
"Doesn't use one," replied Tom. "Just has this sort of wire cagesticking from his helmet, like a loop, but made of two grids set atright angles to each other. But gosh! I never thought about there beinginterferences under water."
"I suppose Henry und
erstands all that," interrupted Rawlins laughingly,"but it means about as much to me as that Dutch talk I heard. Somehow orother I can't get on to this radio a little bit. When you get thatsending outfit rigged you'll have to go down and test it. I'd probablybungle something. I didn't even dare meddle with this gadget for tuning.I tried it once and when your voice stopped I just shoved her back andlet it go at that. That's when I heard that Dutchman."
"Then he's on a different wave length and it proves _we_ can tune outunder water," declared Tom gleefully. "That's another feather in ourcaps."
Henry quickly grasped the boys' ideas and together the three workeddiligently until sundown while Rawlins busied himself devising thefittings for his suit to accommodate the sending apparatus and helpedthe boys tremendously with suggestions for rendering a set watertightand with advice as to mechanical and other details.
By the time they were obliged to stop their work the plans for theunder-sea transmission set were well worked out and, with high hopes andflushed with the success of their achievements, they locked up theworkshop and walked up town discussing plans for the morrow.
The following day they went to the dock right after breakfast, forschool was over for the season and they had all their time tothemselves. Rawlins was already there and before they left that nightthey had the set nearly completed and Tom declared they would be able togive it a test the next day.
Mr. Pauling was of course deeply interested and enthusiastic over theboys' work and promised to go down himself as soon as the instrumentswere perfected. He listened to the boys' glowing accounts of their workand their success and later, when Mr. Henderson called, he too becamemost optimistic regarding their under-sea radio.
"It's merely a question of experimenting, boys," he declared. "We wereon the right track during the war, but radio's jumped ahead a lot sincethen and whatever the government experts accomplish is kept mightyquiet. I'm glad that single control works out so well. We'll have tothank the Huns for that. We found one on a captured U-boat, but as faras I know the government never took it up seriously--don't know whyunless it was because there was no particular need of it. We never didfind out what the Germans used it for--for all we know they may have beenexperimenting along under-sea lines too. And if that new tube ofMichelson's proves good he'll make a fortune and have you boys to thankfor it. I'm coming down to see your outfit just as soon as we get abreathing space. We're rushed to death just now."
With nothing else to do the boys amused themselves listening at theirsets which, with so many other interests, had been sadly neglected oflate, and, out of pure curiosity and never expecting to hear anything,Tom turned his loop aerial to the southeast and tuned for the short wavelengths used by the mysterious talker they had once followed and triedto locate so persistently. To his surprise, the sound of words cameclearly over the set.
"There he is again!" Tom exclaimed to Frank who was listening to abroadcasted speech. "Get him and we'll see what he says."
But despite the fact that the boys could both hear the man plainly hiswords were meaningless, for he was speaking some guttural,harsh-sounding tongue.
"Oh, pshaw!" ejaculated Tom disgustedly after a few minutes of this."Who cares what he's saying. I guess it's some crazy foreigner."
So saying, he again picked up the broadcasting station and forgot allabout the incident in his interest as he listened to a lecture on newdevelopments in radio.
"Some night we'll be listening to that fellow talking about the newunder-sea radio," chuckled Frank as the talk ceased and the boys laidaside their receivers. "Say, won't it be sport to hear him telling aboutus and know all the fellows are listening to it?"
"Well, we won't count our chickens just yet," declared Tom sagely. "Justbecause that receiving set works isn't any proof the sending set will.And without being able to talk back a diver isn't any better off--or atleast much better off--if he can hear what's going on in the air."
But Tom might have been far more confident, for the following day whenthe test was made it worked much better than their most sanguineexpectations had led them to think possible. To be sure, theirexperiments came to an abrupt ending right in the midst of the test, forthe sending set on Tom's suit leaked and, with a feeble buzz andsputter, his words trailed off to nothingness.
But when, upon reaching the surface, Rawlins reported that he had heardeverything Tom had said and Frank and Henry in the shop had also heardhim, the boys knew that their plans and the principles of the outfitwere all right and that only the question of making the set absolutelywatertight remained to be solved.
"I don't see why it should not be inside the suit," declared Rawlins, asthe boys were discussing the matter and were at a loss to know how toaccomplish their aims. "You say these wireless waves go througheverything and we get them through the suit in the receiving set so whyshouldn't they go out through everything just as well. Look here, I wasthinking over this last night and here's my idea."
As the boys gathered about, the diver rapidly sketched his plan of a newsuit in which the sending set could be placed within a receptacle fullof compressed air.
"I believe that _would_ work," cried Tom when he grasped Rawlins'scheme. "I don't see why compressed air should affect the outfit any andit's easy enough to make watertight fittings where the wires come outand there's no tuning to do, We can always use a special wave length andif several men were talking under water each one could have his own wavelength. Yes. I'll bet you've solved the puzzle, Mr. Rawlins."
Keen on the new plan the boys started a new set, or rather two new sets,for they wished to make a test to determine if two men under water couldconverse, while Rawlins busied himself on the special suits and airpockets to be used.
"We'll have to balance the weight of the set against the increasedbuoyancy of this compressed air," he remarked as he worked. "But I seewhere that's an advantage. One of your troubles has been the weight ofbatteries and by this air caisson arrangement weight won't cut anyfigure under water."
"But suppose the air pocket springs a leak?" queried Frank. "We'd bejust as badly off as before."
"Well, I don't calculate to have it leak," replied Rawlins, "but if youmake the sets as near watertight as you can, they'd still go on workingfor some time before they got soaked. And if I can't make a littlecaisson that'll hold a hundred pounds of air for ten or twelve hoursI'll give up diving and drive a taxi."
Several days, however, were required to get the set and the air pocketsuits ready and when, after a test in the workshop, everything seemed inperfect working order, Tom and Rawlins donned their suits and preparedto descend the ladder through the trapdoor.
Just before his head dipped beneath the surface of the water Tom spokeinto his mouthpiece and Frank, listening at his instruments, gave astart as his chum's voice came clearly to his ears.
"So long, old man," came Tom's cheery voice, which somehow Frank hadexpected would sound muffled. "Keep your ear glued to the set and beready for great news. I'll bet we give you a surprise."
The next instant only a few bubbles marked the spot where Tom had sunkbeneath the surface of the water, and little did he or the others dreamhow much truth was in his parting words or what an amazing surprise wasawaiting not only Frank but himself.