CHAPTER XXI
MESSAGES INTO SPACE
Tom Swift's announcement of the practical completion of his wirelessplant brought hope to the discouraged hearts of the castaways. Theycrowded about him, and asked all manner of questions.
Mr. Fenwick and Mr. Damon came in for their share of attention, forTom said had it not been for the aid of his friends he never couldhave accomplished what he did. Then they all trooped up to thelittle shack, and inspected the plant.
As the young inventor had said, it was necessarily crude, but whenhe set the gasolene motor going, and the dynamo whizzed and hummed,sending out great, violet-hued sparks, they were all convinced thatthe young inventor had accomplished wonders, considering thematerials at his disposal.
"But it's going to be no easy task to rig up the sending andreceiving wires," declared Tom. "That will take some time."
"Have you got the wire?" asked Mr. Jenks.
"I took it from the stays of the airship," was Tom's reply, and herecalled the day he was at that work, when the odd man had exhibitedthe handful of what he said were diamonds. Tom wondered if theyreally were, and he speculated as to what might be the secret ofPhantom Mountain, to which Mr. Jenks had referred.
But now followed a busy time for all. Under the direction of theyoung inventor, they began to string the wires from the top of thedead tree, to a smaller one, some distance away, using five wires,set parallel, and attached to a wooden spreader, or stay. The wireswere then run to the dynamo, and the receiving coil, and thenecessary ground wires were installed.
"But I can't understand how you are going to do it," said Mrs.Nestor. "I've read about wireless messages, but I can't get itthrough my head. How is it done, Mr. Swift?"
"The theory is very simple," said the young inventor. "To send amessage by wire, over a telegraph system, a battery or dynamo isused. This establishes a current over wires stretched between twopoints. By means of what is called a 'key' this current isinterrupted, or broken, at certain intervals, making the soundinginstrument send out clicks. A short click is called a dot, and along click a dash. By combinations of dots, dashes, and spacesbetween the dots and dashes, letters are spelled out. For instance,a dot and a space and a dash, represent the letter 'A' and so on."
"I understand so far," admitted Mrs. Nestor.
"In telegraphing without wires," went on Tom, "the air is used inplace of a metallic conductor, with the help of the earth, which initself is a big magnet, or a battery, as you choose to regard it.The earth helps to establish the connection between places wherethere are no wires, when we 'ground' certain conductors."
"To send a wireless message a current is generated by a dynamo. Thecurrent flows along until it gets to the ends of the sending wires,which we have just strung. Then it leaps off into space, so tospeak, until it reaches the receiving wires, wherever they may beerected. That is why any wireless receiving station, within acertain radius, can catch any messages that may be flying throughthe air--that is unless certain apparatus is tuned, or adjusted, toprevent this."
"Well, once the impulses, or electric currents, are sent out intospace, all that is necessary to do is to break, or interrupt them atcertain intervals, to make dots, dashes and spaces. These makecorresponding clicks in the telephone receiver which the operator atthe receiving station wears on his ear. He hears the code of clicks,and translates them into letters, the letters into words and thewords into sentences. That is how wireless messages are sent."
"And do you propose to send some that way?" asked Mrs. Anderson.
"I do," replied Tom, with a smile.
"Where to?" Mrs. Nestor wanted to know.
"That's what I can't tell," was Tom's reply. "I will have to projectthem off into space, and trust to chance that some listeningwireless operator will 'pick them up,' as they call it, and send usaid."
"But are wireless operators always listening?" asked Mr. Nestor.
"Somewhere, some of them are--I hope," was Tom's quiet answer. "As Isaid, we will have to trust much to chance. But other people havebeen saved by sending messages off into space; and why not we?Sinking steamers have had their passengers taken off when theoperator called for help, merely by sending a message into space."
"But how can we tell them where to come for us--on this unknownisland?" inquired Mrs. Anderson.
"I fancy Captain Mentor can supply our longitude and latitude,"answered Tom. "I will give that with every message I send out, andhelp may come--some day."
"It can't come any too quick for me!" declared Mr. Damon. "Bless mydoor knob, but my wife must be worrying about my absence!"
"What message for help will you send?" Captain Mentor wanted toknow.
"I am going to use the old call for aid," was the reply of the younginventor. "I shall flash into space the three letters 'C.Q.D.' Theystand for 'Come Quick--Danger.' A new code call has been institutedfor them, but I am going to rely on the old one, as, in this part ofthe world, the new one may not be so well understood. Then I willfollow that by giving our position in the ocean, as nearly asCaptain Mentor can figure it out. I will repeat this call atintervals until we get help--"
"Or until the island sinks," added the scientist, grimly.
"Here! Don't mention that any more," ordered Mr. Hosbrook. "It'sgetting on my nerves! We may be rescued before that awful calamityovertakes us."
"I don't believe so," was Mr. Parker's reply, and he actually seemedto derive pleasure from his gloomy prophecy.
"It's lucky you understand wireless telegraphy, Tom Swift," said Mr.Nestor admiringly, and the other joined in praising the younginventor, until, blushing, he hurried off to make some adjustmentsto his apparatus.
"Can you compute our longitude and latitude, Captain Mentor," askedthe millionaire yacht owner.
"I think so," was the reply. "Not very accurately, of course, forall my papers and instruments went down in the RESOLUTE. But nearenough for the purpose, I fancy. I'll get right to work at it, andlet Mr. Swift have it."
"I wish you would. The sooner we begin calling for help the better.I never expected to be in such a predicament as this, but it iswonderful how that young fellow worked out his plan of rescue. Ihope he succeeds."
It took some little time for the commander to figure their position,and then it was only approximate. But at length he handed Tom apiece of paper with the latitude and longitude written on it.
In the meanwhile, the young inventor had been connecting up hisapparatus. The wires were now all strung, and all that was necessarywas to start the motor and dynamo.
A curious throng gathered about the little shack as Tom announcedthat he was about to flash into space the first message calling forhelp. He took his place at the box, to which had been fastened theapparatus for clicking off the Morse letters.
"Well, here we go," he said, with a smile.
His fingers clasped the rude key he had fashioned from bits of brassand hard rubber. The motor was buzzing away, and the electric dynamowas purring like some big cat.
Just as Tom opened the circuit, to send the current into theinstrument, there came an ominous rumbling of the earth.
"Another quake!" screamed Mrs. Anderson. But it was over in asecond, and calmness succeeded the incipient panic.
Suddenly, overhead, there sounded a queer crackling noise, avicious, snapping, as if from some invisible whips.
"Mercy! What's that?" cried Mrs. Nestor.
"The wireless," replied Tom, quietly. "I am going to send a messagefor help, off into space. I hope some one receives it--and answers,"he added, in a low tone.
The crackling increased. While they gathered about him, Tom Swiftpressed the key, making and breaking the current until he had sentout from Earthquake Island the three letters--"C.Q.D." And hefollowed them by giving their latitude and longitude. Over and overagain he flashed out this message.
Would it be answered? Would help come? If so, from where? And if so,would it be in time? These were questions that the castaways askedthemselves. As for Tom, he
sat at the key, clicking away, while,overhead, from the wires fastened to the dead tree, flashed out themessages.