Part 4 (1/2)
That night there was a crowd in the a.s.sembly room. Every student was there, half the town, many people from the country around and a few friends of the school from various distances. Doctor Field introduced the occasion briefly. Professor Grant gave a talk on the history and rapid growth of radio communication. Professor Judson, a.s.sistant in physics, talked on the ”little bottles,” as the vacuum tubes are often called. Professor Search talked on the possible future of radio. Then the Doctor arose again and said:
”We want to have members of our student body, also, express to you our interest in this great subject. We are fortunate to have this year a pupil who, though yet a freshman, has shown an unusual grasp of the technicalities of radio. I am going to ask Mr. William Brown to explain briefly some of the methods employed in building, or selecting, a radio receiving set, such as those he has been engaged in making here at the school. His a.s.sociate, Mr. Augustus Grier, who is an artist, in mechanical matters at least, will aid Mr. Brown at the blackboard.”
Bill laid aside his crutch and hobbled forward to the platform, followed by Gus, whose easy motions were in direct contrast. A round of applause greeted the boys. This was increased and a burst of laughter added when Gus took a piece of chalk and with a few quick strokes made what suggested a broadcasting station, with a rooster shouting ”c.o.c.k-a-doodle-doo” into the transmitter. Then he drew a lot of zigzag lines to indicate the Hertzian waves, and at the other end of the board, a hen listening in and registering horror when she hears the sounds translated into ”quack, quack.” Meanwhile, Bill had plunged headlong into his subject.
CHAPTER VIII
RADIO GALORE
”A good many folks,” said Bill, ”get scared when they think about radio construction. The big words come at them all in a bunch like a lot of bees, and it is to dodge. And when they go to the dictionary they are lost for sure. Potentiometer, variometer, variocoupler, radio frequency, amplification, loop aerials, audion and grids--no, I am not saying these words to show off. They are only a part of radio terminology. And you've got to get 'em, or you might as well take radio theory and construction on faith and be satisfied simply to listen in.
”Anybody can commit these words to memory without a dictionary, and that's where my partner s.h.i.+nes. He has heard the big words so much that he talks them in his sleep, and he ought to know all their meanings, but the one most his size is 'grid.'”
Here Gus drew a much scared boy, with hair on end and knees knocking together, surrounded by a lot of the words that Bill had p.r.o.nounced.
Then Bill, putting his hand to the side of his mouth and leaning toward his audience as though in confidence, said in a stage whisper:
”He's doing that to show that he knows how to spell these words.
”To be serious about it, if I'm allowed,” continued Bill, ”this subject of radio is a coiner in every way. Just think of someone saying something in San Francisco and someone else in Maine listening to it, and without any speaking tubes, nor wires to carry the sound along! A good many folks are wondering how it happens--how speech can be turned into electricity that goes shooting in all directions and how this is turned back into speech again.
”Well, it's done on the telephone, over wires. The voice in the receiver is turned into electric energy that pa.s.ses over the wires and at the other end turns again into sounds exactly like the voice that started it. But somebody found out that this same energy could be shot into the air in all directions and carried any distance, maybe as far as the stars, and then when pretty much the same principles were applied to this as to the telephone, with some more apparatus to send and catch the energy, why, then, that was wireless.
”It is really too bad, with all the useless short syllables in our language going to waste, that the fellows who got up the terms for radio work couldn't have used words like 'grid,' for instance. They could have called a variocoupler a 'gol,' a potentiometer a 'dit,' an induction coil a 'lim,' (l-i-m) and a variable condenser would look just as pretty if it were written out as a 'sos'--but no! They forgot the good example set by the grid, the volt and the ohm and they went and used jawbreakers.
”I'll tell you another thing that makes this electro-motive force as used in wireless easier to understand. It is the sun and its light. A great scientist, Doctor Steinmetz, says that light and electric waves are the same thing. Perhaps they are, though they surely work differently under different conditions. But if the sun has an awful lot of heat it can't send it ninety-five million miles--not in reason! The heat only makes light and that light travels through s.p.a.ce. It reaches the atmosphere of our earth and is converted into heat again. Perhaps light of the sun and stars and the reflected light of the planets do not s.h.i.+ne through s.p.a.ce as light, but as radio waves that either by our atmosphere, or by our electrical conditions here are converted into light again,--but this is hardly open to proof even.”
Bill glanced at the blackboard; Gus had drawn a big sun, with radiating rays, a grinning face, a small body with one short leg and two gesturing hands and had labeled it ”Bill Brown, radio radiator.” Bill made a motion of his thumb toward the caricature, then spread his hands in mock despair, but not without a side glance expressing pride in his lieutenant's performance, all of which pleased the audience immensely.
Then Bill proceeded: ”This electro-motive force which travels around and through our little earth is what we can actually experiment with. We do not know just what it is, but we are finding out pretty fast what it will do. Perhaps there is hardly any limit to what it will do. It is generated for power and light and heat, for carrying signals and sounds over wires and through the air. What next? Just now we have got all the thinking we can do about radio. It is the sixth wonder that electricity has sprung upon us. I guess we won't include electrocution.
”Now, there's no use going into technicalities about construction, that's a thing that must be studied out and thought over, not mussed up in a talk like this. I'll say this much, however, it is the vacuum or audion tube detector that gives results, and the application of a loud speaker is only possible with a vacuum or audion tube. It is as easy to build a vacuum tube set as a crystal set and only a very little more expensive. So, whether you are building or buying a set, make it a good set, something that you can hear with a good many hundred miles.
”Now, you can buy the parts and build a receiving set that will generally give more satisfaction than a bought set.” (Bill stepped over to the blackboard and took up a pointer.) ”I may need this for this partner of mine if he persists in caricaturing me instead of drawing what we want. We'll make things about four times as big as they ought to be. You can use an aerial outdoors, which everybody now understands, or, just as well and a lot handier, a loop aerial indoors, the bigger the better, but two feet in diameter is big enough.
”Here is your base and upright panel and this is the way to hook up or wire the parts. Here's your aerial and its ground, between which is placed your variable condenser and tuning coil, thus, off here between condenser and coil comes the wire to your vacuum tube, with its fixed condenser and grid leads, the wire being connected directly to the grid, while here the wire from the tube plate is connected with the six-volt storage battery and in turn with the phones, like this. Then, from the phones to the ground wire, the wire is carried thus through a secondary dry cell battery, on each side of which the wires are taken off to a rheostat, though my partner has sketched this to look more like a bird after a caterpillar.
”I am not going to tell you how to make all these parts--if I did you'd probably go to sleep, if you are not half way there already. So, if you can't find out how to make the parts, or contrive them in some way yourself, why, then, you'd better buy them. Only you can make the base and do the wiring, attaching and so forth. Even my partner can do that if he is watched pretty closely; it is almost as easy as making a sketch of it.
”If any of you really want to know how to build a radio set in a practical, get-there way, all you'll have to do is to get Doctor Field's consent and come round to our shop in the bas.e.m.e.nt of the school dormitory and we won't soak you much. I thank you all for your attention.”
Very warm applause indicated the approval of the audience, as Bill and Gus left the platform. Again the president arose to say:
”Another of our students has a message for us in regard to radio. Among the notable pioneers and probably one to give the subject its greatest practical impetus is William Marconi, whose name is familiar to you all.
The great inventor is now an honored guest of this country, his yacht _Elettra_ lying off our sh.o.r.es. It seems doubly fitting that more than special mention should be made of him, and as Mr. Antonio Sabaste was, in his native land, a neighbor of Marconi, his father being really a friend of the wizard, I think we shall listen with pleasure to what this student of the school has to say.”
CHAPTER IX