The Black Star Passes by Jr. John W. Campbell (classic books for 10 year olds .TXT) 📖

low. It is not the same as that of air, but the difference is so slight that it is practically within the limits of observation error; so small is the difference that there is no 'rainbow' effect. The difference of temperature of the air would give equal effect.

“Now, since this vibration is induced by radio impulse, is it not possible to impress another, opposing radio impulse, that will overcome this tendency and bring the invisible object into the field of the visible once more? It is; and this machine on the table is designed to do exactly that. It is practically a beam radio set, projecting a beam of a wavelength that alone would tend to produce invisibility. But in this case it will make me visible. I'm going to stand right here, and Bob can operate that set.”

Arcot strode to the middle of the room, and then Morey turned the reflector of the beam set on him. There was a low snap as Arcot turned on his set, then he was gone, as suddenly as the coming of darkness when a lamp is extinguished. He was there one moment, then they were staring at the chair behind him, knowing that the man was standing between them and it and knowing that they were looking through his body. It gave them a strange feeling, an uncomfortable tingling along the spine. Then the voice—it seem[Pg. 34]ed to come from the air, or some disembodied ghost as the invisible man called to Morey.

“All right, Bob, turn her on slowly.”

There was another snap as the switch of the disrupter beam was turned on. At once there was a noticeable fogginess in the air where Arcot had been. As more and more power was turned into the machine, they saw the man materialize out of thin air. First he was a mere shadowy outline that was never fully above the level of conscious vision. Then slowly the outlines of the objects behind became dimmer and dimmer, as the body of the man was slowly darkened, till at last there was only a wavering aura about him. With a snap Morey shut off his machine and Arcot was gone again. A second snap and he was solid before them. He had shut off his apparatus too.

“You can see now how we intend to locate our invisible pirate. Of course we will depend on directional radio disturbance locating devices to determine the direction for the invisibility disrupter ray. But you are probably marvelling at the greatness of the genius who can design and construct this apparatus all in one day. I will explain the miracle. I have been working on short wave phenomena for some time. In fact, I had actually made an invisibility machine, as Morey will testify, but I realized that it had no commercial benefits, so I didn't experiment with it beyond the laboratory stunt stage. I published some of the theory in the Journal of the International Physical Society—and I wouldn't be surprised to learn that the pirate based his discovery on my report.

“I am still working on a somewhat different piece of apparatus that I believe we will find very relevant to this business. I'll ask you to adjourn after tonight's meeting for another twenty-four hours till I can finish the apparatus I am working on. It is very important that you be here, Fuller. I am going to need you in the work to follow. It will be another problem of design if this works out, as I hope it will.”

[Pg. 35]

“I'll certainly make every effort to be here, Arcot,” Fuller assured him.

“I can promise you a tough problem as well as an interesting one.” Arcot smiled. “If the thing works, as I expect it to, you'll have a job that will certainly be a feather for your cap. Also it will be a change.”

“Well, with that inducement, I'll certainly be here. But I think that pirate could give us some hints on design. How does he get his glider ten miles up? They've done some high-altitude gliding already. The distance record took someone across the Atlantic in 2009, didn't it? But it seems that ten miles straight up is a bit too steep for a glider. There are no vertical air currents at that height.”

“I meant to say that his machine is not a true glider, but a semi-glider. He probably goes up ten miles or more with the aid of a small engine, one so small it probably takes him half a day to get there. And it would be easy for a plane to pass through the lower traffic lanes, then, being invisible, mount high and wait for the air liner. He can't use a very large engine, for it would drag him down, but one of the new hundred horsepower jobs would weigh only about fifty pounds. I think we can draw a pretty good picture of his plane from scientific logic. It probably has a tremendous wingspread and a very high angle of incidence to make it possible to glide at that height, and the engine and prop will be almost laughably small.”

The next evening the men got together for dinner, and there was considerable speculation as to the nature of the discovery that Arcot was going to announce, for even his father had no knowledge of what it was. The two men worked in separate laboratories, except when either had a particularly difficult problem that might be solved by the other. All knew that the new development lay in the field of short wave research, but they could not find out in what way it concerned the problem in hand.

At last the meal was over, and Arcot was ready to demonstrate.

[Pg. 36]

“Dad, I believe that you have been trying to develop a successful solar engine. One that could be placed in the wings of a plane to generate power from the light falling on that surface. In all solar engines what is the greatest problem to be solved?”

“Well, the more I investigate the thing, the more I wonder which is the greatest. There are a surprising number of annoying problems to be met. I should say, though, that the one big trouble with all solar engines, eliminating the obvious restriction that they decidedly aren't dependable for night work, is the difficulty of getting an area to absorb the energy. If I could get enough area, I could use a very low efficiency and still have cheap power, for the power is absolutely free. The area problem is the greatest difficulty, no doubt.”

“Well,” Arcot junior said quietly, “I think you have a fairly good area to use, if you can only harness the energy it absorbs. I have really developed a very efficient solar engine. The engine itself requires no absorbing area, as I want to use it; it takes advantage of the fact that the Earth is absorbing quintillions of horsepower. I have merely tapped the power that the Earth has already absorbed for me. Come here.”

He led the way down the corridor to his laboratory, and switched on the lights. On the main laboratory bench was set up a complicated apparatus of many tubes and heavy bus bar connectors. From the final tube two thin wires ran to a long tubular coil. To the left of this coil was a large relay switch, and a rheostat control.

“Turn on the relay, Dad, then slowly rotate the controller to the left. And remember that it is rather powerful; I know this doesn't look like a solar engine, and nine o'clock at night seems a peculiar hour to demonstrate such a thing, but I'll guarantee results—probably more than you expect.”

Dr. Arcot stepped up to the controls and closed the switch. The lights dimmed a bit, but immediately brightened again, and from the other end of the room came a low, steady hum as the big transformer took up the load.

[Pg. 37]

“Well, from the sound of that ten K.W. transformer there, if this engine is very efficient we ought to get a terrific amount of power out of it.” Dr. Arcot was smiling amusedly at his son. “I can't very well control this except by standing directly in front of it, but I suppose you know what you're doing.”

“Oh, this is a laboratory model, and I haven't gotten the thing into shape really. Look at the conductors that lead to the coil; they certainly aren't carrying ten K.W.”

Dr. Arcot slowly rotated the rheostat. There was a faint hum from the coil; then it was gone. There seemed to be no other result. He rotated it a bit more; a slight draught sprang up within the room. He waited, but when nothing more startling occurred, he gave the rheostat a sharp turn. This time there was absolutely no doubt as to the result. There was a roar like a fifty-foot wind tunnel, and a mighty blast of cold air swept out of that coil like a six-inch model of a Kansas cyclone. Every loose piece of paper in the laboratory came suddenly alive and whirled madly before the blast of air that had suddenly leaped out. Dr. Arcot was forced back as by a giant hand; in his backward motion his hand was lifted from the relay switch, and with a thud the circuit opened. In an instant the roar of sound was cut off, and only a soft whisper of air told of the furious blast that had been there a moment before.

The astonished physicist came forward and looked at the device a moment in silence, while each of the other men watched him. Finally he turned to his son, who was smiling at him with a twinkle in his eye.

“Dick, I think you have 'loaded the dice' in a way that is even more lucrative than any other method ever invented! If the principle of this machine is what I think it is, you have certainly solved the secret of a sufficiently absorbing area for a solar engine.”

“Well,” remarked the elderly Morey, shivering a bit in the chill air of the room, “loaded dice have long been noted for their ability to make money, but I don't see how that explains that working model of an Arctic tornado. Burr—[Pg. 38]it's still too cold in here. I think he'll need considerable area for heat absorption from the sun, for that engine certainly does cool things down! What's the secret?”

“The principle is easy enough, but I had considerable difficulty with the application. I think it is going to be rather important though—”

“Rather important,” broke in the inventor's father, with a rare display of excitement. “It will be considerably more than that. It's the biggest thing since the electric dynamo! It puts airplanes in the junk heap! It means a new era in power generation. Why, we'll never have to worry about power! It will make interplanetary travel not only possible, but commercially economical.”

Arcot junior grinned broadly. “Dad seems to think the machine has possibilities! Seriously, I believe it will antiquate all types of airplanes, prop or jet. It's a direct utilization of the energy that the sun is kindly supplying. For a good many years now men have been trying to find out how to control the energy of atoms for air travel, or to release the energy of the constitution of matter.

“But why do it at all? The sun is doing it already, and on a scale so gargantuan that we could never hope nor desire to approach it. Three million tons of matter go into that colossal furnace every second of time, and out of that comes two and a half decillion ergs of energy. With a total of two and a half million billion billion billions of ergs to draw on, man will have nothing to worry about for a good many years to come! That represents a flood of power vaster than man could comprehend. Why try to release any more energy? We have more than we can use; we may as well tap that vast ocean of power.

“There is one thing that prevents us getting it out, the law of probability. That's why Dad mentioned loaded dice, for dice, as you know, are the classical example of probability when they aren't loaded. Once they are loaded, the law still holds, but the conditions are now so changed that it will make the problem quite different.”

Arcot paused, frowning, then resumed half apologetic[Pg. 39]ally, “Excuse the lecture—but I don't know how else to get the thought across. You are familiar with the conditions in a liter of helium gas in a container—a tremendous number of molecules, each dashing along at several miles a second, and an equal number dashing in the opposite direction at an equal speed. They are so thickly packed in there, that none of them can go very far before it runs into