When the atoms failed

by Jr. John W. Campbell

"Well, I suppose I have no right to call a cathode ray tube an electronic rocket, but when a cathode ray tube gets that big it really needs a new name. The idea is the same as that of a rocket. You know the experiments the Germans, the millionaire Opel, and others carried out in 1927 with rocket automobiles? They had a terrible time with their rockets because the heat of one set off the next. The result was a disastrous explosion—and they had a whole ocean of air to cool them! What would a rocket do in free space? Also remember the principle of a rocket is that you shoot particles out of the rear at a very high speed and thus impart the kick to the ship. The electronic rocket does the same thing—but instead of shooting molecules of hot gas, it shoots electrons, a giant cathode ray tube such as Coolidge had in 1927, but his was so small that the kick was immeasurable. Remember that as the velocity of the electrons approaches that of light, the mass increases and so the electrons as shot from a cathode ray rocket may weigh as much as a milligram. The problem of propulsion then is not hard with atomic energy to supply the terrific voltages needed to run the tube. But the cathode rays are going to be their first weapon. Cathode rays are absorbed by any object they hit, and their terrific energy is converted to heat. They are deadly in themselves, and the heat is of course deadly. They will also have heat rays. I can make a heat ray with atomic energy, though mine is derived from material. The only way we can fight them is to know beforehand what we are to meet. This is to be a war for a world, and the war will be a battle of titanic forces. The weaker of the forces will be a million times greater than anything man has ever known before, and either of these two forces would, if fully applied, blast our planet from its place around the sun! Such forces can not be withstood. They must be annulled, deflected, or annihilated by some greater force. Only when we know what to expect can we fight them, and live. Remember, if they once succeeded in getting one weak spot in our armor, we can never have another chance, and the world can never hope to fight them—mere armies and a navy or two, with a couple of air forces thrown in—what would they amount to? The energy of atoms could destroy them like paper in a blow-torch—think what would happen to one of those beautifully absorbing grey battleships if a heat ray touched it! Their eighteen-inch steel armor would not melt—it would boil away! A submarine would be no safer—they could explode the water about it into steam and crush it. The effect of a heat ray in water is just that—the water is converted to steam so suddenly that there is a terrific explosion. The cathode rays could sweep an army out of existence as hose might wash away an army of mud soldiers. They won't have gases. They will have no use for them. They could wipe a city off the map, leave only a great crater in the scarred Earth, while men were getting ready to lay a gas barrage. A shell would certainly just bounce off of the armor of my ship and I suspect that it would do the same with the Martian ships. Earth has only one weapon that can even bother them! And that one weapon is the one factor they did not figure on! It is the 'Terrestrian.' But now, if we want to make that one factor upset the whole equation, we have to calculate how to make its value a maximum, and to do that we have to know every other factor in the equation. I have suggested two weapons they will have, the cathode rays and the heat ray. They will, of course, have others; they will have atomic bombs, and I am sure that they will find us so dangerous that they will be willing to lose a ship and crash us. This gives us something else to avoid. Can any of you think of something else?"

"Good Lord Steve, haven't you thought of enough?"

"Plenty, Dave, but it isn't considered good form in military proceedings to permit the enemy to surprise you. In fact, it is highly probable that if he does, you will get a new form, one more adapted to aerial transit."

"Yes, that's true, too. But I remember reading once that ultra-violet light was invisible, and very dangerous to the body. I wonder if they will use that?"

"They may, but I greatly doubt it. Air is very nearly opaque to ultra-violet light, above a certain limit, and below that limit it is not very harmful. The infra-red heat rays, though, are going to be a very great menace. I can't think of any way to make them harmless. Of course, the polished iridium shell of the ship will protect us from the sides, as the heat will all be reflected. The difficulty will be that the heat will fuse the window, and thus attack us. The quartz glass is nearly opaque to heat rays, as is all glass. Being opaque, it absorbs it, 'cuts it out' as we say. The result will be that the glass will melt instantly, whereupon we will go very quickly. The idea of putting a polished metal shutter before the window is the one we will have to adopt, but we must modify it somehow. The heat rays will be turned back all right—and so will the light rays. The question is to shut out heat and let in light. Any suggestions?"

"I wonder if there isn't some selective reflector that we could use, Dr. Waterson?"

"That is a good idea, Wright—but I don't know of any that will pass all the light and reflect all the heat!"

"What is a selective reflector, Steve?"

"There are lots of things that have that property Dave, gold leaf is one, it can transmit green light—that is you can see green light through it, but it reflects yellow light—the complement of the green it transmits. There are a great many organic dyes that are one color when you look at them and the complement of that color when you look through them. The trouble is we need one that transmits the visible portion of the spectrum and—boy—that's it, Wright, that's it—spectrum—take a totally reflecting diffraction grating, reflect out all that part of the spectrum that we don't want, take what we do, pass it through a prism to recombine it to white light, then through lenses so we can see as if through a telescope! We will have absolutely cold light!"

"Again it sounds good, but I'd like to hear it in English, Steve."