The molecular beam projector simply projected the field that caused molecular motion to take place as wanted. As weapons, they were terrifically deadly. If half a mountain is suddenly thrown into the air because all the random motion of its molecules becomes concentrated in one direction, it becomes a difficult projectile to fight. Or touch the bow of a ship with the beam; the bow drops to absolute zero and is driven back on the stern, with all the speed of its billions of molecules. The general effect is similar to that produced by two ships having a head-on collision at ten miles per second.

Anything touched by the beam is broken by its own molecules, twisted by its own strength, and crushed by its own toughness. Nothing can resist it.

"My idea," Arcot went on, "was that since the same power is used for both the beams and the drive, we'll have two separate power-tube banks to generate it. That way, if one breaks down, we can switch to the other. We can even use both at once on the drive, if necessary; the molecular motion machines will stand it if we make them of relux and anchor them with lux metal beams. The projectors would be able to handle the power, too, using Dad's new system.

"That will give us more protection, and, at the same time, full power.

Since we'll have several projectors, the power needed to operate the ship will be about equal to the power required to operate the projectors.

"And I also suggest we mount some heat beam projectors."

"Why?" objected Wade. "They're less effective than the molecular rays.

The molecular beams are instantly irresistible, while the heat beams take time to heat up the target. Sure, they're unhealthy to deal with, but no more so than the molecular beam."

"True enough," Arcot agreed, "but the heat beam is more spectacular, and we may find that a mere spectacular display will accomplish as much as actual destruction. Besides, the heat beams are more local in effect. If we want to kill an enemy and spare his captive, we want a beam that will be deadly where it hits, not for fifty yards around."

"Hold it a second," said Fuller wearily. "Now it's heat beams. Don't you guys think you ought to explain a little bit to the poor goon who's designing this flying battlewagon? How did you get a heat beam?"

Arcot grinned. "Simple. We use a small atomic cavity radiator at one end of which is a rough relux parabolic filter. Beyond that is a lux metal lens. The relux heats up tremendously, and since there is no polished relux to reflect it back, the heat is radiated out through the lux metal lens as a powerful heat beam."

"Okay, fine," said Fuller. "But stop springing new gadgets on me, will you?"

"I'll try not to," Arcot laughed. "Anyway, let's get on to the main power plant. Remember that our condenser coil is a gadget for storing energy in s.p.a.ce; we are therefore obliged to supply it with energy to store. Just forming the drive field alone will require two times ten to the twenty-seventh ergs, or the energy of about _two and a half tons_ of matter. That means a whale of a lot of lead wire will have to be fed into our conversion generators; it would take several hours to charge the coils. We'd better have two big chargers to do the job.

"The controls we can figure out later. How about it? Any suggestions?"

"Sounds okay to me," said Morey, and the others agreed.

"Good enough. Now, as far as air and water go, we can use the standard s.p.a.cecraft apparatus, Fuller, so you can figure that in any way you want to."

"We'll need a lab, too," Wade put in. "And a machine shop with plenty of spare parts--everything we can possibly think of. Remember, we may want to build some things out in s.p.a.ce."

"Right. And I wonder--" Arcot looked thoughtful. "How about the invisibility apparatus? It may prove useful, and it won't cost much.

Let's put that in, too."

The apparatus he mentioned was simply a high-frequency oscillator tube of extreme power which caused vibrations approaching light frequency to be set up in the molecules of the ship. As a result, the ship became transparent, since light could easily pa.s.s through the vibrating molecules.

There was only one difficulty; the ship was invisible, all right, but it became a radio sender and could easily be detected by a directional radio. However, if the secret were unknown, it was a very effective method of disappearing. And, since the frequency was so high, a special detector was required to pick it up.

"Is that all you need?" asked Fuller.

"Nope," said Arcot, leaning back in his chair. "Now comes the kicker. I suggest that we make the hull of foot-thick lux metal and line it on the inside with relux wherever we want it to be opaque. And we want relux shutters on the windows. Lux is too doggone transparent; if we came too close to a hot star, we'd be badly burned."

Fuller looked almost goggle-eyed. "_A--foot--of--lux!_ Good Lord, Arcot! This ship would weigh a quarter of a million tons! That stuff is _dense_!"

"Sure," agreed Arcot, "but we'll need the protection. With a ship like that, you could run through a planetoid without hurting the hull. We'll make the relux inner wall about an inch thick, with a vacuum between them for protection in a warm atmosphere. And if some tremendous force did manage to crack the outer wall, we wouldn't be left without protection."

"Okay, you're the boss," Fuller said resignedly. "It's going to have to be a big ship, though. I figure a length of about two hundred feet and a diameter of around thirty feet. The interior I'll furnish with aluminum; it'll be cheaper and lighter. How about an observatory?"

"Put it in the rear of the ship," Wade suggested. "We'll mount one of the Nigran telectroscopes."

"Control room in the bow, of course," Morey chipped in.

"I've got you," Fuller said. "I'll work the thing out and give you a cost estimate and drawings."

"Fine," said Arcot, standing up. "Meanwhile, the rest of us will work out our little exhibition to impress Mr. Morey and Dad. Come on, lads, let's get back to the lab."

III

It was two weeks before Dr. Robert Arcot and his old friend Arthur Morey, president of Transcontinental Airways, were invited to see what their sons had been working on.

The demonstration was to take place in the radiation labs in the bas.e.m.e.nts of the Transcontinental building. Arcot, Wade, Morey, and Fuller had brought the equipment in from the country place in Vermont and set it up in one of the heavily-lined, vault-like chambers that were used for radiation experiments.

The two older men were seated before a huge eighty-inch three-dimensional television screen several floors above the level where the actual demonstration was going on.

"There can't be anyone in the room, because of radiation burns,"

explained Arcot, junior. "We could have surrounded the thing with relux, but then you couldn't have seen what's going on.

"I'm not going to explain anything beforehand; like magic, they'll be more astounding before the explanation is given."

He touched a switch. The cameras began to operate, and the screen sprang into life.

The screen showed a heavy table on which was mounted a small projector that looked something like a searchlight with several heavy cables running into it. In the path of the projector was a large lux metal crucible surrounded by a ring of relux, and a series of points of relux aimed into the crucible. These points and the ring were grounded. Inside the crucible was a small ingot of coronium, the strong, hard, Venerian metal which melted at twenty-five hundred degrees centigrade and boiled at better than four thousand. The crucible was entirely enclosed in a large lux metal case which was lined, on the side away from the projector, with roughened relux.

Arcot moved a switch on the control panel. Far below them, a heavy relay slammed home, and suddenly a solid beam of brilliant bluish light shot out from the projector, a beam so brilliant that the entire screen was lit by the intense glow, and the spectators thought that they could almost feel the heat.

It pa.s.sed through the lux metal case and through the coronium bar, only to be cut off by the relux liner, which, since it was rough, absorbed over ninety-nine percent of the rays that struck it.

The coronium bar glowed red, orange, yellow, and white in quick succession, then suddenly slumped into a molten ma.s.s in the bottom of the crucible.

The crucible was filled now with a ma.s.s of molten metal that glowed intensely white and seethed furiously. The slowly rising vapors told of the rapid boiling, and their settling showed that their temperature was too high to permit them to remain hot--the heat radiated away too fast.

For perhaps ten seconds this went on, then suddenly a new factor was added to the performance. There was a sudden crashing arc and a blaze of blue flame that swept in a cyclonic twisting motion inside the crucible.

The blaze of the arc, the intense brilliance of the incandescent metal, and the weird light of the beam of radiation shifted in a fantastic play of colors. It made a strange and impressive scene.

Suddenly the relay sounded again; the beam of radiance disappeared as quickly as it had come. In an instant, the blue violet glare of the relux plate had subsided to an angry red. The violent arcing had stopped, and the metal was cooling rapidly. A heavy purplish vapor in the crucible condensed on the walls into black, flakey crystals.

The elder Arcot was watching the scene in the screen curiously. "I wonder--" he said slowly. "As a physicist, I should say it was impossible, but if it did happen, I should imagine these would be the results." He turned to look at Arcot junior. "Well, go on with your exhibition, son."

"I want to know your ideas when we're through, though, Dad," said the younger man. "The next on the program is a little more interesting, perhaps. At least it demonstrates a more commercial aspect of the thing."

The younger Morey was operating the controls of the handling robots. On the screen, a machine rolled in on caterpillar treads, picked up the lux case and its contents, and carried them off.

A minute later, it reappeared with a large electromagnet and a relux plate, to which were attached a huge pair of silver busbars. The relux plate was set in a stand directly in front of the projector, and the big electromagnet was set up directly behind the relux plate. The magnet leads were connected, and a coil, in the form of two toruses intersecting at right angles enclosed in a form-fitting relux case, had been connected to the heavy terminals of the relux plate. An ammeter and a heavy coil of coronium wire were connected in series with the coil, and a kilovoltmeter was connected across the terminals of the relux plate.

As soon as the connections were completed, the robot backed swiftly out of the room, and Arcot turned on the magnet and the ray projector.