"To move around near a heavy mass—in the presence of a strong gravitational field," Arcot said. "A gravitational field tends to warp space in such a way that the velocity of light is lower in its presence. Our drive tries to warp or strain space in the opposite manner. The two would simply cancel each other out and we'd waste a lot of power going nowhere. As a matter of fact, the gravitational field of the sun is so intense that we'll have to go out beyond the orbit of Pluto before we can use the space strain drive effectively."

"I catch," said Fuller. "Now to get back to the generators. I think the power units would be simpler if they were controlled from one electrical power source, and just as reliable. Anyway, the molecular motion power is controlled, of necessity, from a single generator, so if one is apt to go bad, the other is, too."

"Very good reasoning," smiled Morey, "but I'm still strong for decentralization. I suggest a compromise. We can have the main power unit and the main verticals, which will be the largest, controlled by individual cosmic ray heaters, and the rest run by electric power units. They'd be just heating coils surrounded by the field."

"A good idea," said Arcot. "I'm in favor of the compromise. Okay, Fuller? Okay. Now the next problem is weapons. I suggest we use a separate control panel and a separate generating panel for the power tubes we'll want in the molecular beam projectors."

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."