ty of that ... far more than
we'd ever need. We supply the energy, but that's only a small part of
it. The body emitting the gravitational force supplies the fulcrum that
moves us along."

"It would operate beyond the planets," said Greg. "It would operate
equally well anywhere in space, for all of space is filled with
gravitational stress. We could use gravitational bodies many light years
away as the driver of our ships."

A half-wild light glowed momentarily in his eyes.

"Russ," he said, "we're going to put space fields to work at last."

He walked to the chair, picked it up and sat down in it.

"We'll start building a ship," he stated, "just as soon as we know the
mechanics of this gravity concentration and control. Russ, we'll build
the greatest ship, the fastest ship, the most powerful ship the Solar
System has ever known!"

* * * * *

"Damn," said Russ, "that thing's slipped again."

He glared at the offending nut. "I'll put a lock washer on it this
time."

Wilson stepped toward the control board. From his perch on the
apparatus, Russ motioned him away.

"Never mind discharging the field," he said. "I can get around it
somehow."

Wilson squinted at him. "This tooth is near killing me."

"Still got a toothache?" asked Russ.

"Never got a wink of sleep last night."

"You better run down to Frisco and have it yanked out," suggested the
scientist. "Can't have you laid up."

"Yeah, that's right," agreed Wilson. "Maybe I will. We got a lot to do."

Russ reached out and clamped his wrench on the nut, quickly backed it
off and slipped on the washer. Viciously he tightened it home. The
wrench stuck.

Gritting his teeth on the bit of his pipe, Russ cursed soundlessly. He
yanked savagely at the wrench. It slipped from his hand, hung for a
minute on the nut and then plunged downward, falling straight into the
heart of the new force field they had developed.

Russ froze and watched, his heart in his throat, mad thoughts in his
brain. In a flash, as the wrench fell, he remembered that they knew
nothing about this field. All they knew was that any matter introduced
in it suddenly acquired an acceleration in the dimension known as time,
with its normal constant of duration reduced to zero.

When that wrench struck the field, it would cease to exist! But
something else might happen, too, something entirely unguessable.

The wrench fell only a few feet, but it seemed to tak