s; it sounded pretty tame. But I
said, "How did it come out?"

* * * * *

He screwed his pudgy face up thoughtfully. "Synthesized the material,
all right, and it seems to work, but the interesting thing is that it
has a certain--ah--secondary property that would make it quite awkward
to use. Interesting property, though. Unique, I am inclined to
believe."

This began to sound more like it. "And what property is that?" I
poured myself a shot of straight rum from the bottle sitting on the
table beside me. I did not like straight rum, but I preferred it to
Farnsworth's rather imaginative cocktails.

"I'll show you, John," he said. He opened the box and I could see that
it was packed with some kind of batting. He fished in this and
withdrew a gray ball about the size of a golfball and set the box on
the mantel.

"And that's the--eraser?" I asked.

"Yes," he said. Then he squatted down, held the ball about a half-inch
from the floor, dropped it.

It bounced, naturally enough. Then it bounced again. And again. Only
this was not natural, for on the second bounce the ball went higher in
the air than on the first, and on the third bounce higher still. After
a half minute, my eyes were bugging out and the little ball was
bouncing four feet in the air and going higher each time.

I grabbed my glass. "What the hell!" I said.

Farnsworth caught the ball in a pudgy hand and held it. He was smiling
a little sheepishly. "Interesting effect, isn't it?"

"Now wait a minute," I said, beginning to think about it. "What's the
gimmick? What kind of motor do you have in that thing?"

His eyes were wide and a little hurt. "No gimmick, John. None at all.
Just a very peculiar molecular structure."

"Structure!" I said. "Bouncing balls just don't pick up energy out of
nowhere, I don't care how their molecules are put together. And you
don't get energy out without putting energy in."

"Oh," he said, "that's the really interesting thing. Of course you're
right; energy _does_ go into the ball. Here, I'll show you."

He let the ball drop again and it began bouncing, higher and higher,
until it was hitting the ceiling. Farnsworth reached out to catch it,
but he fumbled and the thing glanced off his hand, hit the mantelpiece
and zipped across the room. It banged into the far wall, richocheted,
banked off three other walls, picking up speed all the time.

When it whizzed by me like a rifle bullet, I bega