n to get worried, but
it hit against one of the heavy draperies by the window and this
damped its motion enough so that it fell to the floor.

* * * * *

It started bouncing again immediately, but Farnsworth scrambled across
the room and grabbed it. He was perspiring a little and he began
instantly to transfer the ball from one hand to another and back again
as if it were hot.

"Here," he said, and handed it to me.

I almost dropped it.

"It's like a ball of ice!" I said. "Have you been keeping it in the
refrigerator?"

"No. As a matter of fact, it was at room temperature a few minutes
ago."

"Now wait a minute," I said. "I only teach physics in high school, but
I know better than that. Moving around in warm air doesn't make
anything cold except by evaporation."

"Well, there's your input and output, John," he said. "The ball lost
heat and took on motion. Simple conversion."

My jaw must have dropped to my waist. "Do you mean that that little
thing is converting heat to kinetic energy?"

"Apparently."

"But that's impossible!"

He was beginning to smile thoughtfully. The ball was not as cold now
as it had been and I was holding it in my lap.

"A steam engine does it," he said, "and a steam turbine. Of course,
they're not very efficient."

"They work mechanically, too, and only because water expands when it
turns to steam."

"This seems to do it differently," he said, sipping thoughtfully at
his dark-brown martini. "I don't know exactly how--maybe something
piezo-electric about the way its molecules slide about. I ran some
tests--measured its impact energy in foot pounds and compared that
with the heat loss in BTUs. Seemed to be about 98 per cent efficient,
as close as I could tell. Apparently it converts heat into bounce very
well. Interesting, isn't it?"

"_Interesting?_" I almost came flying out of my chair. My mind was
beginning to spin like crazy. "If you're not pulling my leg with this
thing, Farnsworth, you've got something by the tail there that's just
a little bit bigger than the discovery of fire."

He blushed modestly. "I'd rather thought that myself," he admitted.

"Good Lord, look at the heat that's available!" I said, getting really
excited now.

* * * * *

Farnsworth was still smiling, very pleased with himself. "I suppose
you could put this thing in a box, with convection fins, and let it
bounce around inside--"