ion, Alan unslung his pack and took out
the dog-eared book he knew so well. He riffled through its pages. _The
Cavour Theory_, it said in worn gold letters on the spine. He had read
the volume end-to-end at least a hundred times.

"I still can't see why you're so wild on Cavour," Rat grumbled, looking
up from his doll-sized sleeping-cradle in the corner of Alan's cabin.
"If you ever do manage to solve Cavour's equations you're just going to
put yourself and your family right out of business. Hand me my
nibbling-stick, like a good fellow."

Alan gave Rat the much-gnawed stick of Jovian oak which the Bellatrician
used to keep his tiny teeth sharp.

"You don't understand," Alan said. "If we can solve Cavour's work and
develop the hyperdrive, we won't be handicapped by the Fitzgerald
Contraction. What difference does it make in the long run if the
_Valhalla_ becomes obsolete? We can always convert it to the new drive.
The way I see it, if we could only work out the secret of Cavour's
hyperspace drive, we'd----"

"I've heard it all before," Rat said, with a note of boredom in his
reedy voice. "Why, with hyperspace drive you'd be able to flit all over
the galaxy without suffering the time-lag you experience with regular
drive. And then you'd accomplish your pet dream of going everywhere and
seeing everything. Ah! Look at the eyes light up! Look at the radiant
expression! You get starry-eyed every time you start talking about the
hyperdrive!"

Alan opened the book to a dog-eared page. "I know it can be done
eventually. I'm sure of it. I'm even sure Cavour himself actually
succeeded in building a hyperspace vessel."

"Sure," Rat said drily, switching his long tail from side to side. "Sure
he built one. That explains his strange disappearance. Went out like a
snuffed candle, soon as he turned on his drive. Okay, go ahead and build
one--if you can. But don't bother booking passage for me."

"You mean you'd stay behind if I built a hyperspace ship?"

"Sure I would." There was no hesitation in Rat's voice. "I like this
particular space-time continuum very much. I don't care at all to wind
up seventeen dimensions north of here with no way back."

"You're just an old stick-in-the mud." Alan glanced at his wristchron.
It read 0852. "Time for me to get to work. Kelleher and I are packing
frozen dinosaur today. Want to come along?"

Rat wiggled the tip of his nose in a negative gesture. "Thanks all the
same, but the idea doe