al and line it on the
inside with relux wherever we want it to be opaque. And we want relux
shutters on the windows. Lux is too doggone transparent; if we came too
close to a hot star, we'd be badly burned."

Fuller looked almost goggle-eyed. "_A--foot--of--lux!_ Good Lord,
Arcot! This ship would weigh a quarter of a million tons! That stuff is
_dense_!"

"Sure," agreed Arcot, "but we'll need the protection. With a ship like
that, you could run through a planetoid without hurting the hull. We'll
make the relux inner wall about an inch thick, with a vacuum between
them for protection in a warm atmosphere. And if some tremendous force
did manage to crack the outer wall, we wouldn't be left without
protection."

"Okay, you're the boss," Fuller said resignedly. "It's going to have to
be a big ship, though. I figure a length of about two hundred feet and a
diameter of around thirty feet. The interior I'll furnish with aluminum;
it'll be cheaper and lighter. How about an observatory?"

"Put it in the rear of the ship," Wade suggested. "We'll mount one of
the Nigran telectroscopes."

"Control room in the bow, of course," Morey chipped in.

"I've got you," Fuller said. "I'll work the thing out and give you a
cost estimate and drawings."

"Fine," said Arcot, standing up. "Meanwhile, the rest of us will work
out our little exhibition to impress Mr. Morey and Dad. Come on, lads,
let's get back to the lab."

III

It was two weeks before Dr. Robert Arcot and his old friend Arthur
Morey, president of Transcontinental Airways, were invited to see what
their sons had been working on.

The demonstration was to take place in the radiation labs in the
basements of the Transcontinental building. Arcot, Wade, Morey, and
Fuller had brought the equipment in from the country place in Vermont
and set it up in one of the heavily-lined, vault-like chambers that were
used for radiation experiments.

The two older men were seated before a huge eighty-inch
three-dimensional television screen several floors above the level where
the actual demonstration was going on.

"There can't be anyone in the room, because of radiation burns,"
explained Arcot, junior. "We could have surrounded the thing with relux,
but then you couldn't have seen what's going on.

"I'm not going to explain anything beforehand; like magic, they'll be
more astounding before the explanation is given."

He touched a switch. The cameras began to operate, an