car was
crossing a high rise, where they caught a glimpse of a pale moon newly
risen in the distance. The car stopped suddenly and several figures
took shape out of the dark beside it--these were negroes also. Again
the two young men were saluted in the same dimly recognisable dialect;
then the negroes set to work and four immense cables dangling from
overhead were attached with hooks to the hubs of the great jewelled
wheels. At a resounding "Hey-yah!" John felt the car being lifted
slowly from the ground--up and up--clear of the tallest rocks on both
sides--then higher, until he could see a wavy, moonlit valley
stretched out before him in sharp contrast to the quagmire of rocks
that they had just left. Only on one side was there still rock--and
then suddenly there was no rock beside them or anywhere around.

It was apparent that they had surmounted some immense knife-blade of
stone, projecting perpendicularly into the air. In a moment they were
going down again, and finally with a soft bump they were landed upon
the smooth earth.

"The worst is over," said Percy, squinting out the window. "It's only
five miles from here, and our own road--tapestry brick--all the way.
This belongs to us. This is where the United States ends, father
says."

"Are we in Canada?"

"We are not. We're in the middle of the Montana Rockies. But you are
now on the only five square miles of land in the country that's never
been surveyed."

"Why hasn't it? Did they forget it?"

"No," said Percy, grinning, "they tried to do it three times. The
first time my grandfather corrupted a whole department of the State
survey; the second time he had the official maps of the United States
tinkered with--that held them for fifteen years. The last time was
harder. My father fixed it so that their compasses were in the
strongest magnetic field ever artificially set up. He had a whole set
of surveying instruments made with a slight defection that would allow
for this territory not to appear, and he substituted them for the ones
that were to be used. Then he had a river deflected and he had what
looked like a village up on its banks--so that they'd see it, and
think it was a town ten miles farther up the valley. There's only one
thing my father's afraid of," he concluded, "only one thing in the
world that could be used to find us out."

"What's that?"

Percy sank his voice to a whisper.

"Aeroplanes," he breathed. "We've got half a dozen anti-aircraf