t!"

Murgatroyd said "_Chee!_" in a subdued voice.

"But where the devil did they put them?" demanded Calhoun. "A polar
orbit would be ridiculous! They--" Then he grunted in disgust. "Oh! Of
course! Now, where's the landing-grid?"

He worked busily for minutes, checking the position of the Wealdian
landing-grid--mapped in the Sector Directory--against the look of
continents and seas on the half-disk so plainly visible outside. He
found what he wanted. He put on the ship's solar-system drive.

"I wish," he complained to Maril, "I wish I could think straight the
first time! And it's so obvious! If you want to put something out in
space, and not have it interfere with traffic, in what sort of orbit and
at what distance will you put it?"

Maril did not answer.

"Obviously," said Calhoun, "you'll put it as far as possible from the
landing-pattern of ships coming in to the space-port. You'll put it on
the opposite side of the planet. And you'll want it to stay out of the
way, where anybody can know it is at any time of the day or night
without having to calculate anything. So you'll put it out in orbit so
it will revolve around Weald in exactly one day, neither more or less,
and you'll put it above the equator. And then it will remain quite
stationary above one spot on the planet, a hundred and eighty degrees
longitude away from the landing-grid and directly over the equator."

He scribbled for a moment.

"Which means forty-two thousand miles high, give or take a few hundred,
and--here! And I was hunting for it in a close-in orbit!"

He grumbled to himself. He waited while the solar-system drive pushed
the Med Ship a quarter of the way around the bright planet below. The
sunset line vanished and the planet's disk became a complete circle.
Then Calhoun listened to the monitor earphones again, and grunted once
more, and changed course, and presently made a noise indicating
satisfaction.

Again presently he abandoned instrument-control and peered directly out
of a port, handling the solar-system drive with great care. Murgatroyd
said depressedly;

"_Chee!_"

"Stop worrying," commanded Calhoun. "We haven't been challenged, and
there is a beacon transmitter at work, just to make sure that nobody
bumps into what we're looking for. It's a great help, because we do want
to bump,--gently."

Stars swung across the port out of which he looked. Something dark
appeared,--and then straight lines and exact curvings. Even Ma