without enjoyment. By that time well over
three-quarters of the Air Force on the Pacific Coast was airborne and
more planes shot skyward instant after instant. Inevitably the
multiplied air traffic was noted by civilians. Reporters began to
telephone airbases to ask whether a practice alert was on, or
something more serious.

Such questions were natural, these days. All the world had the
jitters. To the ordinary observer, the prospects looked bad for
everything but disaster. There was a crisis in the United Nations,
which had been reorganized once and might need to be shuffled again.
There was a dispute between the United States and Russia over
satellites recently placed in orbit. They were suspected of carrying
fusion bombs ready to dive at selected targets on signal. The Russians
accused the Americans, and the Americans accused the Russians, and
both may have been right.

The world had been so edgy for so long that there were fallout
shelters from Chillicothe, Ohio, to Singapore, Malaya, and back again.
There were permanent trouble spots at various places where practically
anything was likely to happen at any instant. The people of every
nation were jumpy. There was constant pressure on governments and on
political parties so that all governments looked shaky and all
parties helpless. Nobody could look forward to a peaceful old age, and
most hardly hoped to reach middle age. The arrival of an object from
outer space was nicely calculated to blow the emotional fuses of whole
populations.

But Lockley ate his breakfast without premonitions. Breezes blew and
from every airbase along the coast fighting planes shot into the air
and into formations designed to intercept anything that flew on wings
or to launch atom-headed rockets at anything their radars could detect
that didn't.

At eight-twenty, Lockley went to the electronic base line instrument
which he was to use this morning. It was a modification of the devices
used to clock artificial satellites in their orbits and measure their
distance within inches from hundreds of miles away. The purpose was to
make a really accurate map of the park. There were other instruments
in other line-of-sight positions, very far away. Lockley's schedule
called for them to measure their distances from each other some time
this morning. Two were carefully placed on bench marks of the
continental grid. In twenty minutes or so of cooperation, the
distances of six such instruments coul