m the disabled
engines, we would have evidence of the presence of a new factor. Then we
could proceed with a determination of what effect, if any, this factor
has on the engines."

Ken looked around the group once more. "Any comments, suggestions,
arguments? There being none, we'll consider the project approved, and
get to work this afternoon."

As they left to go to their first classes, Ted shook his head gloomily.
"Man, you don't know what you're biting off! All we've done so far is
build a few ham radios, a telescope, and some Geiger counters. You're
talking about precision work now, and I mean _pree_-cision!"

Throughout the day Ken, too, felt increasing doubts about their ability
to carry off the project. It would be a task of tremendous delicacy to
analyze such microscopic samples as they might succeed in obtaining.
Microchemical methods would be necessary, and none of them had had any
experience in that field. His father was an expert with these methods
and though he might scold them for tackling such a difficult project,
he'd help them, Ken thought. He always had.

This was no ordinary project, however. Ken had no idea how seriously
scientists in general were considering the comet as the offender, but
certainly they must be working frantically on the problem of the
mechanical disorder. Unless they found another cause very soon, they
were certain to turn to an analysis of the comet's tail. It would be
very satisfying if Ken's group could actually be in the vanguard of such
a development.

He tried to ridicule his own conviction that the comet held the key. He
had no reason whatever for such a belief, except the fact of the comet's
universal presence. How it could stop an automobile engine or a railroad
train was beyond his wildest imaginings.

But there was nothing else. Nothing at all.

On the way home after school, there seemed to Ken to be a subtle change
that had come over the valley since morning. Along the streets, cars
were parked in front of houses to which they did not belong. Little
knots of people were standing about, talking in hushed tones. The comet
was aflame in the sky.

There seemed to be not merely an awe and an uneasiness in the people,
but a genuine fear that Ken could not help absorbing as he moved past
them on the sidewalks. Their faces were yellow and flat under the glare
of the comet, and they looked at him and at each other as if they were
strangers in an alien land.

Almost w