smile.

Rick knew from Winston's advance briefing that these were the two
leading radio astronomers of the United Arab Republic, and that both had
international reputations in the field.

The Egyptian scientists made the boys feel at home right away. Dr.
Kerama took Scotty and Winston by the arms, and Dr. Farid fell in step
with Rick as the group walked toward the administration building.

"We're glad you could come," Farid said in excellent English. "We'll try
to make your visit interesting."

Rick thanked him. "I don't know whether we'll be of much use, but we're
willing to do anything we're told. All we ask is a little chance to see
your country."

"You'll have every chance," Dr. Farid told him. "Before there is any
work for you, Parnell will have to do a pretty thorough analysis of data
we've collected. It's a problem that has us ... what's the American
expression? Buffaloed?"

"That's it," Rick agreed. "What kind of problem is it?"

"It's what you might call very strange behavior on the part of a
hydrogen-line impulse we picked up while calibrating our receiver. Are
you familiar with radio astronomy?"

"Not very," Rick admitted. "I tried to read some of the current
literature when I found we were coming, but most of it is over my head."

"Then I won't bore you with a technical discussion. Briefly, the noise
emitted by hydrogen gas in space is very important to us in our analysis
of the nature and distribution of matter. This radio noise is, of
course, random. Usually when we are examining a hydrogen source we get
pretty continuous and regular signals. If we could hear it, there would
be a sort of hissing noise. Do you follow me?"

"So far."

"Good. Our problem is that we are picking up impulses. You might even
call them signals. They are on the frequency of neutral hydrogen, but
it's hard to believe they're natural in origin. We've about concluded
that somehow our amplifier system is modulating the incoming hydrogen
signal from the antenna. The trouble is, we can't locate the cause."

"Is that why you called Dr. Winston?" Rick asked.

"Yes. He has a reputation for finding bugs in electronic circuits. If he
can find this one, we'll be tempted to reward him with a pyramid or
something appropriate."

Rick saw the twinkle in Dr. Farid's eyes. "Better not make it a
pyramid," he said hastily. "His luggage is limited to sixty-six pounds.
They might not let him on the plane with it."

"A happy thought,"