"Is true. They nasty and plenty noisy. They hate work. Driver makes them carry tourists and they holler plenty."

The camel quieted down to a low-voiced grumble. He was letting the world know that the arrangement was not pleasing and that he didn't intend to suffer in silence. Cameras began to snap, recording for the folks back home the undignified ride of the lady tourist on the ungainly camel before the ancient, majestic pyramids and the changeless, unsmiling Sphinx.

The three got back into the little car and Ha.s.san took a road that curved gradually around a hill, past a hotel that he identified as the Mena House, and up to the largest pyramid, once the tomb of Khufu and still the greatest monument in all the world.

On a line into the desert were the slightly smaller pyramids of Kefren and Mankara. These, with the Sphinx, were among the Seven Wonders of the Ancient World.

Later, Rick promised Scotty, they would explore Giza and its wonders inch by inch. But now they were due at Sahara Wells. Ha.s.san sped around the Khufu pyramid and pointed. There, on the horizon, was a strange contrast to the monuments of the Pharaohs. The steel-and-aluminum shape of the great, steerable dish antenna, designed for modern astronomy, was silhouetted against the sky.

Rick was excited. He enjoyed new sights and experiences more than most people, and here, within sight of each other, were unique objects of almost equal interest, but entirely different.

The way led past a single large building surrounded by shabby tents, and a sign in English and Arabic that proclaimed that this was Sahara Wells.

Then the blacktop road curved out into the desert to the great radio telescope.

Ha.s.san drove into a parking lot before the main project building in the shadow of the antenna and Dr. Hakim Farid came out to greet the boys.

"Welcome to Sahara Wells," he said cordially. "How do you like our baby?"

Rick looked up at the huge dish. "It's a good mate for the pyramids," he said.

"Pretty impressive," Scotty added.

"We hope its performance will be impressive, too, once we get this bug ironed out. Come on in. Winston and Kerama are hard at work."

The boys followed him into the building, while Ha.s.san squatted in the sun next to his car. The door opened directly into the main control room, a bewildering confusion of panels, instruments, and controls.

There were several scientists and technicians cl.u.s.tered around Winston and Kerama. The group was studying Sanborn tracings, continuous graphs showing the lines traced by the incoming signals.

Farid introduced the boys to the staff, then took them on a quick tour.

He showed them the controls for the great dish. They were fully automatic. The operator needed only to set the co-ordinates for the part of the sky to be examined, then clock mechanisms of remarkable precision would keep the telescope on target until the target sank below the horizon.

The boys examined banks of amplifiers that would turn faint signals into usable ones. The latest techniques had been used to ensure maximum performance.

Outside, Farid showed them the self-contained diesel-electric power plant. They stood directly under the ma.s.sive concrete mount for the great dish and marveled at its size. The main bearings on which it moved were bigger around than Scotty was tall, yet the whole affair was so delicately balanced that a tiny electric motor could control it with fantastic precision.

Still under construction were offices and barracks. The latter would allow the scientists to stay there for days at a time when working on particular projects. The offices were nearly done, and plasterers were at work, but the forms for the barracks floor were just being completed.

The pouring of concrete would start on the following day.

Rick looked at the pyramids on the horizon and contrasted this scene of construction with the one that had produced the great tombs. Then, it was only men--thousands of them. Today, it was a handful of skilled workers plus machinery.

"Now," Farid said, "let's get back to the control room. Kerama is going to review the situation for the staff. Some of them are new on the job."

As Farid and the boys rejoined the others, Dr. Kerama was pointing to a series of peaks on the Sanborn tracings. "You will note that these peaks occur at intervals, with the s.p.a.cing apparently random. The main sequence of noise out of which the peaks rise is the 21-centimeter hydrogen line. Notice also that the peaks have nearly identical amplitudes. Obviously, the source is neutral hydrogen, which is to say hydrogen in its normal form, not ionized as we find it in plasma in a star's atmosphere. Our problem is simply to locate the source of the peaks. Somewhere in the circuit there seems to be an effect that serves to modulate the incoming signal. Our antenna will be useless unless we eliminate this interference so that the signal can be pure once again."

Rick had seen Sanborn tracings before. The system was a standard method of recording. His first experience with it had been in making permanent records of telemetered signals from rockets.

A technician asked, "Sir, do these peaks occur no matter how the antenna is pointing?"

Kerama shook his head. "No. If you will examine the peaks in terms of time and the co-ordinates, you will see that they began at a particular point during a sweep of the sky. Our first thought was that we had picked up some source emitting pulsed signals, but the source is apparently moving. This is why we concluded the difficulty was in our system, since no sky source moves with such angular velocity."

The Egyptian scientist began giving a.s.signments. Rick and Scotty were given a test kit and put to work checking a part of the circuit one wire at a time. It was slow, difficult work, requiring great care.

It was warm in the control room. Rick hung up his coat, pausing to touch the Egyptian cat in his pocket. He hadn't thought of the little beast for some time. What was he to do with it? From a simple delivery job, as a favor to an acquaintance, the cat had become a problem. Rick couldn't resist a mystery, but this one had him stopped cold for the time being.

He didn't know what to do next. The only solution that had occurred to him was to send a cable to Bartouki, to ask for further instructions.

He shrugged and put the problem aside, and went back to helping Scotty.

It was late before Kerama called a halt. The boys rode back to the hotel with Ha.s.san, grateful for the relief of concentrating on thousands of tiny wires. They told the dragoman to go on home, then went into the dining room for dinner before retiring for the night. Winston, who never seemed to tire when working, had stayed with Kerama and Farid to continue discussions of possible sources of trouble.

After dinner Rick picked up their key at the hotel desk and they rode the tiny elevator to their floor. They opened up and went in. Rick locked the door while Scotty snapped on the lights.

Scotty let out a sudden yell! Rick whirled and gasped. The room was a shambles. Every drawer was open and their contents were dumped out on the floor. Their suitcases had been left open. The bed-clothes were in a heap in the middle of the room, and the mattresses were on the floor.

Rick glanced at the key in his hand and realized that it was a very ordinary type; master keys that would allow a thief access could be bought in any hardware store. He followed Scotty to the closet and saw that their clothes had been searched and dropped carelessly. Nothing was left on the hangers.

The room had been searched inch by inch, and by someone in a hurry.

Rick's hand went to the Egyptian cat in his pocket.

"They wanted the cat," he said slowly. "I can't see that anything is missing. But why is the cat so important?"

He drew it out of his pocket and stared at it. Then his eyes met Scotty's. His pal shrugged. Neither of them had even the slightest clue.

CHAPTER VI

The Cat Has Kittens

The sun blazed down on Sahara Wells. In the distance the pyramids looked hazy, and beyond them Cairo was a thin line of green and brown along the Nile. It was fairly warm in the sun, but a cool wind blew across the desert and coats were comfortable.

Rick and Scotty sat on a box under the antenna while Ha.s.san squatted and watched them. For the moment there was nothing for them to do. The scientists were occupied with calculations, and neither boy could make a contribution to high mathematics of the kind used in radio astronomy.

Rick was glad of the break. His mind hadn't been on the job, anyway--it had been on the Egyptian cat. For perhaps the hundredth time he asked, "Why is the cat valuable? Why would anyone want it enough to stage that scene at El Mouski and then ransack our room?"

Scotty had no answers, but he had some questions of his own. "What I want to know is, did the hall porter just happen to step out at the right moment for the thief? Or is he in the act somehow?"

"It really doesn't make much difference," Rick pointed out. "He might have been paid to take a walk, but that doesn't mean he knows anything."

"Okay. Try this one. Where is the real Ali Moustafa?"

"Good question. Now I'll ask one. What do we do next?"

"You could cable Bartouki, or even phone him," Scotty replied. "You said you had thought about it."

Rick hesitated. He tried to put his reluctance into words. "I just don't think getting in touch with Bartouki is the right thing to do. I don't know why. Call it a hunch."