Hassan arrived during breakfast on the following morning. His colorful costume had given way to European clothes, except for a tarboosh. He wore a topcoat.

At Rick's invitation he joined the boys on the balcony overlooking the Nile, and accepted the offer of coffee. Rick went to the novel push-bell system which had three buttons identified by pictures. One was a porter, another the room maid, and the third a waiter. The little drawings were for the benefit of strangers who knew neither Arabic nor English.

Rick rang for the waiter and ordered more coffee and a cup for the dragoman.

Hassan shed his topcoat and grinned at the boys. "Cat catch mouse last night?"

"No mouse," Scotty replied. "The cat just caught some sleep. And so did we."

Hassan puzzled out the reply, then smiled his appreciation.

Rick thought that the cat hadn't even caught any interest—at least from the scientists. At dinner he and Scotty had described the incident at El Mouski to Winston and the Egyptian scientists. The scientists had only one suggestion, to the effect that perhaps the boys' imaginations had run away with them.

It was obvious that the scientists were far more interested in the problem of the radio telescope than in listening to tales of wild adventure in the bazaar, so the boys let the matter drop. They had excused themselves immediately after dinner and turned in, tired from the long plane trip and the day's excitement.

Rick had gone over the events at the bazaar a dozen times. He had compared notes with Scotty on what Bartouki had told them. Clearly, something was pretty strange about the whole affair. It was simply inconceivable that Bartouki would have given an inaccurate description of Ali Moustafa, so the man in the store had not been Bartouki's partner. Yet, he had known about the cat, and had called Rick by name. Who was he? And where was the real Ali Moustafa? There were no answers, at least for the present. But Rick didn't intend to give up.

He motioned to Hassan's coat. "Is it cold out today?"

"Yes. Good you wear coats when we go out. Later it will be warm, then cool again when sun goes."

The boys had decided to keep Hassan as a guide and driver during their entire stay. The dragoman's services were not expensive, and besides, both of them felt they had found a friend. The way Hassan had pitched in at the bazaar, with no questions asked and their interests obviously at heart, had been a fine example of professional loyalty coupled with a quick mind and fast reflexes.

After breakfast the boys went to the wardrobe and took out the coats they had brought. Rick's was brand new, a Christmas present from his father. It was a short, hip-length woolen coat that could double as a hunting jacket. In addition to the big outer pockets, it had inner game pockets lined with a leatherlike plastic. It was warm, but light. He was thoroughly pleased with it.

Scotty slipped into his own short coat, much like Rick's except for the game pockets. Then the ex-Marine motioned to the Egyptian cat, unwrapped and sitting in elegant repose on the writing desk. "What about Felix?" he asked.

Rick went over and picked up the cat. "We'd better take it along, I guess. It might get lonesome. Or we might run over Ali Moustafa on the way to the project." He slid the cat into an inner pocket. It fit with room to spare.

Scotty asked Hassan, with mock seriousness, "You know Sahara Wells?"

Hassan answered with equal seriousness. "Know Sahara Wells well."

The ride was an interesting one, up the Nile to a bridge different from the one they had crossed en route from the airport, along roads with a palm-shaded center strip, past mosques, stores, and airy, modern apartment houses. There was less traffic than in downtown Cairo, and Hassan went faster.

Scotty muttered, "Fewer close calls today."

Rick winced as the car almost scraped a woman with a basket of fruit balanced on her head. "Fewer, but closer."

The costumes on the street were mixed. There were many people, including women, in Western dress, but there were also many women in cloaks, and men in the traditional Arab bornoss, the enveloping robe called a burnoose in English. For the first time, the boys saw several men in blue gowns, and Rick asked Hassan what they were.

"Fellahin," Hassan replied. "How you say? Farmers. From country. Man tell me that is where your word 'fella' come from."

Rick looked with new interest. He had heard of the fellahin, the farmer-peasants of Egypt. Many of them lived and worked as their ancestors had centuries ago, plowing with wooden plows, living in mud-and-wattle houses. They represented the past of Egypt, as installations like the atomic energy plant at En-Shass, or Inchass as it was sometimes called, represented the future.

There were soldiers along the route, too, dressed in British-style brown uniforms. Some carried Sten guns, vicious little submachine guns originally of English manufacture.

"Why the soldiers?" Scotty asked.

"Camp near," Hassan replied.

And then, abruptly, the boys lost interest in people, because looming ahead, like something from a travel movie, was a pyramid!

Hassan rounded a corner and another pyramid came into view. They were enormous, Rick thought. He hadn't expected anything so huge. "Are we at Giza already?" he asked.

"This Giza," Hassan agreed. He pronounced it more like Gize'h.

"I always thought the pyramids were out in the desert," Scotty objected.

"Is true," Hassan said. "You will see."

They did, within minutes. The terrain changed from the green, fertile, Nile Valley to the bleak Sahara as though cut by a giant knife. For the first time, Rick understood the phrase "Egypt, gift of the Nile." Where the yearly Nile overflow brought fertile silt and moisture, there was lush green land. Where the overflow stopped, the desert began. No intermediate ground lay between. Egypt consisted of the Nile Valley and the desert, with nothing in between.

The road crossed the dividing line and they were in the Sahara Desert. Hassan drove between houses of faded red clay and tan stucco, unlike the modern apartments a few hundred yards back. It was as though they had driven into a different country. Children, goats, chickens, and Arab adults scattered before the car. It was a typical desert-country scene, and right at the edge of modern Cairo!

Hassan turned a sharp corner and Giza lay before them, up a gradual, rising slope.

In the immediate foreground was the Sphinx. Rick's first impression was that it was disappointingly small, as the great pyramids behind it were truly enormous. He could see all three Giza pyramids now.

Then he realized that his impressions had been gained entirely from pictures—and to an extent, the pictures had been false. The Sphinx, always shown in the foreground of pictures or taken from a low angle, loomed large in the camera lenses, with the pyramids looking relatively small in the distant background.

Human vision set the image straight, abruptly. The Sphinx was small, but only in comparison to the pyramids. Actually, it was a monument of heroic proportions.

"Please stop," Rick called, and Hassan did, with skidding wheels. The boys got out and stood gazing, in mixed awe and delight. This was the Egypt of antiquity, Rick thought. These were the monuments of a civilization already ancient when the Old Testament was new, monuments engineered with astounding precision when Rick's Anglo-Saxon forebears were still building crude shelters of mud and reeds.

Scotty's nudge aroused Rick from his reverie, and he turned for a close-up of his first live camel, not counting circuses or zoos. The camel was such a vision of homely awkwardness that Rick had to laugh.

The cameleer led the beast to where a party of tourists, obviously American, waited. The boys watched as the animal came to a halt. The driver bowed to the party. Then, taking a thin stick, he tapped the camel on bony knees that were wrapped in worn burlap. Instantly the camel let out a heartrending groan. Its ungainly legs folded like a poorly designed beach chair, and moaning in pure anguish, it knelt.

A lady tourist, giggling self-consciously, climbed up on the blanket-covered saddle. The camel let out a louder groan, one filled with such phony pain and despair that the boys burst out laughing. A tap of the driver's stick and the camel lurched to its feet, hind legs first like a cow. The lady tourist squealed mightily, the camel wailed in protest, the other tourists cheered, and the boys doubled with laughter.

Rick asked, still chuckling, "Hassan, do camels always complain like that?"

"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 Hassan 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. Hassan 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.

Hassan 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 Hassan 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 clustered 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 massive 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 spacing 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 assignments. 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 Hassan, 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.