“Those are Kigani villages,” Munro said, looking back, shaking his head. “They haven’t a prayer, especially since the men in those helicopters and the troops on the ground are all from the Abawe tribe, the traditional enemy of the Kigani.”

The twentieth-century world did not accommodate man-eating beliefs; indeed, the government in Kinshasa, two thousand miles away, had already decided to “expunge the embarrassment” of cannibals within its borders. In June, the Zaire government dispatched five thousand armed troops, six rocket-armed American UH-2 helicopters, and ten armored personnel carriers to put down the Kigani rebellion. The military leader in charge, General Ngo Muguru, had no illusions about his directive. Muguru knew that Kinshasa wanted him to eliminate the Kigani as a tribe. And he intended to do exactly that.

During the rest of the day, they heard distant explosions of mortar and rockets. It was impossible not to contrast the modernity of this equipment with the bows and arrows of the Kigani they had seen. Ross said it was sad, but Munro replied that it was inevitable.

“The purpose of life,” Munro said, “is to stay alive. Watch any animal in nature-all it tries to do is stay alive, it doesn’t care about beliefs or philosophy. Whenever any animal's behavior puts it out of touch with the realities of its existence, it becomes extinct. The Kigani haven’t seen that times have changed and their beliefs don’t work. And they’re going to be extinct.”

“Maybe there is a higher truth than merely staying alive,” Ross said.

“There isn’t,” Munro said.

They saw several other parties of Kigani, usually from a distance of many miles. At the end of the day, after they had crossed the swaying wooden bridge over the Moruti Gorge, Munro announced that they were now beyond the Kigani territory and, at least for the time being, safe.

IN A HIGH CLEARING ABOVE MORUTI, THE “PLACE of soft winds,” Munro shouted Swahili instructions and Kahega’s porters began to unpack their loads. Karen Ross looked at her watch. “Are we stopping?”

“Yes,” Munro said.

“But it’s only five o’clock. There’s still two hours of light left.”

“We stop here,” Munro said. Moruti was located at 1,500 feet; another two hours’ walking would put them down in the rain forest below. “It’s much cooler and more pleasant here.”

Ross said that she did not care about pleasantness.

“You will,” Munro said.

To make the best time, Munro intended to keep out of the rain forest wherever possible. Progress in the jungle was slow and uncomfortable; they would have more than enough experience with mud and leeches and fevers.

Kahega called to him in Swahili; Munro turned to Ross and said, “Kahega wants to know how to pitch the tents.”

Kahega was holding a crumpled silver ball of fabric in his outstretched hand; the other porters were just as confused, rummaging through their loads, looking for familiar tent poles or stakes, finding none.

The ERTS camp had been designed under contract by a NASA team in 1977, based on the recognition that wilderness expedition equipment was fundamentally unchanged since the eighteenth century. “Designs for modern exploration are long overdue,” ERTS said, and asked for state-of the-an improvements in lightness, comfort, and efficiency of expedition gear. NASA had redesigned everything, from clothing and boots to tents and cooking gear, food and menus, first-aid kits, and communications systems for ERTS wilderness parties.

The redesigned tents were typical of the’ NASA approach. NASA had determined that tent weight consisted chiefly of the structural supports. In addition, single-ply tents were poorly insulated. If tents could be properly insulated, clothing and sleeping-bag weight could be reduced, as could the daily caloric requirements of expedition members. Since air was an excellent insulator, the obvious solution was an unsupported, pneumatic tent: NASA designed one that weighed six ounces.

Using a little hissing foot pump, Ross inflated the first tent. It was made from double-layer silvered Mylar, and looked like a gleaming ribbed Quonset hut. The porters clapped their hands with delight; Munro shook his head, amused; Kahega produced a small silver unit, the size of a shoebox. “And this, Doctor? What is this?”

“We won’t need that tonight. That’s an air conditioner,” Ross said.

“Never go anywhere without one,” Munro said, still amused.

Ross glared at him. “Studies show,” she said, “that the single greatest factor limiting work efficiency is ambient temperature, with sleep deprivation as the second factor.”

“Really.”

Munro laughed and looked to Elliot, but Elliot was studiously examining the view of the rain forest in the evening sun. Amy came up and tugged at his sleeve.

Woman and nosehair man fight, she signed.

Amy had liked Munro from the beginning, and the feeling was mutual. Instead of patting her on the head and treating her like a child, as most people did, Munro instinctively treated her like a female. Then, too, he had been around enough gorillas to have a feeling for their behavior. Although he didn’t know ASL, when Amy raised her arms, he understood that she wanted to be tickled, and would oblige her for a few moments, while she rolled grunting with pleasure on the ground.

But Amy was always distressed by conflict, and she was frowning now. “They’re just talking,” Elliot assured her.

She signed, Amy want eat.

“In a minute.” Turning back, he saw Ross setting up the transmitting equipment; this would be a daily ritual during the rest of the expedition, and one which never failed to fascinate Amy. Altogether, the equipment to send a transmission ten thousand miles by satellite weighed six pounds, and the electronic countermeasures, or ECM devices, weighed an additional three pounds.

First, Ross popped open the collapsed umbrella of the silver dish antenna, five feet in diameter. (Amy particularly liked this; as each day progressed, she would ask Ross when she would “open metal flower.”) Then Ross attached the transmitter box, plugging in the krylon-cadmium fuel cells. Next she linked the anti-jamming modules, and finally she hooked up the miniaturized computer terminal with its tiny keyboard and three-inch video screen.

This miniature equipment was highly sophisticated. Ross’s computer had a 189K memory and all circuitry was redundant; housings were hermetically sealed and shockproof; even the keyboard was impedance-operated, so there were no moving parts to get gummed up, or admit water or dust.

And it was incredibly rugged. Ross remembered their “field tests.” In the ERTS parking lot, technicians would throw new equipment against the wall, kick it across the concrete, and leave it in a bucket of muddy water overnight. Anything found working the next day was certified as field-worthy.

Now, in the sunset at Moruti, she punched in code coordinates to lock the transmission to Houston, checked signal strength, and waited the six minutes until the transponders matched up. But the little screen continued to show only gray static, with intermittent pulses of color. That meant someone was jamming them with a “symphony.”

In ERTS slang, the simplest level of electronic jamming was called “tuba.” Like a kid next door practicing his tuba, this jamming was merely annoying; it occurred within limited frequencies, and was often random or accidental, but transmissions could generally pass through it. At the next level was “string quartet,” where multiple frequencies were jammed in an orderly fashion; next was “big band,” where the electronic music covered a wider frequency range; and finally “symphony,” where virtually the full transmission range was blocked.

Ross was now getting hit by a “symphony.” To break through demanded coordination with Houston-which she was unable to arrange-but ERTS had several prearranged routines. She tried them one after another and finally broke the jamming with a technique called interstitial coding. (Interstitial coding utilized the fact that even dense music had periods of silence, or interstices, lasting microseconds. It was possible to monitor the jamming signals, identify regularities in the interstices, and then transmit in bursts during the silences.)