They exchanged personal histories briefly. By now, Maitland nodeed, there were so many disaster stories, so many confirmed and unconfirmed episodes of heroism, such a confusion of dramatic and tragic events that those still surviving confined themselves to the barest self-identification. In addition, there was the gradual numbness that had begun to affect everyone, a blunting of the sensibilities, by the filth and privation and sheer buffeting momentum of the wind. The result was an increasing concentration on ensuring one's own personal survival, a reluctance, such as he had just seen in a basically confident man like Halliday, to put any trust in the durability of others.

"Our last trip we carried only three passengers," Halliday explained, "so a medic wasn't needed. It's obvious they'll soon be closing the unit down."

Maitland nodded. "What will happen to us then?"

Halliday glanced up at him briefly, then flung his cigarette butt into the coffee dregs. "I'll leave you to guess. Frankly, we rate a pretty low order of importance. As long as movement above surface is possible, the big tractors have a valuable role, but now-well… Just about all the VIP's have got where they want to be; the perimeter's really being pulled in tight. Have you been up top recently?"

"Not for about a week," Maitland admitted.

"It's hard to describe-pretty rough. Solid roaring wall of black air-except that it's not air any more but a horizontal avalanche of dust and rock, like sitting right behind a jet engine full on with the exhaust straight in your face. Can't see where the hell you're going, landmarks obliterated, roads buried under tons of rubble. We steer by the beam transmitted between here and Portsmouth. When the stations close down our job will be over. Only yesterday we lost one of the big rigs-their radio broke down when they were somewhere south of Leatherhead. They tried to make it back by compass and drove straight into the river."

As they neared the tractor Maitland saw a small group of passengers waiting, two men and a young woman. All the hatches were being secured on the rear section of the vehicle, and it looked as if these three were the full complement and would travel in the forward section, leaving the rear empty. As Halliday had said, it seemed a complete waste of fuel and personnel-the Titan would have been better employed rescuing Andrew Symington and Marshall-and Maitland felt a sudden sensation of resentment toward the three passengers.

One was a small plump-faced man with a brush moustache, the other two a tall American in a navy trench coat and the girl wearing a leather helmet, goggles over her forehead. As he approached she slipped her hand under the American's arm, and he recognized the couple who had passed him in the lounge bar.

Halliday gestured Maitland over, introduced him briefly to the passengers. "Commander Lanyon, this is Dr. Maitland. He'll be riding down to Portsmouth with us. If you want your temperature taken, Miss Olsen, just ask him."

Maitland nodded to the trio and helped the young woman, an NBC television reporter, carrying her tape recorder over to the starboard hatchway. She and Commander Lanyon had just reached England from the Mediterranean, had come up to London with the third member of the group, an Associated Press correspondent called Waring, in the hope of getting material for their networks back in the States. Unfortunately their hopes that the wind would have subsided had not been fulfilled, and they were returning empty-handed, en route for Greenland.

Ten minutes later the seven of them-three passengers, Maitland, Halliday, the driver and radio operator-were sealed down into the forward section of the Titan, a narrow compartment 15 feet long by six feet wide, packed with equipment, stores and miscellaneous baggage. Canvas racks folded down from the sides and Maitland and the passengers sat cramped together on these, the three crew members up forward, Halliday at the periscope immediately behind the driver, the radio operator beside him. A single light behind a grille on the ceiling cast a thin glow over the compartment, fading and brightening as the engines varied in speed.

For half an hour they hardly moved, edging forward or backward a few yards in answer to instructions transmitted over the R/T. The roar of the engines precluded any but the most rudimentary conversation between those at the back, and Maitland let himself sink off into a mindless reverie, interrupted by sudden jolts that woke him back to an uneasy reality.

Finally they began to move forward, the engines surging below them, and at the same time the vehicle tilted backward sharply, at an angle of over 10°, as they climbed the exit ramp.

The air in the tractor became suddenly cooler, as if a powerful refrigerating unit had been switched on in the compartment. They appeared to be moving along a tunnel carved through an iceberg, and Maitland remembered someone at the base telling him that the surface air temperature was now falling by a full degree per day. The air stream moving over the oceans was forcing an enormous uptake of water by evaporation, and consequently cooling the surfaces below.

The Titan leveled off on the final exit shelf, then labored slowly up the last incline.

Immediately, as the huge vehicle slewed about unsteadily, its tracks searching for equilibrium in the ragged surface, the familiar tattoo of thousands of flying missiles rattled across the sides and roof around them like endless salvos of machine-gun fire. The noise was enervating, occasionally appearing to slacken off slightly, then resuming with even greater force as a cloud of higher-density particles drove across them.

Standing behind the driver, Halliday steered the Titan by looking through the periscope. Occasionally, when they moved across open country, he left the driver to follow the compass bearing pro. vided by the radio operator, and came back to the passengers, crouching down to exchange a few words.

"We're just passing through Biggin Hill," he told them after they had been under way for half an hour. "Used to be an RAP base here, but it was flooded out after the east wall of the main shelter collapsed. About five hundred people were trapped inside; only six got away.

"Can I take a look outside, Captain?" Patricia Olsen asked. "I've been underground so long I feel like a mole."

"Sure," Halliday agreed. "Not that there's a damn thing to see."

They all moved forward, swaying from side to side like straphangers on a rocking Underground train as the tractor slid and dragged under the impact of the wind.

Maitland waited until Lanyon and Patricia had finished, then pressed his eyes to the binocular viewpiece.

Sweeping the periscope around, he saw that they were moving along the remains of the M5 Motorway down to Portsmouth.

Little of the road was still intact. The soft shoulders and grass center pieces between the lanes had disappeared, leaving in their place a four-foot-deep hollow trough. Here and there the stump of a concrete telegraph pole protruded from the verge, or a battered. overpass, huge pieces chipped from its arches, spanned the roadway, but otherwise the landscape was completely blighted. Occasionally a dark shadow would flash by, the remains of some airborne structure-aircraft fuselage or motor car-bouncing and cartwheeling along the ground.

Maitland leaned against the periscope mounting. With the topsoil gone, and the root-system which held the surface together and provided a secure foothold for arable crops against the erosive forces of rain and wind, the entire surface of the globe would dust bowl in the way that the Oklahoma farmland had literally disappeared into the air in the 1920's.

As he turned away from the periscope, Halliday was right beside the radio operator. A signal was coming through from Brandon Hall, and the operator took off his headphones and passed them to the captain.