Quickly he began to hammer away at the set, smashing in the compass and plunging the torch into the valve-crammed cabinet. Shouting to Halliday, the operator struggled to his feet and tried to pull Maitland away. Then Halliday swung back from the periscope and flung his arms around Maitland's shoulders. The three men wrestled together, their blows muffled by the swaying vehicle and their heavy clothing, then fell to the floor.
As they struggled onto their knees, the tractor, still following the circular course Halliday had been giving to the driver, tipped over sharply as it left the roadway and ran rapidly down the incline.
Halliday pulled Maitland to his feet, his face thick with anger. Lanyon had joined them, and helped the radio operator to rise. The corporal stumbled over to the set and stared blankly at the wrecked console, his fingers numbly tracing the ragged outlines of the compass.
He looked wildly at Halliday. "The set's a write-off, Captain, a total wreck! God knows what our bearing was! We were moving around that bend. I wasn't watching it."
Halliday wrenched at Maitland's jacket. "You damn fool! Do you realize we're completely lost?"
Maitland shook himself free. "No you're not, Captain. I hate to force your hand, but it was the only way. Look."
He reached across to the vhf set and turned up the volume, so that the staccato gabble of the mysterious station sounded out into the compartment over the noise of the wind beating against the tractor. With one hand he rotated the set in its bearings until, at an angle of 45° to the lateral axis of the tractor, it was at maximum strength.
"Our new direction beam. Follow that and it should take us straight to Hardoon Tower."
"How can you be sure?" Halliday snapped. "It could be anything!"
Maitland shrugged. "Maybe, but it's our only chance." He turned to Lanyon, quickly explained what had happened to Andrew Symington.
Lanyon pondered this for a few minutes, then turned to Halliday, who was peering through the periscope.
"Seems as if we've no alternative, Captain. As it's only a few miles away, a short detour won't hurt us. And there's always the chance that if this fellow Hardoon is planning some sort of takeover when the wind blows out, we may be able to anticipate him."
Halliday clenched his fists, scowling angrily, then nodded and swung back to the periscope.
Five minutes later they reversed onto the highway and moved off down a side road toward Leatherhead, following the vfh signal. Maitland had expected that they would have difficulty in locating Hardoon Tower, but Halliday soon noticed something that confirmed his suspicions about Hardoon.
"Take a look for yourself," Halliday said. "This road has been used regularly all through the last four or five weeks. There's even wire mesh laid down at the exposed corners."
Lanyon took the periscope, confirmed this with a nod. "Heavy tracked vehicles," he commented. "Must have been carrying some really big loads." Grinning, he added: "Looks as if Pat may get a story after all."
They followed the signal, steadily increasing in strength, toward the Hardoon estates at Leatherhead, as much guided by signs of recent activity along the road as by the radio beam, the wind pushing them on at a steady 25 mph.
Two hours later they had their first sight of Hardoon Tower.
Maidand was doing his 15-minute turn at the periscope when the operator told him that they had entered the zone of maximum signal strength.
"Could be anywhere within a couple of square miles of here," be reported, swinging the direction-finder aerial without influencing the volume. "From now on we'll have to make visual contact."
Maitland peered through the periscope. Ahead the roadway had broadened into a furrowed band of shattered concrete and wire mesh about 1 oo yards wide, stained with huge white and gray patches which suggested some enormous roadwork had recently been in progress. The tractor edged forward along the center at 15 mph, tacking from left to right across the band. Two hundred yards away the road disappeared into the dim whirling mass of the wind stream. Beside the roadway the ground was black and dark, devoid of all vegetation, dotted with a few huge rolling objects, stumps of giant trees, blocks of masonry, all moving from left to right across their path.
Ahead, high in the air, something loomed for a moment, a lighter patch of sky, apparently an interval in the dust cloud. Maitland ignored it, searching the ground carefully for any hidden side turning.
A few seconds later he realized that the strip of lighter air was still in front of him.
Straight ahead, its massive bulk veiled by the duststorm, an enormous pyramidlike structure reared up, its four-angled sides 100 feet across at the base, tapering to the apex 80 feet above. The tractor was now about a quarter of a mile away and, although partly obscured, the pyramid was the first structure Maitland had seen for weeks which retained hard clean outlines. Even at this distance he could see its straight profiles, the perfectly pointed apex, cleaving the dark air stream like the prow of a liner.
He gestured Halliday over to the periscope. As the captain whooped in surprise, Maitland gestured to Lanyon.
"It looks as if Hardoon's strongpoint is up ahead. About three or four hundred yards away. A huge concrete pryamid."
"It's fantastic," Halliday said over his shoulder, centering the periscope. "Who does the maniac think he is-Cheops? Must have taken years to build."
He handed over the periscope to Lanyon, who nodded slowly. "Either years or thousands of men. The roadways indicate there's been a pretty big construction force on the job."
They edged nearer the pyramid; its great bulk rising above into the flickering sky. Two hundred yards away the tractor struck a low obstacle with its offside front track, and they looked down at a low wall, ten feet high, rising out of the ground and running in the direction of the left-hand corner of the pyramid. The wall was ten feet wide, a massive reinforced concrete buttress. As they moved along it, a second rampart appeared out of the gravellike soil on their right, and they found themselves entering a long approach system of parallel concrete walls, partly intended as windbreakers for the pyramid, and partly to screen entering vehicles.
Maitland searched the face of the pyramid for apertures, but its surface was smooth and unbroken. Gradually, as the height of the supporting walls increased, it was lost from sight and they entered a narrow ramp that led below an overhanging shoulder and then around a right-angle corner into what appeared to be a dead end.
Halliclay tilted back the periscope, craning to look up at the great bulk of the pyramid obscured by the stream of dust and gravel cascading across its surface.
"Looks as if this isn't an approach road after all," Halliday commented. "No entrance bays or locks. We'll have one hell of a job reversing out of here. Why don't they put up some signs?"
Suddenly they swayed on their feet, grabbed at the ceiling straps. The tractor had dropped abruptly, was moving steadily downward like an elevator.
Maitland dived for the periscope, just in time to see the walls around them soar upward into the air, the apex of the pyramid disappear. Seconds later the rectangular outlines of an elevator opening rose above them. The black sides of the shaft ran past, then slowed down as the elevator reached its floor. A horizontal lock slid across the opening and sealed it, shutting out the daylight.
"Well, they must be friendly," Halliday decided. "I was beginning to wonder how we'd get in if they didn't want us."
The driver cut the engines, and as the din subsided they heard mechanics outside the tractor shackling exit ladders to its turret. Halliday began to unlock the hatchway, motioned to the others to get to their feet.
"Stretch your legs, everybody. May be our last chance for days."
He opened the hatch, raising it a few inches, and someone on the roof pulled it back. He climbed out, followed by Maitland and the radio operator.