110 .

Tom cautioned the girls about wearing their boots at all times while walking around. "Watch out for snakes and poisonous Gila monsters," he warned.

It had been arranged that Bud and the girls would live in the Sky Queen, with Chow as chaperon. They would carry on their sightseeing from there by helicopter. Tom would commute back and forth to the Citadel by jeep.

"If that cloud of dust out there is what I think it is," he said, "a fleet of our trucks is coming to meet us now and carry the equipment back."

A few minutes later the trucks rolled up to the plane, kicking dust and sand in every direction. Three of the vehicles were to take Tom, Sterling, Hanson, and equipment to the plant. The fourth was on its way to the only nearby settlement to pick up mail.

"While I'm getting the robot set up," Tom said to Bud, "why don't you act as the girls' escort. You might enjoy a visit to town right now on the mail truck. I've heard that it's an old, one-street, frontier-type setup with all the pioneer-day atmosphere."

Intrigued at the thought, the girls and Bud climbed aboard the truck, and rode off.

Tom, Sterling, and Hanson, using cranes and hoists from the Flying Lab, loaded the small walking robot onto one truck and derricked the drone plane onto the trailer of another.

At six o'clock the convoy set out to navigate the wasteland stretch to the plant. The vehicles picked ARV UNDER SUSPICION 111.

their way over the terrain, avoiding boulders and gullies.

As they rode along, Tom and his two technical advisers, who were alone in one truck, discussed their plans. Tom voiced the hope that the misinformation he had dictated on the tape recorder in his office would reach the Briggin gang and prevent another encounter with them.

"Don't count on that wish too much, Tom," warned Hank Sterling, who had been staring up at the sky. "Look at the formation of crows coming over the horizon."

The flock of large birds, black against the sun, were winging their way directly toward the course being followed by the trucks. Tom watched tensely. In a matter of seconds the two paths would intersect as the trucks moved out of the shadow of a nearby mesa!

"Get ready to break up the motorcade line," Tom radioed to the other trucks.

Then to Hanson he said, "Take a look at them through your binoculars."

Hanson grabbed the binoculars and trained them on the birds. "They're not crows!" he reported. "Real or mechanical. They're vultures!"

They all breathed easier and Tom reversed his order to the drivers ahead of him.

"I never thought I'd be so happy to see vultures," he said with a wry smile. "I still have hopes that they'll believe the false facts I dictated and start looking for us down in Louisiana."

112 .

"Are you sure they got that message?" Hank asked.

"We can only hope Marco mails that one too," Tom said. "By the way, Rad is out at Blackstone Hospital checking on all patients and workers with whom Marco might have been friendly."

Hank gave a start. "You think some mental case might be mixed up in this deal?"

"Could be," said Tom.

As the line of vehicles drew closer to the Citadel, Tom and the others became aware of its immense size. Though they were still a mile away, the buildings loomed up like a vast fortress.

At last they reached the outer barbed-wire electrified fence surrounding the entire installation. Tom stopped before a wide gate where a guard's shack stood.

The other trucks rolled to a stop, one behind another.

A uniformed member of the security police approached Tom's truck. "This the Swift party?" he inquired, glancing in the cab.

"That's right," replied Tom, pleased to note that security measures were being enforced. "Here are our pa.s.ses. I'm Tom Swift. This is Mr. Sterling and Mr.

Hanson."

The uniformed guard took the pa.s.ses, examined them, and said Tom and Hank might enter. Then he shook his head. "I'm sorry, but we can't admit you, Mr. Hanson."

"What!" Tom almost jumped out of the cab.

ARV UNDER SUSPICION 113.

"This man is our chief modelmaker. He built the scale replica of this plant!"

Hanson was speechless. Hank Sterling leaned over, angry and puzzled.

"Why can't he be admitted?"

"His security clearance papers haven't come through from the FBI," replied the guard. "I don't care who he is. He doesn't get through this post. We received clearance for you and Tom Swift Jr., but not for Hanson."

Tom swung open the door and leaped to the ground. He realized that the sentry was doing his job as directed and would not give in.

"Give me your sentry phone," Tom requested in a firm but polite tone.

He called the plant office and spoke to his father. In a short time Mr. Swift arrived at the gate.

"I know nothing about any of this, Tom!" declared the elder inventor. "I can't understand it! We requested clearance for all three of you."

Tom could no longer restrain his impatience. He jiggled the telephone hook.

"Get me long-distance," he told the operator, beckoning to the security guard to listen in on the call.

He explained the urgency of the call and received an immediate line to Washington. A check with the Federal Bureau of Investigation revealed that all three sets of clearance papers had been sent by them. Dashing back to Hanson, he said: "You're in the clear, Arv. Washington is tele- 114 .

graphing confirmation immediately." The young inventor looked grim. "But it doesn't explain what happened to your papers. I wonder if our enemies could somehow have gotten hold of them just to delay us?"

The guard apologized to Hanson and the gate was raised to allow the motorcade to enter.

Later, on the inspection trip through the various laboratories and workshops, Tom and Sterling and Hanson found themselves nodding in approval of the ingenious design and fine engineering of the layout. At last Mr. Swift led them to the main structure, built of white cement. Inside was a corridor extending around four inner walls of lead and concrete. On one of the walls was a relay and television board for messages to and from the robot as he worked in the inner room. The main remote-control panel was in a separate building.

"Tom, I expect your giant to be able to feed slugs of uranium to the oven if necessary," Mr. Swift said.

"He'll do it," Tom a.s.sured his father.

"Now we'll take a look at the heart of this building," Mr. Swift said.

In the huge interior section was a ma.s.s of square lead and concrete pipes arranged longitudinally.

"Looks like a mammoth honeycomb," Hank remarked. "I suppose the slugs of uranium are fed to the pile through these."

"Correct," said Mr. Swift. "The heart of the reactor is in the center. In there the uranium will be ARV UNDER SUSPICION 115.

bombarded with neutrons and changed into the various transuranium elements. Then the slugs are taken from the pile and the robot separates out the new elements in his own completely equipped chemistry lab over there." He pointed to an enclosure whose walls were lined with the necessary chemicals in radiation-proof containers. "After that, he prepares them for shipment to medical and scientific inst.i.tutions."

"And where will the waste products-such as the slug casings-go?" Hanson asked.

"Tom's robot will carry them out through a tunnel to an underground lake we've made. In that way, no living thing can be contaminated by the radioactive waste."

Next, Mr. Swift took them outdoors to a small concrete structure located at a short distance from the pile plant.

"This is where Tom and the other operators will receive reports from the robot and send him orders," Mr. Swift explained.

From the outside the structure resembled a gun pillbox more than a control house. Within, however, the function of the building was obvious, with its large color-television screen, surrounded by loudspeakers and banks of oscillographs.

Control k.n.o.bs and b.u.t.tons were set into a huge desk-height panel. Hank Sterling and Arv Hanson examined the large racks of amplifiers with interest.

Tom now showed them the tape library. "These 116 .

tapes will be a real boon to the robot's operator," he said. "They'll do away with the necessity of direct control on routine acts and motions of the robot. In fact, we can feed in any of more than a thousand different tapes with directions to get him out of every difficulty we've been able to foresee. But when something unexpected comes up, the operator will have to take over."

"It's amazing," Hanson commented. "I'm beginning to have a lot of respect for that giant robot as well as his inventor."

"Thanks." Tom laughed. "Well, I guess we've seen all we can today.

Tomorrow I start work with Stan Lee."

He, Arv, and Hank spent the night in one of the dormitories and were up early the next morning to start work. After breakfast, the elder inventor said: "I guess, son, you're eager to see the tunnel through which the robot will descend and enter the plant. You'll find it built to your specifications."

"Good," said Tom, grinning. He had been worried about clearance, since his giant robot's antenna would need every last fraction of an inch to get through.

Mr. Swift reminded his son that the tunnel had just been completed. "So watch your step, Tom. There may be some loose debris and chunks of concrete that haven't been cleared out."

"I will, Dad."

The others walked with him to the opening and A blinding flash enveloped the opening above him 118 .

peered down into the tunnel. There was a metal rung ladder to the bottom which would later be replaced by a ramp for the giant robot's convenience.

Holding his flashlight, Tom started lowering himself, clinging to the ladder. As he grasped the third rung, a blinding flash suddenly enveloped the opening above him.

The ladder snapped apart and the young inventor toppled to the tunnel floor!

CHAPTER 14.

STRANGE INDIAN STORY.

LOOSE EARTH and cement showered down upon Tom. Sputtering and choking, he fought his way through the mound of debris and gasped for breath in the dust-filled cavern.

Above him there was a deathlike silence and he was worried about the safety of his father and friends. Tom knew that the only way to get aboveground was through the tunnel and into the plant.

His flashlight was buried in the debris and he stumbled along the black pa.s.sageway, feeling his way inch by inch to avoid any pitfalls.

A hundred thoughts filled his mind at once. What had caused the blast? All detonating had been completed months earlier when foundations for the plant were being dug. Surely no workman could have been carrying dynamite at this late date. But then, what?

A dim light ahead indicated that he was approach- 119.

120 .

ing the bas.e.m.e.nt floor of the building that housed the pile. He broke into a run and presently found himself in the vast underground room. It was well lighted.

At its center concrete pillars, twelve feet square and looking even larger because of the low ceiling, supported the framework of the pile on the floor above.

Tom looked around for an exit, found a door, and hastened upstairs. He was between the double walls in the section known as the "hot" corridor because of its nearness to the pile. He started running again, first to the left and then, remembering that the exit was in the other direction, to the right. At last he came to the familiar sight of the relay board and the exit.

Outside, the scene that greeted his eyes was one of disorder. Planks and bricks from piles of construction material had been scattered all over. Nurses and doctors were administering to the injured. Two ambulances were parked near the tunnel entrance. Tom hurried toward the scene of confusion.

"Dad!" he cried. Mr. Swift was seated on an ambulance cot, holding a gauze compress to his head. He called excitedly to his son: "Tom, Tom! Are you all right?"

"I'm fine, Dad. What happened? Where are Hank and Arv?"

"Hanson got a b.u.mp on his head from a flying stone. Sterling's gone to the plant hospital to have a leg cut treated."

STRANGE INDIAN STORY 121.

"Anybody badly hurt?" Tom asked.

"Fortunately no. And not a soul saw what caused the blast."

At this moment a security guard came racing up. In his hands were several metal fragments.

"We found these in the blast area, Mr. Swift," he panted. "They're sections of casing from a large bomb."

"Have these pieces been a.n.a.lyzed?" Mr. Swift asked.

"The labs are going over some of the fragments now," the guard replied. "We think the bomb must have been dropped by a plane that was out of the range of our radarscope."

Tom and his father exchanged glances. "The Briggin boys?" they were asking themselves.

"Or some crank who is opposed to atomic progress and wants us all back in the Stone Age," Tom thought ruefully. Aloud he said, "Dad, this plant needs drone protection badly. I'm sorry we were able to bring only one with us. But I'll drop everything else and get it in the air as soon as possible. Meanwhile, we can order more from Shopton."

A half hour later Hank and Arv insisted that they felt all right and wanted to help Tom with the task. They followed him to the trailer on which the drone plane rested.