Graves shook his head. `He's got five or six workmen there. There's two of us, and two in 702. None of us have guns.' He sighed. `Besides, what if they really are mattresses?'

`They can't be.'

Graves didn't think it possible either. But he wasn't willing to take a chance. He found himself worrying about Wright's new apartment in San Diego. Perhaps this was all a diversion, a feint to get him away from the apartment while something important was done there. He had no confidence in the men sitting across the street, observing and filming. Like every organization in the world, the State Department hired mundane men to carry out mundane jobs. Stationary surveillance was the most mundane. If the men weren't dull when they started, they soon became that way.

`We'll wait,' he said.

The mattresses were taken into the hangar, and the limousine was driven inside. The doors were closed.

`Time?'

`Twelve forty-one,' Lewis said.

A minute passed, and then something remarkable happened. The men came out of the hangar and walked over to the aeroplane. They stood alongside it, ostensibly checking it over but actually doing nothing at all; just waiting.

Wright was not among them.

`I don't get it,' Graves said. `Where's Wright?'

`He must still be inside.'

Their sedan was parked more than 200 yards from the hangar. But the wind was blowing in their direction, and they heard a faint mechanical sound. A kind of thumping or chugging.

Lewis. opened the trunk and took out a directional microphone. It looked like a miniature radar antenna - a dish two feet in diameter, with a central barrel protruding. He put on earphones and tuned in the microphone.

`What are you getting?'

Lewis shifted the direction of the mike slightly. It was quite sensitive, but had to be aimed precisely.

`Wind.'

`Can you get that not -'

`Here.'

He gave Graves the earphones. Graves listened. With the microphone aimed directly, the mechanical sound was clear. It consisted of a low hum with an intermittent pulsing thump.

`Sounds like a pump to me,' he said. He listened to the sound for several seconds more. `What do you make of it?'

`A pump,' Lewis said, glancing at his watch. `It's been going five minutes now.'

Graves turned from the hangar to the aeroplane and the men who were clustered around it. They had broken up into small groups of two and three, talking quietly, occasionally glancing at the hangar. George, the chauffeur, was among them. Several of the workmen asked George questions. George kept shaking his head.

Graves set down his binoculars. Why would you clear everybody out of the hangar? He could think of only one reason: Wright didn't want them to see what was going on. But as he thought about it, he saw a second reason: that Wright was engaged in something very dangerous and wanted the others a safe distance away.

Dangerous how? Radiation? Explosives? What?

`Ten minutes now,' Lewis said.

Graves scratched his head. He lit a cigarette and stared at the others by the aeroplane. It didn't make sense, he thought. Whatever Wright intended, it didn't make sense. If he didn't want the workmen around, he could easily have timed it so that they would be out to lunch. Instead he'd aroused their curiosity. They'd talk about this episode for days, maybe weeks afterwards.

Apparently Wright didn't care about that. Why not? And then as he watched, the workmen began walking back to the hangar. He had seen no signal, but they all moved at once.

Lewis took off the earphones. `Fifteen minuses,' he said. `The pump's stopped.'

Graves checked his watch. It was a few minutes before 1 PM. He was beginning to feel tired. It had been a long day already, starting with the call from Phelps at 4 Am and the trip to Los Angeles.

He tit another cigarette and watched the hangar. And then things began to happen very fast. The limousine drove out and off towards the entrance to the airfield. And a second vehicle emerged from the hangar.

A moving van. It followed the limousine.

Graves got onto the intercom. `702, this is 701. You got them?'

`Got them, 701.'

`Stay with them. If they split up, follow the limousine; forget the van.'

`Right, 701. Are you with us?'

`No,' Graves said. `We're staying here.' He clicked off the microphone and said to Lewis, `I want to look inside that hangar.'

It took them three minutes to get to the hangar, and by that time it was deserted except for an elderly man who was cleaning up with a long broom. There were one or two workmen out by the jet, but they paid no attention as Graves and Lewis went into the hangar.

The old man waved and leaned on his broom. `You looking for Mr Johnson?'

`Yes,' Graves said.

`Just missed him,' the old man said. `Left a couple minutes ago.'

`Damn,' Graves said. `You know where he went?'

`No idea,' the old man said. `He's a strange one. I guess rich people get that way.' He pointed to a corner of the room. `I mean, look at that,' he said. There were several boxes stacked in the corner. `Now what am I supposed to do with that? Oh, bring in plenty of it, says Mr Johnson. And then he doesn't touch it.'

Graves looked at the boxes. `What's in them?'

`Detergent,' the old man said. `Gallon jugs of detergent. He wanted ten of them. Don't ask me why - he didn't touch them.'

`When did he ask for them?' Graves said. He walked ever and opened one of the cardboard boxes. Inside was a jug marked KEN-ALL 7588 INDUSTRIAL DETERGENT.

`Last week. Wanted to be sure he had them.'

`What's this stuff normally used for?'

The old man shrugged and continued sweeping. `This is an airfield,' he said. `We use a lot of it to get grease off parts. That stuff will cut anything. Axle grease, anything, cuts it right off.'

Graves nodded.

Across the hangar Lewis was bent over. `Have a look at this,' he said. He pointed to a small plastic bag on the concrete floor.

`Dozens of those around,' the old man said. `All over the floor when I came in.'

Graves picked up the bag, sniffed it, touched the inside surface. There was some kind of milky, oily stuff inside.

`He's been getting this place ready for a week,' the old man said. `Bring in equipment, take out equipment, new stuff, old stuff. Damnedest thing you ever saw. For instance, he has this washing machine -'

`Washing machine?'

`Sure. It's still here.' He pointed to the corner. `You're probably too young to remember those things.'

Graves walked over to it. It was an old-fashioned hand-operated tub washing machine with two rollers mounted above for a wringer. The rollers were operated with a crank. Beyond the rollers was a long, flat tray of highly polished metal.

Graves looked at the manufacturer's label: WESTINGHOUSE. The year was 1931.

`Now what,' asked the old man, `does Mr Johnson want with an old washing machine? Huh?'

Graves began to feel nervous. For the first time all day, he felt that Wright was too far ahead of him, that the clues were too subtle, that the game was beyond him. A washing machine?

Lewis touched the roller assembly. `I guess you could squeeze out a thin strip of anything on that machine,' he said, `assuming it had the right consistency. A putty kind of consistency.'

Plastic bags on the floor, boxes of industrial detergent in the corner - ordered but unused - and a washing machine. Then he remembered.

`Where's the pump?'

`I don't know,' Lewis said. `But it doesn't matter. Look over here.' He pointed to some equipment near the washing machine. A canvas tarp was draped over it; he pulled it away.