Her hostility had vanished, and now she just looked vulnerable. In her eyes he saw a plea, though he was not sure what she was pleading for.
He looked at Georgy with new eyes: the light skin, the green eyes, the odd resemblance to Daisy. Are you mine? he thought. Can it be true?
But he knew it was.
His heart filled with a strange emotion. Suddenly Georgy seemed terribly vulnerable, a helpless infant in a cruel world, and Greg needed to take care of him, make sure he came to no harm. He had an impulse to take the boy in his arms, but he realized that might scare him, so he held back.
Georgy put down his orange juice. He got off his chair and came around the table to stand close to Greg. With a remarkably direct look, he said: ‘Who are you?’
Trust a kid to ask the toughest question of all, Greg thought. What the hell was he going to say? The truth was too much for a six-year-old to take. I’m just a former friend of your mother’s, he thought; I was just passing the door, thought I’d say hello. Nobody special. May see you again, most likely not.
He looked at Jacky, and saw that pleading expression intensified. He realized what was on her mind: she was desperately afraid he was going to reject Georgy.
‘I tell you what,’ Greg said, and he lifted Georgy on to his knees. ‘Why don’t you call me Uncle Greg?’
Greg stood shivering in the spectators’ gallery of an unheated squash court. Here, under the west stand of the disused stadium on the edge of the University of Chicago campus, Fermi and Szilard had built their atomic pile. Greg was impressed and scared.
The pile was a cube of grey bricks reaching the ceiling of the court, standing just shy of the end wall which still bore the polka-dot marks of hundreds of squash balls. The pile had cost a million dollars, and it could blow up the entire city.
Graphite was the material of which pencil leads were made, and it gave off a filthy dust that covered the floor and walls. Everyone who had been in the room a while was as black-faced as a coal miner. No one had a clean lab coat.
Graphite was not the explosive material – on the contrary, it was there to suppress radioactivity. But some of the bricks in the stack were drilled with narrow holes stuffed with uranium oxide, and this was the material that radiated the neutrons. Running through the pile were ten channels for control rods. These were thirteen-foot strips of cadmium, a metal that absorbed neutrons even more hungrily than graphite. Right now the rods were keeping everything calm. When they were withdrawn from the pile, the fun would start.
The uranium was already throwing off its deadly radiation, but the graphite and the cadmium were soaking it up. Radiation was measured by counters that clicked menacingly and a cylindrical pen recorder that was mercifully silent. The array of controls and meters near Greg in the gallery gave off the only heat in the place.
Greg visited on Wednesday 2 December, a bitterly cold, windy day in Chicago. Today for the first time the pile was supposed to go critical. Greg was there to observe the experiment on behalf of his boss, General Groves. He hinted jovially to anyone who asked that Groves feared an explosion and had deputed Greg to take the risk for him. In fact Greg had a more sinister mission. He was making an initial assessment of the scientists with a view to deciding who might be a security risk.
Security on the Manhattan Project was a nightmare. The top scientists were foreigners. Most of the rest were left-wingers, either Communists themselves or liberals who had Communist friends. If everyone suspicious was fired there would be hardly any scientists left. So Greg was trying to figure out which ones were the worst risks.
Enrico Fermi was about forty. A small, balding man with a long nose, he smiled engagingly while supervising this terrifying experiment. He was smartly dressed in a suit with a waistcoat. It was mid-morning when he ordered the trial to begin.
He instructed a technician to withdraw all but one of the control rods from the pile. Greg said: ‘What, all at once?’ It seemed frighteningly precipitate.
The scientist standing next to him, Barney McHugh, said: ‘We took it this far last night. It worked fine.’
‘I’m glad to hear it,’ said Greg.
McHugh, bearded and podgy, was low down on Greg’s list of suspects. He was American, with no interest in politics. The only black mark against him was a foreign wife: she was British – never a good sign, but not in itself evidence of treachery.
Greg had assumed there would be some sophisticated mechanism for moving the rods in and out, but it was simpler than that. The technician just put a ladder up against the pile, climbed halfway up it, and pulled out the rods by hand.
Speaking conversationally, McHugh said: ‘We were originally going to do this in the Argonne Forest.’
‘Where’s that?’
‘Twenty miles south-west of Chicago. Pretty isolated. Fewer casualties.’
Greg shivered. ‘So why did you change your minds and decide to do it right here on Fifty-seventh Street?’
‘The builders we hired went on strike, so we had to build the damn thing ourselves, and we couldn’t be that far away from the laboratories.’
‘So you took the risk of killing everyone in Chicago.’
‘We don’t think that will happen.’
Greg had not thought so, either, but he did not feel so sure now, standing a few feet away from the pile.
