The Hess Cross (12 page)

"That's only part of what we are doing here, Miss
McMillan," he said. "Actually, what we are looking for is a cheap, compact form of energy. That energy can be released at once, as in a bomb, or released slowly, like a piece of burning wood. It is conceivable that a million-kilowatt electrical power plant with nuclear fission as its source of energy could be no larger than a power substation. Compare this with the enormity of the Grand Coulee Dam and you can see its potential. Or compare uranium with coal. We estimate that one pound of uranium can give off energy equivalent to fifteen hundred tons, not pounds, tons of coal." Fermi paused to see if Heather cared to venture a gasp of disbelief, and when she did not, he continued, "We think that one pound of uranium or plutonium can yield enough energy to supply the total power consumption of the United States for fifteen minutes."

Heather's short question had put Fermi on the defensive. He acted as if he had given this speech many times before, perhaps to himself.

"Some benefits are more immediate," continued Fermi as he switched his gaze to Crown. "Fission does not produce the smog that is Chicago's hallmark. And it's much more economical to transport two pounds of uranium than three thousand tons of coal. And on and on."

"But, nevertheless, your work centers on the production of the bomb?" Heather persisted.

Fermi looked at her with a hint of pleading in his eyes and said, "And there are a lot of nonpower uses that will be the offshoot of our work. Developments in medicine and biology will be greatly accelerated because of the large amounts of radioactive substances that will be available to researchers. It's possible that these substances can be used to treat diseases and wounds. And the availability of high-intensity radiation will have an unprecedented effect on industrial research. Who knows what can be done with
chemicals that have been treated with high doses of radioactive substances? Uses of our research are endless."

Fermi paused to collect himself. He dropped his hands onto the desk and smiled broadly. "You know, Miss McMillan, you have an amazing ability to make me want to justify myself. Very few people do that. My wife, for one."

"I'll take that as a compliment, Mr. Fermi," Heather said, warming to the scientist.

"It is. She's precious." Fermi gestured to the blackboards and said, "Yes, we are working on a bomb. These things I mention, these peaceful uses, are only a secondary goal now. Our first priority is to produce a weapon that will quickly end the war, and to produce it before the Germans do. I don't need contorted logic to rationalize my work on this project, Miss McMillan. I saw what was happening in Italy before I left, what the Germans were doing to Italy.

"Because of economic sanctions against Italy imposed by the League of Nations due to the Ethiopian campaign, Italy has found itself allied with the Germans. This has made most Italians gag, because the Germans are ancient enemies of Italy, and the two countries fought each other as recently as the First World War. Italians couldn't believe we were fighting on the same side as the Germans in the Spanish Civil War. We thought Hitler was a prancing idiot who was doing his best to imitate the Duce. Our newspapers led us to believe that Mussolini was the leader of this strange relationship. This delusion was shattered in 1938, when Hitler occupied Austria without even informing Mussolini in advance. The Duce could do nothing but acquiesce after the fact. Italy has slowly become Germany's slave.

"To my wife and me, the most agonizing aspect of Germany's hold on Italy was the new anti-Jew campaigns announced by Mussolini. Please remember that Italy has never been anti-Semitic. We simply didn't have traces of that
German disease of anti-Semitism in our population. But suddenly the government started announcing anti-Jewish measures.

"The first anti-Semitic laws were passed in September 1938, and that's when Laura and I decided to leave Italy. Not all the laws were aimed at the Jews, however. The Duce went berserk with his laws. He issued laws prescribing proper hairdos for women and proper uniforms for civil-service workers. And Mussolini, always thinking, banned ties for men's clothing, because he said they pressed on certain nerves in the neck, which might prevent men from taking accurate aim with a rifle after they were drafted. We simply couldn't live in such a repressive, silly climate. We left Rome for the last time on December 6, 1938."

"But is a silly government enough of a reason to work on a bomb that can kill hundreds of thousands?" Heather asked.

"No, no." Fermi looked away and searched for words. "Conditions in Germany and Italy have gone far beyond being silly. I'm personally familiar with one example. Laura's piano teacher in Rome is a Jew. We received a letter from her several weeks ago saying she had been taken to a camp in Germany. The letter was newsy. But then she asked us to say hello to her brother Alexander. And she wanted to know how Laura's violin lessons were going. And she asked how I was, but called me Paul. Well, she has no brothers, Laura was taking piano lessons, and my name is not Paul. The letter was full of errors that she knew we would recognize as errors. We can only conclude she is in deep trouble and that conditions at her camp are not as rosy as the letter's censor would like us to believe. She was warning us of what is going on in Germany."

John Crown was uncomfortable. His task was to learn the layout of the experiment and see that Heather was
introduced to some of the technical jargon she would encounter during the Fermi-Hess interviews, not to expose the scientist to a young Englishwoman's concepts of morality. He was sure Fermi felt ill at ease under Heather's constant gaze.

"Well," Fermi said, rising from his seat, "I seem to have run off at the mouth. Let me explain a little about our project before I take you to the squash court."

"Squash court? I've never played squash," Heather said.

"We don't play squash there, Miss McMillan. You'll see that in a few minutes," replied Fermi, glad she was not in total command of the conversation.

Fermi picked up a dusty eraser and wiped clean a portion of blackboard. He said, "Please suffer through a few seconds of physics. It'll make the squash court clearer."

Fermi drew a circle on the board and began, "You know that all matter is composed of atoms, and that they are extremely small. A spoonful of water contains a million billion atoms.

"In 1910, Lord Rutherford first showed that the atom, which theretofore had been thought the smallest particle, was in fact made of even smaller particles—a positively charged nucleus surrounded by negatively charged particles called electrons. Although practically all the mass is in the nucleus, it is very small. And its satellite electrons are also extremely small. The orbit of an electron is not even a hundred-millionth of an inch in diameter."

"I can't even imagine those figures," said Heather.

"Well, if the nucleus could be magnified to the size of a baseball, the outermost electron would be circling it a half-mile away. So even when atoms are packed tightly together, the nuclei are very far apart.

"Later, it was discovered that the nucleus of most elements is a combination of particles—protons and neutrons.
The protons and neutrons within an atomic nucleus are held together by an extremely strong force. What we are trying to do is to split them."

Fermi drew circles and straight and crooked lines as he spoke. Heather leaned forward in her chair and did not even blink as she stared at the blackboard. Crown looked alternately at his fingernails and Heather. She had thawed a little since last night's discussion of Hess, and he was glad of it.

"We've found that we can bombard a nucleus with a tiny projectile, a neutron. Heavy nuclei can be split into almost equal parts. This is nuclear fission. It isn't a hard theoretical concept."

"It doesn't seem that much energy could be released by the splitting of one atom," said Heather.

"That's true. But we're trying to set it up so that the separation of one atom causes the splitting of other atoms, and those cause the splitting of more atoms, and on and on. The potential energy of this chain reaction would be enormous."

Fermi clapped his hands together to rid himself of the chalk dust and said, "Let's take a tour of the contraption we've built, which hopefully will allow us to have a self-sustained nuclear reaction."

"You mean this hasn't been done yet?" Heather asked as she rose from her seat.

"No. the self-sustained reaction is still theory. We'll know in a few days whether my theory is correct. To the squash court."

The soldier was leaning against the hallway wall as the three emerged from the office. Fermi took a key from his sports-coat pocket and threw one of the door bolts. The soldier locked the second with a key chained to his belt.

"Sometimes I yearn for a lab where I don't have to ring six bells and unlock ten doors to go to the bathroom accompanied by a soldier," Fermi said as he led them through the
hallways, past the security doors, and out onto the sidewalk. He discreetly pointed to the Stagg Field grandstand across the street.

"There's the location of our experiment, the basement of Alonzo Stagg Stadium," he said.

The backside of the grandstand was designed in the best architectural tradition of the University of Chicago. Crown wondered why a football field needed castle turrets at each corner of the grandstand. Ivy climbed up the red-brick turrets, in which were small recessed windows. The windowsills were beveled toward the ground to deny footing to a potential attacker. As with all good castles, the top eight feet of the four-story turrets were extended on cantilever beams a foot beyond the circular wall beneath, thereby making a ladder assault difficult. Archers' slits ringed the turrets and the connecting wall. Lest their work be considered too militant, the architects had infused a religious theme into the grandstand. Midway between the turrets was the main entrance, a sweeping arched doorway reminiscent of French Gothic cathedrals. The high, arched windows along the walls on both sides of the entrance continued the cathedral theme. One expected but did not see stained glass. Above these windows were more archers' slits. An architectural mess, thought Crown.

They followed Fermi under the Stagg Field entrance to a small door on the south wall of the lobby. Fermi knocked a certain way, and the iron door opened. Crown could see from the brickwork that the old door had been recently replaced with its solid-metal substitute. Crown and Heather underwent the fingerprint ritual again, and after several minutes were cleared for entry. A second door scraped open, and they walked along a long hallway past several sentries and down a steep flight of stairs.

"These are the university's old indoor courts. Handball, squash, racketball, and such. You can see the shower rooms
over there," Fermi said as they walked past carpenters' tool chests and a small pile of graphite blocks carefully stacked on a canvas sheet. The hallway's dim light flickered dully off the buckles and epaulet buttons on the guards' uniforms. After a close scrutiny by two guards at the final sentry post, Heather, Crown, and Fermi walked through the door and onto a squash-court viewing platform. At one end of the platform, a curly-black-haired, spectacle-wearing technician was meticulously examining electrical components of a control panel. The parts, seemingly hundreds of them, were spread on a white cloth draped over a wooden desk. The technician did not look up as Fermi approached the viewing-platform rail.

"As you can see, this was once a squash court. The courts haven't been used for years, so most students have no idea they exist. Keeping it secret here is much easier than if we had built a new building to hide it in." Fermi grasped the rail, leaned over it slightly, and said, "That's the pile."

Hanging from the ceiling of the squash court in front of them was an immense square balloon whose thick hide concealed its contents. The balloon hung to the floor of the court ten feet below them, and in its side facing the observation platform was an aperture through which workmen were steadily passing. Each carefully sealed the flap behind him as he entered or left the balloon.

"The graphite gives off a fine dust that clogs the gauges and would probably interfere with the reaction. So we've sealed the dust inside the balloon, and just before the experiment, we'll pump it out and open up the balloon."

Fermi walked to the sheet-covered table and asked the youthful electrician if progress was being made. The electrician, whose curly black hair dominated his face, was myopically squinting at a structure which to Crown looked like a vastly complicated fuse box. He was digging around
in it with a pair of rubber-handled tweezers and was so absorbed in his work that Fermi's question startled him.

"Oh, fine, Professor, fine. I'm just doing a routine check, probably for the tenth time. There's no problem. It may not look like it, but I can put all this together again."

"Excellent. Let's take a look at the balloon, John."

They descended an almost vertical circular stairway to court level and entered the squash court through the miniature door peculiar to indoor courts. Fermi held open the balloon flap, and Crown and Heather crouched through the canvas wall. Heather immediately felt dirty. The air was thick with graphite dust that clung to her as if she had a magnetic attraction for the particles. Her eyelids scraped as she blinked, and her tongue felt coated. She brushed her cheek with the back of her hand, and her skin was slimy.

Enrico Fermi didn't seem to notice the graphite dust. "This pile is just what the name implies—thousands of graphite blocks placed in a square pile twenty-four feet in diameter. It's very simple in appearance, as you can see, just a huge black square. But it consists of lumps of uranium spaced eight and a half inches apart, separated by the graphite blocks. Right now, there are about thirty-five thousand of the blocks on the pile, and we will eventually have forty thousand or so. Each layer of solid graphite blocks alternates with a layer of blocks that have holes drilled through them so uranium can be placed in the holes. Now, you may be wondering why we need all these graphite blocks."