The Making of the Atomic Bomb

work there the summer, and then I'll go back to Palermo.”

He said, “You are not going back to Palermo. By this fall, God knows what will happen! You can't go back.”

I said, “Well, I have a return ticket. Let's hope for the best.”

But I had gotten a passport for my wife and my son before leaving, because I smelled that the situation was dangerous. So I took the train in New York, Grand Central, and I bought the newspaper in Chicago. I still remember it. I will remember it as long as I live. I opened the newspaper, and I found out that Mussolini had started the antisemitic campaign and had fired everybody. So there I was. So I had the ticket and went to Berkeley. I started to work on my short-lived isotopes of technetium, but at the same time I tried to get some job. Then I got my wife here.

The pall of racism had dropped over Italy.

The physicists at the institute on Via Panisperna had been alert to the darkening Italian prospect since at least the mid-1930s. Segre remembers asking Fermi in the spring of 1935 why the group's mood seemed less happy. Fermi suggested he look for an answer on the big table in the center of the institute reading room. Segre did and found a world atlas there. He picked it up; it fell open automatically to a map of Ethiopia, which Italy in a show of Fascist bravado was about to invade. By the time the invasion began all but Amaldi were examining their options.

Fermi went off to the University of Michigan's summer school in Ann Arbor, renewing an affiliation he had begun with Laura in the summer of 1930. He liked America. “He was attracted,” Segre notes with an ear for Fermi's priorities, “by the well-equipped laboratories, the eagerness he sensed in the new generation of American physicists, and the cordial reception he enjoyed in academic circles. Mechanical proficiency and practical gadgets in America counterbalanced to an extent the beauty of Italy. American political life and political ideals were immeasurably superior to fascism.” Fermi swam in Michigan's cool lakes and learned to enjoy American cooking. But the pressure of events in Italy was not yet sufficiently extreme, and Laura, Roman to her fine bones, was more than reluctant to leave the city of plane trees and classical ruins where she was born. Nor was anti-Semitism yet an issue in Italy — Mussolini had even declared he did not propose to make it one.

There was less to hold the other men. Rasetti summered at Columbia University that year, 1935, and decided to stay on. Segre had shifted to Palermo but began looking toward Berkeley. Pontecorvo moved to Paris. D'Agostino went to work for the Italian National Research Council. Amaldi and Fermi pushed on alone, Amaldi remembers, Fermi even jettisoning his daily routine for the distraction of experiment:

We worked with incredible stubbornness. We would begin at eight in the morning and take measurements [they were examining the unaccountably differing absorption of neutrons by different elements], almost without a break, until six or seven in the evening, and often later. The measurements… were repeated every three or four minutes, according to need, and for hours and hours for as many successive days as were necessary to reach a conclusion on a particular point. Having solved one problem, we immediately attacked another… “Physics as soma” was our description of the work we performed while the general situation in Italy grew more and more bleak, first as a result of the Ethiopian campaign and then as Italy took part in the Spanish Civil War.

Fermi taught a summer course in thermodynamics at Columbia University in 1936 as the civil war began in Spain that would last three years, claim a million lives and set Mussolini decisively at Hitler's side. The following January Corbino died unexpectedly of pneumonia at sixty-one and the hostile occupant at the north end of the institute's second floor, Anto-nino Lo Sordo, a good Fascist, was appointed to succeed him. “That was a sign that Fermi's fortunes were declining in Italy,” Segre notes. “America,” he concludes of those depressing years, “looked like the land of the future, separated by an ocean from the misfortunes, follies, and crimes of Europe.”

If the Anschluss was a test of Hitler's strength, it was also a test of Mussolini's willingness to acquiesce to complicity in crime. He had posed as Austria's protector; on the night of the March 1938 invasion Hitler waited near hysteria at the Chancellery in Berlin for a response from Rome to a letter he had sent justifying his action. The call came at 10:25 p.m. and the Fuhrer snatched up the phone. “I have just come back from the Palazzo Venezia,” his representative reported. “The Duce accepted the whole thing in a very friendly manner. He sends you his regards… Mussolini said that Austria would be immaterial to him.” Hitler replied: “Then please tell Mussolini I will never forget him for this! Never, never, never, no matter what happens!.. As soon as the Austrian affair has been settled I shall be ready to go with him through thick and thin — through anything!” The Fuhrer visited Rome in triumph in May, parading into districts the Duce had ordered hastily face-lifted to conceal their decay. Fermi's circle repeated the verse passed around the city by word of mouth by which an indignant Roman poet greeted the Nazi dictator:

Rome of travertine splendor
Patched with cardboard and plaster
Welcomes the little housepainter
As her next lord and master.

Italy would only be saved, Fermi told Segre bitterly, if Mussolini went crazy and crawled on all fours.

The summer of 1938, July 14, brought the anti-Semitic Manifesto della Razza of which Segre read in the Chicago newspaper on his way from New York to Berkeley. Italians are Aryans, the manifesto claimed. But “Jews do not belong to the Italian race.” In Germany the vicious distinction had been commonplace; in Italy it was shocking. Italian Jews, only one in a thousand, were largely assimilated. The Fermis' two children — Giulio, a son, had been born in 1936 — might be exempted since they were Catholic, born of a nominally Catholic father. But Laura was a Jew. She was spending the summer with the children in the Dolomites, the South Tyrol district named for the magnesian limestone that rings broad basin meadows with the flat, sharp formations Italians call “shovels.” Enrico came up preoccupied in August to the meadow of San Martino di Castrozza to break the news. When Mussolini pushed through the first anti-Semitic laws early in September the Fermis decided to emigrate as soon as they could arrange their affairs. Fermi wrote four American universities and to avoid suspicion mailed each letter from a different Tyrolese town. Five schools shot back invitations. In confidence he accepted a professorship at Columbia and went off to Copenhagen to Bohr's annual gathering of the brethren.

The previous month the International Congress of Anthropological and Ethnological Sciences had invited Bohr to address it at a special session in Helsing0r, Shakespeare's Elsinore, on the coast of Zealand north of Copenhagen. In the Renaissance castle there Denmark's most prominent citizen used the occasion to challenge Nazi racism publicly before the world. It was a brave statement by a brave man. Bohr understood that the major Western democracies were not likely to rally to the defense of his small, unprotected nation when Hitler eventually turned to look its way. George Placzek, a Bohemian theoretician working in Copenhagen whose tongue was almost as sharp as Pauli's, had already encapsulated that cruel truth. “Why should Hitler occupy Denmark?” Placzek quipped to Frisch one day. “He can just telephone, can't he?”

Against the brutal romanticism of German Blood and Earth, Bohr set the subtle corrective of complementarity. He spoke of “the dangers, well known to humanists, of judging from our own standpoint cultures developed within other societies.” Complementarity, he proposed, offered a way to cope with the confusion. Subject and object interact to obscure each other in cultural comparisons as in physics and psychology; “we may truly say that different human cultures are complementary to each other. Indeed, each such culture represents a harmonious balance of traditional conventions by means of which latent possibilities of human life can unfold themselves in a way which reveals to us new aspects of its unlimited richness and variety.”

The German delegates walked out. Bohr went on to say that the common aim of all science was “the gradual removal of prejudices,” a complementary restorative to the usual pious characterization of science as a quest for incontrovertible truth. To a greater extent than any other scientist of the twentieth century Bohr perceived the institution of science to which he dedicated his life to be a profoundly political force in the world. The purpose of science, he believed, was to set men free. Totalitarianism, in Hannah Arendt's powerful image, drove toward “destroying all space between men and pressing men against each other.” It was entirely in character that Bohr, at