The Making of the Atomic Bomb: 25th Anniversary Edition

by Richard Rhodes

The earth revolves around the sun, not the sun around the earth. “It is a profound and necessary truth,” Robert Oppenheimer would say, “that the deep things in science are not found because they are useful; they are found because it was possible to find them.” Those first atomic bombs, made by hand on a mesa in New Mexico, fell onto a stunned pre-nuclear world.

In the middle years of my life I lived on four acres of land in Connecticut, a meadow completely enclosed within a forested wildlife preserve. It teemed with creatures: deer, squirrels, raccoons, a woodchuck family, turkeys, songbirds, crows, a Cooper’s hawk, even a pair of coyotes. Except for the hawk, every one of those animals constantly and fearfully watched over its shoulder lest it be caught, torn, and eaten alive. From the animals’ point of view, my edenic four acres were a war zone.

Still reluctantly committed to engineering, Szilard enrolled in the Technische Hochschule, the technology institute, in Berlin. But what had seemed necessary in Hungary seemed merely practical in Germany. The physics faculty of the University of Berlin included Nobel laureates Albert Einstein, Max Planck and Max von Laue, theoreticians of the first rank. Fritz Haber, whose method for fixing nitrogen from the air to make nitrates for gunpowder saved Germany from early defeat in the Great War, was only one among many chemists and physicists of distinction at the several government- and industry-sponsored Kaiser Wilhelm Institutes in the elegant Berlin suburb of Dahlem.

Physics students at that time wandered Europe in search of exceptional masters much as their forebears in scholarship and craft had done since medieval days.

If someone whose specialty you wished to learn taught at Munich, you went to Munich; if at Göttingen, you went to Göttingen. Science grew out of the craft tradition in any case; in the first third of the twentieth century it retained—and to some extent still retains—an informal system of mastery and apprenticeship over which was laid the more recent system of the European graduate school. This informal collegiality partly explains the feeling among scientists of Szilard’s generation of membership in an exclusive group, almost a guild, of international scope and values.

In the summer of 1922 the rate of exchange in Germany sank to 400 marks to the dollar. It fell to 7,000 to the dollar at the beginning of January 1923, the truly terrible year. One hundred sixty thousand in July. One million in August. And 4.2 trillion marks to the dollar on November 23, 1923, when adjustment finally began. Banks advertised for bookkeepers good with zeros and paid out cash withdrawals by weight. Antique stores filled to the ceiling with the pawned treasures of the bankrupt middle class. A theater seat sold for an egg. Only those with hard currency—mostly foreigners—thrived at a time when it was possible to cross Germany by first-class railroad carriage for pennies, but they also earned the enmity of starving Germans.

“How did you do it?” Szilard began explaining. “Five or ten minutes” later, he says, Einstein understood. After only a year of university physics, Szilard had worked out a rigorous mathematical proof that the random motion of thermal equilibrium could be fitted within the framework of the phenomenological theory in its original, classical form, without reference to a limiting atomic model—“and [Einstein] liked this very much.” Thus emboldened, Szilard took his paper—its title would be “On the extension of phenomenological thermodynamics to fluctuation phenomena”—to von Laue, who received it quizzically and took it home. “And next morning, early in the morning, the telephone rang. It was von Laue. He said, ‘Your manuscript has been accepted as your thesis for the Ph.D. degree.’ ”42 Six months later Szilard wrote another paper in thermodynamics, “On the decrease of entropy in a thermodynamic system by the intervention of intelligent beings,” that eventually would be recognized as one of the important foundation documents of modern information theory.

A discovery in physics opened the field to new possibilities while discoveries Szilard made in literature and utopianism opened his mind to new approaches to world salvation. On February 27, 1932, in a letter to the British journal Nature, physicist James Chadwick of the Cavendish Laboratory at Cambridge University, Ernest Rutherford’s laboratory, announced the possible existence of a neutron. (He confirmed the neutron’s existence in a longer paper in the Proceedings of the Royal Society four months later, but Szilard would no more have doubted it at the time of Chadwick’s first cautious announcement than did Chadwick himself; like many scientific discoveries, it was obvious once it was demonstrated, and Szilard could repeat the demonstration in Berlin if he chose.61, 62) The neutron, a particle with nearly the same mass as the positively charged proton that until 1932 was the sole certain component of the atomic nucleus, had no electric charge, which meant it could pass through the surrounding electrical barrier and enter into the nucleus. The neutron would open the atomic nucleus to examination. It might even be a way to force the nucleus to give up some of its enormous energy.

An older Hungarian friend, Szilard remembers—Michael Polanyi, a chemist at the Kaiser Wilhelm Institutes with a family to consider—viewed the German political scene optimistically, like many others in Germany at the time.69, 70 “They all thought that civilized Germans would not stand for anything really rough happening.” Szilard held no such sanguine view, noting that the Germans themselves were paralyzed with cynicism, one of the uglier effects on morals of losing a major war.71 Adolf Hitler was appointed Chancellor of Germany on January 30, 1933. On the night of February 27 a Nazi gang directed by the head of the Berlin SA, Hitler’s private army, set fire to the imposing chambers of the Reichstag. The building was totally destroyed. Hitler blamed the arson on the Communists and bullied a stunned Reichstag into awarding him emergency powers. Szilard found Polanyi still unconvinced after the fire. “He looked at me and said, ‘Do you really mean to say that you think that [Minister] of the Interior [Hermann Göring] had anything to do with this?’ and I said, ‘Yes, this is precisely what I mean.’ He just looked at me with incredulous eyes.” In late March, Jewish judges and lawyers in Prussia and Bavaria were dismissed from practice.72 On the weekend of April 1, Julius Streicher directed a national boycott of Jewish businesses and Jews were beaten in the streets. “I took a train from Berlin to Vienna on a certain date, close to the first of April, 1933,” Szilard writes. “The tr...

The second law specifies that heat will not pass spontaneously from a colder to a hotter body without some change in the system. Or, as Planck himself generalized it in his Ph.D. dissertation at the University of Munich in 1879, that “the process of heat conduction cannot be completely reversed by any means.” Besides forbidding the construction of perpetual-motion machines, the second law defines what Planck’s predecessor Rudolf Clausius named entropy: because energy dissipates as heat whenever work is done—heat that cannot be collected back into useful, organized form—the universe must slowly run down to randomness.

The practice of science was not itself a science; it was an art, to be passed from master to apprentice as the art of painting is passed or as the skills and traditions of the law or of medicine are passed.98, 99 You could not learn the law from books and classes alone. You could not learn medicine. No more could you learn science, because nothing in science ever quite fits; no experiment is ever final proof; everything is simplified and approximate.

The rules of the game are what we mean by fundamental physics. Even if we know every rule, however . . . what we really can explain in terms of those rules is very limited, because almost all situations are so enormously complicated that we cannot follow the plays of the game using the rules, much less tell what is going to happen next. We must, therefore, limit ourselves to the more basic question of the rules of the game. If we know the rules, we consider that we “understand” the world.

Polanyi thought science reached into the unknown along a series of what he called “growing points,” each point the place where the most productive discoveries were being made.105 Alerted by their network of scientific publications and professional friendships—by the complete openness of their communication, an absolute and vital freedom of speech—scientists rushed to work at just those points where their particular talents would bring them the maximum emotional and intellectual return on their investment of effort and thought. It was clear, then, who among scientists judged the value of scientific results: every member of the group, as in a Quaker meeting. “The authority of scientific opinion remains essentially mutual; it is established between scientists, not above them.” There were leading scientists, scientists who worked with unusual fertility at the growing points of their fields; but science had no ultimate leaders.106 Consensus ruled.

Plausibility and scientific value measured an idea’s quality by the standards of orthodoxy; originality measured the quality of its dissent. Polanyi’s model of an open republic of science where each scientist judges the work of his peers against mutually agreed upon and mutually supported standards explains why the atom found such precarious lodging in nineteenth-century physics. It was plausible; it had considerable scientific value, especially in systematic importance; but no one had yet made any surprising discoveries about it. None, at least, sufficient to convince the network of only about one thousand men and women throughout the world in 1895 who called themselves physicists and the larger, associated network of chemists.110 The atom’s time was at hand. The great surprises in basic science in the nineteenth century came in chemistry. The great surprises in basic science in the first half of the twentieth century would come in physics.

They discovered that each different radioactive product possessed a characteristic “half-life,” the time required for its radiation to reduce to half its previously measured intensity. The half-life measured the transmutation of half the atoms in an element into atoms of another element or of a physically variant form of the same element—an “isotope,” as Soddy later named it.143 Half-life became a way to detect the presence of amounts of transmuted substances—“decay products”—too small to detect chemically. The half-life of uranium proved to be 4.5 billion years, of radium 1,620 years, of one decay product of thorium 22 minutes, of another decay product of thorium 27 days. Some decay products appeared and transmuted themselves in minute fractions of a second—in the twinkle of an eye. It was work of immense importance to physics, opening up field after new field to excited view, and “for more than two years,” as Soddy remembered afterward, “life, scientific life, became hectic to a degree rare in the lifetime of an individual, rare perhaps in the lifetime of an institution.”

H. G. Wells thought Nature less trustworthy when he read similar statements in Soddy’s 1909 book Interpretation of Radium. “My idea is taken from Soddy,” he wrote of The World Set Free. “One of the good old scientific romances,” he called his novel; it was important enough to him that he interrupted a series of social novels to write it.150 Rutherford’s and Soddy’s discussions of radioactive change therefore inspired the science fiction novel that eventually started Leo Szilard thinking about chain reactions and atomic bombs.

In September 1907, his first term at Manchester, Rutherford made up a list of possible subjects for research. Number seven on the list was “Scattering of alpha rays.” Working over the years to establish the alpha particle’s identity, he had come to appreciate its great value as an atomic probe; because it was massive compared to the high-energy but nearly weightless beta electron, it interacted vigorously with matter.

the Newtonian laws that govern relationships within planetary systems, then Rutherford’s model should not work. But his was not a merely theoretical construct. It was the result of real physical experiment. And work it clearly did. It was as stable as the ages and it bounced back alpha particles like cannon shells. Someone would have to resolve the contradiction between classical physics and Rutherford’s experimentally tested atom. It would need to be someone with qualities different from Rutherford’s: not an experimentalist but a theoretician, yet a theoretician rooted deeply in the real. He would need at least as much courage as Rutherford had and equal self-confidence. He would need to be willing to step through the mechanical looking glass into a strange, nonmechanical world where what happened on the atomic scale could not be modeled with planets or pendulums.

Rutherford spoke warmly of the recent work of the physicist C. T. R. Wilson, the inventor of the cloud chamber (which made the paths of charged particles visible as lines of water droplets hovering in supersaturated fog) and a friend from Cambridge student days.

Bohr married, a serene marriage with a strong, intelligent and beautiful woman that lasted a lifetime. He taught at the University of Copenhagen through the autumn term. The new model of the atom he was struggling to develop continued to tax him. On November 4 he wrote Rutherford that he expected “to be able to finish the paper in a few weeks.”274 A few weeks passed; with nothing finished he arranged to be relieved of his university teaching and retreated to the country with Margrethe. The old system worked; he produced “a very long paper on all these things.”275 Then an important new idea came to him and he broke up his original long paper and began rewriting it into three parts. “On the constitution of atoms and molecules,” so proudly and bravely titled—Part I mailed to Rutherford on March 6, 1913, Parts II and III finished and published before the end of the year—would change the course of twentieth-century physics. Bohr won the 1922 Nobel Prize in Physics for the work.

Shortly he was brought into the presence of the First Lord. As Weizmann remembered the experience of meeting the “brisk, fascinating, charming and energetic” Winston Churchill:330 Almost his first words were: “Well, Dr. Weizmann, we need thirty thousand tons of acetone. Can you make it?” I was so terrified by this lordly request that I almost turned tail. I answered: “So far I have succeeded in making a few hundred cubic centimeters of acetone at a time by the fermentation process. I do my work in a laboratory. I am not a technician, I am only a research chemist. But, if I were somehow able to produce a ton of acetone, I would be able to multiply that by any factor you chose.” . . . I was given carte blanche by Mr. Churchill and the department, and I took upon myself a task which was to tax all my energies for the next two years.

In six months of experiments at the Nicholson gin factory in Bow, Weizmann achieved half-ton scale. The process proved efficient. It fermented 37 tons of solvents—about 11 tons of acetone—from 100 tons of grain. Weizmann began training industrial chemists while the government took over six English, Scottish and Irish distilleries to accommodate them. A shortage of American corn—German submarines strangled British shipping in the First War as in the Second—threatened to shut down the operations. “Horse-chestnuts were plentiful,” notes Lloyd George in his War Memoirs, “and a national collection of them was organised for the purpose of using their starch content as a substitute for maize.”331 Eventually acetone production was shifted to Canada and the United States and back to corn. “When our difficulties were solved through Dr. Weizmann’s genius,” continues Lloyd George, “I said to him: ‘You have rendered great service to the State, and I should like to ask the Prime Minister to recommend you to His Majesty for some honour.’ He said, ‘There is nothing I want for myself.’ ‘But is there nothing we can do as a recognition of your valuable assistance to the country?’ I asked. He replied: ‘Yes, I would like you to do something for my people.’ . . . That was the fount and origin of the famous declaration about the National Home for Jews in Palestine.”332 The “famous declaration” came to be called the Balfour Declaration, a commitment by the British government in the form of a lett...

They writhed in agony, ten thousand of them, serious casualties; and five thousand others died. Entire divisions abandoned the line. Germany achieved perfect surprise. All the belligerents had agreed under the Hague Declaration of 1899 Concerning Asphyxiating Gases “to abstain from the use of projectiles the sole object of which is the diffusion of asphyxiating or deleterious gases.”337 None seemed to think tear gas covered by this declaration, though tear gases are more toxic than chlorine in sufficient concentration. The French used tear gas in the form of rifle grenades as early as August 1914; the Germans used it in artillery shells fired against the Russians at Bolimow at the end of January 1915 and on the Western Front first against the British at Nieuport in March. But the chlorine attack at Ypres was the first major and deliberate poison-gas attack of the war. As later with other weapons of unfamiliar effect, the chlorine terrorized and bewildered. Men threw down their rifles and decamped. Medical officers at aid stations were suddenly overwhelmed with casualties the cause of whose injuries was unknown. Chemists among the men who survived the attack recognized chlorine quickly enough, however, and knew how easy it was to neutralize; within a week the women of London had sewn 300,000 pads of muslin-wrapped cotton for soaking in hyposulfite—the first crude gas masks.

Hahn followed Haber to work on gas warfare. So did the physicist James Franck, head of the physics department at Haber’s institute, who, like Haber and Hahn, would later win the Nobel Prize.342 So did a crowd of industrial chemists employed by I.G. Farben, a cartel of eight chemical companies assembled in wartime by the energetic Carl Duisberg of Bayer.343 The plant at Leverkusen with the new lecture hall turned up hundreds of known toxic substances, many of them dye precursors and intermediates, and sent them off to the Kaiser Wilhelm Institute for Physical Chemistry and Electrochemistry for study. Berlin acquired depots for gas storage and a school where Hahn instructed in gas defense.

The chemists, like bargain hunters, imagined they were spending a pittance of tens of thousands of lives to save a purseful more. Britain reacted with moral outrage but capitulated in the name of parity. It was more than Fritz Haber’s wife could bear.

The United States Army was slow to respond to gas warfare because it assumed that masks would adequately protect U.S. troops. The civilian Department of the Interior, which had experience dealing with poison gases in mines, therefore took the lead in chemical warfare studies. The Army quickly changed its mind when the Germans introduced mustard gas in July 1917. Research contracts for poison-gas development went out to Cornell, Johns Hopkins, Harvard, MIT, Princeton, Yale and other universities.365 With what a British observer could now call “the great importance attached in America to this branch of warfare,” Army Ordnance began construction in November 1917 of a vast war-gas arsenal at Edgewood, Maryland, on waste and marshy land.366, 367 The plant, which cost $35.5 million—a complex of 15 miles of roads, 36 miles of railroad track, waterworks and power plants and 550 buildings for the manufacture of chlorine, phosgene, chlorpicrin, sulfur chloride and mustard gas—was completed in less than a year. Ten thousand military and civilian workers staffed it. By the end of the war it was capable of filling 1.1 million 75-mm gas shells a month as well as several million other sizes and types of shells, grenades, mortar bombs and projector drums. “Had the war lasted longer,” the British observer notes, “there can be no doubt that this centre of production would have represented one of the most important contributions by America to the world war.”

Americans invented the machine gun: Hiram Stevens Maxim, a Yankee from Maine; Colonel Isaac Lewis, a West Pointer, director of the U.S. Army coast artillery school; William J. Browning, a gun maker and businessman; and their predecessor Richard Jordan Gatling, who correctly located the machine gun among automated systems. “It bears the same relation to other firearms,” Gatling noted, “that McCormack’s Reaper does to the sickle, or the sewing machine to the common needle.”

“The War had become undisguisedly mechanical and inhuman,” Siegfried Sassoon allows a fictional infantry officer to see. “What in earlier days had been drafts of volunteers were now droves of victims.”378 Men on every front independently discovered their victimization. Awareness intensified as the war dragged on. In Russia it exploded in revolution. In Germany it motivated desertions and surrenders. Among the French it led to mutinies in the front lines. Among the British it fostered malingering.

A new mechanism, the tank, ended the stalemate. An old mechanism, the blockade, choked off the German supply of food and matériel. The increasing rebelliousness of the foot soldiers threatened the security of the bureaucrats. Or the death machine worked too well, as against France, and began to run out of raw material. The Yanks came over with their sleeves rolled up, an untrenched continent behind them where the trees were not hung with entrails. The war putrified to a close.

Though he was admitted to the University of Budapest and might have stayed, von Neumann chose instead to leave Hungary at seventeen, in 1921, for Berlin, where he came under the influence of Fritz Haber and studied first for a chemical engineering degree, awarded at the Technical Institute of Zürich in 1925. A year later he picked up a Ph.D. summa cum laude in mathematics at Budapest; in 1927 he became a Privatdozent at the University of Berlin; in 1929, at twenty-five, he was invited to lecture at Princeton. He was professor of mathematics at Princeton by 1931 and accepted lifetime appointment to the Institute for Advanced Study in 1933.

The bow of the Carpathians as they curve around northwestward begins to define the northern border of Czechoslovakia. Long before it can complete that service the bow bends down toward the Austrian Alps, but a border region of mountainous uplift, the Sudetes, continues across Czechoslovakia. Some sixty miles beyond Prague it turns southwest to form a low range between Czechoslovakia and Germany that is called, in German, the Erzgebirge: the Ore Mountains. The Erzgebirge began to be mined for iron in medieval days. In 1516 a rich silver lode was discovered in Joachimsthal (St. Joachim’s dale), in the territory of the Count von Schlick, who immediately appropriated the mine. In 1519 coins were first struck from its silver at his command. Joachimsthaler, the name for the new coins, shortened to thaler, became “dollar” in English before 1600. Thereby the U.S. dollar descends from the silver of Joachimsthal.

A highlight of the summer was a pack trip. It started in Frijoles, a village within sheer, pueblo-carved Cañon de los Frijoles across the Rio Grande from the Sangre de Cristos, and ascended the canyons and mesas of the Pajarito Plateau up to the Valle Grande of the vast Jemez Caldera above 10,000 feet. The Jemez Caldera is a bowl-shaped volcanic crater twelve miles across with a grassy basin inside 3,500 feet below the rim, the basin divided by mountainous extrusions of lava into several high valleys. It is a million years old and one of the largest calderas in the world, visible even from the moon. Northward four miles from the Cañon de los Frijoles a parallel canyon took its Spanish name from the cottonwoods that shaded its washes: Los Alamos. Young Robert Oppenheimer first approached it in the summer of 1922.

Light as particle and light as wave, matter as particle and matter as wave, were mutually exclusive abstractions that complemented each other. They could not be merged or resolved; they had to stand side by side in their seeming paradox and contradiction; but accepting that uncomfortably non-Aristotelian condition meant physics could know more than it otherwise knew. And furthermore, as Heisenberg’s recently published uncertainty principle demonstrated within its limited context, the universe appeared to be arranged that way as far down as human senses would ever be able to see.

Newspapers soon published the discovery in plainer words: Sir Ernest Rutherford, headlines blared in 1919, had split the atom. It was less a split than a transmutation, the first artificial transmutation ever achieved. When an alpha particle, atomic weight 4, collided with a nitrogen atom, atomic weight 14, knocking out a hydrogen nucleus (which Rutherford would shortly propose calling a proton), the net result was a new atom of oxygen in the form of the oxygen isotope 017: 4 plus 14 minus 1. There would hardly be enough 017 to breathe; only about one alpha particle in 300,000 crashed through the electrical barrier around the nitrogen nucleus to do its alchemical work.511 But the discovery offered a new way to study the nucleus. Physicists had been confined so far to bouncing radiation off its exterior or measuring the radiation that naturally came out of the nucleus during radioactive decay. Now they had a technique for probing its insides as well.

Atoms do not fall apart, Aston reasoned. Something very powerful holds them together. That glue is now called binding energy. To acquire it, hydrogen atoms packed together in a nucleus sacrifice some of their mass.

Locked within all the elements, he said, but most unstably so in the case of those with high packing fractions, was mass converted to energy. Comparing helium to hydrogen, nearly 1 percent of the hydrogen mass was missing (4 divided by 4.032 = .992 = 99.2%). “If we were able to transmute [hydrogen] into [helium] nearly 1 percent of the mass would be annihilated. On the relativity equivalence of mass and energy now experimentally proved [Aston refers here to Einstein’s famous equation E = mc2], the quantity of energy liberated would be prodigious. Thus to change the hydrogen in a glass of water into helium would release enough energy to drive the ‘Queen Mary’ across the Atlantic and back at full speed.”

Twice as many Americans became physicists in the dozen years between 1920 and 1932 as had in the previous sixty. They were better trained than their older counterparts, at least fifty of them in Europe on National Research Council or International Education Board or the new Guggenheim fellowships. By 1932 the United States counted about 2,500 physicists, three times as many as in 1919.

Scientists and artists proved less similar in personality than in cognition, but both groups were similarly different from businessmen. Dramatically and significantly, almost half the scientists in this study reported themselves to have been fatherless as children, “their fathers dying early, or working away from home, or remaining so aloof and nonsupportive that their sons scarcely knew them.”527 Those scientists who grew up with living fathers described them as “rigid, stern, aloof, and emotionally reserved.”528 (A group of artists previously studied was similarly fatherless; a group of businessmen was not.)

Guiding that research was usually a fatherly science teacher.530 Of the qualities that distinguished this mentor in the minds of his students, not teaching ability but “masterfulness, warmth and professional dignity” ranked first.531 One study of two hundred of these mentors concludes: “It would appear that the success of such teachers rests mainly upon their capacity to assume a father role to their students.”532 The fatherless young man finds a masterful surrogate father of warmth and dignity, identifies with him and proceeds to emulate him. In a later stage of this process the independent scientist works toward becoming a mentor of historic stature himself.

Mimetic desire

I believe that through discipline, though not through discipline alone, we can achieve serenity, and a certain small but precious measure of freedom from the accidents of incarnation, and charity, and that detachment which preserves the world which it renounces. I believe that through discipline we can learn to preserve what is essential to our happiness in more and more adverse circumstances, and to abandon with simplicity what would else have seemed to us indispensable; that we come a little to see the world without the gross distortion of personal desire, and in seeing it so, accept more easily our earthly privation and its earthly horror—But because I believe that the reward of discipline is greater than its immediate objective, I would not have you think that discipline without objective is possible: in its nature discipline involves the subjection of the soul to some perhaps minor end; and that end must be real, if the discipline is not to be factitious.

At the leading edges of science, at the threshold of the truly new, the threat has often nearly overwhelmed. Thus Rutherford’s shock at rebounding alpha particles, “quite the most incredible event that has ever happened to me in my life.” Thus Heisenberg’s “deep alarm” when he came upon his quantum mechanics, his hallucination of looking through “the surface of atomic phenomena” into “a strangely beautiful interior” that left him giddy. Thus also, in November 1915, Einstein’s extreme reaction when he realized that the general theory of relativity he was painfully developing in the isolation of his study explained anomalies in the orbit of Mercury that had been a mystery to astronomers

Quantum theory bloomed while nuclear studies stalled. Rutherford had felt optimistic enough in 1923 to shout at the annual meeting of the British Association, “We are living in the heroic age of physics!” By 1927, in a paper on atomic structure, he was a little less confident.575 “We are not yet able to do more than guess at the structure even of the lighter and presumably least complex atoms,” he writes.576 He proposed a structure nonetheless, with electrons in the nucleus orbiting around nuclear protons, an atom within an atom.

He lived privately until October, then left with his second wife, Elsa, on a long trip to the Far East and Japan, receiving notice of his Nobel Prize en route. He spent twelve days in Palestine on the way back and stopped over in Spain. By the time he returned to Berlin, German preoccupation with politics had temporarily retreated behind preoccupation with the Dadaistic mark, then soaring toward 54,000 to the dollar.644 Einstein went on with his work, including the Einstein-Szilard refrigerator pump and his first efforts toward a unified field theory, but began frequently to travel abroad.

The dispersion of the Jewish people from Palestine—the Diaspora—began in the sixth century B.C. when Babylon conquered the southern Palestinian kingdom of Judah, destroyed Solomon’s temple and carried a large body of Jews into captivity.653 By the beginning of the Christian era, under Roman hegemony, Jews had established communities in Egypt, in Greece, around the Mediterranean and on the shores of the Black Sea and there were Jewish slaves with the Roman legions on the Rhine. Conditions worsened again for the Jews when the Empire was Christianized in the fourth century A.D. with the conversion of the Emperor Constantine; Christianity and Judaism competed, in a Darwinian sense, for the same Holy Land and the same holy books. Under systematic persecution only a small remnant of the Jewish people remained in Judea. The fantasy of Jews as a brotherhood of evil was invented during this era when Christianity fought its missionary way to dominance.

The English were the first to expel the Jews entirely. The Jews of England belonged to the Crown, which had systematically extracted their wealth through a special Exchequer to the Jews. By 1290 it had bled them dry. Edward I thereupon confiscated what little they had left and threw them out. They crossed to France, but expulsion from that country followed in 1392; from Spain, at the demand of the Inquisition, in 1492; from Portugal in 1497. Since Germany was a region of multiple sovereignties, German Jews could not be generally expelled. They had been fleeing eastward from bitter German persecution in any case since the twelfth century. The Jews expelled from Western Europe fled to Poland, a large and thinly populated kingdom where elected monarchs welcomed them with generous charters. The medieval German of these emigrant Ashkenazim evolved to Yiddish; they founded villages and towns; they dispersed up and down the long eastern Polish frontier and lived in relative peace for two hundred years. Twenty-five thousand at the end of the fifteenth century had increased at least tenfold by the middle of the seventeenth. Then, in violent wars with Russia and Sweden, Poland began to break up. Cossacks and their peasant allies murdered great numbers of Jews and sacked hundreds of their communities. The Ukraine was split in two; Poland lost the northern half to Russia. War and disorder continued into the eighteenth century with Prussia, Austria and Turkey variously joining battle.

The enemies of Christ became Russia’s “Jewish problem.” In Russia’s benighted intolerance it framed only two solutions: assimilation (by conversion to Christianity) or expulsion. For the interim it practiced quarantine. A decree of 1791 limited Jewish residence to the formerly Polish territories and the unpopulated steppes above the Black Sea, a region that extended north across 286,000 square miles of central Europe to the Baltic: the Pale of Settlement (“pale” in its old sense of “enclosed by a boundary”). The Ashkenazim numbered one-ninth of the Pale’s total population, and might have prospered there, but they were burdened with further restrictions. They were heavily taxed, they could not live in the villages as they had done for generations, they could not keep the village inns or sell liquor to the peasants. Their traditional local governments, the kehillot, were stripped of legal authority but required to collect Jewish taxes. More horribly, under Nicholas I after 1825 the kehillot were charged to conscript twelve-year-old Jewish children for a lifetime of forced service in the Russian Army—six years of brutal “education” followed by twenty-five years in the ranks—a fate that befell between 40,000 and 50,000 Jewish sons before the requirement was relaxed in 1856.

Emancipations as they progressed within less revolutionary states included Holland-Belgium, 1795; Sweden, 1848; Denmark and Greece, 1849; England by a gradual unmuddling completely in 1866; Austria, 1867; Spain by the withdrawal of its 1492 order of expulsion in 1868; the new German Empire, 1871. Though they were influential out of all proportion to their numbers, the emancipated Jews of Western Europe, many of whom moved directly to assimilate, were only a minute fraction of the Diaspora. The preponderance of the Jewish people, increased by 1850 to 2.5 million, by 1900 to 5 million, struggled in increasing misery in the Pale. At his coronation in 1856, amid remissions and amnesties, Czar Alexander II abolished the special conscription of Jewish children.

Abraham Flexner, the American educator, sought out Einstein at Caltech. Flexner was in the process of founding a new institution, not yet located or named, chartered in 1930 with a $5 million endowment. The two men strolled for most of an hour up and down the halls of the club where Einstein was staying. They met again at Oxford in May and once more at the Einsteins’ summer house at Caputh, outside Berlin, in June. “We sat then on the veranda and talked until evening,” Flexner recalled, “when Einstein invited me to stay to supper. After supper we talked until almost eleven. By that time it was perfectly clear that Einstein and his wife were prepared to come to America.”679 They walked together to the bus stop. “Ich bin Feuer und Flamme dafür” Einstein told his guest as he put him on the bus: “I am fire and flame for it.”680, 681 The Institute for Advanced Study would be established in Princeton, New Jersey. Einstein was its first great acquisition. He had suggested a salary of $3,000 a year. His wife and Flexner negotiated a more respectable $15,000. It was what Caltech had been prepared to pay. But at Caltech, as in Zurich before, Einstein would have been expected to teach. At the Institute for Advanced Study his only responsibility was thought.

The Solvay Conference, devoted for the first time to nuclear physics, drew men and women from the highest ranks of two generations: Marie Curie, Rutherford, Bohr, Lise Meitner among the older physicists; Heisenberg, Pauli, Enrico Fermi, Chadwick (eight men in all from Cambridge and no one from devastated Göttingen), Gamow, Irene and Frédéric JoliotCurie, Patrick Blackett, Rudolf Peierls among the younger. Ernest Lawrence, his cyclotron humming, was the token American that year. They debated the structure of the proton. Other topics they discussed may have seemed more far-reaching at the time. None would prove to be. On August 2, 1932, working with a carefully prepared cloud chamber, an American experimentalist at Caltech named Carl Anderson had discovered a new particle in a shower of cosmic rays. The particle was an electron with a positive instead of a negative charge, a “positron,” the first indication that the universe consists not only of matter but of antimatter as well. (Its discovery earned Anderson the 1936 Nobel Prize.)

When the Scuola Normale examiner saw Fermi’s competition essay on the assigned theme “Characteristics of sound” he was stunned. It set forth, reports Segrè, “the partial differential equation of a vibrating rod, which Fermi solved by Fourier analysis, finding the eigenvalues and the eigenfrequencies . . . which would have been creditable for a doctoral examination.”768 Calling in the seventeen-year-old liceo graduate, the examiner told him he was extraordinary and predicted he would become an important scientist. By 1920 Fermi could write a friend that he had reached the point of teaching his Pisa teachers: “In the physics department I am slowly becoming the most influential authority. In fact, one of these days I shall hold (in the presence of several magnates) a lecture on quantum theory, of which I’m always a great propagandist.”769 He worked out his first theory of permanent value to physics while he was still a student in Pisa, a predictive deduction in general relativity.