Chapter Nine—
Ripening Crops (1950–1954):
Smell of Ripe Wheat

Season of mists and mellow fruitfulness!
John Keats, "To Autumn"

At Berkeley after the war I found myself for the second time in my life (the first had been at Palermo) free to work according to my tastes without the need to produce a certain number of papers or results in order to survive in the profession. It is said that Verdi always complained of having to compose his operas under cruel deadlines, and that only Othello and Falstaff, the masterpieces of his old age, were composed according to his wishes, in full freedom. With all due respect to the differences, my own experience had been similar. First the Italian competitions and the compulsion to pile up printed paper, later my position as a refugee at Berkeley, and later still the exigencies of Los Alamos had forced me to work on short-range projects that could be brought to fruition rapidly or to otherwise work under great pressure. Now that I had "arrived," I could tackle longer-range projects, and I thought that the nucleon-nucleon interaction was a worthy subject of investigation. It seemed to be at the very core of the exploration of nuclear

structure, the nucleus being an assembly of nucleons. Many famous physicists had devoted great efforts to its theoretical study: Werner Heisenberg, Ettore Majorana, Eugene Wigner, Igor Tamm, and others had provided deep theoretical insights into the problem, and low-energy experiments had shed light on many aspects of it, although limited to states of zero angular momentum. The higher energies now available opened up to experiment states of higher angular momentum, and they could give significant new information. To prepare myself for this experimental program, I started learning what was known about the nucleon-nucleon collision by giving a graduate course in nuclear physics with emphasis on that particular area.

The rapidly developing accelerators offered unique opportunities.^[1] During the war, the great magnet planned for an ordinary cyclotron with an energy of 100 MeV, to which I had made a small contribution, served to provide the magnetic field for prototypes of mass spectrographs. After the war, it returned to an accelerator, but of a different type from that previously planned. The plans for the new machine included frequency modulation and the use of the phase-stability principle, it was to become the 184-inch Berkeley synchrocyclotron. This machine started working at the end of 1946 and had a long and glorious history. Initially, it accelerated only an internal deuteron beam to about 195 MeV. These deuterons impinging on any target produced an external neutron beam of about 100 MeV, the first we used in the neutronproton collision investigation started in 1947.

These neutrons caused a funny episode. A hasty investigation of the angular distribution of the neutron beam, performed as soon as the accelerator started functioning, indicated a forward distribution, as expected, but with a minimum at deflection zero. This was reported in a colloquium attended by Oppenheimer, and he immediately gave a learned theoretical explanation of the phenomenon. I listened to it and then said that it was better to check if by chance there was not a lead brick just in front of the target, projecting a shadow. Immediately after the colloquium somebody rushed to check my hypothesis. It was correct.

In the summer of 1948, Owen Chamberlain, who, as previously noted,

after having served in my group at Los Alamos, had gone to Chicago and obtained his Ph.D. under Fermi, returned to Berkeley as an instructor and rejoined my group. Our detailed study of the nucleonnucleon collision was greatly enhanced at the end of that year by the availability of an external proton beam. For many years the measurements we did between 1948 and 1955 remained authoritative.^[2]

Many people collaborated in the experimental side of the enterprise including H. F. York, Chamberlain, Clyde Wiegand, and Tom Ypsilantis.^[3] The contribution of all these colleagues, postdoctoral fellows, and graduate students was essential; without it, it would have been impossible to carry on the enterprise. Measuring not only absolute collision cross sections, but also polarizations, correlations, and similar beauties, we collected a wealth of experimental data. The next step was to derive from them the phase shifts of the partial s, p, d, etc., waves. For this analysis, Ypsilantis, Henry Stapp, and Nicholas Metropolis used the Los Alamos computer.^[4]

In the end, the problem turned out to be less fundamental than either we or the theoreticians believed in the 1940s. At the time, it was believed that the nucleon-nucleon force was a primary natural force mediated by pions according to Hideki Yukawa's ideas. Progress has changed the outlook. We now believe that the true fundamental forces are those between quarks, described by chromodynamics. Nevertheless for nuclear physics in a strict sense, the nucleon-nucleon force is still of capital importance, independently of its origin. Even with this reservation, however, ours was an important piece of work of durable value, or at least as durable as such things are in present-day physics.

In addition to research I regularly taught one or two courses, usually one to upper-division undergraduates and one to graduate students. Over the years I greatly varied the subjects. Often I taught nuclear physics and quantum mechanics, trying to make the subject simple while at the same time presenting significant problems. It seems that the reactions to my courses were of two kinds: one group of students were very appreciative, others not so much. I believe my lectures were not as polished as others, but they had a degree of freshness that made them

appealing. I believe one saw I was not reciting a textbook, but rather telling from experience as a practicing scientist.

Seminars were an important component of my teaching. I often held them with some other professor, such as Chamberlain, with an attendance of about ten students. Students prepared to explain some good review article, often from Annual Reviews of Nuclear Science, to the audience. I tried to pay attention and to learn something new. I also demanded that the speaker understood what he was saying. It was surprising how often formulae would occur where the speaker did not really know the meaning of the symbols he was using, or diagrams where the speaker could not explain what was plotted. Unfortunately, I had a tendency to fall asleep, especially when I did not understand. At a slightly higher level I tried to elicit an explanation of the various "It is easily shown"s that adorn the scientific literature. All told, I hope the courses gave not only specific information on technical points, but also an education in scientific attitude.

I well remembered how once as a young assistant professor I had cut a bad figure on one of the rare occasions when Corbino attended a seminar. He had asked for a subtle, though necessary, explanation in a question of adiabatic demagnetization, and I obviously demonstrated that I did not know what I was talking about.

In the same vein, a few years before his death, in a conversation in which I complained about the many subjects that are supposedly "well known" but in fact are just the opposite, Fermi suggested I make a note of any such questions I came across—such as validity conditions for Born's approximation, subtle questions of B and H in magnetism, signs in the energy expressions in thermodynamics, innumerable questions related to phases in quantum mechanics, and so on—and that when he retired, he would write a book giving all the explanations. Unfortunately, this did not come to pass. It would have been the best-seller in physics. Of course, there are many other physicists who could write such a book. I hope one of them will oblige, and write it with Fermi's clarity and simplicity.

In that period I also started to busy myself with physics literature,

in which I had a long-standing interest. Immediately after the war, knowledge acquired while working on military projects was classified and could be used only by those with appropriate clearances. Much of it, however, had only little and indirect military value, although it was important for scientific and technological progress. Moreover, the very existence of secret reports produced awkward results, because, while cleared personnel knew that certain things had been done or could be done by methods and techniques developed during the war, they could not use or teach what they knew without violating military secrecy. The government had started a big declassification process, but by its nature it was a slow operation, very bureaucratic and occasionally even subject to manipulation.

I then thought that it might be a worthy endeavor to compile a big treatise on the model of the prewar German Handbuch der Physik edited by Hans J. W. Geiger and Karl Scheel, but limited for organizational and time reasons to nuclear physics. It could not be written by any one person, because each chapter would require the expertise of one or more specialists with firsthand information. I assembled a group of experts and directed the compilation, in three fat volumes, of Experimental Nuclear Physics, which was very successful (it was even translated into Russian). The enterprise took longer than I had anticipated, however; the first volume appeared in 1953 and the last in 1959.^[5]

In the same spirit of helping disseminate scientific information, I also started to work for Annual Reviews of Nuclear Science . The series was initiated by others, but I soon became one of its mainstays, and in 1952 its editor. I kept the job until 1977, when I retired because I thought younger forces should carry on.^[6] The work was practically unpaid, but it helped to keep me current, and I believe it has not been the smallest service I have performed for the profession.

I remained in Berkeley during all of 1948. Fermi came there to teach the summer session, after which we went to Los Alamos for a few weeks together. He drove all the way from California, because he did not trust anybody else. In 1949 the problems of SCT required my presence in Italy, and I returned there with Elfriede and children. I would have liked to spend a good part of the time at Tivoli, but Elfriede

demurred. I never fathomed the cause of Elfriede's dislike for Tivoli. A possible explanation, although strenuously denied by her, may have been the contrast between her unhappy childhood at Ostrowo, and later at Breslau, and my own at Tivoli.

In September 1949, I attended an international physics conference at Basel, where for the first time since before the war, we were once again able to meet our old European colleagues and friends and report at least in part on the great novelties developed during the war. I spoke there of our work on nucleon-nucleon collisions.^[7] The great Wolfgang Pauli was in the audience; he listened shaking his head from left to right and simultaneously shifting his heavy body up and down. After my speech, I was going away with the Swiss physical chemist Egon Bretscher, who had been at Los Alamos, when Pauli accosted me and said: "I have never heard a worse report than yours." I did not answer; what could I say? But Pauli turned to Bretscher and added: "I stand corrected; when you spoke [and he mentioned the occasion] it was even worse." Whereupon he departed. Another physicist, who knew Pauli well and had witnessed the performance, smiled at me and said: "Don't listen to him. Your speech must have been quite interesting to him because he oscillated all the time, which means that he was listening carefully." I knew Pauli well enough to know that there was no reason to worry about his remarks.

In an excursion following the Basel meeting, we went to the Cosmic Ray Lab at Testa Grigia near the Theodule Pass under the Matterhorn. I revisited the Breuil basin where I had spent memorable days twenty years earlier. The Breuil was already spoiled by new hotels and ski lifts, which had transformed that Alpine gem into a vulgar commercial resort. At the Cosmic Ray Lab, work was proceeding chiefly under the leadership of Gilberto Bernardini. Several of the Italian physicists were fed up with the difficult working conditions that prevailed there, however, and shortly thereafter, Bernardini, Gian Carlo Wick, and other friends of mine packed up and came to work in the United States, at least for a few years.

Back in Berkeley, Robert Brode, Francis Jenkins, and I kept our eyes open for promising young recruits to the staff of the physics

department. This was one of the reasons for attending the annual meetings of the American Physical Society in Washington, D.C., which functioned as a placement market. Interviewing possible candidates in 1948, I recalled the days when I had attended similar meetings looking for work, particularly my difficult time in 1940. The tables had now turned. The situation in 1948 was radically different; before the war there had been few jobs, whereas now able candidates could always choose among several excellent positions. Birge, though head of the department, hardly took the initiative in the selection of young recruits, but the University of California was in a phase of expansion and qualitative improvement, which facilitated the recruitment process. If one could find an outstanding prospect, we could count on the administration being able to find the means to make an attractive offer. Furthermore, for people interested in nuclear or particle physics, the accelerators and Rad Lab facilities were a powerful attraction. We thus were able to hire many future celebrities. Unfortunately, several left because, especially to theoreticians, the eastern United States offered strong competition by reason inter alia of its superior scope for communication and exchange of ideas. Harvard enticed away several of our best young professors, among them Steven Weinberg, Sheldon Glashow, and Michael Tinkham.

In 1949 the Regents of the University of California, its supreme authority, came up with the idea of requiring a loyalty oath of the faculty, demanding among other things that they declare that they were not members of the Communist Party. The wording of the oath was relatively harmless, but it was not harmless to demand it of professors while exempting all other state employees. The controversy expanded into bitter arguments, and in my opinion the Regents showed that they were not up to their task. They seemed to me more concerned with their prestige and with asserting their paramount authority than with the welfare of the university. The governor of California, Earl Warren, sided with the moderate faction among the Regents; the extremists were led by J. F. Neylan, a former Hearst lawyer noted for his extreme political opinions. This radical faction prevailed, and those who did not swear the loyalty oath were dismissed.^[8]

In physics this resulted in serious losses, among them Geoffrey Chew, Wolfgang Panofsky, Marvin Goldberger, Gian Carlo Wick, and Robert Serber. For theory, it was a body blow; for experiment, something a bit less. Luckily all these men found excellent positions and were not forced to make severe personal sacrifices, except for the inconvenience of moving. None of them were communists, but they refused on principle to take a discriminatory oath.

Lawrence took a hard line, following Regent Neylan and those who demanded the oath. He did not appreciate the nature of the objections of the non-signers; to him they seemed byzantine quibbles. Grotesque episodes ensued. One involved the special pass required at the time for admission to the Rad Lab. Lawrence summoned Wick to his office and, in the presence of Alvarez, curtly asked Wick whether it was true that he had not signed the oath. Wick, taken by surprise, gave an equally curt affirmation. Looking straight into his eyes, Lawrence responded: "Then you can no longer work at the Radiation Lab." Wick, in turn, coldly offered to return his pass to the security officer, and Lawrence said, "Please do." Wick gave Lawrence the pass, and that ended the interview. Under the apparent coldness of the words, feelings ran high. It was clear to Wick that Lawrence was acting illegally, because he had no authority for withdrawing the pass, and that he was in a vulnerable position. Alvarez at once understood the implications and ramifications of Lawrence's action. He must have cautioned and calmed him down, and after a few days Alvarez called Wick on the phone and asked him to forget the whole incident. Ernest, he said, sometimes acts in a fit of emotion; please do not take what he said seriously. Wick got back his pass.

I personally sympathized with the non-signers, but I was not incensed by the controversy. My friends Jenkins and Brode, who shared my opinions on the subject, insisted that the oath and the connected excitement were transient lunacies of a type that had occurred many times in the history of the United States, and that they would pass. In any case, I signed the oath, although I thought such oaths meaningless.

I calculated that I had sworn my allegiance to king, Mussolini, party, constitutions, and institutions at least fifteen times, and I even remem-

bered a pronouncement by Pope Pius XI, elicited by a Fascist oath, explicitly stating that under certain circumstances one could take such oaths with mental reservations that made them void.^[9] I dug the papal document out in the library and translated it, and some colleagues to whom I had sent it posted it in Los Alamos, which administratively depended on the Regents of the University of California. At Berkeley it circulated less openly.

With all this brewing, it was not clear how the situation would evolve, and I thought it advisable to distance myself a little from the University of California and to wait the turn of events, prepared to go elsewhere if worst came to worst. In the meantime the non-signers had started a legal action against the Regents, which ultimately went to the supreme court of the state of California. The court ruled that the oath was unconstitutional, forced the Regents to abolish it, to reinstate the professors who had resigned or been fired, and to pay them damages. All this, however, was still in the future.

The unpleasant atmosphere created by the oath deteriorated further, for me, when Bruno Pontecorvo unexpectedly defected to the USSR. He was vacationing in Italy from his permanent post in England, when about October 20, 1950, he traveled to Finland with his family and vanished. He left no traces, but it was reasonably supposed that he had gone to Russia. I do not know the reason for his flight. One can formulate several hypotheses, few of them flattering to him. In 1940, escaping from the Nazis, Pontecorvo had sought asylum and found hospitality in the United States, thereby indirectly incurring a moral obligation toward the country. I had no information about his disappearance other than what I read in the newspapers. Although I had been Pontecorvo's friend since his student days in Rome, had helped him obtain a job at Tulsa in 1940, and had seen him at the Basel conference, I certainly was not privy to his secrets.

After Pontecorvo's flight, several officers of the U.S. government questioned me, but only as a witness, and with full acknowledgment that I had not had anything to do with his disappearance. On the other hand, G. M. Giannini, who had an interest in our neutron patents and dealt with other parties about them, telephoned to me as though he

wanted to implicate me in Pontecorvo's actions, and Luis Alvarez attacked me, as I recorded in a notebook on October 24, 1950:

Alvarez enters my office. O. Chamberlain present. Asks about Pontecorvo. Then says it is improper to ask for compensation for the Fermi patent because we came to this country and the shelter received was to us worth more than a million dollars. We are guests here and we should be glad to be able to repay in part the USA for the privilege of citizenship. I answer I did not think that citizenships were for sale. That the law fixed such things. He said that to bring a suit (for patent compensation) was like settling a quarrel by fisticuffs in a bar. I answered that a US court will not be flattered by the comparison. He concluded that I should let him know when Pontecorvo writes me from Russia.

I spoke to Birge, Thornton, and Brode about Alvarez's outburst, and all three advised to keep my cool, since nobody suspected me. On Giacomo Ancona's suggestion I also spoke to a former California supreme court justice who was his close friend. He listened intently and then advised me to do absolutely nothing and wait for the storm to blow over. Pontecorvo's flight also made trouble for Serge Scherbatskoy, his old boss at Tulsa, who was the son of a czarist general.

Much bigger and more ominous things were brewing at Berkeley, however, especially after the explosion of the first Russian atomic bomb (August 29, 1949). Lawrence grew increasingly concerned about the United States's atomic weapons, which seemed to him inadequate, and sought to improve them with various technical initiatives, which ended in serious failures.^[10] I had heard of some of these plans, which seemed ill advised to me, and I decided, feeling duty bound, to speak to Lawrence on the subject, trying to give him my reasons and my numerical estimates as well I could. He reacted with great vehemence, accusing me of being unpatriotic, lazy, selfish, and God knows what more. I was not surprised and did not lose my temper. I must also add that Lawrence, apart from a few insults, did not do anything against me, left me the use of the machines, and continued his support as before.

In the meantime, Lawrence and Teller were striking an alliance for the building of the hydrogen bomb. Teller had been obsessed with it since the time of Los Alamos, and this had given rise to serious conflicts

with Oppenheimer, Bethe, and others. Fermi, whose scientific prestige was paramount, was against the hydrogen bomb, but felt it incumbent upon him to inform the government about the technical situation, although he advised against building such a weapon.^[11] After the development of the Soviet atomic bomb, Teller redoubled his efforts and entered an alliance with Lawrence, the Air Force, and other scientists and politicians to push the development of the hydrogen bomb.

I personally did not want to get involved in a military project that I regarded as being of doubtful usefulness. In any case the pressures exerted on me were moderate and easy to resist. Not only did I not take part in the struggles, machinations, and intrigues of this period, but I did not even know of them. I was not among Lawrence's confidants. We both knew the chasm between our ideas and it was not worth his while for Lawrence to try to convert me to his views, especially since I was unimportant in science policy. I, on my side, neither knew how to approach Lawrence nor had any hope of changing his ideas. On the other hand, I had several conversations with Teller, whom I had known well since my time at the Physics Institute in Rome. I soon realized, however, that he was dominated by irresistible passions much stronger than even his powerful rational intellect.

Students and postdoctoral fellows were in a much more difficult position than I. For them to say no to Lawrence might seriously threaten their careers, and Lawrence also had a technico-scientific ascendancy over them that he lacked over me. Moreover, although presented chiefly as a patriotic duty, war work was not devoid of financial attractions. I tried to give to my students and younger colleagues my candid appraisal of the situation as I saw it, but I always concluded by insisting that the decision must be theirs alone. All these struggles poisoned the scientific atmosphere and part of the scientific community. Too often the political authorities were deprived of cool, informed technical advice; too often they heard only confirmation of their own wishful thinking. Battles strangely similar to those of that period still persist and are a serious threat to humanity.

At that time I had frequent offers of university positions, and, considering the turmoil generated at Berkeley by the loyalty oath contro-

versy, I decided to go to the University of Illinois at Urbana to wait things out. The chairman of the physics department and local czar at Urbana was W. F. Loomis, an able and agreeable person. He was entirely dedicated to the improvement of his department, which was then undergoing expansion, and was striving to enrich an already excellent faculty. Gilberto Bernardini had moved to the University of Illinois from Columbia, and Urbana was relatively close to Chicago, where I could visit Fermi. Bernardini and I had been close friends since our student days, and we had pleasant exchanges in and outside science, including memorable parties playing scopone (an Italian card game). Donald Kerst's betatron seemed to be an interesting accelerator, although it failed to completely fulfill my hopes. All this was needed to compensate for the climate and surroundings, which could not compare with those of California.

Before going to Urbana, however, I was able to spend a few months in Europe and in 1951 we went to Paris, where I renewed my acquaintance with the Joliot-Curies. I had received a Fulbright fellowship for Italy and had been invited to give the Accademia dei Lincei's Donegani Lectures. (This was quite an honor because they had been given only once before, by Fermi, in 1949.) The lectures I gave in Rome and Milan in April 1951 were later published in a booklet by the Lincei.^[12]

The president of the Accademia dei Lincei, Professor Francesco Giordani, a physico-chemist, told me that the Academy would like to elect me a member or honor me in some other way. Being an American citizen, however, I could become only a foreign member, and they would have preferred to have me as a national member, with voting rights. I said that I did not mind becoming a foreign member, which happened in 1958, such being the speed at which the Academy moves. In the meantime, I was awarded the prestigious Cannizzaro Medal (1955).

On the occasion of the Donegani Lectures I also met Dr. Luigi Morandi, then vice president of the Montecatini Company, the biggest Italian chemical company, the steel magnates Falck, the publishers Mondadori, the newspaper publisher I. Montanelli, and several other Italian personalities, with whom I remained in contact.

At the end of 1951, International Business Machines Corporation offered me the directorship of a scientific laboratory it proposed to establish, which would be connected with Columbia University in New York and devoted to fundamental research without any short-term commercial application. The offer was alluring and merited serious consideration. The university connection, important for me, would have been preserved by a chair at Columbia. On the other hand, I would hardly be able to continue my nuclear work, which was too remote from IBM's interests. The salary IBM offered was about twice what I was earning at Berkeley.

"Dr. Segrè, where do you come from?" Thomas Watson, Jr., the president of IBM, asked me in the course of our discussions.

"From Berkeley, California," I replied.

"Strange, I have been to California many times, but I have never met a person who talks like you," Watson said.

We both started laughing, and I explained that I was Italian. I also went to see IBM's great research laboratory at Poughkeepsie, a trip of which I remember best the red flame of the autumn foliage against a deep blue sky, a natural spectacle I still vividly recall after so many years. During my negotiations with IBM, I started formulating some plans for the future lab and suggesting some people it would be desirable to hire. Among them were Erwin Hahn and Richard L. Garwin. I had heard of the first at the University of Illinois and of the second from Fermi, who had praised him to me in unusual terms. The two were ultimately hired by IBM, and Garwin is still there in a senior position, while Hahn has become a Berkeley professor.

To further complicate my deliberations, I also received another attractive offer, from the Brookhaven National Laboratory. While I was trying to make up my mind, importuned by these fastidi grassi (fat troubles), as my father would have called them, the Berkeley situation was improving. The Regents were getting a tough and deserved lesson from the California supreme court, and at the same time the Board's composition was changing, as the most extreme members were being replaced at the end of their terms by more moderate ones. In the end, having considered my options, I decided to return to Berkeley.

Not that everything there was easy. I had to wobble between the physics department and the Rad Lab. I say wobble, because on the one hand I needed the accelerators, and my work was supported by the Rad Lab, but on the other hand I had difficulties with Lawrence. What had happened in my early years at Berkeley had left its scars, and besides I did not like the little I knew of Lawrence's military activities. I grant that he was friendly and generous in giving me access to the machines, but I felt that if I had entered the circle of his close friends, I would have lost my freedom. I thus avoided going on his payroll even during the summer, while almost everybody else did. I wanted to make sure that he could not consider me as his employee. I also rather childishly avoided appearing in group photos taken on the inauguration of accelerators and similar occasions.

It was not easy for me to speak to Lawrence, as it had not been easy many years earlier to speak to Corbino, and possibly Lawrence too was uncomfortable with me. The differences between our scientific outlooks, cultural backgrounds, and political ideas were obstacles difficult to surmount. I clearly saw that Lawrence's relations with Alvarez (then, because later they changed appreciably), McMillan, and even Panofsky were different from what they were with me; they ran on a much smoother and easier basis. R. L. Thornton and Don Cooksey, two true gentlemen and close friends of both Lawrence's and mine, when necessary acted as intermediaries. It was easier for them to speak with both parties. I do not want to appear ungrateful to Lawrence, and certainly I owe him much, as I said in my Nobel speech, but the truth is that I rather avoided him. I note now that I have always called him "Lawrence" here; everybody in the lab called him "Ernest," but it took me many years and considerable effort to do the same.

Like everyone involved, Lawrence recognized that my group was doing good physics, and it did not cost him much; as a consequence my requests were always promptly satisfied, and more than once Lawrence personally intervened to assign me time I needed on the accelerators. In hindsight, I believe I should have made greater efforts to pierce the crust that separated us, and perhaps we would both have

profited from it, although I am afraid a close friendship would have been unlikely.

It is not easy for me to describe my scientific work. The titles of my publications speak to physicists, but without explanations, my work is not easily understandable to lay people. I must anyway emphasize that science was by far my main occupation, and that it absorbed my time and energies. Even when I was away from the lab, I thought of physics, and I generated many ideas in places not usually connected with work. Mountain outings had always also been scientific occasions.

The general thrust of my work, from the very beginning, was to explore various more or less recondite consequences of modern theories, or to measure things thought to be important. My aims were not spectacularly inventive, like those of people who look for unexpected new phenomena, and neither were they based on development of new techniques that made new regions accessible to experimentation, although accelerators, developed by others, were mostly essential to my work. My strong points were a good knowledge of physics and a certain imagination, which enabled me to see things not immediately apparent to everybody. For many years the techniques I used were very simple, almost rudimentary, and I spoke of doing "physics without apparatus." Later, mostly thanks to Chamberlain and Wiegand, we refined known techniques and applied them with a critical eye, avoiding errors and obtaining results that at the time were the best available.

Physics strategy changed very much after the war. Many experiments are rather obvious, and the problem is only to perform them at the highest possible energy and with a clean technique. At Urbana I used to call such experiments "battleship experiments," implying a parallel between physics and naval warfare. I compared the function of Admiral Nelson with that of an admiral at the beginning of World War II. Nelson had to guess where the enemy would be, divine the weather, and maneuver his fleet accordingly, whereas a modern admiral who had guns that shot farther than his opponent's could simply hit him without danger of retaliation. Today in physics it is often possible to make discoveries simply by having more powerful apparatus—not that this

counts for little, because to create such tools and to know how to use them is not given to everybody. Of course, it is also essential to know which problems are important and promise solution—the more so as the investments in time, money, and effort involved in each experiment have grown immensely. The time when a Faraday could perform several significant experiments in a single day is as long gone in physics as that of Nelson in naval warfare.

Berkeley after the war was especially suited for "battleship experiments" because its accelerators excelled both in energy and in the quality of their performance. Working conditions were very different from prewar times; with more money available it was possible to build adequate detectors, and it was easier to get access to the accelerators, because all their time was not taken up with development work or medical experiments, as often happened before the war.

Among my endeavors in "physics without apparatus," I count, in chronological order: my work on forbidden lines, and in particular on quadrupole radiation;^[13] that on "swollen atoms" (now Rydberg states);^[14] the finding of the new chemical elements technetium, astatine, and plutonium;^[15] the chemical separation of nuclear isomers;^[16] and the changing of the radioactive decay constant by chemical action.^[17] On the other hand, my investigations into nucleon-nucleon collisions and antiproton work were typical "battleship experiments."^[18] I have omitted the neutron work performed with Fermi and the work on molecular beams in Otto Stern's lab.^[19] In the neutron work, Fermi's contribution was paramount; in the molecular beam work performed in the general framework of Stern's research, I devised the experimental trick that made that specific experiment possible, but Rabi better understood its significance.

I want to add a word on how accelerator time was assigned. The apportionment was an administrative decision, taken after consultation with user groups, which defended their requests at scheduled meetings. I found that the key for obtaining what I wanted was to show that we used the time effectively. This in turn depended upon going to the machine with well-prepared experiments and achieving interesting results. It was also very important to secure the enthusiastic cooperation

of the technical staff who operated the machines. This we obtained by telling them what we were doing, why, our hopes, and the reasons for our operational requirements. This resulted in an intelligent, diligent, and generous cooperation that greatly helped the work, for which I am still very grateful.

In recent times, physics has evolved in the direction of increasing specialization and technical complication. Apparatus now costs sums unthinkable only thirty years ago; research teams have expanded to hundreds of people, the part played by computers has become preeminent and so has engineering collaboration. Physics is certainly unrecognizably different today from what it was when I started work. It requires personal qualities quite different from those once required. The chief of a team must often be an organizer and a charismatic type more than a thinker. What I have said applies especially to particle physics, but the situation in other specialties is evolving in the same direction. Chemistry has undergone a similar sea change. The whole process is connected to applications, military, industrial, and of other kinds. It is not clear where all this will lead.

In 1953 the old questions relative to nuclear power patents came to a head. I had an interest in two patents: the Rome neutron patent and the one pertaining to plutonium. The latter, however, had not yet been granted; it was still only an application.

The Fermi group applied for the neutron patent directly after the discovery of slow neutrons. As soon as he heard of our findings, Corbino recognized their potential practical importance and urged us to file for patents. We applied with the help of the attorney Laboccetta, and the Italian patent N. 324 458 was granted on October 26, 1935. It concerns a method of producing radioactive substances by neutron collisions and in particular covers the increase of efficiency obtainable by slowing the neutrons with multiple elastic collisions. Because slow neutrons are central to nuclear power production, the patent is basic to the nuclear industry. It is basic also for military applications that use both slow and fast neutrons. The Italian patent was later extended to other countries, including the United States. The inventors were

Fermi, Amaldi, Pontecorvo, Rasetti, and Segrè. We agreed however to share profits with Oscar D'Agostino and G. C. Trabacchi as well, in equal shares.

The increasingly precarious European situation prompted us from the very beginning, in 1935, to transfer our rights to an American company, in the hope that the patent might better escape a possible European catastrophe. For this reason, we entered into an agreement with G. M. Giannini, a young businessman we knew, who had emigrated to the United States. Giannini took title to the patent, sharing in the profits as one of the other partners. Patent expenses were paid by Philips of Eindhoven, which also had a share in the profits. Fermi and I tried to interest some of the big U.S. corporations, such as General Electric, but without success, although Fermi personally tried to illustrate the potential of the field to their technical bigwigs. Their reaction contrasted with the vision of Corbino and of Philips.^[20]

After the discovery of fission, when nuclear energy development started in earnest, the neutron patent became obviously fundamental to all applications and hence of considerable value. This was well understood by Fermi and by myself, who were involved in secret work. On the other hand during the war it was neither possible nor desirable to raise questions about compensation for the patent. At the end of the war, there was a long period of uncertainty while Congress debated the Atomic Energy Act, which among other subjects, was expected to regulate the whole question of patent rights and compensation for their expropriation by the government.

Fermi, as the chief inventor, had the paramount voice in all decisions. After the war, in the transition period, the U.S. government bargained doggedly with Fermi through his patent lawyers. He would readily have renounced his own rights, as he had done for other most important inventions relative to the pile, but he felt an obligation to protect the rights of the Italian inventors. After all, the invention had been made in Italy, ten years earlier, and the patent had been granted long before the U.S. government had any interest in the matter. The shenanigans used by the lawyers to obstruct and minimize the "just compensation" mandated by the law ended by disgruntling Fermi to the extent that he

declined reappointment to important government advisory boards on which he served (of course without compensation). I believe that the zealous government lawyers, in finding possible conflicts of interest and other technicalities, did grave damage to their client. While the negotiations proceeded slowly and laboriously, Pontecorvo's flight in October 1950 further complicated matters. Ultimately, compensation for the neutron patent was fixed at $400,000, which became a sort of standard for the most important patents. After expenses, each inventor received about $20,000.

The history of the plutonium patent is different. On request of government agencies, Kennedy, Seaborg, Wahl, and I filed a patent application on plutonium. The application covered work done by us, on our own initiative, before any government participation. If the government, ex post facto, had not asked us to file the application, we might not have done so. Later, however, the government changed its position and wanted to obtain our rights free of charge. There were years of maneuvering and negotiations on the subject, first with the Manhattan District and later with the AEC.

After the war, one did not know how the law would treat patents or patent application rights whose content was classified secret and that were of public interest, as in our case. The McMahon Act of 1946 required the government to expropriate these rights, paying "just compensation." A special committee was appointed to determine "just compensation," but it had hardly any guidelines to go by. The uncertainty extended over several years.

At one point, the University of California made claims, and these interacted even with the loyalty oath controversy. The majority of the Regents were determined to assert their authority over the faculty in every possible way, and patent rights entered, although remotely, into this picture. Lawrence, a strenuous defender of this majority, took an adversary position against the inventors. Among other things, he said he feared the effect that compensation for our patents would produce on the morale of the Rad Lab. Seaborg negotiated with great ability on behalf of the inventors; he succeeded in placating everybody concerned and very effectively protected our interests.

The AEC paid $400,000, the same as for the neutron patent. Since there were no legal expenses, each inventor received $100,000, which in those times was an appreciable sum. When the inventors settled with the goverment, R. G. Sproul, president of the University of California, wrote us a nice letter thanking us for the monies he expected we would turn over to the university. He must have been disappointed when we did not give him anything. Later, when my dear friend Joseph Kennedy, much to our grief, fell ill with stomach cancer, he wrote me a letter thanking me for insisting that the compensation to the inventors had been fully earned, and that we should spend it as we liked. The sum he had kept gave him a certain peace of mind for the future of his family.

I think the cases of the two inventions were very different. When the government entered the picture, the neutron patent had already been granted and had international validity; it was much more than an application. Moreover, it had been granted to inventors who had nothing to do with the U.S. government. I think we were vastly underpaid for it. The treatment we received as inventors from the U.S. government reflects the mindset of lawyers and bureaucrats, who believed that by squeezing the inventors as much as possible, they were properly serving the government, and who also hoped to acquire merit. They may have saved a few dollars, but how much did they lose in the advice a person like Fermi could have given the government? And what about the goodwill of many others?

The British have done better; I do not believe they have been lavish with money, but they conferred knighthoods and even life peerages on men like John Cockcroft, Rudolf Peierls, James Chadwick, William Penney, and Patrick Blackett. It is an inexpensive form of compensation, but it gives satisfaction to many. I believe that the pettiness, the jealousy, and the inclination to litigation prevailing in a democracy such as the United States are in the long run sources of weakness.

In 1953 I went to a Gordon Conference in Laconia, New Hampshire, which gave me the opportunity of visiting part of New England, and I spent the rest of the summer at the Brookhaven National Laboratory, where I found Fermi and Chamberlain. Riccardo Rimini came to New

York too, accompanying one of his wealthy Uruguayan patients, and we spent many hours together. In the same period I first met the brilliant physicist Oreste Piccioni, whose ideas on impulse approximation with virtual particles and similar subjects I was interested to hear. At Brook-haven I again worked on astatine;^[21] I also did some chemical experiments, which I have never published.

Meanwhile, Clyde Wiegand and some of my students continued our experiments at Berkeley. Among the students was Tom Ypsilantis, who had studied chemistry, but had recently come to me because he wanted to change to physics. I soon recognized his human qualities as well as his uncommon scientific ability. During my absence, Tom and Clyde succeeded in polarizing the proton beam of the synchrocyclotron by collision. The method was not new; it had been theoretically predicted and experimentally demonstrated at Rochester, New York,^[22] but Ypsilantis succeeded in obtaining superior results and started the exploitation of polarized protons, opening up new possibilities to the study of nucleon-nucleon collisions. The success obtained and Ypsilantis's spirit of initiative impressed me, and I proposed a faculty appointment for him. He was one of the most promising young physicists at Berkeley, where be continued to do brilliant work for several years. Unfortunately, his bright flame did not last long; some demon, still unidentified by me, attacked him. He lost some of his drive and later sought to resign his Berkeley post. His friends on the faculty, myself among them, tried to persuade him to reconsider the decision and ask for a year's leave of absence instead. The following year, however, he insisted on resigning. Thereafter he held several positions, but he ended by achieving less than his great potential had seemed to promise. Ultimately, he moved to CERN in Europe and elsewhere. He is an exceptionally agreeable and gifted person and one whom I sincerely love.

In February 1954, during a visit at Chicago, I talked at length about our group's polarization work with Fermi, my last serious scientific conversation with him. Fermi developed the formulae at the blackboard while I took notes, and he subsequently wrote a paper on the subject.^[23]