Franck, James, 1882-1964

James Franck was born August 26, 1882 in Hamburg, Germany, where his Sephardic Jewish forebears had lived for over two hundred years [Box 20, folder 58 and Box 21, folder 1]. His father, Jacob Franck, was a banker who wanted his son to follow a business career in keeping with family tradition. From childhood on, however, James could imagine no other life but science. An X-ray photograph illustrates his fascination with new discoveries in physics. He had already read of Roentgen's X-ray photography when he broke his arm in 1896. A mere boy of thirteen, he went alone to a municipal physics laboratory for a demonstration of Roentgen's discovery on his broken arm, which he later proudly recalled was the first use of X-ray in Hamburg [Box 21, folder 9]. Despite these scientific interests, Franck was considered a very dull schoolboy, for success within the curriculum of the classical gymnasium depended on one of his weakest faculties, rote memory.

In his first year of studies at Heidelberg, 1901, Franck met Max Born and others who shared his love of science. Born helped him persuade his parents to let him study physics, although at that time a scientific career offered little financial security. In 1902, he went to Berlin to study at the Friedrich Whilhelm University with some of Germany's most famous physicists, including Max Planck, whose formulation of the quantum in 1900 had given the new mechanics its names, and Emil Warburg, who became his thesis advisor. Among the remains from his student days are his notes of Planck's lectures, entitled "Mechanik nach Planck." [Box 11, folders 1 and 3 (Notebook 2).}

After earning a doctorate in physics in 1906 and spending a few months as a research assistant at Frankfurt am Main, Franck returned to the University of Berlin to work with Heinrich Rubens. Berlin became the setting for important personal as well as professional developments in Franck's life. There he met a talented pianist, Ingrid Josephson of Göteborg, Sweden, whom he married on December 23, 1907 [Box 21, folder 5]. Two daughters were born of this marriage, Dagmar on October 2, 1909, and Elisabeth on December 19, 1911.

In 1911, James Franck and Gustav Hertz began the study of elastic collisions between electrons and atoms. Their work led to the discovery of excitation potentials, the amount of energy which an electron must absorb before it can move further away from the nucleus of the atom. Two laboratory notebooks, stamped "Dr. G. Hertz," contain data from some of these experiments [Box 11, folders 7, 8, and 9 (Notebooks 5 and 6)].

The outbreak of World War I in 1914 ended the collaboration of Franck and Hertz. Both joined the German army. For his war service, Franck received the Iron Cross, first and second class, and the Hanseatic Cross of his native city, Hamburg [Box 21, folders 13 through 15]. His front line service ended in 1916 when he contracted severe polyneuritis affecting his legs [Box 21, folder 12].

After the war, Franck joined the faculty of the Kaiser Wilhelm Institute for Physical Chemistry in Berlin, where he continued the experiments which he had begun earlier with Gustav Hertz. Franck's work in this period is represented by three folders of data from helium experiments he conducted with Paul Knipping and Fritz Reiche [Box 11, folders 10 through 12]. In their November 1, 1919, article in Physikalische Zeitscrift reporting some of the findings of these helium experiments, Franck and Knipping added to the vocabulary of physics the term "metastable" to describe an atom in a condition of marginal stability.

It was during these postwar years in Berlin that Franck met Niels Bohr and realized for the first time that the Franck-Hertz experiments of 1911-1914 provided the first experimental evidence for Bohr's revolutionary and highly controversial atomic theory published in 1913. A lifelong friendship between Franck and Bohr developed from the respect the two scientists held for each other's work. The Franck-Bohr correspondence dates from October 19, 1920 to 1962, the year of Bohr's death [Box 1, folder 5].

Franck went to Göttingen in 1921 as professor physics and director of the Second Physics Institute. The years he spent there were among the happiest and most productive of his life. He was fortunate to have as colleagues Max Born and Robert Pohl, physicists who were also his longtime friends. Born, who had encouraged Franck to study physics when they were students at Heidelberg in 1901 and 1902, accepted the post of professor of theoretical physics at Göttingen in 1920 on the condition that Franck be offered a professorship for experimental physics [Box 21, folder 58]. Pohl, who had been a student with Franck in Berlin, held the professorship of experimental physics at the First Physics Institute [Box 20, folder 1 (1905 photograph)].

Franck, Born, and Pohl attracted some of the best young physicists in Germany to Göttingen. Among Franck's students and assistants whose correspondence is preserved in the collection are Günther Cario, Whilhelm Hanle, Gerhard Herzberg, Arthur von Hippel, Fritz G. Houtermans, Werner Kroebel, Hans Kopfermann, Heinrich G. Kuhn, Walter Lochte-Holtgreven, Rienhold Mannkopf, Heinz Maier-Leibnitz, Otto Oldenberg, Eugene Rabinowitch, and Hertha Sponer. [Arthur von Hippel married Dagmar, the elder of Franck's two daughters, in 1930]. The reputation of the Physics Institutes also drew many foreign students. Of those who worked with James Franck, two Englishmen, Patrick M. S. Blackett and Robert d'E. Atkinson, and three Americans, Francis Wheeler Loomis, Louis A. Turner, and J. Gibson Winans, are represented in the Franck correspondence. The mood of these Göttingen years is caught in an album of photographs kept by Hertha Sponder, Franck's research assistant at Göttingen [Box 19]. The pictures in Miss Sponer's album of group outings, parties at local inns, and afternoon coffees evoke the warmth and informality of Franck's relationships with his students.

Franck's international reputation was established during his years at the Second Physics Institute. In November, 1926, he received word that he and Gustav Hertz were to receive the 1925 Nobel Prize in physics. With this award, the Swedish Academy of Science gave recognition to the Franck-Hertz experiments which had led to the "discovery of the laws governing the collisions of electrons [with atoms]." [Box 5, folder 9]. The Franck Papers contain the Nobel certificate [Box 23, folder 4] and Franck's gold Nobel medal, as well as pictures of James and Ingrid Franck and Gustav and Ellen Hertz traveling to Stockholm and of the presentation ceremony on December 10, 1926 [Box 22. In 1934, Franck placed his Nobel medal in an office safe at Niels Bohr's Institute for Theoretical Physics in Copenhagen, and apparently forgot to reclaim it when he emigrated to America the following year. The medal remained in the safe until April, 1940, when, to keep it from the invading German army, George de Hevesy converted it to powder along with Bohr's Nobel medal. In 1950, Bohr sent the gold dust from the two medals to the Nobel Foundation for recasting (Box 5, folder 9). At the presentation of the recast medal in 1951, Franck said: "I am so delighted about this, as I know now that half of my medal is Niels Bohr's." (Victor Weisskopf, verbal communication to Elisabeth Lisco, October, 1974.) [Box 20, folders 7 through 14]. The Papers contain no scientific manuscripts or notebooks produced at Göttingen or reflecting Franck's distinguished work during that period.

The course of James Franck's life was radically altered in 1933 by the enactment, under the national socialist government, of laws removing Germans of Jewish descent from government positions. Franck's war record made him eligible for an individual exemption from this provision of the Jewish exclusion laws and would have allowed him, despite his Jewish background, to remain director of the Second Physics Institute. As director, however, he would have been required to take part in the dismissal of Jewish assistants and students. In a letter to the Minister of Culture, dated April 17, 1933, he resigned both his professorship and the directorship of the Second Physics Institute in protest of "the position of the government toward German Jews." [Box 7, folder 4]. Because of Franck's statures as a veteran of World War I and a Nobel laureate, his resignation created a sensation. In the following days and weeks he received many letters of praise and support for his stand not only from friends and colleagues but also from strangers [ Box 7, folders 5 through 7].

Franck's desire to continue his scientific work in Germany proved impossible. Months of searching failed to turn up a suitable position which would not require political compromises. At the end of 1933 he left Germany for America to accept a temporary appointment as Speyer Professor of Physics at Johns Hopkins University.

In 1934, Franck returned to Europe as a guest professor in Niels Bohr's laboratory at the Institute for Theoretical Physics, Copenhagen. Bohr attracted to the Institute many of the best German physicists of the mid-1930's, both Jews and non-Jews, who were leaving the German institutes then deteriorating under the Jewish exclusion laws and the Nazi attack on "Jewish" science [For example, see Box 7, folder 4, "German Physics and Jewish Physics," Volkischer Beobachter, February 28, 1936 [ A group photograph shows the remarkable wealth of scientific talent gathered in Copenhagen in 1935; seated beside James Franck in the front row of a lecture hall are Otto Stern, Lise Meitner, Max Born, Werner Heisenberg, Pascual Jordon, and Wolfgang Pauli. During his stay in Copenhagen Franck performed experiments with Hilde Levi on the fluorescence of chlorophyll [Box 20, folder 21]. Four notebooks from these experiments are preserved in the Franck papers [Box 11, folders 13 through 16].

Franck returned as a professor of physics to Johns Hopkins in 1935 where, for the next three years, he taught and continued his research on the fluorescence of chlorophyll. The small amount of material from his work at Baltimore consists of three folders of lecture notes,[ Box 12, folders 2 through 4] one notebook of laboratory data, [Box 12, folder 1 (Notebook 14)] and two folders of drafts and notes [Box 12, folders 14 and 15].

In 1938 Franck accepted an invitation to become professor of physical chemistry at the University of Chicago, where a special laboratory, supported by the Samuel S. Fels Fund of Philadelphia, was established for his photosynthesis research. The outbreak of World War II in 1939, however, cast a shadow on this promising beginning. As the war progressed, Franck considered the German fascist threat so grave that he laid aside his photosynthetic work to support the war effort. Despite misgivings about the atomic bomb's potential for destruction, he joined the Manhattan Project on December 1, 1942, one day before the first self-sustaining, controlled nuclear reaction was achieved. He directed the Chemistry Division of the Metallurgical Laboratory at the University of Chicago until December, 1943, when he began gradually to disengage himself from the project by becoming associate director, then serving as a consultant from May 1, 1944, until July 1, 1945.

The unprecedented destructive capability of the atomic bomb continued to trouble Franck as well as many other scientists who had helped create it. In 1944, when the main activity of the Manhattan Project had shifted to Los Alamos, Chicago became a center of discussion about the consequences of the bomb's impending use. During the summer and fall of that year, Franck served on a committee chaired by Zay Jeffries which solicited from group leaders at the scattered project sites opinions for a report on the future of nuclear energy. The "Jeffries Report," formally entitled "Prospectus on Nucleonics," was given to Arthur Compton on November 18, 1944, who forwarded it to General Leslie Groves [Box 18, folder 11] In the spring of 1945, Franck directed a personal appeal to the executive branch of the federal government in a memorandum he wrote with Eugene Rabinowitch [ Box 18, folder 13] On April 21, he delivered this memorandum to Secretary of Commerce Henry A. Wallace at a breakfast meeting in Washington arranged by Arthur Compton.

The following June, Franck chaired a committee composed of six other members of the Metallurical Laboratory (Eugene Rabinowitch, Leo Szilard, Joyce Clennam Stearns, Glenn T. Seaborg, James Joseph Nickson, and Donald J. Hughes) which produced a second memorandum on the social and political implications of atomic energy [Box 18, folder 23]. The "Franck Report," the name by which this memorandum became known, was a further development of the April 21 memorandum. J. J. Nickson's handwritten notes on a Franck Committee meeting in early June outline the ideas contributed by individual members of the committee [Box 18, folder 15]. At Franck's request, Rabinowitch drafted the report [Box 18, folder 18] and D. J. Hughes, Glenn T. Seaborg, and Robert S. Mulliken (who was not on the Franck Committee) wrote criticisms of it [Box 18, folder 21]. Although Rabinowitch, more than any other individual, was the author of the "Franck Report," it was essentially a group effort, summarizing months of informal discussion among Metallurgical Laboratory scientists on the implications of their work.

Franck traveled to Washington on June 11 to present the report at the office of the Secretary of War, Henry Stimson, in hopes of preventing the military use of the atomic bomb against Japan [Alice Kimball Smith, A Peril and A Hope: The Scientists' Movement in America, 1945-1947. Chicago: University of Chicago Press, 1965. p 14-48]. Although the recommendations of the "Franck Report" went unheeded, it became a symbol of awareness among scientists of the political and social impact of their discoveries. For Franck, the report was the product of a bitter lesson he had learned in Germany-that he could not afford to be apolitical. He expressed this insight in a letter written to German Ambassador Knappstein in 1964: "What has happened in our lifetime stems, I believe, from the fact that the people as a whole have left the solution of political questions chiefly to the government." [Box 3, folder 8 (German Embassy correspondence)].

World War II significantly altered Franck's personal life. Initially, it severed his lines of communication with Germany by curtailing the extensive correspondence he had carried on with German friends and colleagues since his emigration in 1935. At the same time, it strengthened his commitment to his American citizenship, which he received in July, 1941. In a letter written to the Baden Minister of Education in response to the offer of an appointment at Heidelberg after the war, Franck explained that his new allegiance made it impossible to consider returning to Germany: "I took this step, as soon as it was legally possible, not only to free myself from enforced statelessness, but also because I earnestly wanted to create a new homeland here. I have neither the wish to go back on this step, nor would I consider it justified." [Box 3, folder 12 (Heidelberg Universität correspondence)].

The close of the war enabled Franck to resume his correspondence with friends and former colleagues in Germany. Just as before the war many German Jews had turned to him for help in finding new jobs abroad, now many non-Jewish Germans asked him for money, food, and clothing. Franck responded generously out of his modest salary. The CARE packages Franck sent to his former teacher, Max Planck, occasioned an especially poignant exchange of letters in 1946 and 1947, for the frail and aged Planck had lost everything in the war, including his favorite son executed by the Nazis [Box 6, folder 4].

The reestablishment of contact with former friends who had stayed in Nazi Germany was sometimes painful. Franck was asked to understand and forgive compromises with totalitarianism and to vouch to the Occupation authorities for the character and conduct of men with whom he had not communicated for years. In a letter written May 26, 1947, to Eugene Wigner, Franck expressed his dilemma: "Within my narrow limits, I try to help everyone whose behavior I know was decent….After all that happened and after so many disillusionments about people whom I trusted in earlier times, I take nothing for granted anymore; now I have to know that those I trust are deserving of it." [Box 10, folder 5].

Despite his feelings of having been betrayed by some Germans whom he had considered friends, Franck remained open to reconciliation with a reconstructed Germany. In 1945, he joined other German and Austrian émigrés in America in signing an appeal for the economic rebuilding of Germany as a prerequisite to its moral recovery [Box 18, folder 26]. In the same spirit, he accepted German gestures of restitution. He agreed to rejoin the Göttingen Academy of Sciences, which had expelled him under fascist pressure in 1933, because, as he wrote to Theodore von Karman in a letter of February 11, 1948, "if one does not help the people who want to work for a future Germany free of nationalism and racism, etc. the chances for such a Germany to develop become practically zero." [Box 3, folder 8 (Göttingen Akademie der Wissenschaften correspondence)].

Immediately after the war, Franck was concerned not only with Germany, but also with the development and control of atomic energy in America. In the earliest days of the Cold War, the American government's policy of secrecy, designed to keep the technology of the atomic bomb from the Soviets, threatened to hinder research in atomic energy by suppressing the exchange of scientific information. Franck, with other scientists who had chafed under the security requirements of the Manhattan Project, was unwilling to see wartime restrictions continue in peace and sought to change the policy of secrecy in favor of international controls. To inform the American public of the issues, he became one of the founding members of the Atomic Scientists of Chicago, which on December 10, 1945, produced the first issue of the Bulletin of the Atomic Scientists. But Franck remained uncomfortable with political activity, although he considered it imperative. Frustration at continued distraction from his work is expressed in a letter he wrote to Peter Pringsheim on September 13, 1945: "Against my wishes, I am again busy with discussions and plans on how to make it clear to the so-called statesmen and to the public what is at stake-that secrecy will not save the country and that a real world agreement is absolutely necessary; furthermore, that scientists are not obedient servants that one can muzzle at will…Damn it all! I really long for undisturbed concentration on scientific work." [Box 6, folder 7].

Franck returned to photosynthesis research after the interruptions of the war and post-war politics. Upon Frank's retirement in September, 1947, from his position as professor of physical chemistry at the University of Chicago, the University and the Samuel S. Fels Fund made arrangements to continue supporting his work. In 1948, the original ten-year Fels Fund grant was renewed for an indefinite period. Franck's photosynthesis laboratory was absorbed by the Institute of Radiobiology at the University of Chicago in July, 1949. The Fels Fund agreed in 1951 to provide a lifetime salary for Franck as director emeritus of the photosynthesis project [Box 2, folder 9] Hans Gaffron, Franck's research associate at the University of Chicago since 1939, assumed the directorship of the project in 1952.

Until his death in May of 1964, Franck continued to devote as much of his time as his health permitted to theoretical work on photosynthesis. He spent the winter months in Durham, North Carolina, with his second wife, Hertha Sponer-Franck, who had been a member of the Physics Department at Duke University since 1936. The Francks usually spent the summer at their house in Falmouth, Massachusetts. Each year, in the spring and fall, James Franck returned to Chicago for about a month in order to continue scientific discussions with his colleagues and to work on his publications. This pattern continued until about 1960, when Hans Gaffron moved the photosynthesis project from Chicago to Florida State University at Tallahassee. In collaboration with Jerome L. Rosenberg, Franck further developed his theoretical model of photosynthesis; a paper summarizing his ideas was finished shortly before he departed on his last journey to Europe in the spring of 1964 [See below, page 17].

Studies in Photosynthesis

From his first publication on photosynthesis in 1935, [Box 12, folder 14] Franck's attention focused on mechanisms by which quanta are absorbed and their energy transferred. Franck's interest in photosynthesis represents a logical progression from his pre-World War I studies leading to the discovery of excitation potentials of atoms. At Göttingen, Franck continued to study excitation potentials, using fluorescence to measure the conversion of excitation energy to other forms of energy. At the same time, biochemists and plant physiologists were just beginning to describe similar processes in plants, but the question of how light energy was transformed into energy utilizable by plants remained a mystery. In the early 1930's, observations of fluorescence in plant extracts were reported. As Franck became aware of these and other studies which paralleled his own work with fluorescence of free radicals in solution and of dye stuffs, he became increasingly interested in the question of energy conversion and transfer in plants [Although his major preoccupation from the 1930's on was photosynthesis, Franck did not completely abandon physics. A small group of manuscripts in the Franck Papers (Box 12, folder 5-13) relates to his publications in physics between 1935 and 1958, chiefly with Robert Platzman (Box 12, folder 6, 8, 10-11, 13), but also including one article with Edward Teller in 1938 (Box 12, folder 5) and one with his wife, Hertha Sponer in 1956 (Box 12, folder 12)].

Perhaps Franck's most enduring contribution to the advance of knowledge about photosynthesis is that his hypotheses and critiques stimulated other researchers to reconsider previously accepted theories, often resulting in the formulation of new theories [Roderick K. Clayton, Molecular Physics in Photosynthesis (New York: Blaisdell Publishing Company, 1965), p 182-91]. An example of this process is the effect of Franck's and Edward Teller's critique of the photosynthetic unit theory, published in the Journal of Chemical Physics in 1938, as part of an article on excitation energy in crystals [Box 12, folder 5]. The photosynthetic unit, as proposed by Robert Emerson and William Arnold in 1932 and modified by the reaction center hypothesis of Hans Gaffron and Kurt Wohl in 1936, was defined as a set about 2,000 chlorophyll molecules acting together with associated enzymes to reduce carbon dioxide and to produce glucose. The reaction center was postulated as the site in the photosynthetic unit where the light energy gathered by chlorophyll molecules is changed into chemical energy. In their 1938 article, Franck and Teller used quantum mechanical principles to distinguish among three types of energy transfer, later designated by Theodore Förster as "fast," "intermediate," and "slow." Each of these three types of energy transfer became an area of major research interest from which developed theoretical advances in the description of the size and organization of the photosynthetic unit and of its reaction center.

Frank's photosynthesis research under the first ten-year Fels Fund grant (1938-48) is represented in the Franck Papers by only two folders of manuscripts and notes [Box 12, folders 16 and 17]. Sometime after his retirement in September, 1947, Franck went through his files and disposed of his rough notes and drafts. Most of the manuscripts preserved in the Franck Papers date from the period after 1948 when Franck's need to conserve his energy for work on his publications left him no time for sorting and discarding his papers.

Franck's work on photosynthesis received greater attention after 1949, when he became involved in a bitter controversy [This controversy followed Franck to the grave when Warburg published, in Die Naturwissenschaften 23 (1964), pp. 550-51, a rebuttal to Wernre Kroebel's obituary of Franck, "Zum Tode von James Franck," Die Naturwissenschaften 18 (1964), pp. 421-23 (Box 21, folder 51)] with the German biochemist, Otto Warburg (the son of the Franck's thesis advisor, Emil Warburg) [See the tribute to Emil Warburg on his eighty-fifth birthday by James Franck and Robert Pohl, Box 21, folder 44]. The "Warburg controversy" centered on the quantum yield of photosynthesis, i.e., the measurement of the amount of light energy necessary to effect the primary photochemical act. Otto Warburg reported a quantum requirement of four quanta per carbon dioxide molecule for the process of photosynthesis. This requirement would have made photosynthesis a highly complex chemical reaction proceeding with virtually no friction at seventy-five per cent overall efficiency in the conversion of light energy into chemical energy. To Franck this finding was physically impossibly by the laws of thermodynamics and of the quantization of energy; four quanta could not effect the conversion. According to his interpretation of quantum theory, thermodynamics, and chemical kinetics, the requirement had to be at least eight quanta, and most experimentalists reported measurements of between six and ten. Warburg denied that these laws of physics applied to the living cell and stood by his measurements even though no other research groups could verify them. Warburg's obstinacy was particularly irritating to Franck, who characteristically would alter his photosynthetic model to take into account experimental data from other laboratories as well as his own.

In his 1949 article in Archives of Biochemistry, [Later the Archives of Biochemistry and Biophysics] Franck explained the disparity between quantum yields obtained by Robert Emerson at the University of Illinois and those of Warburg's group in Berlin by suggesting that Warburg was measuring the photochemical reduction of respiratory intermediates rather than normal photosynthesis [Box 12, folder 18 through 21]. Warburg not only refused to be persuaded, but also published new measurements which lowered the quantum requirement from four to two and seven-tenths quanta per carbon dioxide molecule. In a second article, appearing in the July, 1952 Archives of Biochemistry and Biophysics, Franck marshaled evidence for another attempt at convincing Warburg. The extensive notes and drafts of this article in the Franck Papers testify to the care Franck took in preparing it [Box 13, folders 1 through 29]. His closely reasoned essay provided a physical explanation for the reaction mechanisms of the Calvin-Benson cycle of carbon dioxide reduction and for the high quantum yields obtained by Warburg's research group.

One of Franck's arguments in this 1953 article illustrates his characteristic ability to keep in view, in the most complex discussions, consideration so simple and obvious that others tended to overlook them: Warburg's highest quantum yields occurred under conditions unfavorable to plant growth. Franck made this point about Warburg's technique with subtle humor: "In principle it is certainly justified to vary the conditions until the photochemical process works at its highest efficiency. However, the value of such variation becomes dubious if one finds that the photosynthetic apparatus can only be induced to do its 'best' under conditions where other tests show that the cells are not functioning well…Thus we find that high yields seem to be connected with influences generally regarded as harmful to the plants." [Box 13, folder 1, p. 26-27].

The Gatlinburg Conference on Photosynthesis held October 25-29, 1955, in eastern Tennessee, [Box 14, folders 1 through 13] was organized specifically to discuss the mechanism of the primary process of photosynthesis [Hans Gaffron, ed., Research in Photosynthesis (New York: Interscience Publishers, Inc., 1957), p. v-vi]. The quantum yield controversy was excluded from the conference agenda because it was stalemated. In the mid-1950's, there appeared to be no prospect of resolving the issue. It was only after Franck's death that Warburg was proven wrong.

Franck was unable to attend the Gatlinburg Conference which related so directly to his interests because of a heart attack. Before being stricken, however, he had prepared two papers for the conference on the theoretical implications of the experiments on the chemiluminescence of chlorella algae, which his young University of Chicago colleague, John E. Brugger, had performed for his dissertation research [Box 14, folder 6]. Brugger presented the first of Franck's two Gatlinburg papers, as well as two papers of his own. Robert Livingston of Minnesota presented Franck's second paper. One significant outcome of the Gatlinburg Conference was a book edited by Franck's co-worker Hans Gaffron, Research in Photosynthesis, containing all of the conference papers, and transcripts of a good portion of the ensuing discussions [Box 14, folders 4, 9-13] The papers of Franck and Brugger which were presented at Gatlinburg in 1955 were not summarized for publication in a journal until 1958, since Franck, with characteristic thoroughness, wanted to develop a theory encompassing all observed afterglow phenomena [Box 14, folders 11-33].

In 1955, Franck agreed to prepare a section of the Handbuch der Pflanzenphysiologie (Berlin: Springer-Verlag, 1960) on the fluorescence of chlorophyll in relation to the primary processes of photosynthesis. He reluctantly undertook what was to become a major project because he did not want to see the article written by researchers whose ideas he did not respect. He was somewhat chagrined at his own motivation, as he explained to his collaborator on the project, Robert Livingston: "I feel in this matter like the dog who is willing to eat salad if only to prevent the other dog from getting it even if he dislikes it himself." [Box 9, folder 1 (Springer-Verlag correspondence)]. The lively and sometimes acrimonious debates sparked by photosynthesis research led Franck to take great care that his publications were as accurate and comprehensive as he could make them. The effort that went into the Handbuch article is clear from the large amount of material related to it in the Franck papers [Box 15, folders 1-21].

Toward the end of his life, James Franck's poor health increasingly frustrated his efforts to continue his work. He agreed to serve as a moderator at the Symposium on Light and Life sponsored by the McCollum-Pratt Institute of Johns Hopkins University; but, as he wrote to William D. McElroy in October, 1959: "My health is unreliable…I have the great wish to come to your meeting, and if you want me to be the moderator of Session II, I think that I could do that without undue stress on my health. However, I don't want to write a paper because I know by experience that to work for a deadline in writing papers is something which does me no good, and I took a solemn vow not to do it anymore. So my answer would be 'yes' with pleasure, but there is a risk involved for you that until March maybe my health will deteriorate." [Box 5, folder 3].

Franck was able to participate in the Symposium on Light and Life, however, which met in Baltimore, March 28-31, 1960. At this symposium, he became involved in a debate with University of California biochemist Melvin Calvin, regarding light activation in photosynthesis. Calvin insisted that the role of light in photosynthesis was limited to the photoionization of chlorophyll in chloroplasts, resulting in a migration of charged electrons and positive holes to a "solar battery" which then electrolyzed water. Franck found Calvin's thesis inadequate for explaining a number of experimental observations, including the Emerson effect, the doubling of fluorescence, the afterglow phenomena, and the chemical kinetics of photosynthesis rates under various external conditions [Box 15, folder 22. Franck's contributions to the discussions following the session which he moderated and to other symposium session are recorded in a book edited by William D. McElroy and Bentley Glass, A Symposium on Light and Life (Baltimore: Johns Hopkins Press, 1961)].

The Calvin controversy was the background for James Franck's last three publications in 1962, 1963, and 1964, which he wrote with Jerome L. Rosenberg of the University of Pittsburgh. Rosenberg had been at the University of Chicago from 1948 to 1950 on an Atomic Energy Commission post-doctoral fellowship. After the fellowship expired, he had stayed at the University with the photosynthesis project until 1953, when he was appointed to the Chemistry Department at the University of Pittsburgh. In 1961, 1962, and 1963, Franck spent some months working with Rosenberg in Pittsburgh. Their first article, "The Primary Photochemical Step in Photosynthesis: A Comparison of Two Theories," was published in Luminescence of Organic and Inorganic Materials (New York: John Wiley and Sons, Inc., 1962), under the editorship of Hartmut P. Kallman and Grace Marmor Spruch. This article dealt specifically with Franck's and Rosenberg's critique of Calvin's theory of light utilization.

Before Rosenberg left the United States in the summer of 1962 to spend his sabbatical year in Israel, he and Franck completed an article for the Journal of Theoretical Biology, which offered an alternative to Calvin's model of light utilization. On October 10, 1962, Franck wrote to Rosenberg to tell him that he had decided to withdraw their article for revision in view of new observations by Melvin Calvin, C. S. French, Warren Butler, and R. A. Olsen. He explained to Rosenberg the probable consequences when word of this got out: "I believe my reputation as an absolutely unreliable character will certainly be considerably enhanced among the biochemists…At least, there will not be many physical chemists who believe that someone's changing his mind is proof for utter lack of character. I personally regard it not as too bad a sign that at my age, I'm not incorrigible, but able to be slowly reformed." [Box 7, folder 10].

Franck and Rosenberg presented a short abstract of this article at a symposium sponsored by the Committee on Photobiology of the National Academy of Science-National Research Council, held at Airlie House in Warrenton, Virginia, October 14-18, 1963. Eugene Rabinowitch later recalled that Franck found very gratifying the serious and critical response which met his presentation at this symposium [Box 21, folder 61]. Subsequently the abstract appeared with other papers from the symposium in a book entitled Photosynthetic Mechanisms in Green Plants (Washington, D. C.: National Academy of Sciences-National Research Council, 1963). The revised article finally was published in the Journal of Theoretical Biology shortly before Franck's death in the spring of 1964.

Recognition of a Scientific Legacy

James Franck took a modest view of his scientific achievements. Talking on the pioneer era of quantum physics, at the International Conference on Luminescence, New York University, October 1961, he praised Max Planck, Albert Einstein, Niels Bohr, and Walther Nernst for opening the "new path," and described himself as one of those who "went along and picked flowers to the right and to the left which were growing in abundance." [Box 21, folder 9]. That his achievements were not esteemed so lightly by others is evident from the many honorary degrees, certificates of society membership, and medals preserved in the Franck Papers [Box 22 and Box 23, folder 4 through Box 24, folder 2].

Franck's self-effacing attitude toward many of the awards which came late in his life is expressed in a letter of August 21, 1963, to Robert Livingston: "In most cases, it [an honorary degree] is just a sign of old age." [Box 5, folder 1]. Several of the honors must have given him special satisfaction, however. He was deeply moved by the personal tributes from his friends, colleagues, and former students, collected by Robert Platzman, and presented in a leather-bound volume at the Franck summer house in Falmouth, Massachusetts on his seventieth birthday, August 26, 1952 [Box 23]. Also gratifying to him were the Rumford Medal awarded by the American Academy of Arts and Sciences in 1955 [See his letter to George Wald, Box 10, folder 1] and the Dannie-Heineman Prize given by the Göttingen Academy of Sciences in 1962. These two awards recognized his contributions to the understanding of photosynthesis which he often felt were not appreciated.

The receipt of honors sometimes provided occasions for trips to Germany to visit old friends. As he became frail, Franck recognized that each visit might be the last, and in the spring of 1964 he made his final trip abroad. The highlight of this trip was a Berlin reunion with colleagues from his days at the Friedrich Wilhelm University and the Kaiser Wilhelm Institute. With Lise Meitner, he visited Gustav Hertz in East Berlin, and then met briefly with Wilhelm Westphal in West Berlin. From Berlin, he took the train to Göttingen, where he died of a heart attack on May 21, 1964.

A James Franck Memorial Symposium on energy exchange in molecular systems, sponsored by the Department of Chemistry of the University of Chicago with the support of the Samuel S. Fels Fund, was held at the University on May 12-13, 1966. In the symposium's four scientific sessions, talks on physical chemistry were given by Gerhard Herzberg, William Klemperer, Edwin N. Lassettre, Lewis M. Branscomb, Alfred Kastler, and Mark G. Inghram; a talk on photochemistry was presented by G. S. Hammond, and one on photosynthesis by Eugene Rabinowitch. These talks acknowledged Franck's scientific legacy, as exemplified by current research in which his theories and methods were being employed. In a luncheon address on May 12, Rabinowitch spoke of Franck's political contributions, focusing on the best-known example, the "Franck Report." At dinner, Hans Gaffron and Edward Teller recalled Franck's remarkable personal qualities, as did Robert Pohl in a talk delivered for him by his son. All of the symposium talks and discussion were recorded on tapes, which are preserved in the Franck Papers [Box 19]. Photographs taken at the session of the Franck Memorial Symposium are included in the photograph collection [Box 20, folder 47-54].

On the occasion of this symposium, a volume of "selected papers" of James Franck was to have been published. For this project, Robert Platzman compiled a bibliography of Franck's published writings, selected a number of those works to be reprinted in the volume, and solicited from Franck's co-authors memoirs to introduce each paper [See Appendix, p. 124-34]. The correspondence, manuscripts, Platzman's annotate copy of the bibliography and related notes, and a set of photocopies of Franck's published articles are preserved in the Franck Papers [Box 24, folder 3 through Box 26, folder 4]. According to notes appended to his draft of the Franck bibliography, Platzman never was satisfied that the bibliography was comprehensive. Following the symposium, he continued to work on the Franck volume, but the project was left unfinished at his death in the summer of 1973 [Box 25, folders 5-9].