Pauling and the Dutch Stellingen

Linus Pauling in lecture, 1935.

Linus Pauling in lecture, 1935.

LP: One interesting thing that you may not know is that I guess I introduced the proposition system into the United States.

Q: Proposition system?

LP: Yes, in doctor’s examinations.

Q: Oh, the Dutch theses?

LP: The Dutch Stellingen. In 1935, I think it was, I’d been talking about these propositions. The doctor’s examinations were pretty boring, for the faculty anyway. One of my students named Harker, David Harker, volunteered to prepare some propositions. So I said, ‘all right,’ and he brought in about four propositions. This was such a success that the division of chemistry and chemical engineering here required from then on that students prepare and submit a set of propositions. Then, when Harker went to Johns Hopkins, he got them to introduce the system there. Then other students went to Berkeley and various other places so that it’s rather widespread. It even has spread to some physics departments. I wrote a paper about it. One of my papers is on the use of propositions in doctor’s examinations.

Q: Do you encourage the type that Goudsmit used in which he threw in one or two about Egyptian hieroglyphics?

LP: Yes, what the Dutch called the 13th proposition, we encourage that too. One of my students had a proposition that the Southern Pacific, instead of having trains over the Tehachapi, should run buses from Los Angeles to Bakersfield connecting with the train there; and a few years later they did. One student had a 13th proposition: ‘It would be possible for the chemistry division to give two more graduate fellowships without any increase in the budget.’ When he was asked, ‘How could that be done?’ he said, ‘Fire both of the janitors in the building and hire one good one.’ He was complaining about the janitors. Well, I went down into the room in which our seminars used to be given, and opened the door. It was dark; I turned on the light, and there were the janitors sitting in the dark. Just sitting there.

-Linus Pauling, interview with John L. Heilbron,  March 1964

For more facets of Linus Pauling, see Linus Pauling: Scientist and Peacemaker, now available in paperback from the Oregon State University Press.

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The Guggenheim Trip, Part III: Unexpected Colleagues

Walter Heitler, Fritz London, and Ava Helen Pauling in Europe. 1926.

Walter Heitler, Fritz London, and Ava Helen Pauling in Europe. 1926.

The paper of Heitler and London on H2 for the first time seemed to provide a basic understanding, which could be extended to other molecules. Linus Pauling at the California Institute of Technology in Pasadena soon used the valence bond method. . . . As a master salesman and showman, Linus persuaded chemists all over the world to think of typical molecular structures in terms of the valence bond method.” – Robert Mulliken. Life of a Scientist, pp. 60-61. 1989.

After Linus Pauling’s publication of “The Theoretical Prediction of the Physical Properties of Many-Electron Atoms and Ions,” he was ready for an even greater challenge – the problem of the chemical bond was a tantalizing enigma for Pauling, and he wanted more time in Europe to work on it. In the winter of 1926, he applied for an extension of his Guggenheim fellowship and with the help of a particularly complementary cover letter from Arnold Sommerfeld, Pauling was granted six more months of support.

Boosted by this news, he quickly began planning visits to Copenhagen and Zurich, both cities boasting of some of Europe’s finest research facilities. His first stop was Copenhagen, where he hoped to visit Niels Bohr’s institute and discuss ongoing research with the renowned scientist. Unfortunately, he had arrived uninvited and found it almost impossible to obtain a meeting with the physicist. Bohr, with the help of Werner Heisenberg and Erwin Schrödinger, was deeply engaged in research on the fundamentals of quantum mechanics, and was specifically attempting to root out the physical realities of the electron, in the process developing a theory which would eventually be termed the “Copenhagen Interpretation.”

Pauling did, however, did make one valuable discovery in Denmark — that of a young Dutch physicist named Samuel Goudsmit. The two men quickly became friends and began discussing the potential translation of Goudsmit’s doctoral thesis from German to English. Their work did eventually get them noticed by Bohr, who finally granted Pauling and Goudsmit an audience. Unfortunately for the pair, Bohr was neither engaging nor encouraging. Nevertheless, the two continued to work together, their cooperation eventually culminating in a 1930 text, The Structure of Line Spectra, the first book-form publication for either scientist.

In 1926 though, frustrated by his unproductive time in Copenhagen, Pauling departed, stopping briefly at Max Born’s institute in Göttingen before traveling to Zurich where other advances in quantum mechanics promised an interesting stay. Unfortunately, the man Pauling was most interested in, Erwin Schrödinger, proved to be just as unavailable as Bohr. The quantum mechanics revolution was consuming the time and thoughts of Europe’s leading physicists and Pauling, a small-fry American researcher, simply wasn’t important enough to attract the interest of men like Bohr and Schrödinger.

Fritz London

Fritz London

As a result, Pauling chose to converse and work with men of his own status in the scientific community. Fritz London and Walter Heitler, acquaintances of the Paulings, had spent the past several months working on the application of wave mechanics to the study of electron-pair bonding.

Heitler and London’s work was an outgrowth of their interest in the applications and derivations of Heisenberg’s theory of resonance, which suggested that electrons are exchanged between atoms as a result of electronic attraction. Heitler and London determined that this process, under certain conditions, could result in the creation of electron bonds by cancelling out electrostatic repulsion via the energy from electron transfer. Their work on hydrogen bonds likewise agreed with existing theories, including Wolfgang Pauli’s exclusion principle and G.N. Lewis’ shared electron bond. The Heitler-London model was well on its way to contributing to a new truth about the physics of the atom

Walter Heitler

Walter Heitler

Pauling used his time in Zurich to experiment with the Heitler-London work. While he didn’t produce a paper during his stay, the new model made a great impression on him and he returned to Caltech with a renewed sense of purpose. He was preparing to tackle the problem of atomic structure, in all its manifestations, and make history as one of the greatest minds of the twentieth century.

For more information, view our post “Linus Pauling and the Birth of Quantum Mechanics” or visit the website “Linus Pauling and the Nature of the Chemical Bond: A Documentary History.”

Our Newest Addition: Pauling-Goudsmit Letters

Portrait of Samuel Goudsmit, 1937.

Portrait of Samuel Goudsmit, 1937.

Goudsmit and I were never together, I think, during the period when [The Structure of Line Spectra] was written. He would write a draft of some material that he thought ought to go in the book and then using that as a basis I wrote the corresponding sections of the book.”
– Linus Pauling. AHQP (Archive for the History of Quantum Physics), interview transcript part 2. Interview by John Heilbron. March 27, 1964.

The Oregon State University Libraries Special Collections is pleased to announce an important addition to the Ava Helen and Linus Pauling Papers — the donation, by history of science scholar and dealer Jeremy Norman, of a series of letters between Linus Pauling and Samuel Goudsmit.

This correspondence, originally a part of Goudsmit’s personal papers, relates primarily to Pauling’s first book publication, The Structure of Line Spectra, a work largely-derived from Goudsmit’s original paper of the same name and co-authored by Goudsmit himself. The Pauling-Goudsmit donation includes 14 autographed letters, 5 typed signed letters, 1 typed signed note and 3 unsigned carbons, concerning the scientists’ collaboration on The Structure of Line Spectra and other topics.

This fascinating series of letters between Pauling and Goudsmit reflects their long scientific and personal association. Most of the letters were written during the 1930s and roughly half focus on The Structure of Line Spectra. While the line spectra textbook had its origins in Goudsmit’s doctoral thesis, it was translated from the German by Pauling and extensively reworked by both Pauling and Goudsmit for nearly three years before its publication in 1930. The pioneering text was the first work to be published in book form by either author.

Samuel Goudsmit, born in the Netherlands in 1902, became famous for his 1925 work with Eugene Uhlenbeck in which the physicists introduced the concept of electron spin to the scientific community. Pauling and Goudsmit met in 1926 in Europe, where Pauling had traveled on a Guggenheim fellowship to study quantum mechanics. At the time, Goudsmit was continuing his investigations into complex spectra and the Zeeman effect. The two men formed a strong friendship during their work together and, in a 1931 letter to Goudsmit, Pauling described their month of collaboration in Copenhagen as “the happiest period of scientific cooperation in my life, and the most profitable for me.”

In 1927, after obtaining his doctorate, Goudsmit accepted a professorship at the University of Michigan, where he taught until 1946. Much the correspondence from the Norman donation dates from Goudsmit’s time in Michigan, during which Pauling served first as an assistant professor and then as a full professor at Caltech. During World War II, Goudsmit was a member of the Alsos mission, a part of the Manhattan Project, in which he and other scientists were charged with assessing the German nuclear weapons development project.

After the war, Goudsmit took a position at the Brookhaven National Laboratory and served as editor-in-chief of the Physical Review, a prominent physics journal. Goudsmit was also an amateur Egyptologist, occasionally publishing in his work in archaeological journals. He passed away in at the age of seventy-six in Reno, Nevada.

The Pauling-Goudsmit letters are sprinkled with references to other famous or noted physicists, including but not limited to Sir William Lawrence Bragg (1890-1971), co-recipient of the 1915 Nobel Prize for physics for his studies in x-ray crystallography; Robert Millikan (1868-1953), Nobel laureate in 1923 for his work on electron charges and the photoelectric effect; Arthur Amos Noyes (1866-1936), professor of chemistry at Caltech and Pauling’s mentor; and Richard Tolman (1881-1948), thermodynamics expert and co-author of the first American commentary on relativity theory. Many of these men were associates of Pauling’s at Caltech, where the majority of the letters in this collection were written.

The OSU Libraries Special Collections is very grateful to Jeremy Norman of Jeremy Norman’s HistoryofScience.com for his incredibly generous donation of the Pauling-Goudsmit letters. Norman is a collector and seller of historical documents relating to science, medicine and technology whose blog can be found here.

Read more about Samuel Goudsmit’s work on the website “Linus Pauling and the Nature of the Chemical Bond: A Documentary History.”