Pauling Becomes a Researcher

Roscoe Dickinson, 1923.

Roscoe Dickinson, 1923.

[Part 2 of 3 in a series investigating Linus Pauling’s life as a graduate student]

As a graduate student at the California Institute of Technology (CIT), Linus Pauling tailored a research program that was focused on the properties of matter, with a particular emphasis placed on molecular structure. This interest and the techniques that he learned would shape Pauling’s scientific thinking for the rest of his life.

Pauling’s focus on the theoretical, and his questioning of why processes move forward as they do or why structures are built as they are, was in keeping with contemporary trends in physical chemistry. Pauling enrolled at Caltech with a strong desire to learn more about the discipline of physical chemistry and his early mentor, Caltech chemistry chair A.A. Noyes, encouraged him to build up his background in x-ray crystallography to further enable this pursuit.

When Pauling began classes in September 1922, he also began his research in x-ray crystallography under the direction of his major professor, Roscoe Gilkey Dickinson.  Not much older than Pauling and a recently minted PhD himself, Dickinson would soon become Pauling’s friend. Within weeks, Pauling began receiving invitations for dinners at the Dickinson house and was soon spending the odd weekend on camping trips with Dickinson and his wife.  After Ava Helen and Linus were married, she too joined in these social gatherings.

Dickinson and Pauling worked closely together for most of Pauling’s first year of grad school, but once Pauling had mastered the techniques necessary to prepare his own research, he mostly moved without Dickinson’s direct supervision. In a 1977 interview, Pauling recalled that Dickinson “was remarkably clear-headed, logical, and thorough” while working in the lab.  And as for the research,

Fortunately the field of x-ray diffraction was in an excellent state in that the procedures were rather complicated but they were thoroughly logical, [and] consisted of a series of logical tests.

The rigor and the logic that were fundamental to the field both pleased Pauling immensely.  And before long, the prodigious young student had moved beyond the expertise of his mentor and had begun to conduct original research that was outside of Dickinson’s own capability. In fact, Pauling’s acumen in the lab and facility as an x-ray crystallographer advanced so rapidly that, by his own recollection

…after about three years…I was making structure determinations of crystals that the technique was not powerful enough to handle, by guessing what the structure was and then testing it.

X-ray apparatus at Linus Pauling's desk, Gates Laboratory, California Institute of Technology. 1925.

X-ray apparatus at Linus Pauling’s desk, Gates Laboratory, California Institute of Technology. 1925.

But in his earlier days, Pauling still needed some help. During November and December of his first year as a graduate student, Pauling prepared approximately twelve crystals and attempted to analyze them using x-rays, but none of the crystals yielded images sufficient enough to make a structure determination.

At this point, Dickinson stepped in and directed Pauling to the mineral molybdenite (MoS2), in the process showing him how to take an adequate sample, mount it, and analyze it using x-ray crystallography. This assistance in hand, Pauling was able to determine the structure of the crystal and Dickinson returned to his own work, confident in his feeling that Pauling was capable of doing the crystallography himself.

Soon after completing the experiment, Pauling was confronted by a very different type of confusion. With a successful structure determination in hand, he assumed that the next step would be to publish the work. So too did he assume that Dickinson would provide him with more direction, but he found that none was offered.  As such, Pauling wrote up his findings and presented them for review to his major professor.

Not long after, A.A. Noyes summoned Pauling to his office and carefully explained to the young graduate student that he had written up a paper with only his name on it and in the process had failed to acknowledge the crucial help that Dickinson had provided. Chagrined, Pauling revised the paper and listed himself as a second author, behind Dickinson. The experience proved to be an important one for Pauling, who was reminded early on of how easy it can be to minimize or discount the role that colleagues can play in one’s own research.

Molybdenite model, side view.

Molybdenite model, side view.

By the end of April 1923, Dickinson and Pauling had submitted their paper on the structure of molybdenite to the Journal of the American Chemical Society (JACS); it was published in June of that same year.  Together they had found the simplest crystal structure of molybdenite – which contains two molecules in a hexagonal unit – based on Laue and spectral photographs, and using the theory of space groups.  Although he published a piece on the manufacture of cement in Oregon while he was in undergrad at Oregon Agricultural College, the molybdenite paper was Pauling’s first true scientific publication.

Later that year, Pauling arrived at another milestone by publishing his first sole-author paper, one in which he described the structure of magnesium stannide (Mg2Sn) as determined, once again, by using x-rays. The paper was a huge accomplishment for another reason as well: the x-ray processes used by Pauling had never been successfully deployed for the study of an intermetallic compound before.  And even though this was his first single author paper, Pauling still made sure to thank Roscoe Dickinson in his conclusion, taking pains to avoid another scholarly faux pas.  He would continue in this practice throughout his graduate career.

Richard Tolman, 1931.

Richard Tolman, 1931.

“The crystal structure of magnesium stannide,” was one of eight articles that Pauling published during his grad school years – he completed an impressive total of six structures before receiving his doctorate. Having authored these articles, Pauling found himself on the forefront of a shift in physical chemistry: as crystallography advanced, it was becoming increasingly clear that the properties of specific compounds were based on their structures, which could now be described with mounting confidence. Indeed, several of Pauling’s articles included reevaluations of existing structures, with revised explanations as to why the structures in question had not complied with the new data that Pauling collected.

One such article was “The Entropy of Supercooled Liquids at the Absolute Zero,” which Pauling wrote with CIT faculty member Richard C. Tolman.  In their paper, the two authors corrected an earlier claim made by Ermon D. Eastman, a professor of physical chemistry at Berkeley, who had stated that complicated crystals (those with large unit cells) have greater entropy at absolute zero than do simple crystals. Using statistical mechanical techniques, Pauling and Tolman were able to show that, at absolute zero, the entropy of all perfect crystals, even those with large unit cells, also has to be zero.

Detail from 'Atombau und Spektrallinien' containing x-ray diffraction images.

Detail from ‘Atombau und Spektrallinien’ containing x-ray diffraction images.

Pauling had become familiar with Tolman through a different means. During his third term at Caltech, Spring of 1923, Pauling took Tolman’s course in advanced thermodynamics, an experience that boosted his subsequent interest in quantum theory. It was also during this period that he read Arnold Sommerfeld’s Atombau und Spektrallinien (Atomic Structure and Spectral Lines) and began to be exposed to cutting edge research in quantum theory through the numerous physics and chemistry research colloquia hosted by Caltech.

Sommerfeld would become a lasting influence on Pauling’s life and Pauling would eventually study with him in Germany while there on a Guggenheim Fellowship in 1926-27. But well before then, in 1923, Sommerfeld visited CIT to talk about his work with the new quantum theory. As an aid to his lectures, Sommerfeld used crystal models that he brought from Germany, which he hoped would help him to better explain this complicated work. Afterward, Pauling felt emboldened enough to to show Sommerfeld some of the models that he himself had made in the course of his own research; models that turned out to be much better than those constructed by Sommerfeld.

Post 500

Linus and Ava Helen Pauling.  Angeles National Forest, Thanksgiving Day, 1952.

Linus and Ava Helen Pauling. Angeles National Forest, Thanksgiving Day, 1952.

This is the five-hundredth post that we’ve published on the Pauling Blog, and in this season of thanksgiving we find ourselves in a grateful mood.  Five-hundred posts, surely at least a half-million words and, recently, our 500,000th view.  Great thanks to you, our readers, who continue to seek out and use this resource in steadily increasing measure.

To celebrate this milestone, we are publishing a few excerpts from one of our favorite Pauling manuscripts.  Titled “An Extraordinary Life: An Autobiographical Ramble,” the piece was written by Pauling for presentation to the Institute for the Humanities in Saledo, Texas, April 1989.  The text finds Pauling in an unusually reflective mood, speaking with serenity, at age 88, of a life spent dipping in and out of scientific disciplines in a most remarkable way.

Young Pauling, ca. 1910s.

Young Pauling, ca. 1910s.

[…] I am moderately smart. I estimate that there are 20,000 people in the United States who are smarter than I am, perhaps 15,000 women and 5,000 men. I reached this conclusion because a month after my wife and I got married, we had carried out some intelligence tests, and I discovered she was smarter than I, but we were already married. It was too late for me to do anything about it. Of course, I recognize that there are many physicists who are smarter than I am – theoretical physicists, most of them. There are a lot of smart people who have gone into theoretical physics, so there is a lot of competition there. I console myself with the thought that they may be smarter than I am and deeper thinkers than I am, but I have broader interests than they have. I don’t suppose that there is anybody else in the world who has a good background, knowledge of physics, mathematics, theoretical physics, and who knows a great deal about chemistry – the amount that I know.

When I was eleven years old with no outside inspiration – just library books – I started collecting insects. Not only collecting insects but reading about insects. I was filling my mind with a lot of information about the lepidoptera and diptera and so on. My father, a druggist, died when I was nine. There was another druggist who was a friend of the family to whom I went if I needed some chemicals when I got interested in chemistry, but I wasn’t interested in chemistry yet. I was just interested in insects when I was eleven. I said, “A person who collects insects needs to have a killing bottle.” And I got a Mason jar from my mother. So all I needed now was ten grams of potassium cyanide and perhaps fifty grams of plaster of paris. So Mr. Ziegler, the druggist, gave me ten grams of potassium cyanide and fifty grams of plaster of paris, and I took them home, went out on the back porch, because I knew that potassium cyanide was dangerous, and I dumped the potassium cyanide into the bottle. I mixed the plaster of paris with some water and put it in the bottle on top of it and let it harden. I had my killing bottle. I collected a lot of insects.

Next year I got interested in minerals. I didn’t have very many minerals, at least that I could recognize, only agates. So about all I could do was go around Portland looking for piles of gravel where someone was putting in a house foundation or sidewalk. I’d go through the gravel looking for chunks of agate.

Just think of what the difference is now.  A young fellow gets interested in chemistry and is given a chemical set.   The chemical set doesn’t contain any potassium cyanide. It doesn’t even contain any copper  sulphate  or anything interesting because  they are all  poisonous  substances. Most chemicals are poisonous substances. These young budding chemists don’t have any chance to do anything interesting when they are given a chemical set anymore.   As I look back, I think it is pretty remarkable that Mr. Zieglar, this friend of the family,  would have just turned over one third of an ounce of potassium cyanide to me at age eleven. […]

Linus and Ava Helen, camping near Palm Springs, 1924.

Linus and Ava Helen, camping near Palm Springs, 1924.

[…] I  was   very  fortunate  when   I   came  to  the   California   Institute   of Technology.    There was a new experimental technique that had been discovered only eight years before.    This was the determination of the structure of crystals by the x-ray diffraction method.    Roscoe Dickinson,  a  few  years older than I, had been using this technique for three or four years at the California Institute of Technology.    He was the first man to get a Ph.D.  from the California Institute of Technology. He taught me the technique.    I was very much excited about it.    It took only a couple of months for him to teach me how to determine the structure of a rather simple crystal by taking x-ray diffraction photographs of it and then analyzing those photographs.    Perhaps the greatest thing that he taught me was how to assess the reliability of your own conclusions.   He taught me to ask every time I reached some conclusion:

“Have I made some assumption in reaching this conclusion?    And what is the assumption? And what are the chances that this assumption is wrong? How reliable is the conclusion?” I have remembered this ever since and have continued to feel grateful to him ever since. It is possible to delude yourself if you have an original idea into thinking that there are observations that support this idea. Or it is possible when you think that you have developed some idea on the basis of a rational argument that you have made an assumption somewhere that isn’t justified. So this was very important in my development.

I hear people often describing me as a biochemist or as an organic chemist or something else. In fact, I never did like organic chemistry. I liked biochemistry even less. I didn’t have any courses to speak of in organic chemistry and no course at all in biochemistry. No course in any aspect of biology, nothing in medicine. But I have made contributions in the nutritional field and the biochemical field. If I were to go through my some eight hundred scientific papers, and see what fields of science I have made contributions   to,   I  could  say  I  am a x-ray  crystallographer. I am a mineralogist, because the American Mineralogist Society gave me their Roebling Medal which they give every year to an outstanding mineralogist. I am a physical chemist. That was what I called myself originally and what my Ph.D. diploma says. I am a chemical engineer too with a degree and five years of practical experience. I am an analytical chemist. When I was nineteen years old,   I didn’t have enough money to go back to my junior year at Oregon Agricultural College. As a sophomore I had taken the course in Quantitative Chemical Analysis and they gave me a job full time to teach the sophomore  Chemical Analysis. So I am an analytical chemist too. And I am an organic chemist.   I laid the theoretical  foundation for the tetrahedral carbon atom and developed resonance hybrid concept. I explained a lot of things in organic chemistry. I am a biochemist. I am a molecular biologist and sort of originated this field in a sense. I am a geneticist and have made contributions.   I’m an evolutionary scientist. […]

Pauling in 1989 - an extraordinary life. Photo by Paolo M. Sutter.

Pauling in 1989 – an extraordinary life. Photo by Paolo M. Sutter.

[…] In 1937, I was invited to give the prestigious George Fisher Baker Lectures at Cornell University. I went there for one semester. There had been famous chemists who had held this appointment. One requirement was that you write a book. My lectures were on the nature of the chemical bond, and the book came out in 1939, The Nature of the Chemical Bond. It was a bestseller, published by Cornell University Press. After a year the editor of Cornell University Press wrote to me and said, “Your edition of 10,000 copies is just about sold out. Would you prepare a second edition?” And I said, “Well, it hasn’t been a year yet. Nothing much has happened, but there have been some changes in this field. But why should I prepare a second edition of the book?”   He said, “Well, you don’t get any royalties from the book.   It was a condition of your appointment as George Fisher Baker Lecturer in Chemistry that you should write the book and present the manuscript.   There has never been a George Fisher Baker book that has gone into a second edition, but if you write a second edition, Cornell University Press will give you royalties on it.”

Well, that was a really good incentive.    I got busy and added ten pages perhaps and it came out as the second edition in 1940 and ever since then I have collected royalties.   On thinking back on this man, editor of Cornell University Press, he is really a remarkable man in that he should think that it would be unjust to me not to get royalties on that book that had become a scientific bestseller.    He was Amish from Pennsylvania and perhaps this may have something to do with his ethical standards.    It is a good thing that people have ethical standards.

People keep saying to me, “How does it come about that you shifted your field every five or ten years in a remarkable way?” In fact, all that I did was to expand my field of interest. I started out first determining the structure of minerals, and the second job I did was to determine the structure of an intermetallic compound — the first intermetallic compound to have its structure determined. For about ten years I worked on the structure of silicate minerals and of various other inorganic compounds.

So that was one period, but then I got interested in the structure of organic molecules. And there was another technique. We built the first apparatus in the United States to determine the structure of gas molecules by electron diffraction. A friend of mine, Herman Mark in Germany, was the man who built the very first apparatus of this sort. So I began determining interatomic distances, and applying quantum mechanics which I had learned as one of the first people in the field in 1926 when I was in Germany on a Guggenheim Fellowship.   All of this related to the question of the nature of the chemical bond. In the 1930s I formulated several new ideas about chemical bonds.

In 1935 the Rockefeller Foundation had been supporting my work on the crystal structure of the sulphide minerals, and they said to me, “You know, we’re not really interested in the sulphide minerals.    We’re interested in biological substances.”   They had been giving me five thousand dollars a year.   I thought, “What do I know about biological materials?   Not very much.   Hemoglobin, red cells in the blood, molecular weight about 68,000, that has four iron atoms in it.   Iron compounds often are paramagnetic.    So why don’t I apply to the Rockefeller Foundation  and  suggest  that  I  measure  the  magnetic   susceptibility  of hemoglobin and hemoglobin derivatives?”   So I did. And they gave me fifty thousand dollars.    This shows that these fellows in the big foundations can influence  activities  of  scientists.

So we measured  the magnetic susceptibility of blood. Venus blood turned out to be paramagnetic, and arterial blood was diamagnetic,  meaning repelled by a magnet.    Careful measurements  of this sort gave  astonishing  information  about   the  structure  of  the hemoglobin molecule. So then I thought, “Well, what about the rest of the hemoglobin molecule?    There are four iron atoms and 9,996 other atoms.   What are they doing?    So I had better work on the structure of proteins.”  I was giving a talk in 1936 at the Rockefeller Institute for Medical Research about the magnetic properties of hemoglobin.    A man named Karl Landsteiner sent word to me, asking me to come to his laboratory to talk to him.   I did.   He said he was making immunological studies — antibodies, antitoxins.   He wanted to know if I could explain some of his observations.    So I thought about them for four years and finally wrote a paper, and when the second edition of his book came out there was a chapter by me on the molecular structure of antibodies.    I hadn’t changed my course.    I’d just gone on roads that have diverged a  little from the ones I’d been  going  on.

The Crystal Structure of Molybdenite

[Ed note: This is the first in a six part series of posts featuring models of crystal structures solved by Linus Pauling during the early years of his career.  The models were built by two undergraduate students working in the OSU Libraries Special Collections.  More about their work can be found on page 10 of this PDF link.]

Molybdenite model, side view.

Molybdenite, MoS2 (molybdenum = pink; sulfur = yellow).  A hexagonal crystal system constructed of molybdenum ions bonded to two layers of sulfur atoms through ionic bonding. The sulfur layers do not present strong bonds with other sulfur layers, which creates perfect cleavage.

After moving to Pasadena to begin his graduate studies in 1922, it was decided that Linus Pauling would begin working as Roscoe Dickinson’s sole graduate student. Dickinson received the first doctorate from the California Institute of Technology in 1920, having joined the staff there after completing his undergraduate studies at M.I.T. in 1917.

In late September of 1922, Pauling and Dickinson were working on structure determinations of crystals with the use of X-ray diffraction, and Pauling was initially encouraged to determine the structure of the lithium hydride crystal. However, after three weeks of synthesizing the crystals and setting up his photographic apparatus, he was forced to abandon his work upon receiving word that the structure had recently been determined in Holland.

Pauling then created crystals of fifteen different organic substances. He subjected some of them to preliminary stages of X-ray analysis, but none of the samples proved sufficient for the work. After these disappointments, Dickinson helped Pauling work through the process of determining the complete structure of the molybdenite crystal.

Molybdenite, or molybdenum sulfide, is a very soft metallic mineral. Its properties include a bluish-silver color and a greasy feel that can leave marks on fingers. It has a very high melting point, so it is often alloyed with steel to make it stronger and more heat resistant. It is also an important material for the chemical and lubricant industries, and can be used as a catalyst in some chemical applications.

Molybdenite model, top view

Molybdenite crystals bend easily but are not elastic, making X-ray spectral photo analysis, the method used by Pauling and Dickinson, somewhat difficult. Despite these issues, Pauling and Dickinson managed to take a suitable photograph and were able to determine the crystal’s structure. Molybdenite was expected to have an octahedral atomic structure. Pauling and Dickinson discovered that it was instead comprised of six atoms surrounding the corners of a trigonal prism. This surprise demonstrated, among other things, the potential for unpredictability and excitement in chemical experimentation.

Fresh off their laboratory success, Pauling co-authored his first scientific paper with Dickinson. It appeared in a 1923 issue of the Journal of the American Chemical Society under the title “The Crystal Structure of Molybdenite.” The success renewed Pauling’s confidence in his capacity to carry out professional scientific analysis, and instilled in him an understanding of the value of well-planned experimentation. The process likewise provided him with a valuable framework that he began shaping and developing to fit his particular temperament. Throughout the rest of the 1920s and 1930s, he would use this method to write and publish multiple crystal structure papers nearly every year.

Pauling notebook entry documenting work on molybdenite, 1922.

Much of Pauling’s early work on the structure of molybdenite is detailed in his Research Notebook 2.  For more on his amazing achievements in structural chemistry, see the website Linus Pauling and the Nature of the Chemical Bond: A Documentary History.

The Paving Inspector Job

Linus Pauling (second from right), part of a work crew stationed in Sutherlin, Oregon.  Summer 1922.

Linus Pauling (second from right) with a highway work crew, Sutherlin, Oregon. Summer 1922.

A unique chapter of Linus Pauling’s life played out over the summers of his undergraduate years at Oregon Agricultural College. A theme that had shadowed much of his young adult life – problems with finances – would continue to follow him into his graduate studies. The absence of a steady source of income, as well as short periods of more intensified financial hardship, significantly shaped the transition years between his start as an undergraduate and the beginning of his rigorous studies at the California Institute of Technology.

Pauling worked odd jobs on campus to make ends meet during the school year, but during most summers he was employed by the Oregon State Highway Commission as a paving plant inspector, living in a tent and charged with monitoring the quality of the bitumen-stone mixes used in the building of roads. His employment at the highway commission would stretch from the end of his sophomore year to the beginning of his doctoral studies. Over this course of time, particularly his final summer, distinguishing themes and aspects of Pauling’s professional life began to blossom.

Though it was not glorified work, and at times very boring, Pauling did enjoy his time working outdoors. He wrote of his love for the sun, and the benefits of spending a substantial portion of the year outside of a laboratory. Though Pauling would go on to work three additional summers for the highway commission, his first year was not without conflict. At this time he worked under the partial jurisdiction of a man named E.W. Lazell, a chemical and efficiency engineer stationed in Portland. A series of letters and reprimands from Mr. Lazell, as well as consultations with third parties, became common toward the end of Pauling’s first summer at the commission. In early September Pauling replied to department official Leland Gregory, apparently in regard to a complaint lodged against his handling of paving material temperatures. The “misinformed informant,” as Pauling referred to the unnamed complainant (Lazell), could apparently have been better informed had he referred to Pauling’s reports.

At the end of his first season with the commission, Pauling’s mother Belle informed him that she had been forced to use the money he had been sending her over the summer. The money had been meant to pay his school expenses for the following year, and with no additional funds at his disposal, Pauling chose to continue working into the fall.

Luckily, in late autumn of the same year, Pauling was offered a job by the chemistry department at O. A. C. Though it entailed a $25 per month pay cut, Pauling returned to the college as a full-time assistant instructor in quantitative analysis. The following summer he began work once again for the highway commission, and saved enough money to continue his studies as an undergraduate.

As has been well-documented, it is during Pauling’s stint as “boy professor” that he met Ava Helen Miller, his future wife, while teaching chemistry to her and twenty-four other home economics students. The two began dating toward the end of the school year, and the exchange of letters between them during Pauling’s last summer as a paving plant inspector gives one of the clearest and most intimate views of the future Nobel Prize winner’s advancing train of thought. All in all Pauling received 94 letters over the summer from Ava Miller, and replied in kind every day, sometimes two or three times.

You are my own darling girl, and your love is my only priceless possession. I shall try to make my life perfect in order that it may be good enough for you. I love your beautiful big blue eyes, your dainty little ears, your adorable own darling self. I love you.

-Linus Pauling to Ava Helen Miller, June 14, 1922.

The elements that generally defined Pauling’s correspondence with his future wife were a) their wish to be engaged, and b) the strong opposition to marriage that the two faced from their respective families. Always the romantic, Pauling was accused by some of Ava’s friends as being consistently “too mushy,” and indeed there is much written between the two about marriage, children and love.

However, over the course of their exchanges, Pauling likewise discussed much of his evolving personal philosophy. Both suggested reading materials to one another, with the bulk of the books suggested by Ava generally being metaphysical or philosophical in nature. As a result, Pauling discussed, in great detail, his perceptions of the soul, his conflicted feelings between animism and materialism, and his predisposition towards pacifism.

Money, a common theme for the duration of his undergraduate experience, also makes its presence felt throughout their correspondence. At times Pauling secretly mailed money to Ava to help finance trips to see him. He also devoted a substantial portion of his energies to trying to acquire the funds that would allow the two to marry after the summer’s end, with or without help from their parents.

Through youthful confessions, bouts of jealousy, and bold declarations, much can be gleaned about the budding relationship between Pauling and his wife-to-be. Other precursors such as Ava’s influence on Pauling’s diet, as well as his developing fascination with fruits, hint at patterns that would come to define important periods of his future life.

Hand-tinted photo of Pauling at the Sutherlin work site, 1922.

Pauling also read from his own selection of books, and took quite a liking to David Copperfield among others. Far and away, however, a major defining characteristic of his summer evenings was the time that he spent working through proof sheets of the first nine chapters of a newly revised chemistry textbook, Chemical Principles, sent to him by Arthur Amos Noyes, the head of the Division of Chemistry and Chemical Engineering at the California Institute of Technology.

Worked while stationed near the Pacific Coast at Astoria, Pauling devoured all 500 of the listed problems. After discussing his other interests with Noyes by mail, Pauling also began reading books on x-ray crystallography, a new technique being used to study the structure of crystals.  (One of these texts was X-rays and Crystal Structures by W. H. and W. L. Bragg, the latter of whom would eventually become a chief scientific rival of Pauling’s.)  Having completed his reading, and prompted by some nudging from Noyes, Pauling would begin his career as an x-ray crystallographer under the direction Professor Roscoe Dickinson at Caltech the following year.

It is clear by the end of his final summer with the highway commission that Pauling had grown weary of his summer occupation. (In an August 1922 letter to Ava Helen he writes: “I really hate working in a paving plant.  I do it just because I earn more than I would elsewhere.”) Bored, lonely and finished with the problem sets given to him by Professor Noyes, it appears that Pauling was left in an ideal state of mind to begin his graduate studies, and start what would become a brilliant career as an academic, a scientist and an activist for peace.

For more information on Linus Pauling in Oregon, check out our Oregon 150 series. For general information on Linus Pauling, please visit the Linus Pauling Online portal.

Pauling’s Methodology: X-ray Crystallography

X-ray apparatus at Linus Pauling's desk, Gates Laboratory, California Institute of Technology. 1925.

X-ray apparatus at Linus Pauling's desk, Gates Laboratory, California Institute of Technology. 1925.

I was very fortunate in having A.A. Noyes suggest to me, or tell me, that I was to work with Roscoe Dickinson on x-ray crystallography, determination of the structure of crystals by x-ray diffraction. This technique gave for the first time detailed information about how atoms are related to other atoms in a crystal and how far apart they are from the other atoms.
Linus Pauling, 1988.

As a graduate student, well before Pauling began to research hemoglobin in earnest, he spent a great deal of his time using the technique of X-ray crystallography to determine the crystalline structure of a number of inorganic compounds. Pauling recalled that at that time X-ray crystallography “was a new technique, ten years old when I began. Quite a number of structures had been determined but there was a tremendous field open, a tremendous amount of work that could be done.”

Listen: Pauling discusses the importance of X-ray crystallography to his early structural chemistry research

The young Pauling obviously reveled in the excitement of being able to use a new and powerful technology. “We have a pretty extensive collection of apparatus” he once wrote to William Lawrence Bragg, the senior author of a 1922 textbook that started Pauling on X-ray crystallographic research. Any one of Bragg’s student’s, Pauling remarked, “no matter how physical his training,” need not “be frightened at coming to a chemical laboratory” so well-stocked with mechanical apparatus.

Initially Pauling used the technique of X-ray diffraction to determine the structures of fairly simple inorganic compounds, but later, as his own expertise grew and as he discovered new sources of funding, Pauling oriented this new technology toward complex organic compounds, including hemoglobin.

What was ultimately important to Pauling was not what X-ray crystallography could tell him about the size, structure, or relative placement of atoms within a molecule, but rather, what broader theories that information could then be used to support. His growing allegiance to structural chemistry, his developing ideas about the nature of the chemical bond, and his still nascent interest in biochemical interaction were all fed by his experience of rigorously determining molecular structure through new technological methods.

Pauling’s manuscript notes concerning his early experiments with hemochromogen, for instance, indicate the wide spectrum of experimental results he had to assimilate in order to create a coherent picture of the hemoglobin molecule.

The difficulties presented by the need to combine the information he had obtained from x-diffraction with information from other kinds of experimentation, including solubility and more traditional experimental methods, are readily apparent in Pauling’s notes.  Indeed, the impressive new technology of X-ray crystallography is relegated to just one entry in a list of experimental results.

Ultimately it wasn’t the technology at Pauling’s disposal that helped him become such a successful researcher, but rather his attitude in approaching technology and his ability to use the results it gave him to construct more broadly-applicable and intellectually-powerful theories.

To learn more about Linus Pauling’s use of x-ray crystallography, see the websites Linus Pauling and the Nature of the Chemical Bond: A Documentary History and It’s in the Blood!  A Documentary History of Linus Pauling, Hemoglobin and Sickle Cell Anemia.

The Paulings’ Wedding Anniversary

Linus and Ava Helen Pauling, Wedding, June 17, 1923.

Linus and Ava Helen Pauling, wedding photo, June 17, 1923.

I suppose that I am responsible to some degree for Linus’s deciding to put so much of his effort into peace activities. In talking with him, I said I thought that it was of course important that he do his scientific work. But if the world were destroyed, then that work would not be of any value — so he should take part of his time and devote it to peace work.”
– Ava Helen Pauling. Interview. June 1977.
Today marks the eighty-fifth wedding anniversary of Linus and Ava Helen Pauling. In honor of the occasion, we would like to briefly share the story of their meeting, courtship and marriage.

On January 6, 1922, Linus Pauling, still an undergraduate, entered a classroom as instructor rather than student. Oregon Agricultural College, now Oregon State University, had hired him to teach a freshman level chemistry course to a class of home economics majors. Thomas Hager, a Pauling biographer, tells us:

[H]e knew the best way to avoid any “boy professor” sniggering was to get right to the subject. This was the second term of a three-term course, and he decided to start by measuring the class’s basic knowledge. “Will you tell me all you know about ammonium hydroxide, Miss…” He ran his finger down the registration sheet, looking for a name he couldn’t possibly mispronounce. “Miss Miller?” He looked up and into the eyes of Ava Helen Miller. She was a small, delicate, strikingly pretty girl with long, dark hair. She was barely eighteen years old. She was a flirt. And, as it turned out, she knew quite a bit about ammonium hydroxide. (Force of Nature: The Life of Linus Pauling. New York: Simon & Schuster, 1995. 69.)

In the months that followed, a relationship between the two blossomed and, at the end of the term, Pauling asked Ava Helen to marry him. She accepted. That fall, Pauling departed for Caltech where he continued his education and served as a teaching assistant. The couple corresponded regularly, but the distance between them grew unbearable. Against the wishes of both mothers, they chose to cut their engagement short and marry in the spring of 1923.

To make the trip up from southern California for the ceremony, Pauling purchased a Model T Ford from Roscoe Dickinson, a Caltech professor, and headed north for Oregon. Unfortunately, Pauling’s driving experience was limited to just a few minutes of practice and, come nightfall, he crashed into a roadside pit in the Siskiyou Mountains, resulting in an injured leg and a wrecked car. After waiting all night for help, Pauling was able to get his car repaired and arrived at the wedding on time.

Over the next six decades, the couple only grew closer. Together they raised four children, were leading activists for world peace, and were extremely instrumental in the creation of legislation banning the above-ground testing of nuclear weapons. Despite the pressures of Pauling’s work and activism, the couple remained inseparable until Ava Helen’s death in 1981.

In interviews, Pauling often cited his wife’s intelligence, good sense, patience and kindness as the foundation for many of his greatest achievements.

A plaque now hangs in Education Hall Room 201 on the Oregon State University campus, marking the location where Ava Helen Miller and her future husband first met.

For further information, visit the Linus and Ava Helen Pauling Papers.