A Cold War Division Chair: Political Activism and Institutional Pressure

Linus Pauling, 1950

[Pauling as Administrator]

Even before becoming Chairman of the Division of Chemistry and Chemical Engineering at the California Institute of Technology, Linus Pauling had been viewed by some of his colleagues, particularly his predecessor A.A. Noyes, as being inclined to delegate responsibilities. This tendency became more evident following the conclusion of World War II, as the push to promote biochemical research within the division moved forward. While Pauling continued to steer the division toward a future focused intently on biochemistry – advocating for and securing funds to support biochemical medical research – he also began to withdraw from other duties, shifting some of them to his colleagues.

A significant factor behind the need to delegate was Pauling’s increasing involvement in peace activism and, particularly, his schedule of public speaking related to the use and testing of nuclear weapons. These activities ultimately brought Pauling before Caltech’s Board of Trustees, who contemplated his dismissal.


In 1949 the board communicated to Caltech President Lee DuBridge that public statements being made by Pauling on issues of peace and nuclear weapons were “damaging” to Caltech’s reputation. In response, Pauling is said to have “pledged” to DuBridge that he would cut back on his political activism, since he did not want his political views to interfere with his scientific work. President Truman’s decision to develop a hydrogen bomb the next year changed Pauling’s mind however, and he was again brought to the attention of Caltech’s leadership. This time, Pauling told DuBridge that he wished to speak with the trustees directly.

Meanwhile, the board had formed a committee made up of five trustees and five faculty members who were asked to determine whether or not Pauling should be dismissed from Caltech. In a statement dated July 14, 1950, Pauling expressed shock at having learned of this unexpected action by the trustees. In particular, Pauling’s tenure rank and hugely successful twenty-eight year career at Caltech had not prepared him for such an extreme possibility.

Three days later, on July 17, Pauling was given the chance to speak to the board and repeated to the trustees what he had earlier told DuBridge: he wanted to cut back on his political activities. But this ambition was couched, with Pauling noting that

I still propose to do this, at a rate determined by the world situation; however, I remain unwilling to pledge myself to cease all political activities.

Regardless, Pauling made it clear that he did not want to harm Caltech and would do “anything compatible with my conscience and my principles” to protect its reputation.


Sidney Weinbaum

In actual fact, Pauling did not believe that he was harming Caltech’s reputation at all. Rather, after surveying several colleagues and students who told him that his activities had caused no “appreciable damage” to them, Pauling concluded that he was actually helping the institution’s standing.

President DuBridge harbored a decidedly different point of view, informing the board that “many staff members” had told him that Pauling’s actions had “damaged them greatly.” These sentiments focused in particular on Pauling’s support for Sidney Weinbaum, a Russian émigré who became a United States citizen in 1927 and completed his Ph.D. at Caltech in 1933.

Weinbaum, who was Pauling’s research assistant in 1929, had been charged with being a communist, and his case eventually drew the FBI to Caltech. This led to Weinbaum’s removal, as a possible security risk, from his position at the Jet Propulsion Laboratory in 1949. During his appeal, which was supported by Caltech, Weinbaum denied being a communist. The government subsequently dropped their previous allegations against Weinbaum in favor of new charges of perjury, for which he was arrested.

Pauling and Weinbaum were friends, so much so that the Paulings offered a room in their home to Weinbaum’s spouse following his arrest. Pauling also offered $2,000 for Weinbaum’s legal defense, and helped to raise more from other sources.

But DuBridge did not like the potential optics of the situation and suggested in particular that Pauling raise money by word of mouth, and not through the mail. An undated form letter authored by Pauling and five others, and appealing for money to support Weinbaum’s case, suggests that Pauling either ignored DuBridge’s advice or that DuBridge was trying to reel Pauling back in. Ultimately, Pauling’s efforts did not take, and Weinbaum was sentenced to four years in prison.


As the year moved forward, Pauling’s public persona continued to emerge as a source of concern for DuBridge and Caltech’s board. In October 1950, Pauling came under further scrutiny after being named by Senator Joseph McCarthy as a communist. McCarthy fanned the flames of this allegation by also defining Pauling as an atomic scientist who had received classified information from the Atomic Energy Commission as a result of his connections with the Guggenheim Foundation. The Senator was quick to add that the foundation was rumored to have “a flagrant record of giving fellowships to Communists.”

Responding internally, Pauling explained to Charles Newton, DuBridge’s assistant, that he was only on the Committee of Selection for the Guggenheim Foundation and could in no way be involved with the organization in the ways that McCarthy had suggested. Pauling added that McCarthy was likely targeting him for his peace work.

With interest in his politics hanging over his status at Caltech like a sword of Damocles, Pauling remained in the dark about any conclusions reached by the Board of Trustees’ select review committee, before which he had never been called to testify. Another twelve years would pass before DuBridge finally informed Pauling that the committee had recommended, in May 1952, that nothing be done to punish Pauling. Instead, the committee suggested that Pauling be continually pressed to end his political activities in order to forestall criticism of the Institute. And indeed, as time went on, the internal pressure on Pauling was increased.


Though Pauling’s political activism began to intrude more frequently on his daily responsibilities, he continued to take pride in heading Caltech’s chemistry division, which was racking up the successes. In 1950, Pauling reported to division staff that the Committee on Professional Training had given the chemistry program an overall grade of A, as well as A grades in physical chemistry, inorganic chemistry, and analytic chemistry, with a lone B issued for organic chemistry. Pauling delighted in boasting of these types of accomplishments, and also continued to actively work with incoming students.

One such student, Fernando L. Carraro of Brazil, first wrote to Pauling in 1950, expressing an interest in Pauling’s research on antibodies. Over subsequent exchanges, it became clear that Carraro wanted to study with him at Caltech. In response, Pauling suggested that Carraro apply to the Institute in 1953, and that he also seek funding from the Guggenheim Fellowship for Latin American students. In the meantime, Carraro wanted to know what he should study, to which Pauling offered the idea of mathematics.

In providing guidance related to the Guggenheim fellowship, Pauling further suggested that Carraro could focus on the structure of proteins, the application of quantum mechanics to molecular structure, or the analysis of gas molecules by electron diffraction during his stint in Pasadena. Pauling also warned Carraro that he would likely not be given a graduate assistantship since he had not attended an American university.

Carraro’s fellowship was ultimately approved and he studied under Pauling from 1954 to 1955. Though a small story in the grand scheme of Pauling’s life, his interactions with this student from Brazil serve as evidence that, despite everything else that was vying for his attention, he continued to set aside time for those wishing to learn.

Louis Budenz, Informant

Louis Budenz, March 1956.

Uncover a red doing his stuff on a college faculty and a hue and cry is raised over ‘academic freedom,’ as though these people had a God-given right to infect our children with their made-in-Moscow virus….We should understand that this ’cause of peace’ as peddled by the reds is the destruction of the government of the United States.

-Louis Budenz, November 1951.

Louis F. Budenz (1891-1972), a former Communist Party member, became an FBI informant in the late 1940s. Before starting what was effectively a career as a professional informant, he had been managing director of the Daily Worker, a nationally distributed socialist news outlet. Budenz began consultation with the FBI after submitting to an inquiry by the House Un-American Activities Committee. He became a staff-member at Fordham University shortly thereafter, at which point began writing books about his former association with the Communist Party. He made his living lecturing, writing, and testifying, claiming in 1953 to have earned $70,000 as a witness.

In one of his books, Men Without Faces, Budenz claimed to know the names of 400 concealed communists currently employed in positions of influence across the United States.  Predictably, a government panel in Washington, D.C. wanted the names of them all. Budenz dutifully sat before the panel and listed all of the names that he could think of, eventually issuing that of Linus Pauling.

The denunciation resulted in an investigation by the FBI, and Pauling was put under increased surveillance. The investigation concluded that, even in light of his activities with questionable organizations, no evidence could be found that Pauling was involved with the Communist Party. Nonetheless, Pauling was still put onFBI director J. Edgar Hoover’s Security Index, a list of high profile citizens that were considered a threat to American security.

Using the Security Index as his platform, Senator Joseph McCarthy claimed that communists had infiltrated America’s atom projects. In the sweep of these claims, Pauling’s name was pulled from the Budenz testimony and mistakenly added to a list of researchers that had worked on atomic science research. (Though Pauling conducted a great deal of research on behalf of his country during World War II, he was not involved with the Manhattan Project or any affiliated projects.)

Though backed by no tangible evidence, this torrent of accusations significantly damaged Pauling’s reputation. The claims were subsequently magnified by coinciding events, including his support of Sidney Weinbaum and his continued political activism.

Pauling’s reputation was not the only thing damaged as a consequence – the allegations and denunciations were hurting his pocket book too. The Eli Lilly pharmaceutical company, to name one example, discontinued Pauling’s $4,800 a year consulting position – a contract that had been renewed less than a year earlier.

Invitations from a number of organizations previously extended to Pauling were rescinded as well.  Shortly before Budenz’s denunciation, Pauling had been invited to keynote the dedication ceremony for a new chemistry laboratory at the University of Hawaii. A month after extending the invitation, the Board of Regents of the University of Hawaii canceled the offer that had previously been unanimously approved. Pauling suspected that the accusations made by Budenz were chiefly responsible for the rescinded invitation.  In short order, Pauling was subsequently invited to lecture by a number of other university departments and societies, and wound up speaking several times in Hawaii, though not as originally planned.

Meanwhile, the attacks continued with Budenz openly criticizing Pauling’s decision to lecture in Hawaii in a 1951 American Legion Magazine article.

American Legion Magazine, November 1951.

Pauling’s record being disclosed, the invitation was withdrawn by the University; but he went out there anyway to spread Stalin’s views of ‘peace’ among the students of that institution. He deserves the laurels he has received from the communists, and the fact that he is an atomic physicist in one of our leading universities on the west coast is something to think over seriously. The recent condemnation by Moscow of Dr. Pauling’s celebrated ‘resonance theory’ in chemistry does not seem to have dimmed his ardor on behalf of Stalinite causes.

– Louis Budenz, “Do Colleges Have to Hire Red Professors?”, American Legion Magazine, November 1951.

The article contained a number of other statements about Pauling, all of which were refuted in a letter that Pauling wrote to the editor of the magazine.

Though Pauling did his best to reply to his critics, he was granted little respite.  In 1952 a House special committee was formed to investigate charitable foundations for the presence of communist influence on aid distribution. Budenz testified and once again denounced Pauling, who was at that time a member of the Guggenheim Foundation advisory board. Though Budenz was the accuser, it was members of the committee that brought up Pauling’s name to begin with, allowing the witness to validate their own suspicions.

Mr. Keele: I just want to say this. I believe that Dr. Linus Pauling was on the advisory boards which chose, or is yet perhaps on the advisory boards which chose, fellows for the Guggenheim Fund. What do you know about Linus Pauling?

Mr. Budenz: In connection with Dr. Pauling’s many memberships on Communist fronts, I was officially advised a number of times in the late-, that is, in the middle-Forties, that he was a member of the Communist Party under discipline. The Communist leaders expressed the highest admiration and confidence in Dr. Pauling.

– Testimony transcript, Select Committee on Foundations, 1952.

Though Pauling had been trying to diminish his presence in political affairs, he felt strongly inclined to defend himself publicly against the new accusations. Just one of a growing chorus denouncing Budenz as a professional liar, Pauling vehemently denied the allegations and suggested that Budenz be prosecuted for perjury, a fate suffered by his Caltech associate Sidney Weinbaum. However, unlike Weinbaum, Budenz was not liable for perjury, because his testimony was protected by congressional privilege. Pauling was angered by the whole affair, and particularly disturbed by the fact that Budenz’s behavior was aided by a committee of the United States Congress.

Though Pauling did his best to put these events behind him, the allegations would not be so easily discarded. Even as Budenz’s influence began to diminish, the claims that he made against Pauling hovered over subsequent investigations of Pauling’s activity. Two years after Budenz’s charges against Pauling, and despite the lack of any new evidence, the suspicion that Pauling was a concealed communist topped a list of allegations that held up Pauling’s multiple passport requests.

The whispers resurfaced again in 1953 when Pauling – his passport finally restored – made a visit to Europe, where he attended a dinner held by a world government sympathizer and a number of Russian delegates. The visit prompted J. Edgar Hoover to file a report to the criminal division of the U.S. Attorney General’s office, a copy of Budenz’s statement attached.

The pattern was established. Though Pauling would persevere and continue to achieve at an historic level, the stigma thrust upon him as a result of the actions of Louis Budenz would, in the minds of many, color his persona for the remainder of his life.

The Story of Sidney Weinbaum

Sidney Weinbaum, June 1950.

Sidney Weinbaum, born and raised in Western Russia, came to the U.S. in 1922 after studying at the Charkoff Institute of Technology. He earned a Bachelor of Science degree at Caltech in 1924 before working for several years in the chemical industry. Weinbaum was a talented mathematician and, as chance would have it, met Linus Pauling in an advanced mathematics class his first year at Caltech. He returned to the Institute in 1929 and received his doctorate in physics, under Pauling’s guidance.

A newly minted Ph.D., Weinbaum was next given a research fellowship in the chemistry department, and aided Pauling’s work with crystal structure determinations, quantum mechanics and general research on molecular structures, spending much of his time solving complex mathematical calculations. Weinbaum co-published two crystal structure determinations with Pauling in 1934, those of enargite and calcium boride, and his handwriting can be found in several years’ worth of Pauling’s research notebooks dating to the 1930s. He delivered a number of lectures in Pauling’s quantum mechanics course, and was one of several students who helped put together a published textbook based on the course’s content.

Both Sidney and his wife Lina enjoyed a somewhat close relationship with the Paulings, getting together several times a year over the course of their time in Pasadena. Outside of his academic responsibilities, and aside from his enthusiasms for the piano and chess, Weinbaum was very active in politics. Though Weinbaum later maintained that he never spoke with Pauling about politics during their acquaintanceship, he was himself engaged in political discussion groups throughout the 1930s and 1940s. He distributed petitions and was well acquainted with a variety of activists, some of them communist, with whom he discussed world issues and shared friendship.

In 1943 Weinbaum left Pauling’s lab to join the aviation industry. He returned to Caltech in 1946, this time working at the school’s Jet Propulsion Laboratory. As part of his new job, which involved work on classified projects, Weinbaum was required to hold a security clearance. After working on the job for three years, on July 7, 1949, both the Jet Propulsion Laboratory and Weinbaum were sent a letter from the 6th Army Headquarters in San Francisco, denying Weinbaum clearance to access classified material. He was removed from classified work, and his position was terminated soon thereafter.

According to the authorities that had revoked Weinbaum’s extended security clearance, he had “willfully omitted” previous involvement with any communist organization during a 1949 Army security questionnaire. As a result, several hearings were held before the Industrial Employment Review Board concerning the matter, during which Linus Pauling himself submitted an affidavit that attested to Weinbaum’s loyalty. Weinbaum’s case was appealed, and he appeared before a military review board during the spring of 1950, where he denied charges of communist membership under oath.

Weinbaum defense fund letter, circulated by Linus Pauling, 1949.

Though he continued to maintain his innocence, Sidney Weinbaum was eventually arrested on charges of perjury. (but not disloyalty)  His attendance of “communist club” meetings and association with known communists during his days as a student were held against him as proof of his perjury. In response, Pauling and several other Friends of Sidney Weinbaum began raising money to aid Weinbaum’s legal expenses, setting up a defense fund to help ease the financial burden. In September of 1950 however, at the Federal District Court in Los Angeles, Weinbaum was convicted of perjury and sentenced to four years imprisonment.

Before and during Weinbaum’s case, Pauling himself was under investigation by several authorities for any ties he might have had to the communist party. Though his support of Weinbaum did not help his cause, no convincing evidence could ever be found to suggest that Pauling himself was a communist. The damaging investigations did not end any time soon, however. The FBI continued to monitor his interaction with the Weinbaums, and even the social time that Ava Helen Pauling spent with Lina Weinbaum was marked by federal agents.

After the perjury trial, Pauling’s relationship with Weinbaum was frequently held against him and often used as a passive barb by investigatory committees. Pauling maintained his composure throughout the process, but the strain of so much focus deeply affected him. Particularly, Pauling was hurt by the distrust and distancing that occurred between him and many of his colleagues at Caltech. He did his best to go on with his life as it had always been, but it was impossible to ignore certain difficulties. Though it continued to place him under suspicion, Pauling wrote to Sidney fairly frequently during his imprisonment.

After spending over two years in jail for perjury, Weinbaum was finally released on parole in 1953. The Paulings had maintained contact with Sidney and his wife during his trial and sentence, but their circumstances began to force a divide between them. Sidney faced difficulties acquiring a permanent job, not least of all because of his history, and Lina was left largely debilitated by illness. Though the Paulings were sympathetic, Linus was unable to lend the Weinbaums much assistance. The stress and misfortune of their circumstances led to the Weinbaums’ divorce soon afterward. Though Lina continued to send the Paulings letters up through the early 1990s, Linus received his final letter from Sidney Weinbaum in 1953, shortly after he was paroled.

Letter from Sidney Weinbaum to Linus Pauling, sent from prison, December 1950.

Pauling and Weinbaum remained cordial during their correspondence, but it is evident that both individuals were resentful for what had happened. Weinbaum, the victim of a witch hunt and subject of capricious inquisition, blamed Pauling and his associates for not helping more. Pauling, who had done more on Sidney’s behalf than almost anyone, blamed his involvement in the affair for significant damage to his reputation and the loss of a $4,800/year consulting job. The circumstances that they shared served as apt illustration for the madness of the times.

Though he suffered through great difficulties, Sidney Weinbaum’s story ended on a sunnier note. A man he knew through chess associations eventually found him a job at a factory. Shortly afterward he met the woman who would become his second wife, and though his scientific pursuits were ended, he lived a relatively happy existence thereafter, well into elder years.

The Crystal Structure of Enargite

Enargite model, front view.

Enargite, Cu3AsS4 (copper = dark silver, arsenic = light silver, sulfer = yellow)

A crystal system classified as orthorhombic pyramidal, with a construction consisting of arsenic or copper atoms surrounded by four sulfur atoms in a tetrahedron.  Each sulfur atom is similarly surrounded by a tetrahedron of one arsenic atom and three copper atoms.


As we mentioned in this post, in the early 1930s Linus Pauling began turning his attention from silicate crystals to sulfide minerals. The work on silicates was approaching completion, and Pauling hoped to form a similar understanding of sulfide structures.

He began his work with sulfides by studying the first crystal structure that had ever been determined in the United States. The mineral was chalcopyrite, and Pauling discovered that an initial analysis of the mineral’s structure was incorrect, and that the correct structure was twice as large and featured a different atomic distribution than was initially reported. Pauling continued to work with sulfide minerals and other crystals during this time, publishing structural analyses of sulvanite, zunyite and binnite. He was also busy working on the nature of chemical bonds, quantum mechanics, and the theoretical study of covalent crystals and bonds.

Pauling began studying enargite in March 1931, but was forced to temporarily halt his examination both because of difficulties with the photographs used for structural analysis, as well as the pressures of more pressing priorities. He eventually finished his analysis, and published the findings with Sidney Weinbaum in 1934.

Enargite is a somewhat rare mineral, composed of copper, arsenic and sulfide. It is used as a minor ore of copper and as a mineral specimen. It has a very uncommon symmetry, belonging to the hemimorphic class of crystals – hemi meaning “half” and morph meaning “shape.” This name references the tendency of these crystals to generally have different shaped tops compared to their bottoms.

Enargite model, top view.

Pauling and Weinbaum used data from Laue and oscillation photographs of crystals taken in the Philippine Islands to investigate enargite’s structure, and found that it very closely resembled that of wurtzite, a zinc sulfide. The duo determined that the structure of enargite consists of arsenic and copper atoms which are each surrounded by four sulfur atoms, each sulfur atom being similarly surrounded by a tetrahedron of one arsenic atom and three copper atoms.

In their study, Pauling and Weinbaum verified the mainstream theorized structure of enargite, but found some slight discrepancies in the assumed arrangement. They discovered, for example, that the crystal was incorrectly classified, being orthorhombic pyramidal instead of orthorhombic bipyramidal, as was initially believed.

Sidney Weinbaum, June 1950.

Despite his success with enargite, Pauling found the pace of his sulfide work to be slow, and sought help from the Geological Society of America in the form of a grant proposal during the spring of 1934. Pauling requested a total of $4800;  $1200 for a new apparatus and $3600 to provide three years wages for a postdoctoral fellow. The new position would designate a point person to carry out the “extensive and laborious graphical and numerical calculations” needed to determine the structure of more complex crystals and minerals. During the three years covered in the proposal, Pauling planned to determine the structures of pyragyrite, proustite, pentlandite, covellite, chalcocite, and the minerals of the niccolite group.

Unfortunately for Pauling, Waldemar Lindgren, chairman of the Projects Committee of the Geological Society of America, refused the request. He reasoning for rejection rested primarily upon the feeling that more money would need to be spent on the apparatus initially, in order for a supplemental grant to be provided.

Pauling's notes on enargite, ca. 1930s.

Pauling defended the relevancy of his first proposal, but altered his request so that it only included funding for the three year postdoctoral fellow’s salary. After receiving no reply from Lindgren, Pauling once again repeated his request. He never received a response, and was deeply hurt as a result, later revealing that the incident had contributed to leading him away from crystal-structure determinations in favor of the field of biology.

Though Pauling went on to determine several more crystal structures, the incident was a turning point in his career. From this point on, his relationship with crystal structure work moved from a general systematic determination of mineral group structures, to an occasional examination of substances that piqued his curiosity.

Several pages of notes on enargite by Pauling and Weinbaum are available in Pauling’s Research Notebook 8.  For more on Pauling’s structural chemistry work, see the website Linus Pauling and the Nature of the Chemical Bond: A Documentary History.