Chapter Twenty-Nine

MARIE-HENRIETTE, MARIETTA, et al. (Aluminum)

MARIE HAD EVERYTHING Pierre had ever wanted. By 1933 her large laboratory employed more than sixty scientists, her course at the university turned new students into radioactivists each year, and the factory at Arcueil made the radioelements needed for research.

She had feared, when Pierre died, that Irène might falter without his guidance. Instead, their daughter had found her own place here in the lab.

Closing in at last on the evasive element actinium, Marie was aided by a bevy of associates that included her longtime colleague Catherine Chamié, who still taught school in the mornings at the Lycée russe; the newcomer Willy Lub; Sorbonne graduate student Marie-Henriette Wibratte; and a superb lab technician named Marguerite Perey. In April 1933, a highly regarded radioactivist from the Vienna Radium Institute, Marietta Blau, also joined the group as a visiting scholar on a grant from the International Federation of University Women.

With the same openness that Marie had shown years earlier in regard to her hard labor on radium, she published the Curie lab’s step-by-step procedure for obtaining actinium. The lengthy, laborious recipe, years in the making, began with a slurry of Congolese pitchblende waste dissolved in water and hydrochloric acid, to which various precipitants, neutralizers, oxides, nitrates, and other reactants were added one at a time, and the matrix subjected to dozens of precipitations and fractionations. “The treatment, on the whole, presented numerous complications,” she explained in the Journal de Chimie Physique, “because the chosen chemical operations frequently proved incomplete and had to be repeated, either partially or totally.”

As an alternate plan, she suggested perfecting the extraction of actinium’s parent element, proto-actinium, and then waiting for it to produce offspring. The process would perforce be slow, given proto-actinium’s half-life of approximately thirty thousand years, yet two decades’ time might yield as much as half a milligram of actinium—ten times what she had gleaned—with a lot less work.

When Bronya came to visit at Easter time, Marie took her on a scenic drive several hundred kilometers south to Luz, on the edge of the Pyrenees near Lourdes, at a place Irène had chosen as the latest site for replenishing her red blood cells. “We had no trouble with the car,” Marie wrote to Ève, whose Citroën she had borrowed, “except it doesn’t do all that well on the hills.” She declared herself pleased to be in the Pyrenees and not the Alps, for hiking as well as driving, since these lower heights were better suited to “my possibilities.”

“I wish you a good rest, and a long one,” Ève replied. “You were very tired when you left, and your face looked drawn.” Marie still felt tired a week later when she and Bronya returned to Paris. She had counted on a second road trip with her sister, this time to Cavalaire, but the League of Nations pressured her at the last minute to drop everything and preside over a conference on “The Future of Culture,” to be held the first week of May in Madrid. When Marie consented to go, Bronya saw her off but stayed in Paris near her nieces.

Marie had to admit that her years of service with the League’s International Committee on Intellectual Cooperation had borne very little fruit. None of her pet projects, such as sponsoring science students to spend their summer vacations in foreign laboratories, had been realized. Even her major goal of creating an annotated international bibliography of research in specific disciplines was stalled for lack of enthusiasm: The relevant government agencies, publishers, and professional societies seemed unwilling to relinquish their own traditions, customs, and tastes for the greater good.

As a rule Marie favored small programs of direct benefit to some few over the sort of lavish public event that “The Future of Culture” promised to be. Still, the League’s summons to Madrid gave her a platform for speaking about science to an audience of mostly nonscientists. “I stand among those who think that science has great beauty,” she said in her address to the congress. “A scientist in the laboratory is not only a technician, but also a child confronted by natural phenomena more enchanting than any fairy tale.”

To be a scientist, she maintained, was to follow one’s curiosity wherever it led—“to push against the limits of knowledge, to pursue the secrets of matter and of life with no preconceived idea of the eventual outcome.”

PAUL LANGEVIN, reputed to be the foremost physical theorist in France, seemed perfectly suited to take over the leadership of the Solvay Physics Councils in 1930, after the death of Hendrik Lorentz. The years had proven Paul to be diplomatic, quick-witted, truly fluent in all three languages of science (French, German, and English), and fully conversant with the new realm of nuclear physics that radioactivity, relativity, and quantum theory had revealed.

Paul’s longstanding marriage to Jeanne Desfosses, unfortunately, held no more happiness now than before. Outside its bounds, he formed a relationship with his former student Éliane Montel, who had entered the Radium Institute on the strength of his recommendation in 1927, and remained there till she joined his lab at the Collège de France in January 1931. They had a child together, Paul-Gilbert Langevin, born July 5, 1933.

No public outcry attended this infidelity, or the illegitimate birth. Nor did any challenge to Paul’s authority arise as he changed some established Solvay Council protocol in preparation for the seventh session coming up that October in Brussels. He began by increasing the traditionally small number of invitees to forty, while asking only a handful of them to prepare formal remarks. He was setting the stage for extensive discussion around the few presentations on this year’s theme, “Structure and Properties of the Atomic Nucleus.” In another innovation, Paul pressed the several designated speakers to submit their written reports in September, allowing time for these to be translated and distributed to the entire group for reading beforehand.

Paul tapped James Chadwick of the Cavendish Laboratory to elaborate on the discovery of the neutron, and the team of Irène Curie and Frédéric Joliot to describe their experiences with “penetrating radiation of atoms under the influence of alpha rays.”

Frédéric arrived in Brussels fresh from physics conferences in Leningrad and Moscow. Irène, only the second female physicist ever admitted to the closed circle of a Solvay Council, encountered a third one there, Lise Meitner. Although Professor Meitner had lately been stripped of her university teaching privileges by harsh new racial laws enacted under Chancellor Adolf Hitler, she still headed the physics section at the Kaiser Wilhelm Institute for Chemistry in Berlin.

Marie’s friend Albert Einstein did not attend the 1933 Council. Horrified by Hitler’s rise, Einstein had renounced his German citizenship in March and was actively seeking a new permanent residence.

“We have with us young people of the very highest caliber from all over Europe and America,” Paul Langevin announced on the first day of discussions. As the only participant other than Mme. Curie to have attended every single council, Langevin declared himself pleased indeed to see the infusion of youth. “Young physics needs young physicists,” he said. “We are counting on the young ones; it is they who will be writing the papers and carrying out the greater part of the work.”

Throughout the preceding year, Irène and Frédéric had crashed their alpha particles into a wide array of substances, followed the ensuing neutrons, and watched positrons make tracks through cloud chambers. One notable observation of theirs concerned the dual behavior of aluminum under bombardment by alpha particles. With a direct hit, an atom of aluminum absorbed the alpha particle, now known to consist of two protons and two neutrons. The aluminum atom transformed into an atom of silicon, setting one of the protons free. But sometimes—and this was the big surprise—sometimes the collision yielded a silicon atom, a neutron, and a positron. Irène and Frédéric called these positrons “the positrons of transmutation.”

Seventh Solvay Council, Brussels, 1933: Irène Curie is seated second from left, with her husband immediately behind her and Niels Bohr to her left. Mme. Curie sits near the center with Chairman Paul Langevin to her left. Lise Meitner is seated second from right, with James Chadwick to her left and Ernest Rutherford four places to her right.

Wikimedia Commons

Lise Meitner, who had undertaken similar experiments, spoke up first to object to the French team’s idea. “I have not observed the positrons your hypothesis implies,” she said. Other council members also raised skeptical questions, leading to a debate.

“We were fairly desolate at that point,” Frédéric said later. But during a break Niels Bohr, the reigning architect of atomic structure, approached the couple. “He took my wife and me aside to tell us that he thought our results very important.” A bit more encouragement came from Irène’s childhood friend Francis Perrin, now a professor at the Collège de France, and from Wolfgang Pauli of the Swiss Federal Institute of Technology in Zurich, the author of an influential new textbook on quantum physics. Others seemed to think Irène and Frédéric had blundered or missed something yet again.

Stung by the coolness of their reception in Brussels, they turned to other lab work over the next few weeks. At the end of November, a note reached them from Lise Meitner, saying she had retried her own attempts and refigured the statistics, and now her findings actually did align with theirs.

In January 1934, acting on a suggestion from Francis Perrin, the couple rejigged their experiment and worked at a frantic pace over the next few days to arrive at a striking conclusion.