light was being emitted or absorbed. They were not a real-world feature of light itself, he argued. Einstein, in his talk to the conference, sorrowfully demurred: “These discontinuities, which we find so distasteful in Planck’s theory, seem really to exist in nature.”29
When he was finished, Einstein faced a barrage of challenges from Lorentz, Planck, Poincare, and others. Some of what Einstein said, Lorentz rose to point out,“seems in fact to be totally incompatible with Maxwell’s equations.”
Einstein agreed, perhaps too readily, that “the quantum hypothesis is provisional” and that it “does not seem compatible with the experimentally verified conclusions of the wave theory.” Somehow it was necessary, he told his questioners, to accommodate both wave and particle approaches to the understanding of light. “In addition to Maxwell’s electrodynamics, which is essential to us, we must also admit a hypothesis such as that of quanta.”30
It was unclear, even to Einstein, whether Planck was persuaded of the reality of quanta. “I largely succeeded in convincing Planck that my conception is correct, after he has struggled against it for so many years,” Einstein wrote his friend Heinrich Zangger. But a week later, Einstein gave Zangger another report: “Planck stuck stubbornly to some undoubtedly wrong preconceptions.”
As for Lorentz, Einstein remained as admiring as ever: “A living work of art! He was in my opinion the most intelligent of the theoreticians present.” He dismissed Poincare, who paid little attention to him, with a brusque stroke: “Poincare was simply negative in general, and, all his acumen notwithstanding, he showed little grasp of the situation.”31
Overall he gave low marks to the conference, where most of the time was spent bewailing rather than resolving quantum theory’s threat to classical mechanics. “The congress in Brussels resembled the lamentations on the ruins of Jerusalem,” he wrote Besso. “Nothing positive has come out of it.”32
There was one interesting sideshow for Einstein: the romance between the widowed Marie Curie and the married Paul Langevin. Dignified and dedicated, Madame Curie was the first woman to win a Nobel Prize; she shared the 1903 physics prize with her husband and one other scientist for their work on radiation. Three years later, her husband was killed by a horse-drawn wagon. She was bereft, and so was her late husband’s protege, Langevin, who taught physics at the Sorbonne with the Curies. Langevin was trapped in a marriage with a wife who physically abused him, and soon he and Marie Curie were having an affair in a Paris apartment. His wife had someone break into it and steal their love letters.
Just as the Solvay Conference was getting under way, with both Curie and Langevin in attendance, the purloined letters began appearing in a Paris tabloid as a prelude to a sensational divorce case. In addition, at that very moment, it was announced that Curie had won the Nobel Prize in chemistry, for discovering radium and polonium.* A member of the Swedish Academy wrote her to suggest that she not appear to receive it, given the furor raised by her relationship with Langevin, but she coolly responded, “I believe there is no connection between my scientific work and the facts of private life.” She headed to Stockholm and accepted the prize.33
The whole furor seemed silly to Einstein. “She is an unpretentious, honest person,” he said, with “a sparkling intelligence.” He also rather bluntly came to the conclusion, not justified, that she was not pretty enough to wreck anyone’s marriage. “Despite her passionate nature,” he said, “she is not attractive enough to represent a danger to anyone.”34
More gracious was the sturdy letter of support he sent her later that month:
Do not laugh at me for writing you without having anything sensible to say. But I am so enraged by the base manner in which the public is presently daring to concern itself with you that I absolutely must give vent to this feeling. I am impelled to tell you how much I have come to admire your intellect, your drive, and your honesty, and that I consider myself lucky to have made your personal acquaintance in Brussels. Anyone who does not number among these reptiles is certainly happy, now as before, that we have such personages among us as you, and Langevin too, real people with whom one feels privileged to be in contact. If the rabble continues to occupy itself with you, then simply don’t read that hogwash, but rather leave it to the reptile for whom it has been fabricated.
35
As Einstein wandered around Europe giving speeches and basking in his rising renown, his wife stayed behind in Prague, a city she hated, and brooded about not being part of the scientific circles that she once struggled to join. “I would like to have been there and listened a little, and seen all these fine people,” she wrote him after one of his talks in October 1911. “It is so long since we saw each other that I wonder if you will recognize me.” She signed herself, “Deine alte D,” your old D, as if she were still his Dollie, albeit a bit older.36
Her circumstances, perhaps combined with an innate disposition, caused her to become gloomy, even depressed. When Philipp Frank met her in Prague for the first time, he thought that she might be schizophrenic. Einstein concurred, and he later told a colleague that her gloominess “is doubtless traceable to a schizophrenic genetic disposition coming from her mother’s family.”37
Thus it was that Einstein’s marriage was once again in an unstable state when he traveled alone to Berlin during the Easter holidays in 1912. There he became reacquainted with a cousin, three years older, whom he had known as a child.
Elsa Einstein* was the daughter of Rudolf (“the rich”) Einstein and Fanny Koch Einstein. She was Einstein’s cousin on both sides. Her father was the first cousin of Einstein’s father, Hermann, and had helped fund his business. Her mother was the sister of Einstein’s mother, Pauline (making Elsa and Albert first cousins). After Hermann’s death, Pauline had moved in with Rudolf and Fanny Einstein for a few years, helping them keep house.
As children, Albert and Elsa had played together at the home of Albert’s parents in Munich and on one occasion had shared a first artistic experience at the opera.38 Since then, Elsa had been married, divorced, and now, at age 36, was living with her two daughters, Margot and Ilse, in the same apartment building as her parents.
The contrast with Einstein’s wife was stark. Mileva Mari was exotic, intellectual, and complex. Elsa wasn’t. Instead, she was conventionally handsome and domestically nurturing. She loved heavy German comfort foods and chocolate, which tended to give her a rather ample, matronly look. Her face was similar
