photographs. “They are all good of the sun, showing a very remarkable prominence; but the cloud has interfered with the star images.” In his telegram back to London that day, he was more telegraphic: “Through cloud, hopeful. Eddington.”18
The team in Brazil had better weather, but the final results had to wait until all of the photographic plates from both places could be shipped back to England, developed, measured, and compared. That took until September, with Europe’s scientific cognoscenti waiting eagerly. To some spectators, it took on the postwar political coloration of a contest between the English theory of Newton, predicting about 0.85 arc-second deflection, and the German theory of Einstein, predicting a 1.7 arc-seconds deflection.
The photo finish did not produce an immediately clear result. One set of particularly good pictures taken in Brazil showed a deflection of 1.98 arc-seconds. Another instrument, also at the Brazil location, produced photographs that were a bit blurrier, because heat had affected its mirror; they indicated a 0.86 deflection, but with a higher margin of error. And then there were Eddington’s own plates from Principe. These showed fewer stars, so a series of complex calculations were used to extract some data. They seemed to indicate a deflection of about 1.6 arc-seconds.
The predictive power of Einstein’s theory—the fact that it offered up a testable prediction—perhaps exercised a power over Eddington, whose admiration for the mathematical elegance of the theory caused him to believe in it deeply. He discarded the lower value coming out of Brazil, contending that the equipment was faulty, and with a slight bias toward his own fuzzy results from Africa got an average of just over 1.7 arc-seconds, matching Einstein’s predictions. It wasn’t the cleanest confirmation, but it was enough for Eddington, and it turned out to be valid. He later referred to getting these results as the greatest moment of his life.19
In Berlin, Einstein put on an appearance of nonchalance, but he could not completely hide his eagerness as he awaited word. The downward spiral of the German economy in 1919 meant that the elevator in his apartment building had been shut down, and he was preparing for a winter with little heat. “Much shivering lies ahead for the winter,” he wrote his ailing mother on September 5. “There is still no news about the eclipse.” In a letter a week later to his friend Paul Ehrenfest in Holland, Einstein ended with an affected casual question: “Have you by any chance heard anything over there about the English solar-eclipse observation?”20
Just by asking the question Einstein showed he was not quite as sanguine as he tried to appear, because his friends in Holland would certainly have already sent him such news if they had it. Finally they did. On September 22, 1919, Lorentz sent a cable based on what he had just heard from a fellow astronomer who had talked to Eddington at a meeting: “Eddington found stellar shift at solar limb, tentative value between nine-tenths of a second and twice that.” It was wonderfully ambiguous. Was it a shift of 0.85 arc-second, as Newton’s emission theory and Einstein’s discarded 1912 theory would have it? Or twice that, as he now predicted?
Einstein had no doubts. “Today some happy news,” he wrote his mother. “Lorentz telegraphed me that the British expeditions have verified the deflection of light by the sun.”21 Perhaps his confidence was partly an attempt to cheer up his mother, who was suffering from stomach cancer. But it is more likely that it was because he knew his theory was correct.
Einstein was with a graduate student, Ilse Schneider, shortly after Lorentz’s news arrived. “He suddenly interrupted the discussion,” she later recalled, and reached for the telegram that was lying on a window sill. “Perhaps this will interest you,” he said, handing it to her.
Naturally she was overjoyed and excited, but Einstein was quite calm. “I
But, she asked, what if the experiments had shown his theory to be wrong?
He replied, “Then I would have been sorry for the dear Lord; the theory is correct.”22
As more precise news of the eclipse results spread, Max Planck was among those who gently noted to Einstein that it was good to have his own confidence confirmed by some actual facts. “You have already said many times that you never personally doubted what the result would be,” Planck wrote, “but it is beneficial, nonetheless, if now this fact is indubitably established for others as well.” For Einstein’s stolid patron, the triumph had a transcendent aspect. “The intimate union between the beautiful, the true and the real has again been proved.” Einstein replied to Planck with a veneer of humility: “It is a gift from gracious destiny that I have been allowed to experience this.”23
Einstein’s celebratory exchange with his closer friends in Zurich was more lighthearted. The physics colloquium there sent him a piece of doggerel:
To which Einstein replied a few days later, referring to the eclipse:
In defense of Einstein’s poetic prowess, it should be noted that his verse works better in German, in which the last two lines end with “gekommen” and “aufgenommen.”
The first unofficial announcement came at a meeting of the Dutch Royal Academy. Einstein sat proudly onstage as Lorentz described Eddington’s findings to an audience of close to a thousand cheering students and scholars. But it was a closed meeting with no press, so the leaks about the results merely added to the great public anticipation leading up to the official announcement scheduled for two weeks later in London.
The distinguished members of the Royal Society, Britain’s most venerable scientific institution, met along with colleagues from the Royal Astronomical Society on the afternoon of November 6, 1919, at Burlington House in Piccadilly, for what they knew was likely to be a historic event. There was only one item on the agenda: the report on the eclipse observations.
Sir J. J. Thomson, the Royal Society’s president and discoverer of the electron, was in the chair. Alfred North Whitehead, the philosopher, had come down from Cambridge and was in the audience, taking notes. Gazing down on them from an imposing portrait in the great hall was Isaac Newton. “The whole atmosphere of tense interest was exactly that of the Greek drama,” Whitehead recorded. “We were the chorus commenting on the decree of destiny . . . and in the background the picture of Newton to remind us that the greatest of scientific generalizations was, now, after more than two centuries, to receive its first modification.”26
The Astronomer Royal, Sir Frank Dyson, had the honor of presenting the findings. He described in detail the equipment, the photographs, and the complexities of the calculations. His conclusion, however, was simple. “After a careful study of the plates, I am prepared to say that there can be no doubt that they confirm Einstein’s prediction,”
