Along with those luxuries, chocolate began to disappear as well. Shopkeepers faced steep fines if they sold any. As the blockade intensified, it became common to have to stand in line for meat. There was a famous incident where some thousands of people queued to buy margarine (butter was essentially gone). There was never enough protein to go around. Sugar bowls were usually empty. And the worst shortage of all: tea. His pipe, Eddington could do without. But tea? Impossible.
Even with these difficulties, London and Cambridge didn’t have the problems of Berlin. Bread was never rationed and the black market was quite small. In any case, the fortunes of the war were beginning to improve. It seemed that the sleeping giant, America, had finally been roused and would be entering the conflict on the side of the Allies. America was hardly champing at the bit for war. Instead, the shift came about because of some spectacularly poor choices on the part of the Germans. The reintroduction of unrestricted submarine warfare was one of the few actions that would almost certainly bring in the Americans. Even worse, someone in the kaiser’s diplomatic corps decided that it would be a good idea to convince Mexico to attack the United States preemptively (in hopes of recapturing Texas, New Mexico, and Arizona), thus preventing their intervention in Europe.
Incredibly, the offer to Mexico (now known as the Zimmermann telegram) was sent via the American embassy in Berlin. Since the British cut their undersea cables, Germany had few options for fast international communication, and the Americans allowed the use of their lines as a favor. The telegram was in code, at least, though British intelligence deciphered it almost immediately. On April 6, the United States of America declared war on Germany. At that moment, the United States essentially had no army. No one thought their raw recruits were a match for the seasoned troops currently occupying the trenches. But there were a lot of them. Their entry into the war meant that Germany was essentially fighting an enemy with limitless reserves. They had no intention of giving up, though. The German High Command had made a daring strategic decision to pull some of their troops back from their farthest positions to a new, more defensible set of fortifications—the Hindenburg Line. This would be much more difficult for the Allies to breach. The Germans made it clear that they were in the war for the long term. They finished their withdrawal the day before the American declaration of war and awaited their new enemies.
Along with vast numbers of soldiers, America brought with it an enormous industrial capacity and technical expertise. When Churchill was asked what he most wanted from the United States he replied, “Send us chemists.” The historian Roy MacLeod has documented how American scientists had been preparing for this moment for a while. George Ellery Hale had been trying to put US science on a war footing since the Lusitania, well before any combatant was asking for technical help. Hale wore wire-rimmed glasses under a high forehead and stubbornly parted hair, and always sported a high collar. He suffered from depression and insomnia while still making American astronomy the world leader in powerful telescopes. His expertise was solar astronomy, far from any war work, but he was unrivaled in his powers of scientific organization. His efforts resulted in the formation of the National Research Council within the National Academy of Sciences. Hale even visited Europe in August 1916 to see how best to organize the NRC for potential war work and see what was most needed. So when the country joined the war, Hale was able to present a “chemical reserve” ready to deploy thousands of scientists instantly.
Sir Horace Darwin (ninth child of Charles) wrote to Hale asking for a hundred or so scientists to come work on British military projects. He also warned Hale that the United States needed to avoid the same mistake Britain had made and not to conscript scientists as common soldiers. That, he said, had been a disaster. Cooperation among the Allied scientists was not easy. The British and French had made little progress. Hale had thought about it extensively, though the American scientists found it difficult to work within the constraints of classified communication and military priorities.
Despite the challenges, Hale and his colleagues worked hard to create a genuine sense of “Allied science” as a community. They had numerous conferences tackling chemical weapons, munitions production, and so on. Hale saw these meetings as models for what science would look like after the war: American, British, French scientists working closely (with maybe a couple of Belgians). The Germans would be unwelcome for a hundred years. The arrival of the Americans, ironically, had broken international science even further. The practice of science was pushed to become tied even closer to nationalism and partisanship.
* * *
THAT NATIONALISM MADE it difficult when Eddington went to his friend to ask a favor. A big favor. In some sense, when your friend is the Astronomer Royal—the most important scientist in the country—any favor that takes up his time will be fairly big. He had known Frank Dyson for years and they were close. But Eddington needed some help with enemy science—relativity.
It was not obvious that Dyson would be amenable to providing what Eddington needed. He was something of an internationalist, in that he helped set up the replacement system for the Kiel telegraph network. That system, where scientific messages were sent to neutral Copenhagen, was increasingly seen as being pro-German (in that the Germans were not explicitly excluded and that Strömgren was too friendly with them). H. H. Turner had stopped using it. French and American astronomers asked Dyson to switch the system’s hub to an Allied country. One British astronomer supported this merely because it would inconvenience the Germans. Dyson capitulated and wrote to Strömgren officially withdrawing the Royal Observatory. He complimented him on the efficiency with which the system had been run: “I am very sensible of the good feelings towards Astronomers of the belligerent countries which prompted you to undertake the transmission of Astronomical telegrams during the war, instead of the Kiel central station. . . . Nevertheless I have reluctantly come to the conclusion that for the present at any rate the Greenwich Observatory should withdraw from this society.” Dyson enclosed a payment for services rendered. We don’t know precisely where Dyson’s political views lay; he was certainly no fan of the Germans, though. He wrote to a friend, “I hardly know whether to be glad or sorry that our boys are too young to go [to war].” Near the end of the war he announced his pleasure that the “great evil with which the world was threatened is being overcome.”
So Eddington was not likely to get much traction with his friend by using internationalist arguments. Nor was Dyson particularly interested in relativity itself. Even Eddington had to acknowledge that Dyson was “very skeptical about the theory.” The best Eddington could do was get Dyson interested. The Astronomer Royal was gradually persuaded that relativity was scientifically important even if it might be wrong. Technical interest and personal friendship seem to have been enough for Dyson to join in on Eddington’s project. He was willing to help.
Eddington didn’t need help with the theory itself. The mathematics was far beyond Dyson, and Eddington had already spent months working through the physics and philosophy of relativity (he relaxed by reading The Brothers Karamazov). He had come to the same conclusion as Einstein, that even with a fully formed theory, what relativity needed was some kind of physical test—an observation that could support or wreck one of its unique predictions. Mercury was good but insufficient. It was technically a retrodiction, not a prediction, because Einstein knew what the answer should be before he developed his equations. Observations of the gravitational redshift were, at best, not supporting Einstein’s prediction; at worst, they were strongly against it.
That left the gravitational deflection of light, visible only at a total solar eclipse. And the person in charge of British eclipse observations? Frank Dyson. The Astronomer Royal headed the Joint Permanent Eclipse Committee (JPEC), which handled British-sponsored expeditions to solar eclipses, so no test of relativity was going to happen without his approval. Once Dyson had agreed to support Eddington on this, his first move was
the same as the one made by the astronomers in Germany—check photographs from old eclipses to see if the gravitational deflection was visible. The effect was small enough that if you weren’t looking for it you could easily miss it. He and the staff at Greenwich searched through the records with no luck.
That meant a whole new expedition would need to be mounted to look for the deflection. Unlike Einstein and Freundlich, trapped in central Europe, the British ruled the waves (unless there were U-boats around) and at least had the possibility of going eclipse hunting. Total solar eclipses can be hard to come by; fortunately astronomers even then were very, very good at predicting where and when they would occur (down to the second). We do not know who did the calculations, but Eddington and Dyson quickly realized that there was a perfect opportunity coming up soon. On May 29, 1919, there would be a total eclipse in which the sun would be squarely in front of a prominent star cluster. The deflection of light would appear visually as stars near the edge of the eclipsed sun being slightly displaced from their actual location. So ideally an astronomer hoping for a clearer measurement would want to have several bright stars close together—the Hyades.
How star images in the Hyades are deflected from their positions by the sun’s gravity. Detail from the Illustrated London News, November 22, 1919.
COURTESY OF THE AUTHOR
The path of the eclipse was not particularly convenient, stretching over Africa and South America. No one knew if the war would be over by 1919 and Dyson was unsure whether the JPEC would be able to mount such an expensive, complicated expedition. Eddington thought the difficulty of such a project was actually a good thing. He had been trying to convince his colleagues of the necessity of truly international science, and this expedition could be the perfect example. A German theory, British astronomers, travel across three continents—exactly the sort of international cooperation that Eddington had been saying was essential to the very spirit of science. Even better, it was an opportunity to bring a pacifist, brilliant “enemy” scientist to the world’s attention. This expedition would not just be a scientific test, it would be a scientific demonstration—of international science as Eddington saw it. The stakes were high. In March 1917, even before he fully understood relativity, Eddington convinced Dyson to make a brief statement of support for sending an expedition in 1919. Everything was still uncertain, but it was the first step.
Even the Astronomer Royal couldn’t make this happen on his own, though. Eddington knew he needed to persuade the British scientific community that relativity was important and interesting enough to spend scarce resources on. He was an apostle bringing good news to a strange land. What he needed was some scripture—a fundamental text that he could point to and say, “This is what relativity means.” And, of course, it had to be in English. Einstein wasn’t likely to write it, so that meant Eddington had to do it himself. Once he felt he had a genuine command of the theory, he sat down to begin writing.
As is often the case when trying to convert a land to a new belief system, the locals in Britain already had their own deity: Newton. Most scientists were perfectly happy with the Newtonian system and did not appreciate Eddington’s missionary efforts. Chief among those was Sir Oliver Lodge, a walking, talking embodiment of the science of the Victorian age. He was an expert in electricity and magnetism at the University of Birmingham, developing many of the technologies that would eventually become radio (his patent dispute with Guglielmo Marconi over wireless telegraphy lasted for decades). He was also one of the great science writers of the time, with a few dozen books to his name. For a generation his name was synonymous with physics. He was famous enough to be caricatured in Vanity Fair. The drawing captured his lanky frame and the way his face-enveloping beard was balanced by an impressively smooth crown.
Lodge’s science was completely intertwined with the ether. He saw radio as the ultimate evidence for the ether’s reality. Maxwell had predicted that if there was ether, there would be electromagnetic waves. Hertz found those waves, and now Lodge was using them to talk across the sea. Surely that was definitive proof that the ether was real? However, Lodge’s ether did more than just allow for radio waves. Tragically, his son Raymond had been killed on the battlefield near Ypres in 1915. Two weeks later, though, they were talking again—through a spiritualist medium. Lodge had been trying to study psychic phenomena for many years (a fairly respectable Victorian scientific project) and he had concluded that the ether not only carried electromagnetic waves but also the spirits of the dead. The ether, superfluous for Einstein, was the very foundation of reality for Lodge. It provided both physical laws and spiritual meaning. It surrounds us and binds us.
While the ether was technically from Maxwell’s physics, Lodge thought of it as part of Newton’s universe. Newton did not have much to say about electromagnetism, but to Lodge it was simply an extension of the kind of physics that Newton did. It was part of his universe’s absolute space and time, objective knowledge, and clear concepts of force and mass. So to Newtonians like Lodge, relativity was dangerous not just because it denied the ether. Instead, it attacked everything that seemed essential to science, everything that had made science work since Newton published his Principia Mathematica in 1687. This strange German theory was not just an irritating enemy intrusion, it was a threat to the very foundations of human knowledge. Lodge stepped forward to defend Newton and all that he stood for.
Lodge was no dogmatist, though. Einstein’s successful explanation for the wobble in Mercury’s orbit was impressive. It needed to be met with equally impressive physics. Lodge used a fairly standard move in science. If an opponent pointed to a piece of observable evidence as support for their theory, you came up with your own theory that explained that piece of evidence in your own terms. If successful, both theories went back to the starting line and other arguments could be deployed. This kind of scientific judo—using your rival’s successes for your own benefit—is an essential part of theoretical physics. In a sense, this is what Einstein had already done with Newton’s entire theory of gravity. He had struggled to make sure general relativity was equivalent to Newton’s theory in most circumstances and thus could take over all of the evidence associated with the earlier theory.
In summer 1917, Lodge decided to create an alternative theory that preserved Newtonian physics and the ether but could also explain Mercury. His idea was that perhaps as our solar system moved through the stationary ether, there was a kind of drag that would cause the wobble. It proved to be a challenge just understanding his competitor, though. His brother Alfred, a mathematician at Oxford, and Joseph Larmor helped. But there was only one person he could turn to who really understood relativity: Eddington.
So, amazingly, Eddington helped Lodge understand relativity well enough to attack it. Letters flew back and forth. By January, Lodge had developed a full-fledged neo-Newtonian theory of gravity that accounted for Mercury’s wobble. Eddington gently pointed out that, unfortunately, Lodge’s theory would throw off the orbits of all the other planets, so that was not much of a victory. One interesting side effect, though, was that Lodge’s theory also predicted a deflection of light near the sun: 0.74 arc-seconds, roughly half of Einstein’s predicted value. Two different predictions of the same effect, for different reasons. Eddington realized this could be of great value for his missionary campaign.
* * *
CHEMISTS SUCH AS Haber had also been thinking about how to achieve the same effect with different means. Chlorine proved to be fairly easy to defend against, once the shock value had worn off. Phosgene gas, with its distinct musty hay smell, was introduced as an alternative. In July 1917, just as Lodge was preparing to embark on his new ether theory, the Germans introduced a new weapon: mustard gas. Its yellow-brown clouds caused blisters on the skin and lungs, and induced temporary blindness. It rarely killed, though it created one of the definitive images of the Great War: a column of broken, sightless soldiers, gauze over their eyes, eac
h with a hand on the man in front, slowly making their way back from the trenches.
That summer also saw air raids on England on a scale never before seen. The Germans set up their 3rd Bombing Squadron, consisting of the Gotha heavy bombers, around Ghent, in occupied Belgium. The first day of raids from that base caused 286 casualties and inaugurated what came to be known as the “Gotha Summer.” This was three weeks of bombing that included a daring daylight raid on Liverpool Street Station that killed and wounded 594, which led to yet another round of anti-German rioting in London. The royal family, horrified that the formal title of their house—“Saxe-Coburg and Gotha”—shared a name with the German bomber, changed their appellation to the charmingly English “Windsor.”
In the aftermath, Parliament gave the Home Secretary the power to revoke the naturalization of citizens of German descent and declare them to be enemy aliens. The leadership of the Royal Society took their equivalent move. Scientists resident in enemy countries still technically held membership in the Royal Society, and the group took action to finally expel them. The resolution read:
In view of the war having continued . . . without any indication that the scientific men of Germany are unsympathetic towards the abominable malpractices of their Government and their fellow-countrymen, and having regard to the representative character of the Royal Society among British scientific bodies as recognized by the patronage of His Majesty the King, this Council forthwith take the steps necessary for removing all enemy aliens from the foreign membership of the Society .
The stated reason for throwing them out was that no German scientists had made any statements against the “abominable malpractices” of their government and military. There had not been any such statements, had there? Everyone of importance had surely signed the Manifesto of 93. If there had been resistance, someone in Great Britain would have heard about it, wouldn’t they? No, German science was surely united in support of the war.
Einstein's War Page 23
