A student on Príncipe. Photo: Courtesy of the Astronomy Club of the Príncipe Secondary School.
‘After six weeks carrying heavy photographic plates, the expedition reached Príncipe.’
The travel magazine promised lush plant life and beaches. But Fiona Meadley also found an island preparing to celebrate a Quaker’s historic experiment
It started with an article in a travel magazine. Remote volcanic islands that we’d never heard of, just off the coast of West Africa. The photographs promised lush tropical plant life, pristine beaches, unusual rock formations, and a gentle pace of life.
The last thing we expected to find were Quaker links. These are tiny islands with a Portuguese colonial history, and Príncipe has fewer inhabitants than our Gloucestershire village (with a population under 7,000). Yet not only did we discover one Quaker connection, by the end of our stay we had counted three!
Let’s start with cocoa. Once, São Tomé and Príncipe was one of the largest exporters in the world, and the Cadbury’s company imported from here. Then, in 1905, a campaign by a British journalist brought attention to the appalling conditions in these plantations, alleging it was akin to slavery. the Cadbury’s company was called to justify its use of Portuguese cocoa in an English court, and afterwards it boycotted the islands, instead importing from the Gold Coast, where production was on locally-owned land. Cocoa production in São Tomé and Príncipe went into decline, and after independence it had all but collapsed. That said, artisanal producers are now reviving the industry, making their own chocolate from their beans. This is known as ‘tree to bar’ production, ensuring extremely high quality chocolate. One pioneering producer sells what some connoisseurs say is the best chocolate in the world.
The better known Quaker link is the 1919 expedition by the astronomer and mathematician Arthur Eddington, who was seeking proof of Albert Einstein’s theory of general relativity. According to the theory, stars with light rays that pass near the Sun would appear to have been curved by the Sun’s gravitational field. This effect is normally obscured by the Sun’s brightness, but is observable during a solar eclipse. Astronomers selected two locations for the best sightings: this tiny island Príncipe in the Atlantic, and Sobral in Brazil. Arthur Eddington led the Príncipe expedition.
After six weeks of travel, on several boats, carrying a telescope and heavy glass photographic plates, the expedition reached Príncipe. The scientists stayed in one of the largest cocoa plantations, Roça Sundy.
Today, Roça Sundy is a beautifully restored hotel. We enjoyed a cool drink on its shady terrace overlooking the sea, and imagined Arthur Eddington pacing the verandah waiting for the rain to stop.
What did he make of the twist of fate that had brought him to the very plantations boycotted by the Cadbury’s company, staying as a guest of the Portuguese colonial owners? No reference is made in his letters back home.
While on the island, we found ourselves limited to basic exchanges with the locals using sign language and sometimes French – English is not spoken here. Perhaps Arthur Eddington was similarly hampered, and was only able to converse with the other expedition member, clockmaker Edwin Cottingham.
And who knows what the owners made of their unusual guests? Were they aware of the Quaker link? The cocoa boycott must have led to a significant downturn in the plantation’s fortunes. Did they entertain the serious Englishmen in their huge dining room, or consign them to separate quarters?
Most likely Arthur Eddington was simply preoccupied in the challenge before him, conversation dominated by detailed planning, checking and rechecking the equipment with Edwin Cottingham, taking note of the weather with increasing dismay. All those months of preparation… would the expedition end in failure because of clouds during the precious few minutes of the eclipse?
On the chosen day, however, the rains stopped and the clouds cleared. He had four minutes to take a series of photographic exposures. He took a quick glimpse at the resulting plates and telegraphed Frank Dyson, the astronomer royal: ‘THROUGH CLOUD. HOPEFUL.’
The rest is history. Back in England, after analysing the results, Arthur Eddington’s observations were hailed as evidence of Albert Einstein’s theory of general relativity. Not only was this a landmark in scientific development and international scientific relations, the news was reported all over the world as a major story. The world had been torn apart by war. Here was a story to bring it together again, and commentators seized on it: ‘A new theory of the universe, the brainchild of a German Jew working in Berlin, was confirmed by an English Quaker on a small African island’, wrote JP McEvoy in Eclipse.
Later, both men’s shared pacifist leanings would be seized on to question the validity of the findings. Arthur Eddington’s stance was a matter of public record. He had been up before the tribunal to claim conscientious objector status and eventually had been granted exemption from conscription, to allow him to take part in the expedition.
He was known to be a champion of Albert Einstein’s theory even before his departure. The Príncipe expedition produced only two good photographic plates, and his calculations were based on just those two. The Sobral photographs, however, supported the prevailing theory (Isaac Newton’s theory of gravity) but had been dismissed. Critics cited this as an example of the predictor effect.
In 2007, the astrophysicist and historian Daniel Kennefick exonerated Arthur Eddington. After a long study of the records, he concluded that it was Frank Dyson, Arthur Eddington’s boss – a sceptic of Albert Einstein’s theory – who had excluded the Sobral results, on the grounds that their equipment was faulty. Experiments repeated in 1922, and on many other following eclipses, gave the same results as Arthur Eddington.
This phenomenon has emerged as one of the most powerful probes of the cosmos. Known now as ‘gravitational lensing’, it provides us with a signature that enables us to see objects otherwise too far away for even the largest telescopes. It can also be observed around any nearby concentration of mass, regardless of whether that material is shining. Crucially, dark matter, the most abundant gravitating material in the universe, does not interact via the electromagnetic force, so is completely invisible, but it does create a gravitational field and can thus be revealed by gravitational lensing. Using this technique to investigate dark matter, astronomy is currently leading particle physics in what may turn out to be the most important scientific investigation of the twenty-first century.
There are a number of plaques at Roça Sundy that commemorate that first, historic, experiment. The latest was unveiled ten years ago, following a campaign by a social anthropologist then working on the islands. Her initiative saw the start of a project to celebrate Arthur Eddington’s expedition to Príncipe as an event of world significance. With the support of The Royal Astronomical Society, HBD (which operates Roça Sundy), various governments, universities and other organisations, the project has taken off. This year will be the centenary of the expedition, and a week of celebrations in Príncipe are planned, from educational activities with local school children, to an international symposium to which Jocelyn Burnell has been invited to talk – our third Quaker connection! We bumped into the man tasked with project-managing a museum which is to be launched during the celebrations. He is expecting the presidents of São Tomé, Príncipe and Portugal, as well as a host of dignitaries and international scientists. We smiled as we bumped our way back to our hotel along a dirt track partly submerged in rainwater, brushing off jungle creepers, wondering if the presidential entourages would have to ride along here too.
On our last night in Príncipe, another guest, a scientist who had also been researching Arthur Eddington, pointed out a star below Orion’s Belt: ‘That’s Hyades, the star he photographed.’ So we stood looking at the constellations, the waves lapping beneath us, and I thought of Arthur Eddington, us and the Príncipe schoolchildren, all looking up to the skies. Past, present and future, connected by the stars.
