In 1798, Dr Nathaniel Vince and a small group of friends gathered on the shores of the English Channel and witnessed a strange thing. They were watching the barque Holstead, which had recently departed Ramsgate. The Holstead hovered above the horizon when, slowly, her masts inverted before disappearing in an instant as if she had toppled over the edge of the Earth. Vince and his friends were aghast and immediately reported what they’d witnessed to the harbour master. It was startling proof that the Earth is flat and surely the work of the devil himself.
Despite the Greek philosopher Eratosthenes’ proposal and measurement of a spherical Earth as early as 240 BCE, flat-Earth theories persisted in many cultures as a constant background belief. Strangely, it was the advent of Darwin’s theory of evolution and its challenge to religious dogma during the late 1800s that led to the flourishing of modern flat-Earth theory.
It was the life and work of Samuel Rowbotham that best illustrates the fervour of these times. Rowbotham was an English inventor, utopian socialist, quack and soap boiler who, in 1849, published a 16-page pamphlet titled “Zetetic Astronomy: Earth Not a Globe” under the pseudonym Parallax. He concluded that the Earth was a flat disk after finding a lack of curvature in his measurements of the drainage ditches of the Bedford Levels in Cambridgeshire. This emboldened him to launch into a career lecturing on his flat-Earth theories. He charged sixpence a head to attend his lectures and, over time, honed his debating skills to a fine edge, convincing many people of his hypothesis.
For Brocklesby, looming and the other phenomena he described were all the wonders and works of God.
Thanks to his passionate disciples, the Universal Zetetic Society continued after Rowbotham died in 1884. Although it faltered slightly after World War, I it reappeared in 1956 as the Flat Earth Society. This small ember survived until the arrival of the internet and social media fanned the flames so that a 2018 YouGov poll found 84% of Americans surveyed believed the Earth was spherical, a further 14% were sceptical, and 2% firmly believed the Earth was flat.
Broad horizon
Although I am not a subscriber to the flat-Earth theory, I’ve always been a big fan of a sweeping horizon. From somewhere like Matuku Takotako/Sumner beach, it dominates the vista as it stretches across the seascape.
It is rare in a dense city to find a true horizon, one that allows your eyes to wander to the edge of the Earth where the sky and the sea meet. The horizon in such places is usually short, constrained by buildings, trees and fences. These clutter the scene and give the impression that the world is a much smaller place full of people and things.
Walking through thick bush is a similar sensation, shortening the world down to a few body lengths at most. It is in the deserts and on the ocean that the true horizon asserts itself.
On a winter’s morning, there are plenty of people promenading along the Sumner Esplanade. There are dogs being walked and conversations with friends being had on the hoof. Occasionally, one of these walkers will pause and look towards the sea and be greeted by a sweeping horizon and, on rare occasions with the right conditions, they may be tricked by looming.
Looming is an optical phenomenon peculiar to the sea, one of those obscure maritime topics that have been ignored by all but a few acutely observant sea gazers. The effect was first described by John Brocklesby in his 1848 book Elements of Meteorology, which included questions for examination designed for schools and academies. Until then, looming had been cast aside as the work of the devil, but Brocklesby, who was a professor at Trinity College, Connecticut, had written and published on a wide range of natural science subjects and was able to dispel all the witchcraft with a dose of hard physics.
Brocklesby was a man of formidable temper and God-fearing beliefs. Although his Elements of Meteorology was the work of a scientific mind, for Brocklesby, looming and the other phenomena he described were all the wonders and works of God. For him, science and religion walked side by side. Unlike Darwin, he never had to challenge the religious dogma that surrounded him, and unlike Rowbotham, he was never deceived by unsound methods or well-formed persuasion.
Sea gazers and sailors had frequently reported such oddities as sailing ships appearing to hover in the air and distant coastlines seemingly projected upside down. All of this had an air of sorcery about it until Brocklesby set out to explain these optical phenomena of the sea as “looming”. Complex looming, as he described it, was caused by “local changes in the temperature of the atmosphere causing irregularities in refraction and distortions in perspective”.
He used drawings and diagrams to illustrate arcane Euclidean geometry and Newtonian optics in a way that was easy to digest. He revealed how different atmospheric conditions sometimes caused refraction and reflection to merge and form fantastic hybrid images, and even demonstrated how to create miniature artificial looming in a laboratory, which put any remaining notions of sorcery to rest.
Brocklesby’s descriptions of simple refraction state that the distance to the visible horizon at sea is sometimes further than the distance based on a simple geometric calculation. If the ocean is colder than the air above it, a cold, dense layer of air forms close to the surface, causing light to be refracted downward as it travels and is slightly bent around the curvature of the Earth.
The reverse happens if the ground is hotter than the air above it, as often occurs in deserts or on long stretches of road, producing mirages. Seeing around corners sounds like a superpower – one most people don’t realise they possess.
Great day for looming
It is a calm winter’s morning as I lean on the wall edging the Sumner Esplanade and there is a crisp horizon cutting the sky and the sea in half. Each does impersonations of blue, the sea adding a hint of green while the sky mixes in a touch of white. Wedged neatly between them is a container ship heading north, looking like a collection of tall apartment blocks that are slowly shrinking as they head towards the horizon.
The sea is cold and the air is unusually warm, which bodes well for some looming. The hull of the ship slips quietly over the horizon, but the towers of containers, the deck cranes and the smokestack all persist. The ship is “hull down”, as sailors call it. The remains of its superstructure now begin to elongate into weird Dalí-esque spires before vanishing in an instant, as if the ship has just toppled over the edge of the horizon.
I look at the promenaders to see if anyone else has noticed, but all of them are deep in conversation or looking at their phones. I fear I have just witnessed what all landlubbers and 2% of the American population already know deep in their souls: that the Earth is flat and you can sail clean off the edge.
I keep it to myself.