In January of 1870, Alfred Russel Wallace found himself on a collision-course with a group of creationists who fervently believed the earth is flat. The father of biogeography, co-discoverer of the theory of evolution by natural selection, seems an unlikely sort to be mixed in with religious fanatics on a question of geography settled since the 3rd century BC. Why was such a venerable 19th century man of science accepting wagers from flat-earthers regarding the shape of our planet?

Simply put: It looked like easy money.

Really, ten minutes and a telescope should have done it. Alas, nothing is easy when it comes to creationists, as Wallace would learn to his sorrow:

The next matter was a much more serious one, and cost me fifteen years of continued worry, litigation, and persecution, with the final loss of several hundred pounds. And it was all brought upon me by my own ignorance and my own fault—ignorance of the fact so well shown by the late Professor de Morgan—that "paradoxers," as he termed them, can never be convinced, and my fault in wishing to get money by any kind of wager. It constitutes, therefore, the most regrettable incident in my life.

Sir Charles Lyell, father of modern geology, shared Wallace's ignorance. They may have steered a much different course had they known the history of the men they hoped to defeat.

***

19th century Britain was one of the epicenters of the scientific revolution. But with progress comes pushback. Alarmed believers strove to shore up the Bible's authority, some going much further than others. Not many of them went to greater extremes than Samuel Birley Rowbotham.

Known as Parallax, he was a Biblical literalist, young earth creationist, and quack who believed in a flat, disc-shaped Earth. The North Pole stood at its center, and that was it; in his cosmology, there was no such beast as a South Pole. He backed his contentions with bad math, bogus experiments, and Bible verses. He revived the ancient flat-earth idea and gave it a modern patina of "science," then used the result to stir up controversy for cash.

One of his many popular lectures on the subject converted William Carpenter, who loved the idea more for its poke in the eye it gave to the scientific establishment than for reasons of biblical fealty. Determined to rid the world of round-earth ideas, he wrote a scathing book called Theoretical Astronomy Examined and Exposed under the (mis)nom(er) de plume Common Sense.

This book soon came to the attention of the man who was to vex Alfred Russel Wallace so sorely. John Hampden, a Protestant rector's son and all-round arch-conservative, had plenty of leisure time for engaging in argument. His father had left him independently wealthy, although, perhaps suspecting his eldest son would prove prone to causing controversy, stipulated in his will that John would be reduced to a meager £50 per year if he ever did anything to sully the venerable name of Hampden.

John Hampden wasted little time doing just that. After dropping out of Oxford, he occupied himself by publishing various tracts demanding that the Church of England be reformed "on strict Protestant lines." A staunch biblical literalist "bent on defending Genesis to the hilt," he was ripe pickings for Carpenter's flat-earth crusade. Upon reading Theoretical Astronomy, he became convinced the earth was flat, and he had the Bible verses to prove it. Putting his tract-making skills to work, he quickly produced pamphlets such as The Popularity of Error and the Unpopularity of Truth: Shewing the World to be a Stationary Plane and Not a Revolving Globe, purporting to prove the pancake-osity of the planet.

This was the era of steam-powered printing presses and vastly expanding public interest in science, fed by vigorous journalism - a veritable Information Age rather like our own. Like our modern creationists, John Hampden looked on in horror as the masses slurped up all the science they could hold, including the round-earth heresy. He made it his mission to eradicate such ideas from the public consciousness, even when his bombastic techniques horrified his flat-earth grandfather Parallax. Sounding like the Borg of Hampden, he declared that spherical earth theories had to go: "All further resistance is useless."

And he was willing to wager his money on it.

***

On January 12th, 1870, Hampden threw down his gauntlet in the weekly journal Scientific Opinion.

What is to be said of the pretended philosophy of the 19th century, when not one educated man in ten thousand knows the shape of the earth on which he dwells? Why, it must be a huge sham! The undersigned is willing to deposit from £50 to £500, on reciprocal terms, and defies all the philosophers, divines and scientific professors in the United Kingdom to prove the rotundity and revolution of the world from Scripture, from reason, or from fact. He will acknowledge that he has forfeited his deposit, if his opponent can exhibit, to the satisfaction of any intelligent referee, a convex railway, river, canal, or lake. JOHN HAMPDEN

Alfred Russel Wallace saw the ad. Though it must have seemed like the easiest of easy money, he was cautious, and consulted a man whom he held in the highest esteem.

Before accepting this challenge I showed it to Sir Charles Lyell, and asked him whether he thought I might accept it. He replied, "Certainly. It may stop these foolish people to have it plainly shown them."

Poor Wallace, like Lyell, thought that Hampden only needed to be shown some proof in order to accept the plain fact that the earth is round. He knew nothing of Hampden and his ilk, or he may never have accepted the wager. But in addition to wanting to win a cool £500, he believed "that a practical demonstration would be more convincing than the ridicule with which such views are usually met." He was about to find out that practical demonstrations have absolutely no effect on these truest of true believers.

The first signs that Hampden was determined to win by crook if he couldn't manage a victory by hook came when Wallace wrote in response to his advertisement, graciously accepting the challenge. Wallace offered to prove the earth's curvature by measuring "the convexity of a canal or lake." As for where this was to be done, he was amenable to any suitable stretch of water. "A canal will do if you can find one which is nearly straight for four miles without locks; if not, I propose Bala Lake, in North Wales, as a place admirably suited for the experiment." He thought any of the editors of several popular science or sporting journals could would be suitably unbiased referees; if not them, then perhaps "any well known Land Surveyor, or Civil Engineer, or any Fellow of the Royal Geographical Society."

Hampden at first seemed quite above-board about the thing, agreeing that Mr. John Henry Walsh, editor of the Field magazine, should serve as referee. Walsh was an ideal choice, as he knew neither of them, was a non-scientist with no skin in the globe-vs-flat-earth game, and had prior experience deciding wagers. But shortly after funds were placed in Walsh's hands to guarantee the wager, Hampden demanded a referee of his own.

Wallace didn't see a problem with this, writing back:

Your wish to have a second referee is quite reasonable, and I accede to it at once, only stipulating that he shall not be a personal acquaintance of your own, and shall be a man in some public position as Editor, Author, Engineer, &c.

Hampden, having no scruples in his crusade to prove the earth flat like he was certain the Bible proved, wasted no time in choosing William Carpenter. Yes, that William Carpenter. The one who had converted him to flat-eartherism, with whom he was monetarily entangled, and who could only just be called an author. Having thus secured a referee biased wholly in his favor, Hampden proposed a straight six-mile stretch on Old Bedford Canal for the location of the experiment.

Wallace didn't know that this same stretch had already been used by Parallax in his own attempts to prove the earth flat - which feat he'd managed by holding his telescope a mere eight inches above the water, thus allowing refraction to interfere with his measurements and give the impression that he was sighting along an utterly flat stretch of water resting on a flat earth. It was a classic example of a poorly-designed experiment yielding invalid results. Hampden was loading the dice as much as he could manage.

So that was how Alfred Russel Wallace, venerable naturalist and science legend, ended up that March on a cold canal in Norfolk, England, squinting through telescopes in a valiant but vain effort to prove the shape of the earth to committed creationists. Since Walsh couldn't be there for the whole week of experiments, a surgeon and amateur astronomer named Mr. Martin Wales Bedell Coulcher acted as Wallace's referee. All the interested parties watched Wallace's painstaking experiment, which had been designed to correct for refraction.

The iron parapet of Welney bridge was thirteen feet three inches above the water of the canal. The Old Bedford bridge, about six miles off, was of brick and somewhat higher. On this bridge I fixed a large sheet of white calico, six feet long and three feet deep, with a thick black band along the centre, the lower edge of which was the same height from the water as the parapet of Welney bridge; so that the centre of it would be as high as the line of sight of the large six-inch telescope I had brought with me. At the centre point, about three miles from each bridge, I fixed up a long pole with two red discs on it, the upper one having its centre the same height above the water as the centre of the black band and of the telescope, while the second disc was four feet lower down. It is evident that if the surface of the water is a perfectly straight line for the six miles, then the three objects—the telescope, the top disc, and the black band—being all exactly the same height above the water, the disc would be seen in the telescope projected upon the black band; whereas, if the six-mile surface of the water is convexly curved, then the top disc would appear to be decidedly higher than the black band, the amount due to the known size of the earth being five feet eight inches, which amount will be reduced a little by refraction to perhaps about five feet.

This experiment showed curvature, as it could not fail to do. Hampden's mentor and referee Carpenter signed the sketch of the results produced by Mr. Coulcher, affirming it indeed showed what they both had seen.

However, he declared those results were unable to prove the earth was a globe "because the telescope was not leveled, and because it had no cross-hair!"

Wallace, being at pains to ensure that there would be no doubt about the results, proceeded to recalibrate the experiment to Carpenter's specifications, and ran it again.

At his request to have a spirit-level in order to show if there was any "fall" of the surface of water, I had been to King's Lynn and borrowed a good Troughton's level from a surveyor there. This I now set up on the bridge at exactly the same height above the water as the other telescope, and having levelled it very accurately and called Mr. Carpenter to see that the bubble was truly central and that the least movement of the screws elevating or depressing it would cause the bubble to move away, I adjusted the focus on to the distant bridge, and showing also the central staff and its two discs.... We then fixed a calico flag on the parapet to make it more visible, and drove back with the instruments to Old Bedford bridge, where I set up the level again at the proper height above the water, and again asked both the referees to make sketches of what was seen in the level-telescope. This they did. Mr. Carpenter's was rather more accurately drawn, and Mr. Coulcher signed them as being correct, and both are reproduced here.

This new setup showed the same thing as the first: the earth was indubitably curved. No reasonable person could doubt it. Alas, Wallace was not dealing with reasonable persons. They responded in true creationist fashion: by completely refusing to deal with reality.

Mr. Hampden declined to look through either telescope, saying he trusted to Mr. Carpenter; while the latter declared positively that they had won, and that we knew it; that the fact that the distant signal appeared below the middle one as far as the middle one did below the cross-hair, proved that the three were in a straight line, and that the earth was flat, and he rejected the view in the large telescope as proving nothing for the reasons already stated.

They were at an impasse. At first, Hampden refused an umpire to decide between the referees. Eventually, he agreed to have Walsh review the results, and both sides sent in sketches and reports. Walsh weighed the evidence, decided it did indeed prove the earth was spherical, and published both materials and his conclusion in the Field.

Hampden threw a fit. Carpenter wrote "a long argument to show that the experiments were all in Mr. Hampden's favour." This diatribe didn't sway Walsh. He declared Wallace the positive winner, and, despite Hampden demanding his money back, gave the winnings to Wallace.

Unfortunately, British law didn't protect gentlemen's interests when it came to bets, even if the wager was strictly along scientific lines, and would eventually force Wallace to give the money back. Of course, by then, that amount was offset by the judgements entered in Wallace's favor against Hampden, who had embarked on an extraordinary 15-year campaign of abuse and libel that landed him in both jail and court several times. He sent vitriolic letters to everyone he could think of, including Wallace's wife:

"Mrs. Wallace,—Madam, if your infernal thief of a husband is brought home some day on a hurdle, with every bone in his head smashed to pulp, you will know the reason. Do you tell him from me he is a lying infernal thief, and as sure as his name is Wallace he never dies in his bed. "You must be a miserable wretch to be obliged to live with a convicted felon. Do not think or let him think I have done with him. "John Hampden."

Death threats were beyond the pale of English law, as were various and sundry libelous statements and a refusal to desist when court-ordered to. Wallace won several actions, but Hampden declared bankruptcy, probably to prevent him from collecting damages. In the end, with all the court costs, and despite being the wronged party throughout it all, Wallace's woeful wager cost him several hundred pounds and no end of trouble.

Still, he'd done his best to, as Lyell said, "stop these foolish people." He'd learned a valuable lesson we would be wise to heed today: don't accept wagers from men who are religiously motivated to believe in easily-disproved notions such as the idea of a flat earth. And he'd shown with an elegant little experiment that the earth is definitely round, which our images from space gorgeously support.

Flat-earth belief didn't die with Hampden. You can read all about it in Christine Garwood's remarkable book, Flat Earth: the History of an Infamous Idea.

References:

Garwood, Christine (2007): Flat Earth: the History of an Infamous Idea. New York, NY: Thomas Dunne Books.

Wallace, A.R. (1905): My Life: A Record of Events and Opinions. London: Chapman and Hall. Volume 2.

Wallace, A.R. Reply to Mr Hampden's Charges Against Mr Wallace. The Pamphlet Collection of Sir Robert Stout: Volume 22