“Earth Not a Globe”: Parallax’s Zetetic Astronomy (1865)

How sincere are flat earthers, really? When “Saddam Hussein” posted on the Flat Earth Society forum in November 2007, he addressed the peanut gallery. “Everything you know is a lie. A lie which has been forced so thoroughly into the masses [sic] subconcious [sic], that nobody dares to question it. This, the rotating Earth, is the centre of it! Not the Earth itself but the shape of it!. [sic] We do not live on a blue ball hurtling through the cosmos but upon the back of a great disk, thousands of miles wide. This is what the Earth looks like!”

The naysayers immediately rolled in. “What dicease [sic] did you say you suffered from?” “people who believe the earth is round: / every ship navigator and captain / every airplane pilot / every mapmaker / everyone who lives south of the equator / everyone in NASA / everyone working for anything related to satellites / every weather forecaster.” He would not be deterred: “They have no proof. If I look out the window, I see flatness. I see no curvature.” In his profile picture, the former president of Iraq gazes skeptically leftward, a noose photoshopped over his left shoulder.

As of September 28, 2026, “Hussein” had posted on the forums of the Flat Earth Society 35,188 times, with variations of the same singular argument: NASA, through devious machinations, had convinced the people — through lies about the existence of penguins and the nonexistence of a vast ice wall at the end of the earth. He was and is, obviously, joking — though the skeptics who have come to the forum to argue with him over the past nineteen years are no less infuriated by his claims.

When “Parallax”, the author of Zetetic Astronomy. Earth Not a Globe! An Experimental Inquiry into the True Figure of the Earth: Proving it a Plane, Without Axial or Orbital Motion; and the Only Material World in the Universe! (1865), went on a lecture tour of Great Britain, he provoked similar reactions, and similar doubts about his sincerity. More or less responsible for the revival of Flat Earth theories in the modern period, Parallax held raucous public talks in towns all over Britain, presenting the result of his experiments and then inviting the local worthies to debate him.

According to the historian of science Christine Garwood, he was — to his critics’ embarrassment — astoundingly successful. Furious amateur scientists would go to his lectures and fall one by one. Invariably polite and unflappable (and willing to cut and run when necessary), the Greenwich Free Press would report in May 1862 that “it seems impossible for any one to battle with him, so powerful are the weapons he uses. Mathematicians argue with him at the conclusion of his lectures, but it would seem as though they held their weapons by the blade and fought with the handle, for sure enough they put the handle straight into the lecturer’s hand, to their own utter discomfiture and chagrin.” (He would reproduce this report in the second, 1873 edition of Zetetic Astronomy, which did some clever editing of skeptical newspaper coverage.)

Born in 1816 as Samuel Birley Rowbotham to a wealthy Stockport merchant family, Parallax had dabbled in utopian socialism and medical quackery before embarking on his quest to flatten the world. He was not the first Brit to attempt to disprove the concept of the round earth — a pamphlet titled The Anti-Newtonian had made a minor splash in 1819 — but his public debates quickly made him the most famous and Zetetic Astronomy the foundational text of all modern Flat Earth thought.

In the book, he set out — using the principles of zetetic astronomy, that is, an astronomy that begins from first principles rather than received ideas — to establish the theory that “Saddam Hussein” would defend some 150 years later: that the Earth is a wide, flat, immobile disc above which the Sun and the Moon move, surrounded by an ice wall that keeps the water in and humans from the edge. He conducted his own experiments to debunk reported convexity of the Earth:

In the county of Cambridge there is an artificial river or canal, called the “Old Bedford.” It is upwards of twenty miles long, and passes in a straight line through that part of the fens called the “Bedford level.” The water is nearly stationery [sic] — often entirely so, and throughout its entire length has no interruption from locks or water-gates ; so that it is in every respect well adapted for ascertaining whether any and what amount of convexity really exists. A boat with a flag standing three feet above the water, was directed to sail from a place called “Welney Bridge,” to another place called “Welche’s Dam.” These two points are six statute miles apart. The observer, with a good telescope, was seated in the water as a bather (it being the summer season), with the eye not exceeding eight inches above the surface. The flag and the boat down to the water's edge were clearly visible throughout the whole distance !

He also took aim at traditional proofs of globularity: the variability of motion between pendulums at the equator and in the northern hemisphere could be attributed to temperature changes; lunar eclipses could be caused by the presence of some other earth satellite; things seem to fall below the horizon because of perspective, not the shape of the planet. The speculations of Newtonian-Copernican astronomy were committed to irresponsibly playing fast and loose with Biblical truth, leaving Christian and Jewish congregations in a state of “smouldering scepticism”. But zetetic astronomy provided the answer. “Being demonstrably fallacious, [the theories] fall to the ground as valueless. They can no longer be weilded [sic] as weapons against religion. If used at all it can only be that their weakness and utter worthlessness will be exposed. Atheism and every other form of Infidelity are thus rendered helpless.”

Did he mean it? Garwood thinks his socialist beginnings would have been at odds with the religious revivalism of the text, and people at the time weren’t sure either. In 1867, George Scott, a Gloucester wine merchant, wrote to George Biddell Airy, the Astronomer Royal, for help against Parallax’s onslaught, complaining that “I do not for one moment believe that he believes his own theory.” But personal faith turns out to have been less persuasive than the ability to show up pompous experts: “Unfortunately in Leeds he has got many converts — and amongst people one would least expect.”