Samuel Birley Rowbotham (1816–1884) was an English inventor and writer who wrote Zetetic Astronomy: Earth Not a Globe under the pseudonym "Parallax". His work was based on his decade-long studies of the earth and was originally published as a 16-page pamphlet (1849), which he later expanded into a 430 page book (1881). According to Rowbotham's method, which he called Zetetic Astronomy, the earth is a flat disk centered at the North Pole and bounded along its southern edge by a wall of ice, with the sun, moon, planets, and stars only a few hundred miles above the surface of the earth.
Rowbotham started out as an organiser of an Owenite commune in the Fens, where he first observed the strange phenomenon on the Bedford level that led to his theories about the earth. Following several false allegations of sexual misconduct he reinvented himself as a itinerant lecturer under the name Parallax. He took a little time to learn his trade, running away from a lecture in Blackburn, Lancashire when he couldn't explain why the hulls of ships disappeared before their masts when sailing out to sea (Flat Earth Theory was far less complete at this point). However, as he persisted in filling halls by charging sixpence a lecture his quick-wittedness and debating skills were honed so much that he could "counter every argument with ingenuity, wit and consumate skill".
When finally pinned down to a challenge in Plymouth in 1864 by allegations that he wouldn't agree to a test, Parallax appeared on Plymouth Hoe at the appointed time, witnessed by Richard Proctor, a writer on astronomy, and proceeded to the beach where a telescope had been set up. His opponents had claimed that only the lantern of the Eddystone lighthouse, some 14 miles out to sea, would be visible. They were, of course, incorrect, and so that many Plymouth folk left the Hoe agreeing that "some of the most important conclusions of modern astronomy had been seriously invalidated".
His book Zetetic Astronomy - The Earth not a Globe appeared in 1864. His lectures continued and concerned citizens addressed letters to the Astronomer Royal seeking rebuttals for his claims. None came.
One of Rowbotham's followers, John Hampden, a Christian polemicist, gained notoriety by engaging in raucous public debates with leading scientists of the day. A bet involving the prominent naturalist Alfred Russel Wallace in the famous Bedford Level experiment led to several lawsuits for libel and Hampden's imprisonment, as well as a count of fraud on Wallace's behalf, which only required him to return the money.
After Rowbotham's death, Lady Elizabeth Blount founded the Universal Zetetic Society which attracted thousands of followers, published a magazine entitled The Earth Not a Globe Review and remained active well into the early part of the 20th century. After World War I, the movement underwent a slow decline, but it was revived in 1956 as The Flat Earth Society.
In the United States, Rowbotham's ideas were taken up by the Christian Catholic Apostolic Church and promoted widely on their radio station. His work in the United States was continued by William Carpenter. Carpenter, a printer originally from Greenwich, England, a supporter of Rowbotham and published Theoretical Astronomy Examined and Exposed - Proving the Earth not a Globe in eight parts from 1864 under the name Common Sense. He later emigrated to Baltimore where he published A hundred proofs the Earth is not a Globe in 1885.