Flat Earth: The History of an Infamous Idea
by Christine Garwood
Macmillan ₤20, 400 pages
FT bookshop price: ₤16

Flat-earthers are round (if they will forgive the word) the bend. As Christine Garwood points out in her wonderful Flat Earth, it wasn’t Columbus’s Atlantic expedition which made people realise the world was spherical. Pythagoras and his school are credited as the first to make this observation in the 6th century BC. Aristotle may have thought that the earth was at the centre of the universe but he at least came up with proof that it was curved: the hull of a ship on the horizon sinks out of sight before the mast. So when ”Parallax”, one of the aliases used by snake-oil salesman Samuel Rowbotham, began to propound his flat-earth ideas in the 19th century, he was pushing back the clock by a good two millennia.

The flat world of this Extreme Creationist was rather like a map with the North Pole at its centre. The northern hemisphere was spread around it in the normal way, but the southern hemisphere was spread out even more round that. The South Pole was not a single point but a vast, impenetrable barrier of ice encircling the entire map. Above this stationary disc stretched the canopy of the heavens. Beneath that the sun and moon roamed at a height of a few hundred miles. Hell, naturally, lay below. A disciple of Rowbotham later added the refinement of Atlantis being under the North Pole, which had an entrance for flying saucers.

Flat-earthers occasionally set up experiments to challenge ”globularists”. A telescope at one end of a six-mile straight canal in East Anglia showed that the other end was lower than the middle, which would seem to support the curvature hypothesis - but not to flat-heads, who complained that the experiment wasn’t a level playing field. They would agree with those who now assert that there is no such thing as global warming. How could there be? There’s no globe.

Garwood has produced an intriguing chronicle of 150 years of self-delusion, from Parallax in the mid-19th century to the late 20th century’s Charles Johnson, who pushed membership of the International Flat Earth Society of America well into triple figures. Garwood has a doctorate in the history of science but here shows that non-science has its charms. Instead of dishing out the ridicule which these fundamentalists invite, she remains dispassionate and understanding. Level-headed, in fact.