Firmament dossier · Pioneers · 3 min read
Samuel Rowbotham and Zetetic Astronomy
The Bedford canal, 1838: the boat that didn't disappear
The full text of this study is in Portuguese; the summary, key points and official view are in English.
In 1838, the Englishman Samuel Birley Rowbotham waded into the Old Bedford Level, a straight canal about ten kilometres long in the Cambridgeshire fens, and, with a telescope a few centimetres above the water, watched a boat with a flag move away to the end of the stretch. According to him, the boat stayed visible the whole time, which would be impossible if the water curved. Under the pseudonym “Parallax”, Rowbotham turned the experiment into a method, Zetetic Astronomy (from zētéō, “to investigate”), and into a book, Earth Not a Globe, which founded the modern flat Earth movement.
Key points
- Samuel Birley Rowbotham (1816–1884) published the pamphlet Zetetic Astronomy in 1849 and the book Earth Not a Globe in 1865 (expanded in 1873 and 1881).
- The stretch of canal between Welney and Old Bedford Bridge runs about 6 miles (9.7 km) in a straight line.
- By the globe calculation, a target at water level 9.7 km away would be about 7 metres below the line of sight of an observer close to the water.
- Rowbotham advocated investigating only through the senses and experience, without accepting ready-made theories.
- After his death, Lady Elizabeth Blount founded the Universal Zetetic Society (1893).
What the official version says
For physicists, the 1838 experiment was done close to the water, where atmospheric refraction is strong and variable: cold air over water bends light rays and can “lift” distant objects. Repetitions with a higher line of sight, such as Alfred Russel Wallace’s in 1870 and Henry Yule Oldham’s in 1901, recorded the expected curvature.
Keep investigating
- The 1870 wager: Hampden versus Wallace Five hundred pounds, three markers and a feud that lasted years
- Horizon, perspective and the boat that comes back with zoom What eyes and cameras show at a distance
- Water always finds its level Lakes, canals and the movement's simplest question
Other languages: Português · Español
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