Proving the curvature of the earth on the Old Bedford River, Chris Howes explores!
From the secure perspective of the 21st Century we all know which camp we belong to, Zetetics or Globularists. No longer do heated arguments rage in the Pub over whether the Earth is flat (Zetetic) or round (Globularist). However in the 19th Century this important concern was a hot subject for debate. Thanks to its straightness the Old Bedford River became the proving ground for the counter arguments.
In 1838 Samuel Rowbotham endeavoured to prove the earth flat by making observation along the 6 mile straight above Welney. Using a telescope he observed barges six miles away. Samuel argued that if the earth was round (as some scientists then argued) the barges would only be visible for 3 miles before they disappeared from sight as a result of the curvature of the Earth. As he could still make the barges out that were 6 miles distant, ipso facto there was no curve.
We now understand that Rowbotham’s apparent ability to see further than the expected 3 miles was caused by the phenomenon of the refraction (bending) of light over water.
This apparent ‘proof’ stood unchallenged until 1870 when Alfred Russel Wallace, inspired to renewed scientific scrutiny by Charles Darwin’s work on evolution, conducted a further experiment on the Old Bedford River. Three barges, each with a pole of identical length erected on them, were moored at two mile intervals. If the earth was flat, the tops of the three rods would line up when observed through a telescope. However the second marker was a clear 32 inches above a line between the first and third markers, proving, quod erat demonstrandum, the curvature of the Earth.
Remarkably, when these measurements were employed to calculate the diameter of the earth, a figure of 7,920 miles was achieved. We now believe, with the benefits of modern scientific instrumentation, that the diameter of the earth at the equator is 7,926 miles !
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