In 1838, Samuel Rowbotham waded into a drainage canal in Norfolk and sighted along its length with a telescope. Six miles away, an assistant held a flag three feet above the water. If the earth were round, its curvature should hide the flag from him. But he decided he could see it clearly. “It follows,” he wrote, “that the surface of standing water is not convex, and therefore that the Earth IS NOT A GLOBE!”

Rowbotham’s triumphant result stood until 1870, when naturalist, surveyor, and obvious crackpot Alfred Russel Wallace attempted to disprove the result. His endeavor ended only in a heated argument — and eventually a libel suit against the “planists.” (Round-earthers are clearly desperate men.)

In fairness, we must note that not all observations have agreed with Rowbotham’s. In 1896 a newspaper editor conducted a similar experiment in Illinois and discovered that the earth is concave. Clearly more work is needed.