not even flat — found a 1897 Florida cult that 'proved' we live INSIDE a hollow sphere

For variety since everyone here does flat-disc: there was a Florida cult that ran a real field experiment to prove earth is CONCAVE and we live on the inside. Found it linked off a hollow-earth wiki, had to double check it wasn't satire. It's not. Cyrus Teed, called himself Koresh (no relation to t……