Some 300 years after Pythagoras wrote about Earth being round, another Greek, Eratosthenes, calculated the Earth’s radius. He used the distance between two cities and the angle of the sun’s rays made at midsummer at noon. His measurement turned out to be 15 percent too large, but still impressive, considering it was done over 2600 years ago. Auðvitað trúði honum enginn og þetta var bara bölvað bull og þvaður. http://www.pa.msu.edu/sciencet/ask_st/071592.html