8_21_2001
Ancient Measuring Well, Aswan, Egypt, 1998
"Several stories down but still sunlit, the waters of an ancient well near Aswan, Egypt, mark the arrival of the summer solstice. In the third century B.C. in Alexandria, the Greek scholar Eratosthenes relied on both geometry and reports of the sun's annual appearance almost directly over Aswan to calculate Earth's circumference, arriving at an estimate close to the actual distance. His successors put the figure at far less, giving Columbus the mistaken idea that India lay half as far from Portugal if traveling west across the Atlantic as east across land."
古代的测量井,阿斯旺,埃及,1998
这口在埃及阿斯旺附近的古井有几层楼深但仍然被阳光照射,井水标志着夏至的到来。在亚历山大公元前第三世纪,希腊学者埃拉托色尼依据几何学和每年太阳出现在阿斯旺差不多正上方的记录来计算地球的周长,估计的数字接近实际距离。他的后继者把数字估计得更小,使哥伦布得出了错误的概念,他认为如果往西穿过大西洋航行,从葡萄牙出发到达印度会比往东跨越陆地减少一半的距离。