Eratosthenes

Eratosthenes OF CYRENE, born 276 B.C., was an eminent mathematician, astronomer, and geographer. Among his teachers were Lysanias the grammarian and Callimachus the poet. By Ptolemy Energetes he was called to Alexandria to superintend his great library. Here he died of voluntary starvation, at the age of eighty, having become blind, and wearied of life. Eratosthenes measured the obliquity of the ecliptic with an accuracy wonderful for his time, drew up a catalogue of the fixed stars, amounting to 675, which is now lost, and made an attempt to measure the magnitude of the earth in the method used at the present day. He found the circumference of the earth to be 252,000 stadia, which, according to Pliny, is 31,500 Roman miles. His most important work was a systematic treatise on geography, which was used by Strabo. He wrote also on moral philosophy, history, and grammar. Such fragments of his writings as are still extant have been collected by Bernhardy in his Eratosthenica (Berlin, 1822). See also Berger, Die geographischen Fragmente des Eratosthenes (Leip. 1880).