Page:Arrian's Voyage Round the Euxine Sea Translated.djvu/171

170 and Rhodes to be no more than 3750 tadia, and taking this interval to be (what it is not) a forty-eighth part of the earth's circumference, he reduced his computation to 180,000 tadia ; and this meaure, in which the number of degrees aigned by Poidonius, and the number of tadia meaured by Eratothenes, are made ue of, was received by Marinus of Tyre, and others, and is generally acribed to Ptolemy, becaue he makes ue of it in his geography.

Beides, Eratothenes, who lived during the interval between Aritotle and Poiidonius, and 123. years later than Aritotle, had concluded the circumference of the earth to- be 250,000 tadia; or, as mot account it, 252,000 tadia, from an obervation of the ditance between Syene and Alexandria, and the repective meridian altitude of the fun at each place.