Note 268 — Chapter I

The stadium comprised six hundred feet, but the length of the Greek foot is uncertain; indeed, there were at least two varieties, the Olympic and the Attic, as in Egypt there was a royal and a common ell, and a much larger number of supposititious feet (and, consequently, stadia) have been discovered or invented by metrologists. Early French scholars, like Ramé de l’Isle, D’Anville, Gosselin, supposed the true length of the earth’s circumference to be known to the Greeks, and held that all the estimates which have come down to us were expressions of the same value in different stadia. It is now generally agreed that these estimates really denote different conceptions of the size of the earth, but opinions still differ widely as to the length of the stadium used by the geographers. The value selected by Peschel (Geschichte der Erdkunde, 2d ed., p. 46) is that likewise adopted by Hultsch (Griechische und Römische Metrologie, 2d ed., 1882) and Muellenhof (Deutsche Alterthumskunde, 2d ed., vol. i.). According to these writers, Eratosthenes is supposed to have devised as a standard geographical measure a stadium composed of feet equal to one half the royal Egyptian ell. According to Pliny (Hist. Nat., xii. 14, § 5), Eratosthenes allowed forty stadia to the Egyptian schonus; if we reckon the schonus at 12,000 royal ells, we have stadium = 12,000/40 × .525m = 157.5m. This would give a degree equal to 110,250m, the true value being, according to Peschel, 110,808m. To this conclusion Lepsius (Das Stadium und die Gradmessung des Eratosthenes auf Grundlage der Aegyptischen Masse, in Zeitschrift für Aegypt. Sprache u. Alterthumskunde, xv. [1877]. See also Die Längenmasse der Alten. Berlin, 1884) objects that the royal ell was never used in composition, and that the schonus was valued in different parts of Egypt at 12,000, 16,000, 24,000, small ells. He believes that the schonus referred to by Pliny contained 16,000 small ells, so that Eratosthenes’s stadium = 16,000/40 × .450m = 180m.