Chapter Seven

Alan C. Bowen and Robert B. Todd

in Cleomedes' Lectures on Astronomy

Published by University of California Press

Published in print January 2004 | ISBN: 9780520233256
Published online March 2012 | e-ISBN: 9780520928510 | DOI:
Chapter Seven

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This chapter reports on Posidonius' and Eratosthenes' measurements of the circumference of the Earth. Eratosthenes' doctrine about the size of the Earth demonstrates its size by a geodesic procedure, while Posidonius' is less complicated. Each [philosopher] takes certain assumptions [as being the case], and then arrives at demonstrations via the implications of the assumptions. Eratosthenes says, and it is the case, that (E6) Syene is located below the summer tropical circle. Those who say that the Earth cannot be spherical because of the hollows occupied by the sea and the mountainous protrusions, express a quite irrational doctrine.

Keywords: Earth; Posidonius; Eratosthenes; circumference; geodesic procedure; assumptions; spherical

Chapter.  2947 words. 

Subjects: Classical Philosophy

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