H e rodotus, equally oblivious of the sphere, criticized and Herodotus rid i culed the circular outline of the oekumene, which he knew to be longer from east to west than it was broad from north to south.
While the theory of the sphere was being elaborated the efforts of practical geographers were steadily directed towards ascertaining the outline and configuration of the oekumene, or habitable F i tting the world, the only portion of the terrestrial surface known oekumene to the ancients and to the medieval peoples, and still to the retaining a shadow of its old monopoly of geographical sphere.
The fitting of the oekumene to the sphere was the second theoretical problem.
Pythagoras had speculated as to the existence of antipodes, but it was not until the first approximately accurate measurements of the globe and estimates of the length and breadth of the Problem oekumene were made by Eratosthenes (c. 250 B.C.) that of the the fact that, as then known, it occupied less than a quarter Antipodes.
The old instinctive idea of symmetry must often have suggested other oekumene balancing the known world in the other quarters of the globe.
The Stoic philosophers, especially Crates of Mallus, arguing from the love of nature for life, placed an oekumene in each quarter of the sphere, the three unknown worldislands being those of the Antoeci, Perioeci and Antipodes.
It was the ambition of Ptolemy to describe and represent accurately the surface of the oekumene, for which purpose he took immense trouble to collect all existing determinations of the latitude of places, all estimates of longitude, and to make every possible rectification in the estimates of distances by land or sea.
The symmetrically placed hypothetical islands in the great continuousocean disappeared, and the oekumene acquired a new form by the representation of the Indian Ocean as a larger Mediterranean completely cut off by land from the Atlantic. The terra incognita uniting Africa and Farther Asia was an unfortunate hypothesis which helped to retard exploration.
Ptolemy used the word geography to signify the description of the whole oekumene on mathematical principles, while chorography signified the fuller description of a particular region, and topography the very detailed description of a smaller locality.