Of all the ancient writings which deal with such questions, the Hebrew Scriptures have the greatest antiquity, and in them are laid down many details of known countries, from which a fair map of the world as known to them might be made out. The prophet Esdras believed that six-sevenths of the earth was dry land--an idea which could not well be exploded till the great oceans had been traversed and America discovered. More interesting, as being more complete, and written to a certain extent for the very purpose of relating what was known of the geography of the earth, are the writings of the oldest Grecian poets. The first elements of Grecian geography are contained in the two national and almost sacred poems, the _Iliad_ and _Odyssey_. So important have these writings been considered in regard to ancient geography, that for many centuries discussions have been carried on with regard to the details, though evidently fictitious, of the voyage of Ulysses, and twenty lines of the _Iliad_ have furnished matter for a book of thirty volumes. The shield of Achilles, forged by Vulcan and described in the eighteenth book of the _Iliad_, gives us an authentic representation of the primitive cosmographical ideas of the age. The earth is there figured as a disc, surrounded on all sides by the _River Ocean_. However strange it may appear to us, to apply the term _river_ to the ocean, it occurs too often in Homer and the other ancient poets to admit of a doubt of its being literally understood by them. Hesiod even describes the sources of the ocean at the western extremity of the world, and the representation of these sources was preserved from age to age amongst authors posterior to Homer by nearly a thousand years. Herodotus says plainly that the geographers of his time drew their maps of the world according to the same ideas; the earth was figured with them as a round disc, and the ocean as a river, which washed it on all sides.