The Geography of Strabo, Volume 1 (of 3)

under the same parallel of latitude as Athens, (which is the opinion of Eratosthenes,) but many thousand stadia to the north, as the data supplied by that writer himself prove.

But here, for the formation of his right-angled triangle, Hipparchus not only makes use of propositions already overturned, but assumes what was never granted, namely, that the hypotenuse subtending his right angle, which is the straight line from Thapsacus to Babylon, is 4800 stadia in length. What Eratosthenes says is, that this route follows the course of the Euphrates, and adds, that Mesopotamia and Babylon are encompassed as it were by a great circle formed by the Euphrates and Tigris, but principally by the former of these rivers. So that a straight line from Thapsacus to Babylon would neither follow the course of the Euphrates, nor yet be near so many stadia in length. Thus the argument [of Hipparchus] is overturned. We have stated before, that supposing two lines drawn from the Caspian Gates, one to Thapsacus, and the other to the mountains of Armenia opposite Thapsacus, and distant therefrom, according to Hipparchus’s own estimate, 2100 stadia at the very least, neither of them would be parallel to each other, nor yet to that line which, passing through Babylon, is styled by Eratosthenes the southern side [of the third section]. As he could not inform us of the exact length of the route by the mountains, Eratosthenes tells us the distance between Thapsacus and the Caspian Gates; in fact, to speak in a general way, he puts this distance in place of the other; besides, as he merely wanted to give the length of the territory between Ariana and the Euphrates, he was not particular to have the exact measure of either route. To pretend that he considered the lines to be parallel to each other, is evidently to accuse the man of more than childish ignorance, and we dismiss the insinuation as nonsense forthwith.

30. There, however, are some instances in which one may justly accuse Eratosthenes. There is a difference in dissecting limb by limb, or merely cutting off portions [indiscriminately], (for in the former you may only separate parts having a natural outline, and distinguished by a regular form; this the poet alludes to in the expression,

“Cutting them limb from limb;”[571]

whereas in regard to the latter this is not the case,) and we may adopt with propriety either one or other of these plans according to the time and necessity. So in Geography, if you enter into every detail, you may sometimes be compelled to divide your territories into portions, so to speak, but it is a more preferable way to separate them into limbs, than into such chance pieces; for thus only you can define accurately particular points and boundaries, a thing so necessary to the geographer. When it can be done, the best way to define a country is by the rivers, mountains, or sea; also, where possible, by the nation or nations [who inhabit it], and by its size and configuration. However, in default of a geometrical definition, a simple and general description may be said always to answer the purpose. In regard to size, it is sufficient to state the greatest length and breadth; for example, that the habitable earth is 70,000 stadia long, and that its breadth is scarcely half its length.[572] And as to form, to compare a country to any geometrical or other well-known figure. For example, Sicily to a triangle, Spain to an ox-hide, or the Peloponnesus to a plane-leaf.[573] The larger the territory to be divided, the more general also ought its divisions to be.