Greek Texts & Translations

the inference would be just. ^note For then the line [from the common frontier of Carmania and Persia] to Babylon if produced to the meridian of Thapsacus, would appear to the eye equal, or nearly equal, to that from the Caspian Gates to Thapsacus. Consequently, Babylon would only be east of Thapsacus in the same proportion as the line drawn from the Caspian Gates to Thapsacus exceeds the line drawn from the frontier of Carmania to Babylon. ^note Eratosthenes, however, does not tell us that the line which bounds the western coast of Ariana follows the direction of the meridian; nor yet that a line drawn from the Caspian Gates to Thapsacus would form right angles with the meridian of the Caspian Gates. But rather, that the line which would form right angles with the meridian, would be one which should follow the course of the Taurus, and with which the line drawn from the Caspian Gates to Thapsacus would form an acute angle. Nor, again, does he ever say that a line drawn from Carmania to Babylon would be parallel to that drawn [from the Caspian Gates] to Thapsacus; and even if it were parallel, this would prove nothing for the argument of Hipparchus, since it does not form right angles with the meridian of the Caspian Gates. 29

But taking this for granted, and proving, as he imagines, that, according to Eratosthenes, Babylon is east of Thapsacus rather more than 1000 stadia, he draws from this false hypothesis a new argument, which he uses to the following purpose; and says, If we suppose a right line drawn from Thapsacus towards the south, and another from Babylon perpendicular thereto, a right-angled triangle would be the result; whose sides should be, 1. A line drawn from Thapsacus to Babylon; 2. A perpendicular drawn from Babylon to the meridian of Thapsacus; 3. The meridian line of Thapsacus. The hypotenuse of this triangle would be a right line drawn from Thapsacus to Babylon, which he estimates at 4800 stadia. The perpendicular drawn from Babylon to the meridian of Thapsacus is scarcely more than 1000 stadia; the same amount by which the line drawn [from the Caspian Gates] to