132 STRABO. BOOK ii. To this we reply, that the line drawn from Babylon to Car- mania was never intended as a parallel, nor yet that which divides the two sections as a meridian, and that therefore no- thing has been laid to his charge, at all events with any just foundation. In fact, Eratosthenes having stated the number of stadia from the Caspian Gates to Babylon as above given, 1 [from the Caspian Gates] to Susa 4900 stadia, and from Babylon [to Susa] 3400 stadia, Hipparchus runs away from his former hypothesis, and says that [by draw- ing lines from] the Caspian Gates, Susa, and Babylon, an -obtuse-angled triangle would be the result, whose sides should be of the length laid down, and of which Susa would form the obtuse angle. He then argues, that "accord- ing to these premises, the meridian drawn from the Gates of the Caspian will intersect the parallel of Babylon and Susa 4400 stadia more to the west, than would a straight line drawn from the Caspian to the confines of Carmania and Persia ; and that this last line, forming with the meridian of the Caspian Gates half a right angle, would lie exactly in a direction midway between the south and the equinoctial rising. Now as the course of the Indus is parallel to this line, it cannot flow south on its descent from the mountains, as Eratosthenes asserts, but in a direction lying between the south and the equinoctial rising, as laid down in the ancient charts." But who is there who will admit this to be an ob- tuse-angled triangle, without also admitting that it contains a right angle ? Who will agree that the line from Babylon to Susa, which forms one side of this obtuse-angled triangle, lies parallel, without admitting the same of the whole line as far as Carmania ? or that the line drawn from the Caspian Gates to the frontiers of Carmania is parallel to the Indus ? Never- theless, without this the reasoning [of Hipparchus] is worth nothing. " Eratosthenes himself also states," [continues Hipparchus, 2 ] The frontiers of Carmania would thus be east of the Caspian Gates, and Persia would consequently be comprised, not in the third, but in the second section of Eratosthenes, being east of the meridian of the Caspian Gates, which was the boundary of the two sections." Strabo, in the text, points out the falsity of this argument. 1 Viz. 6700 stadia. 2 These two words, continues Hipparchus, are not in the text, but the ar- gument is undoubtedly his.
