134 STRABO. BOOK ii. tosthenes has committed either serious or slight errors, for on one hand what he may have said concerning such great dis- tances, can never be verified by a geometrical test, and on the other, his accuser, while endeavouring to reason like a geometrician, does not found his arguments on any real data, but on gratuitous suppositions. 36. The fourth section Hipparchus certainly manages better, though he still maintains the same censorious tone, and obstinacy in sticking to his first hypotheses, or others similar. He properly objects to Eratosthenes giving as the length of this section a line drawn from Thapsacus to Egypt, as being similar to the case of a man who should tell us that the diagonal of a parallelogram was its length. For Thap- sacus and the coasts of Egypt are by no means under the same parallel of latitude, but under parallels considerably distant from each other, 1 and a line drawn from Thapsacus to Egypt would lie in a kind of diagonal or oblique direction between them. But he is wrong when he expresses his sur- prise that Eratosthenes should dare to state the distance be- tween Pelusium and Thapsacus at 6000 stadia, when he says there are above 8000. In proof of this he advances that the parallel of Pelusium is south of that of Babylon by more than 2500 stadia, and that according to Eratosthenes (as he supposes) the latitude of Thapsacus is above 4800 stadia north of that of Babylon ; from which Hipparchus tells us it results that [between Thapsacus and Pelusium] there are more than 8000 stadia. But I would inquire how he can prove that Eratosthenes supposed so great a distance between the pa- rallels of Babylon and Thapsacus ? He says, indeed, that such is the distance from Thapsacus to Babylon, but not that there is this distance between their parallels, nor yet that Thapsacus and Babylon are under the same meridian. So much the contrary, that Hipparchus has himself pointed out, that, accord- ing to Eratosthenes, Babylon ought to be east of Thapsacus more than 2000 stadia. We have before cited the statement of Eratosthenes, that Mesopotamia and Babylon are encircled by the Tigris and Euphrates, and that the greater portion of the Circle is formed by this latter river, which flowing north and south takes a turn to the east, and then, returning to a 1 The difference of latitude between Thapsacus and Pelusium is about 4 27'.
