11.

In like manner, that the voyage from Amisus to Colchis, and the route to the Caspian, and thence on to Bactra, are both due east, is proved by the winds, the seasons, the fruits, and even the sun-risings. Frequently evidence such as this, and general agreement, are more to be relied on than the measurement taken by means of instruments. Hipparchus himself was not wholly indebted to instruments and geometrical calculations for his statement that the Pillars and Cilicia lie in a direct line due east. For that part of it included between the Pillars and the Strait of Sicily he rests entirely on the assertion of sailors. It is therefore incorrect to say that, because we cannot exactly determine the duration of the longest and shortest days, nor the degree of shadow of the gnomon throughout the mountainous region between Cilicia and India, that therefore we are unable to decide whether the line traced obliquely on the ancient charts should or should not be parallel, and consequently must leave it unreformed, keeping it oblique as the ancient charts have it. For in the first place, not to determine any thing is to leave it undetermined; and to leave a thing undetermined, is neither to take one view of the matter nor the other: but to agree to leave it as the ancients have, that is to take a view of the case. It would have been more consistent with his reasoning, if he had told us to leave Geography alone altogether, since we are similarly unable to determine the position of the Alps, the Pyrenees, and the mountains of Thrace,495 Illyria,496 and Germany. Wherefore should we give more credit to the ancient writers than to the modern, when we call to mind the numerous errors of their charts which have been pointed out by Eratosthenes, and which Hipparchus has not attempted to defend.