Message #20000

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STRABO - Book III Chapter 5




7.   Polybius says that there is a spring in the Heracleium170 at Gades, with a descent of only a few steps to the water (which is good to drink), and that the spring behaves inversely to the flux and reflux of the sea, since it fails at the time of the flood-tides and fills up at the time of the ebb-tides. And he alleges as the cause of this that the air p145which is expelled from the depths of the earth to the surface, if the surface be covered by the waters at the time of the overflows of the sea, is shut off from its proper exit there, and turning back into the interior blocks up the passages of the spring and thus causes a failure of water, whereas if the surface be bared of waters again the air passes straight forward and thus sets free the veins of the spring, so that it gushes forth abundantly. As for Artemidorus, although he speaks out against Polybius and at the same time puts forth a cause of his own, and also recalls the opinion of Silanus the historian, he does not seem to me to have stated anything worth recording, since both he himself and Silanus are, you might say, laymen with respect to these matters. But Poseidonius, although he calls the story of this spring false, says that there are two wells171 in the Heracleium and a third in the city; and, of the two wells in the Heracleium, if you draw water continuously from the smaller it actually fails in the same hour, and if you leave off drawing the water, it fills up again; whereas you may draw water all day long from the larger (though it is diminished thereby, of course, just as all other wells are), and it fills up by night if you no longer draw from it, but since the ebb-tide often occurs at the particular time of the well's fullness, the natives have believed anew in the inverse-behaviour. Now not only has Poseidonius told us that the story has been believed, but I too, since it is told over and over again among the paradoxes,172 have been taught the story. And I p147have been hearing that there are still other wells, some in the gardens in front of the city, and others within the city, but that on account of the impurity of the water reservoirs of cistern-water are prevalent in the city. Whether, however, any of these wells proves the truth of the supposition of the inverse-behaviour, I do not know. But as for the causes alleged — if it be true that the case is as reported — we should, regarding the problem as a difficult one, welcome them. For it is reasonable to suppose that the cause is what Polybius says it is; and it is reasonable to suppose also that some of the veins of the spring, if soaked from the outside, become relaxed and thus afford their water an outflow at the sides, instead of forcing it up along the old channel into the spring (the veins are necessarily soaked when the tidal wave has washed over the land). Yet if, as Artemidorus says, the case with the flood-tides and with the ebb-tides is like inhalation and exhalation,173 then, of the flowing waters, he says, there might be some which by certain passages (whose mouths, of course, we call fountains or springs) naturally have their outflow to the surface, and by certain other passages are drawn in together to the depths of the sea; that is, in helping raise the sea174 to flood-tide when the exhalation, as it were, takes place, they abandon their proper channel, and then retreat to their proper channel again when the sea itself takes its retreat.