XXVI
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To prove my point I might have used, somewhat unfairly perhaps, the authority of the great writers who relate that Egypt never experienced an earthquake shock, the reason they allege for it being that it is all composed of mud. If one may believe Homer, Pharos used to be as far from the mainland as a ship under full sail could reach in a day’s voyage; but it has now become attached to the mainland. The Nile’s swollen stream brings down great quantities of mud, and by adding it from time to time to the existing land it has by an annual increase constantly carried forward the coast of Egypt. The country thus is composed of rich loamy soil without interstices, as it has become solid just by the drying up of the mud. The composition of the mud was close and firm, the particles of it being stuck together; no vacant space could intervene, since the solid was always being added to by the liquid and soft slime. But Egypt is, as a matter of fact, subject to earthquake; and Delos, too, though Virgil bade it stand fast,
And granted that it should be a settled land of tillage, and should laugh the winds to scorn.
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The philosophers, too, a credulous set of people, relying on Pindar’s authority, said that it did not experience movement. Thucydides asserts that in former times it was unshaken, but sustained a shock about the time of the Peloponnesian War. Callisthenes asserts that the same thing happened on another occasion also. Among the numerous portents—these are his words—by which warning was given of the overthrow of the two cities Helice and Buris, the most remarkable were the appearance of a huge pillar of fire and the earthquake shock in Delos. Yet he will have it that the island is comparatively firm for the reason that it is placed on the sea and has hollow crags and porous rocks, which afford a way of escape to air imprisoned in them. For this reason, too, islands have, he thinks, a firmer soil, and cities are safer in proportion to their proximity to the sea. The falsity of such an opinion surely Pompeii and Herculaneum learned to their cost. Add now the fact that every sea-coast is particularly subject to earthquakes. Paphos, for instance, was more than once ruined, and the famous Nicopolis is already intimately acquainted with this mischief. Cyprus is surrounded by a deep sea, but is subject to shocks. Tyre is as regularly shaken by earthquake as it is washed by the waves. Such, then, are for the most part the explanations that have been suggested for the trembling of the earth.