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 I cannot tell how it is that Posidonius, who describes the Phœnicians as sagacious in other things, should here attribute to them folly rather than shrewdness. The sun completes his revolution in the space of a day and night, being a portion of the time beneath the earth, and a portion of the time shining upon it. Now he asserts that the motion of the sea corresponds with the revolution of the heavenly bodies, and experiences a diurnal, monthly, and annual change, in strict accordance with the changes of the moon. For [he continues] when the moon is elevated one sign of the zodiac1 above the horizon, the sea begins sensibly to swell and cover the shores, until she has attained her meridian; but when that satellite begins to decline, the sea again retires by degrees, until the moon wants merely one sign of the zodiac from setting; it then remains stationary until the moon has set, and also descended one sign of the zodiac below the horizon, when it again rises until she has attained her meridian below the earth; it then retires again until the moon is within one sign of the zodiac of her rising above the horizon, when it remains stationary until the moon has risen one sign of the zodiac above the earth, and then begins to rise as before. Such he describes to be the diurnal revolution. In respect to the monthly revolution, [he says] that the spring-tides occur at the time of the new moon, when they decrease until the first quarter; they then increase until full moon, when they again decrease until the last quarter, after which they increase till the new moon; [he adds] that these increases ought to be understood both of their duration and speed. In regard to the annual revolution, he says that he learned from the statements of the Gaditanians, that both the ebb and flow tides were at their extremes at the summer solstice: and that hence he conjectured that they decreased until the [autumnal] equinox; then increased till the winter solstice; then decreased again until the vernal equinox; and [finally] increased until the summer solstice. But since these revolutions occur twice in the four-and-twenty hours, the sea rising twice and receding twice, and that regularly every day and night, how is it that the filling and failing of the well do not frequently occur during the ebb and flow of the tide? or if it be allowed that this does often occur, why does it not do so in the same proportion? and if it does so in the same proportion, how comes it that the Gaditanians are not competent to observe what is of daily occurrence, while they are nevertheless competent to the observing of revolutions which occur but once in the year. That Posidonius himself credited these reports is evident from his own conjecture respecting the decrease and increase [of the sea] from solstice to solstice. However, it is not likely, being an observant people, that they should be ignorant of what actually occurred, whilst giving credit to imaginary phenomena.
1 Thirty degrees.
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