Book 8
5.1
To these seemingly probable reasons another was added, which confirmed the ingenuity of the sailors by a very natural proof. For some said that they took up their water by night because then it was clear and undisturbed; but at daytime, when a great many fetched water together, and many boats were sailing and many beasts swimming upon the Nile, it grew thick and muddy, and in that condition it was more subject to corruption. For mixed bodies are more easily corrupted than simple and unmixed; for from mixture proceeds disagreement of the parts, from that disagreement a change, and corruption is nothing else but a certain change; and therefore painters call the mixing of their colors φθοράς, corrupting; and Homer expresseth dyeing by μιῆναι (to stain or contaminate). Commonly we call any thing that is simple and unmixed incorruptible and immortal. Now earth being mixed with water soonest corrupts its proper qualities, and makes it unfit for drinking; and therefore standing water stinks soonest, being continually filled with particles of earth, whilst running waters preserve themselves by either leaving behind or throwing off the earth that falls into them. And Hesiod justly commends The water of a pure and constant spring.Works and Days, 595. For that water is wholesome which is not corrupted, and that is not corrupted which is pure and unmixed. And this opinion is very much confirmed from the difference of earths; for those springs that run through a mountainous, rocky ground are stronger than those which are cut through plains or marshes, because they do not take off much earth. Now the Nile running through a soft country, like the blood mingled with the flesh, is filled with sweet juices that are strong and very nourishing; yet it is thick and muddy, and becomes more so if disturbed. For motion mixeth the earthly particles with the liquid, which, because they are heavier, fall to the bottom as soon as the water is still and undisturbed. Therefore the sailors take up the water they are to use at night, by that means likewise preventing the sun, which always exhales and consumes the subtler and lighter particles of the liquid.
