On Architecture

5. There is also a kind of cold water containing natron, found for instance at Penne in the Vestine country, at Cutiliae, and at other similar places. It is taken as a purge and in passing through the bowels reduces scrofulous tumours. Copious springs are found where there are mines of gold, silver, iron, copper, lead, and the like, but they are very harmful. For they contain, like hot springs, sulphur, alum, asphalt, . . . and when it passes into the body in the form of drink, and spreading through the veins reaches the sinews and joints, it expands and hardens them. Hence the sinews, swelling with this expansion, are contracted in length and so give men the cramp or the gout, for the reason that their veins are saturated with very hard, dense, and cold substances.

6. There is also a sort of water which, since it contains . . . that are not perfectly clear, and it floats like a flower on the surface, in colour like purple glass. This may be seen particularly in Athens, where there are aqueducts from places and springs of that sort leading to the city and the port of Piraeus, from which nobody drinks, for the reason mentioned, but they use them for bathing and so forth, and drink from wells, thus avoiding their unwholesomeness. At Troezen it cannot be avoided, because no other kind of water at all is found, except what the Cibdeli furnish, and so in that city all or most of the people have diseases of the feet. At the city of Tarsus in Cilicia is a river named Cydnus, in which gouty people soak their legs and find relief from pain.