‹‹‹ Vitr. 1.4.10 | Table of Contents | Vitr. 1.4.12 ›››
11When, therefore, a city is built in a marshy situation near the sea-coast, with a northern, north-eastern, or eastern aspect, on a marsh whose level is higher than the shore of the sea, the site is not altogether improper; for by means of sewers the waters may be discharged into the sea: and at those times, when violently agitated by storms, the sea swells and runs up the sewers, it mixes with the water of the marsh, and prevents the generation of marshy insects; it also soon destroys such as are passing from the higher level, by the saltness of its water to which they are unaccustomed. An instance of this kind occurs in the Gallic marshes about Altinum, Ravenna, and Aquileia, and other places in Cisalpine Gaul, near marshes which, for the reasons above named, are remarkably healthy.
11If the walled town is built among the marshes themselves, provided they are by the sea, with a northern or north-eastern exposure, and are above the level of the seashore, the site will be reasonable enough. For ditches can be dug to let out the water to the shore, and also in times of storms the sea swells and comes backing up into the marshes, where its bitter blend prevents the reproductions of the usual marsh creatures, while any that swim down from the higher levels to the shore are killed at once by the saltness to which they are unused. An instance of this may be found in the Gallic marshes surrounding Altino, Ravenna, Aquileia, and other towns in places of the kind, close by marshes. They are marvellously healthy, for the reasons which I have given.