15. The form of these gardens was square; and, according to Diodorus and Strabo, each side was four hundred feet in length, so that the area of the base was nearly four acres. They were made to rise with terraces constructed in a curious manner above one another, in the form of steps, and were supported by stone pillars to the height of more than three hundred feet, gradually diminishing upwards till the area of the superior surface, which was flat, was reduced considerably below that of the base. This building was constructed by vast, stone beams placed on pillars of stone (arches not being then invented), which were again covered with reeds, cemented with bitumen, over which was placed a double row of bricks united by cement. These bricks were covered with plates of lead, which effectually prevented the moisture from penetrating downwards. Above all was laid a coat of earth, of depth sufficient for plants to grow in it; and the trees planted there were of various kinds, and were ranged in rows on the side of the ascent, as well as on the top, so that at a distance it appeared as an immense pyramid covered with wood. The situation of this extraordinary effort of human skill, aided by wealth, was nearly adjoining to, or upon, the river Euphrates, from which water was supplied by machinery for the fountains and reservoirs employed for cooling the air and watering the garden. Dr. Falconer's Historical View of the Gardens of Antiquity, p. 17.)
