The Outer Terrace.
Τὸ ἔξω παρατείχιον.[[202]]

The embankment or terrace between the Outer Wall and the Moat is some 61 feet broad. While affording room for the action of troops under cover of the battlement upon the scarp of the Moat,[[203]] its chief function was to widen the distance between the besiegers and the besieged.

The Moat.
Τάφρος: σοῦδα.[[204]]

The Moat is over 61 feet wide. Its original depth, which doubtless varied with the character of the ground it traversed, cannot be determined until excavations are allowed, for the market-gardens and débris which now occupy it have raised the level of the bed. In front of the Golden Gate, where it was probably always deepest, on account of the importance of that entrance, its depth is still 22 feet. The masonry of the scarp and counterscarp is 5 feet thick, and was supported by buttresses to withstand the pressure of the elevated ground on either side of the Moat. The battlement upon the scarp formed a breastwork about 6-½ feet high.

At several points along its course the Moat is crossed by low walls, dividing it into so many sections or compartments. They are generally opposite a tower of the Outer or Inner Wall, and taper from the base to a sharp edge along the summit, to prevent their being used as bridges by an enemy. On their southern side, where the ground falls away, they are supported by buttresses.

Dr. Paspates[[205]] was the first to call attention to these structures, and to him, also, belongs the credit of having thrown some light upon their use. They were, in his opinion, aqueducts, and dams or batardeaux, by means of which water was conveyed to the Moat, and kept in position there. But this service, Dr. Paspates believed, was performed by them only in case of a siege, when they were broken open, and allowed to run into the Moat. At other times, when no hostile attack was apprehended, they carried water across the Moat into the city, for the supply of the ordinary needs of the population.

That many of these structures, if not all, were aqueducts admits of no doubt, for some have been found to contain earthenware water-pipes, while others of them still carry into the city water brought by underground conduits from the hills on the west of the fortifications; and that they were dams seems the only explanation of the buttresses built against their lower side, as though to resist the pressure of water descending from a higher level.

Aqueduct Across the Moat of the Theodosian Walls.