The modern additions to this curtain consist in a line of casemates, storehouses, canteens, magazines, and workshops, built against and concealing its inner face, and giving a rampart or platform of 30 feet width. This exterior wall has been built with great care on a broad and deep foundation, since it shows no sign of settlement, though built in what, until recently, was a deep and muddy ditch. At one part indeed, close south of Brass Mount, it has been strengthened by three very clumsy buttresses of 12 feet in breadth and 22 feet projection. One covers the internal angle of the bastion; the next is about 40 feet distant; and the third, at about the same space, is in fact a rectangular mural tower resembling Galleyman, and contains a small chamber having two loops on each of its three free faces. Its parapet is new, and pierced for two guns. Middle Tower is the outwork of Byward Tower, and a barbican covering the landward entrance to the fortress. It stands on the counterscarp of the ditch, at the outer end of the bridge, and was originally enveloped by a special ditch of its own, a loop from the main ditch of the place, filled up in the eighteenth century. In design and execution it resembles closely Byward Tower, though rather smaller, its breadth being 40 feet, and its height 30 feet from the roadway. It is evidently of the date of Byward, and like it was open at the rear. It also has been cased with Portland stone. Its portal has a double portcullis, gateway, vertical holes, side loops and lodges, and its central part is ceiled with timber. In neither tower is there now any trace of a drawbridge. The lodges are tolerably perfect; the stair in the north-east angle is in use, and corresponds to the Byward oratory; and in the south-east turret is a lobby and a garderobe, and above these a chamber 7 feet by 8 feet 6 inches, and again on the leads another chamber 7 feet 4 inches by 10 feet 10 inches. [Illustration: MIDDLE TOWER.—FIRST FLOOR.] Between the two gatehouses the ditch is traversed by a stone bridge, 130 feet long, and at the narrowest 20 feet wide. As the towers are not precisely opposite, the line of the bridge is broken by a slight zigzag. In the centre appears to have been an opening of 20 feet, now a stone arch, once the place of a drawbridge, as shown in old drawings. The Quay does not appear to have had any permanent parapet wall, which indeed would have interfered with its uses. It was sufficiently commanded by the defences of the outer ward. It was probably the work of Henry III., in the twelfth of whose reign it is first mentioned, and called “Kaia Regis”; and John de Crumbwell, custos 8–9 Edward III., had then an order for 300 alder poles from Windsor forest for repairing it. The quay is in length about 1,130 feet, that being the full frontage of the Tower.