The loops of the basement are seen to open just below those, now windows, of the second stage. The openings of the third stage, once probably single-light windows of moderate size, but now enlarged, appear, one between each pair of pilasters, and each below a large plain round-headed and slightly-recessed relieving arch, springing from a strip of wall left as a sort of pier against each pilaster. The base of this arcade is a set-off in the wall stopped by the pilasters. The lights of the fourth or upper stage may be of about their original size. On the south wall, between the two western pilasters, the windows, of 2 feet opening, are in pairs, having a plain baluster in common, and each pair being within a shallow, round-headed recess, so that the eight windows form a short arcade. One pair are probably the only windows in the keep that present quite their original appearance; for the baluster, long since removed, was found bricked up in the adjacent wall, and is now in its proper place. It is believed to have been from one of these windows that Bishop Flambard, here a prisoner, let himself down. The exterior has been defaced by pointing with flint chips and mortar, and the substitution of Portland for the old ashlar dressings, but the windows, though enlarged into casements, represent the old openings. The staircase, 11 feet diameter, contained within the circular or north-east turret, rises from the floor to the summit, and communicates with every floor, and with the leads. The basement is slightly below ground on the north, and at the ground level on the south front. The walls are from 12 feet to 15 feet thick, and the internal area about 91 feet by 73 feet. This is crossed by a wall 10 feet thick, built with much neglect of the plumb-line. It rises to the summit, and divides the building into a larger western and smaller eastern portion. The latter is again subdivided into a larger northern and smaller southern part, by another wall, also carried through, so that every floor is divided into three chambers. The larger chambers are all ceiled with timber; all the smaller are vaulted. The basement was reached only from above by the great well-stair. The west chamber is 91 feet by 35 feet; the eastern, 67 feet by 28 feet; and the vault, the lower or sub-crypt of the chapel, known in Tower phrase as “Little Ease,” is 15 feet by 47 feet, the east end being semicircular. A door leads from the east into the west chamber, and from the former into Little Ease. Bold recesses in the walls ascend to a line of loops, giving air, but very little light.