As usual, these loops were for air and light, not for defence. Between this loop and the south angle is a square-headed door, of 3 feet opening, under a curious round-headed arch, of which the tympanum is partly formed by the arch stones. This leads to the well, which is in the centre of the wall. It is 4 feet diameter, and much choked up. It ascends to the upper floor. At the north end of this side the wall has been broken away and a small mural chamber laid open, 5 feet wide by 8 feet long, having a plain barrel vault. A door opened into it from the great chamber, and it was lighted by a loop, now converted into a sort of window. The inner wall about the doorway has been strengthened by a pilaster of 1 foot projection, which stops at the first floor. In the recent restoration, this chamber has been made the lobby at the foot of the staircase. In the west wall is a plain, round-headed doorway, of 6 feet opening, and with ashlar ring-stones 2 feet deep. This is the opening of a straight passage through the wall, here 12 feet 9 inches thick. There are in the passage rebates for two doors, opening towards each other. At Rochester, a small door in this position led only into a sort of prison in the base of the forebuilding, and this may have been the case here; but the size of the door, as at Corfe, makes it at least possible that it was a regular entrance, approached through the forebuilding from the common exterior door. In small keeps the basement was often entered from the first floor only, as at Clitheroe, by a trap, or, in the larger keeps, by a well-stair, as at Middleham. Unfortunately, as the forebuilding is almost always more or less injured, it is impossible in most cases where there is a large basement door to say positively whether it was an independent entrance. There is also the further doubt, as at the Tower of London, Guildford, and Malling, whether the doorway in the basement be not a later introduction. The cill of this doorway is about 10 feet above the outer or main entrance of the forebuilding, the floor of which rises to it. Close north of the large doorway is a small one, of 2 feet 6 inches opening, which leads into a garderobe, the seat of which is corbelled out into the interior of the north-west turret. This interior, 10 feet 6 inches square, seems to have been a vast cesspit, receiving the contents of garderobes from each floor and from the battlements. There is no drain below, and the lower part of the pit contained sand, which has recently been removed. There is a somewhat similar pit in the keep at Ludlow, and one at Sherborne which resembles them. Large as this pit is for such a purpose, it is much smaller than the turret, the wall of which to the west, if solid, must be 11 feet thick. Can there be a second and smaller shaft in that part of the turret, not now accessible? There was no way from this floor to either of the southern turrets, both of which, at this level, were filled with earth.