The portal arch, wide enough to admit a wain, or three men-at-arms abreast, was usually of the form known as “drop.” Within, the first defence was a herse or portcullis, and behind it a door of two leaves, opening inwards, and, when closed, held by one or two stout bars of oak, which could be pushed back into cavities in the wall. Behind the door the vaulting was often replaced by a flat roof of timber, through which worked a second portcullis, and then came two lateral doorways opening into porters’ lodges, usually connected with a small prison. At St. Briavels the lodge doors are portcullised. At the end of the boarded space the vault recommenced, and there was a second pair of doors and a second portcullis. These two were intended against assaults from within, each gatehouse being constructed for an independent defence. Usually, in addition to these gates and doors, the vault was pierced with from one to five square or round holes, about a foot across, called “meurtrières.” These might serve to hold posts to check the entrance of a body of men, or for thrusting pikes down upon them. They have also been supposed to be intended to allow water to be poured down, supposing the passage filled with bushes set on fire, though it is difficult to see how any quantity of water could be obtained, any more than melted lead or pitch, which are spoken of. The first floor of the larger gatehouses contained a handsome chamber with lateral doors leading to the ramparts of the curtain, and sometimes, as at Caerphilly and the Tower, to an oratory. The portcullises were worked through the floor, and their tackle must have given an air of warlike reality to the room, like the guns in a state-cabin at sea. At Caerphilly and Chepstow the passage to the curtains is protected by a portcullis and a drawbridge, of which the pit is a deep hollow in the wall. The walls of these Edwardian castles varied from 25 to 40 feet in height and were from 6 to 8 feet thick, or even more, to allow of mural galleries, as at Chepstow, Caerphilly, and Beaumaris. Upon their top was a path called the “allure,” or rampart walk, protected in front by an embattled parapet, and in the rear by lower and lighter walls. Frequently there was a loop in each merlon, and each embrasure was fitted with a hanging shutter, both of which are seen at Chepstow. Where the curtain crosses a ward or projects as a spur, as at Caerphilly and Beaumaris, it was embattled on both faces. The ramparts were usually reached from the adjacent mural towers, but sometimes, as at Warwick, by an open staircase of stone. Occasionally, where a wall is too slight to allow of a rampart wall, it was, in time of war, provided with a platform of wood, like a builder’s scaffold. This seems to have been the case with the city wall of York where it bounds the cathedral garden.