166 Mediceval Military Architecture in England, 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 s'een 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 plat- form 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. Mural towers vary much in form and size, but are more usually round, or half-round, or half-round with prolonged sides, than square. Now and then they are polygonal, as at Stokesay, Warwick, Cardiff, and the Bishop's Gatehouse at Llandaff. Stokesay is of the thirteenth century, but usually these towers are later. Mural towers have seldom much internal projection. In Roman Avorks they are usually solid, but in later castles they are sometimes open in the rear or gorge to prevent their being held when taken by the assailants. The towers of Cologne and Avignon are so open, and at the Tower the Byward and Traitors' Gate towers are closed only with a wooden brattice. The annexed drawing shows the back view of Traitors' Gate, with the large arch over the water and the timber-work above it. Where there was an outer ward and a second wall, this was considerably lower than the inner wall, and commanded from it ; and the mural towers often became mere bastions, not rising above the curtains. The second ward, besides being too narrow to allow of troops being massed or machines posted for the attack on the inner wall, was traversed by cross walls with gates, so as to isolate any body of assailants who had breached the outer wall. Such cross walls may be seen at Caerphilly and at the Tower. The barbican was sometimes a mere walled space attached in front of the gateway, as at Carlisle, Alnwick, Richmond, or the Bars at York. Sometimes it was a tcte dti pout, detached
