Book 2
9
When the height of the tower reached the level of a story they built the floor into the walls in such a way that the heads of the beams were hidden in the outside structure of the walls, to prevent any projection on which the firebrands of the enemy could lodge. Above this timber-work they built up with brick, only so far as the shelter afforded by the shed and the penthouses allowed, and above this part they laid across two beams not far from the outer walls, whereon to raise aloft the wooden frame which was to serve as the roof of the tower, and over these beams they laid joists across at right angles and fixed them in place by tie-beams. These joists they made rather longer and projecting beyond the outside of the walls, so that there might be a place to hang out screens to ward off and repel blows while the walls were being built up below this timber frame; and on the top of this flooring they made a layer of bricks and clay so that the firebrands of the enemy might do no harm. And they further laid thereon mattresses, that missiles hurled by engines might not crash through the flooring or stones from catapults dislodge the brickwork. They made moreover three fenders four feet broad out of anchor-ropes to cover the length of the walls of the tower and fastened these on the three sides towards the enemy from the beams projecting round the tower. This was the only kind of protection that they had found by experience in other places to be impervious to any missile or catapult. But when that part of the tower which was finished was protected and defended from every weapon cast by the enemy they removed their sheds to other works, and began to poise and lift the roof of the tower independently by leverage from the first-floor stage. When they had raised it to the height allowed by the hanging fenders, being thus concealed and protected within these defences they proceeded to build up the walls with brick, and again by further leverage made themselves space for fresh building. When the opportunity came for a second story they built in beams, just as at first, concealed in the outside of the walls, and from this flooring again they proceeded to raise the topmost story and the protecting fenders. So safely and without any wounds or peril they built up six stories, and in the course of erection they left openings, where it seemed suitable, for the discharge of darts from catapults.
