33. Methods of setting on fire
1. On shelters brought up by the enemy you should pour pitch and drop tow and sulphur: then fasten to a rope some burning brushwood and let it down onto the shelter.
Materials of this kind may be slung out from the wall and dropped on the engines which are being brought up. 2. The best way to set fire to them is to get pieces of wood shaped like pestles, but much larger, and hammer sharp iron spikes into the ends of the wood; and round the other parts of it, both on the top and underneath, fasten separate pieces of highly inflammable stuff, till it looks like a thunderbolt as represented in pictures. This instrument should be dropped on the engine which is being brought up: it is made in such a way that it will fix itself in the engine, and so that the burning stuff will not fall off when it is fixed. 3. If there are any wooden towers in the city, or if any part of the wall is made of wood, they must have coverings of felt and hide on the side facing the enemy, to prevent their being set on fire. 4. If the gates catch fire, you should bring logs and pile them up to make the fire as big as possible, until you can dig a trench inside and build a retired wall with such materials as are immediately at hand: if there are none forthcoming, you must get them by pulling down the nearest houses.