From the Introduction:
The great bombard, an engine of war, that puts fear in the hearts of those besieged and on some occasions the hearts of those manning it as well. A few well placed shots from this siege engine are more then enough to knock down any but the sturdiest walls. And even for those it just takes a little longer. But every shot bears a chance for disaster for the gunnery crew as well. Even the slightest mistake or just plain bad luck could cause the cannon to blow up around their ears.
The bombard itself is assembled from many pieces. The most important of those is the inner barrel, cast from brass in one piece. It is surrounded by a layer of steel beams all around its circumference, which are held together by weathered brass clamps. This whole assembly in turn is suspended by sturdy ropes from a massive wooden frame.
Stacked next to the gun are a small number of the massive stone balls which are usually used as ammunition for the bombard. And a slightly behind the bombard keeps the powder for the next shot dry. A small muddy pond next to the barrel is used to cool the barrel after firing. The emplacement as a whole is secured by earthworks.