Upon this was built a chamber of marble mason-work, forty feet long, three and a half feet broad, as many high, and with side-walks [walls?
D.W.] five feet in thickness.
This was the crater.

It was filled with seven thousand of gunpowder, of a kind superior to anything known, and prepared by Gianibelli himself.

It was covered with a roof, six feet in thickness, formed of blue tombstones, placed edgewise.

Over this crater, rose a hollow cone, or pyramid, made of heavy marble slabs, and filled with mill-stones, cannon balls, blocks of marble, chain-shot, iron hooks, plough-coulters, and every dangerous missile that could be imagined.

The spaces between the mine and the sides of each ship were likewise filled with paving stones, iron-bound stakes, harpoons, and other projectiles.