Treatise on Armament Technology: Illustrated Naval Firearms

The Across-Water Divine-Machine Cannon original: 渡水神機砲 (Dushui shenji pao)

The "Across-Water Divine-Machine Cannon" is intended for situations where the enemy is positioned across a body of water and you wish to overcome them using fire-based attacks. If our troops are few and the enemy's strength is such that we cannot withstand them in a direct confrontation, we must secretly dispatch scouts original: 細作 (xizuo); specialized agents or spies to bury these cannons in dangerous and narrow passes.

The ingenious secret of this weapon lies in the fuse original: 藥信 (yaoxin); literally "powder message". Twenty or thirty cannons are all connected to a single fuse; once the mechanism is triggered, the cannons fire simultaneously.

To prepare the site, dig a trench in the ground. Use Mao bamboo original: 猫竹 (maozhu); a sturdy species of bamboo split into two halves, with the inner nodes hollowed out. Wrap the fuse in paper that has been soaked in alum water original: 礬水 (fanshui); used here to make the paper moisture-resistant and dried in the sun. This ensures that the fuse does not become damp.

Place the protected fuse inside the bamboo, bury it in the ground trench, and cover it with soil. Take porcelain basins, join them together, and knock a hole in them to align with the bamboo opening. This setup is used to house the "buried fire." The "fire-seed" a perpetual pilot light or slow-burning ember is made using a mixture containing asbestos original: 不灰木 (buhuimu); literally "wood that does not turn to ash". The mixture is composed of iron filings, dry lacquer, asbestos, saltpeter, and sulfur.

When buried in the ground, this fire-seed will not be extinguished for one or two months, even if it encounters rainwater. The mechanism involves a long rope tied to the fuse, which hangs beside the fire-seed. When the enemy arrives, pull the rope to move the mechanism bringing the fuse into contact with the fire-seed, and the cannons will fire instantly. The cannons are loaded with "Divine Sand," which strikes the enemy and immediately blinds both eyes, and porcelain shards, which cause the enemy to bleed upon impact.