'That bag,' said Hooke, 'came from the magazine of one of His Majesty's Ships of War. The practice used to be, and still is on some ships, that powder is introduced into the bore of a cannon by scooping it up out of a keg and pouring it in. Similar to how a musketeer charges the barrel of his weapon. But in the heat of battle, our gunners are prone to mis-measure and to spill the powder on the deck. And to have open containers of powder near active cannon is to tempt disaster. A new practice is replacing the old. Before the battle, when it is possible to work calmly, the powder is carefully measured out and placed into bags, such as that one, which are sewn shut. The bags are stockpiled in the ship's magazine. During battle, as they are needed, they are ferried one at a time to the guns.'