At such a time as this, the splendid and punctilious discipline of the navy is exhibited to the best advantage. What to the casual observer, in the still waters of a peaceful harbor, may seem terribly formal and ridiculously precise, is the foundation of success in the ordeal of a mighty naval conflict. Every man knows his place, and has a definite duty assigned to him in case of any emergency that can happen. Every one of the gallant tars at gun No. 9 had a double, and some a triple, duty assigned to him. Every manœuvre of the piece was performed in order, with the utmost promptness and precision. At quarters, the men are stationed on each side of the gun; and the same crew handle the gun on the opposite side of the ship,--a division consisting of three guns on the starboard, and three on the port-side. As the Harrisburg went up the river on this momentous occasion, her port-battery first engaged Fort Jackson; but when she reached Fort St. Philip, on the other side of the river, her starboard battery delivered the terrible broadside. The second-captain of gun No. 9, with his crew, went over to the other side, and manned the other gun No. 9. Jack Somers, as we have before stated, was first-loader and second-boarder. The man opposite to him was first-boarder and second-loader. The next was a shot-and-wad-man, who was also a pumpman and pikeman. The third was a sponger, who was also a boarder. The fourth was a crow-and-handspike-man, who was also a fireman and sail-trimmer. The fifth was a train-tackleman, and also a boarder. The sixth was a captain of the gun. The men on the opposite side had corresponding duties; and each is designated by his proper ordinal, as first-boarder, second-boarder, etc. The gun is secured by three classes of ropes. The breeching is the heavy piece of cable passing through an eye at the breech of the gun, with each end fastened to the side of the ship, which prevents the recoil from throwing the piece out of position. The train-tackle is a rope with double blocks, attached at one end to the carriage, and at the other to a ring in the deck, by which the gun is hauled back from the port, or secured for loading. The side-tackles are the purchases attached to the side of the carriage, by which the gun is drawn up to the port. Modern gun-carriages have but two wheels, the aftermost part resting on the deck. A handspike with rollers on the end, called a rolling handspike, by which the carriage is pried up and made to bear upon the rollers, is now used when the gun is to be run out at the port. The cartridges are brought up from below, one at a time, in a leathern bucket having a cover, which removes the liability to accident. Shot-stands are placed near the breech of the gun, to hold the balls,--five in each,--which are replenished as occasion requires.