The method is to lay down the railroad--it can be done very swiftly by men carefully trained in the art of laying tracks over all kinds of ground--put the gun and its mount, with a specially prepared base of extremely heavy timbers, on the tracks, and trundle it to the place where it is needed to pour a rapid fire into the enemy. Here a pit has been dug, in which is laid down the heavy timber base, riveted together with heavy steel bolts. Then it is well packed with dirt and stone, and the gun carriage made fast ingeniously. The single-stick derrick has been erected alongside, guyed out in four directions with heavy ropes, which are made fast to the ground by means of "dead men," and manipulated by very live gangs of husky marines. A chain block of powerful type is used to pick up the gun carriage and put it in place, and afterwards to swing the gun into its sockets on the carriage. Later the breech locks and sights are added, and the big five-inch, 40-caliber naval gun is ready to go into action. These big and heavy guns, suitable for long range work with high explosive shells, can be taken a quarter of a mile or so from the ship which carried them, over rough ground, set up and put in operation in a few days' time. But the heavy artillery base is only one of the Marines' work. They have big howitzers, of the more modern type, most of which are kept at Annapolis, where they can be loaded aboard ship in short order. Men and machines can be mobilized at the strategic points in a very short time. EVERY MAN'S SERVICE. The Marine service is unique in many respects. For one thing, it is every man's service. The proportion of officers who have risen from the ranks or who have been commissioned from civilian life is higher in the Marine Corps than in either the Army or the Navy. This, of course, makes for democracy in the corps. An enlisted man, who does not wait until he is too far up in the 20's to enlist, has a very fair chance of earning his commission. Another thing--and this is of prime importance to the ambitious fellow--promotion goes by merit. In the army and navy the young officer is promoted by seniority. Things are a bit different in the Marine Corps. In this organization a man doesn't absolutely have to wait for his number to come around. If he distinguishes himself above his fellows, he may be promoted without much regard for age or length of service. He goes up as he is able to, by his active ability and his readiness to work hard and effectively for Uncle Sam. There are advocates, of course, of both systems. There are merits which both systems can justly claim. But it goes without saying that this possibility of promotion keeps everybody in the Marine Corps on the jump.