Saps at Vicksburg.In the center rises “Coonskin” Tower, a lookout and station for sharpshooters. It was built under the direction of Lieutenant Henry C. Foster of the Twenty-third Indiana Infantry. In honor of his raccoon-fur cap, the soldiers nicknamed him “Coonskin.” The sap-roller, shown in the illustration below, was used for construction of a sap or trench extending toward the defenders' works in a siege. A famous sap appears in the upper photograph — that built by Logan's busy men, winding its way toward the strong redan of the veteran Third Louisiana Regiment on the Jackson Road. First a parallel is opened — that is, a trench is constructed parallel to the besieged entrenchments. From this are constructed several approaches, or saps, to enable an approach to be made under cover to a position where a second parallel may be. These are built in a zigzag direction, so that the defender cannot enfilade the trench, except when very close to the opposing works, when it is frequently necessary to approach directly. Here is where the saproller comes into play. It is rolled at the head of the trench in such a manner as to protect the workmen from their opponents' fire. It must therefore be thick enough to stop bullets. To construct a sap-roller in the form shown, two cylindrical baskets of the same length are made, a small one to form the interior wall, and a larger one for the outer wall.