repaired. Timber for a permanent pile bridge was prepared in the woods, which bridge was to be built in January. A detachment of engineer troops accompanied the expeditionary force to Fort Fisher.
January.-As the enemy frequently opened a heavy mortar fire from in front of his works opposite Fort Harrison, and as the artillerymen were unable to stand to their guns during its continuance, it was deemed advisable to make protection to the guns on the front of Fort Harrison. The mortars used by the enemy were Coehorns, placed outside of their works and behind the line of picket reserves, protected in their front by a strong line of abatis. It was designed to bombproof the whole front of the work and put in casemates enough, constructed somewhat on the Hoxo plan, for the guns on the front. There was a banquette for infantry on top, reached by broad, wide stairs in rear, which gave the infantry good cover and enabled them to see perfectly every point in advance. The ditch was deepened and widened and a fraise placed in the scarp to prevent scaling. But four of these casemates were constructed, and two bombproof, a sketch of which is shown on the opposite page.
There were also three strong lines of abatis and wire entanglement placed in front of the ditch, making the whole work quite formidable and easy to hold.
In order ot save sand-bags, which at this time became very expensive, Lieutenant King, Engineer Corps, designed some loop- holes for riflemen and for use in the picket-lines, which proved admirably well adapted for their purpose, and being prepared at slight cost at the saw-mills, were used on all the works and rifle-pits. They were constructed of boards, and of the form shown in the diagram. They presented a smaller target for the enemy's sharpshooters and at the same time gave a large field of fire. They were not easily discernible at any distance and could easily be removed and replaced.
NOTE.-The rebel device for the same purpose consisted in placing logs of various lengths, ten to fourteen inches in diameter, hewn on two sides, with notches cut in the lower side once in about six feet along the interior crest of the parapet, and banking these logs in front with earth. The notches which formed the loop-holes were tapering toward the outside, similar to our own, and where there was much sharpshooting the orifice was still further reduced by a plate of thin boiler iron eight or ten inches square, with a hole in the center but little larger than the barrel of a musket. These plates were spiked to the front side of the logs (covering the notches), and in some cases were found with fifteen to twenty bullet marks upon them, many of which were so near the edge of the opening that the bullets probably went through, and it is quite likely that all the bullets that struck the plate would have struck the man in the rear of it had ordinary sand-bag loop-holes been used.
The engineer may at times find this expedient worthy his attention, observing that the logs near the crest of the parapet are not suitable where artillery can be used against them.
The permanent pile bridge was finished after a little more than two weeks" labor, being 1,368 feet long. It became necessary as a substitute for the pontoon bridge owing to the great freshest in the river, the floating ice, and the driftwood that came down the river at this time. It was a pile bridge, each pier consisting of three piles driven firmly into the bed of the river and connected by a cap piece, and the piers joined by strong pieces to form bays each fifteen feet wide. An inclined low was attached to each pier to war off drift and ice. This