few during the day fired at the south angle and the north wall. A mortar shell (13-inch) struck immediately over the sally-port casemate arch near the northwest angle. The effect was visibly to jar the arch; the filling over it is 7 feet. I have begun a centering for the arch and shall, besides, add to filling. This and the adjacent arches bear evidence of much wear and tear, being cracked in various directions by previous bombardments. Day fire: Parrott, 332, of which 68 missed; mortar, 126, of which 53 missed. Night fire: Parrott, 71, of which 19 missed; mortar, 175, of which 55 missed. Total, 694, of which 195 missed. It will thus be seen that the firing of these twenty-four hours has been the heaviest yet. The night fire was particularly annoying to the working parties, and diminished the amount of repair I had hoped to effect. The casualties for the same period of twenty-four hours were as follows: Mr. Bedell, of signal corps, slightly wounded while signaling on the western berm; 2 enlisted men slightly wounded; 1 negro killed and 2 severely wounded; 5 negroes slightly wounded; total, 1 killed and 10 wounded.

Wednesday, 20th.- The firing began as usual at an early hour, upon the southwest angle, from the two 8-inch Parrotts at Battery Gregg, and has been particularly destructive, carrying away large masses of brisk from sharp and sand from slope of angle just over the stone re-enforced buttress. This still remains in large part unhurt, but the fire has begun to take effect upon the mass above it, and about noon to-day obliged us to fill rapidly the small gallery leading to window in old shell-room at the south end of second tier, west quarters. The gallery was filled before penetration occurred, and to-night I shall complete a more extensive and substantial filling, retained with heavy timber revetting, and this I expected will resist for a long time. The west end of the heavy parapet over stairway has been shot away, and the adjacent howitzer platform I fear lost to us. I expect hereafter the piece will have to be fired from the top of the parapet, and consequently more withdrawn from the line of a raking fire along the gorge slope. There has been no firing of consequence to-day upon any other part of the fort. The mortar shelling has made some holes but no damage, the shells chiefly bursting over the west berm and wharf. The boom requires immediate repair and will, I hope, now have it. The transportation in small boats, some of which are occasionally struck band sunk at the wharf, is entirely inadequate to the wants of the fort in sand and general material. A regular supply of at least 1,000 bags every night is considered to be very necessary under such a severe bombardment. I am also in want of lumber, which was to have been brought down last night. It becomes my sad duty to record the death to-day of the commanding officer, Captain C. Mitchel, ban accomplished officer and high-toned gentleman. He had gone up to the lookout sentinel on the rampart at southwest angled and was observing the effect of the firing, when we was struck and mortally wounded by a fragment of mortar shell hitting him below the left hip and causing his death at 5 p. m., being four hours from the time he was wounded. Day firing: Parrott, 161 (24 missed); mortar, 274 (101 missed); total, 435 (125 missed).

JNO. JOHNSON,

Captain, Engineer in Charge.

Major W. H. ECHOLS,

Chief Engineer, South Carolina.