41. Between the 17th, and 19th July, a large quantity of frieze was made, and the ground in front of our position examined personally for 600 yards toward Wagner, with a view to the establishment of parallels or batteries. The next day, triangulated the position of the enemy's works on James Island, and having, by order of General Gillmore, requested Captain [George] Bacon, of the U. S. gunboat Commodore McDonough, to make a reconnaissance up the Light-House Inlet, went with him, and succeeded in shelling out the rebels, dismounting one gun they had just put in position.
42. During the following two days, the party making frieze were at work, and all the available strength and resources of the command that could be applied were kept at constantly improving the means of crossing the inlet from Folly to Morris Islands, and in making sap-rollers and 150 more panels of frieze. The piers were by this time in a good condition to use them.*
43. On the 25th, two batteries were begun in the first line of works, which was now known as the first parallel, in which to mount four naval guns. Heavy parties wee worked at night and, as far as practicable, during the day until these batteries were finished. They occupied the center of the line, and had two 200-pounder Parrott rifled guns and two 80-pounder Whitworth guns mounted in them.
44. The Naval Battery as finally completed is represented in Plate X. Fig. 1 is a plan, and Fig. 2 a cross-section, on the line a b.
45. On the morning of the 27th, a very thorough survey of Black Island and its situation, relative to the enemy's works on James Island, was made. During the next day, a lookout was built at an advanced point, in the top of a very high pine tree, and a causeway across the march from the sand ridge on the left of Morris island, near where the left center batteries had been established, to Black Island, was begun, under the direction of Captain Eaton, Volunteer Engineers.
46. During the night of the 28th of July, an attempt was made to put in abatis across the beach from the right of the second parallel, beginning at low-water mark, but when some 15 or 20 yards had been planted, the enemy came out on the beach in front of Wagner, and poured in such a heavy fire of grape and canister from four field guns, that the party was very much annoyed, and several of the horses which had been used in bringing up the material having been either killed or wounded, the others took fright, although stationed 300 yards to the rear of the work, and ran off with 23 wagons which had not yet been unloaded.
47. A number of attempts were made to continue the work, and the men behaved well, but before the materials could again be brought together and the work proceeded with, the tide had risen so much as to make it impracticable. Some good men were lost in this affair, and daylight and the enemy's sharpshooters terminated the effort. Captain Charles P. McKenna and Sergeant [Theodore] Mandeville, Volunteer Engineers, were very useful. Sergeant Mandeville was killed.
48. Experiments were now made for the purpose of continuing the investigations as to the practicability of erecting batteries on the marsh.
*The temporary per at south end of Morris Island is represented in Plate IX, in plan, elevation, and sections.