right flank, as we progress, will be irreparably open. At all times the dry, intermediate marsh, between mud and sand, on the left endangers that flank, for this marsh is too wet to trench, but still entirely passable for troops.
For the first difficulty there is so remedy; we can only make the most of what earth there is. Our counter-batteries, and the fire of the navy against Sumter and Wagner, together with the more efficient corps of sharpshooters* now forming, will lessen the amount of the enemy's fire.
To protect the flanks of our advanced parallels, two plans are proposed. First, to construct two nearly parallel lines of obstacle (abatis or palisading), extending toward Wagner, and keeping progress with the approaches, which lines will embrace all the ground fit for siege operations, averaging about 75 yards in width; this obstacle to be defended by the guard of the advanced trenches, assisted by an artillery fire from parallels in the rear, enfilading its fronts. Second, to build keeps (block-houses, or inclosed stockade works), in which the guard of the advanced trenches could take refuge, and make an independent until support could arrive from the rear.
The second plan was officially approved. It will require far less material than the first. This material is brought from Folly Island, and carried from the second parallel forward by men.
I was ordered by the general commanding to direct the opening this night (August 9), by the flying sap, of a third parallel, 330 yards in advance of the right of the second and 540 yards from Wagner, and construct an approach to it from the obstacle of the second parallel.
My official instructions relating to these approaches against Wagner were to devote only my spare men to them, attending more particularly to keeping in repair and strengthening the works already built in the second parallel. My daily details at this time were 300 men.
I was informed that those approaches would probably only amount to a feint, as, on the demolition of Sumter, the monitors can invest Morris Island, and thus reduce Wagner and Battery Gregg.
The detail for to-night's work is 124 volunteer engineers, under Lieutenants Farrand and Talcott, and 80 infantry, under Captain Walker. The engineers were in advance. Two hundred and sixty yards of trench were opened, and a splinter-proof parapet, from 6 1/2 to 8 feet high, built throughout its length. No portion was rivetted. Our grand-guard outposts were but 30 yards in front of the working party, and the enemy's pickets, who could be seen, were apparently not over 30 yards farther. The engineers, on their knees, shoveled almost noiselessly. I could scarcely hear or see them from the line of outposts, 30 yards distant. The following method of setting the engineers at work was adopted: They carried no arms. Each man held a short-handled shovel in his right hand; in the left, at intervals of 6 feet, each grasped a marked rope. The engineer officer who located the line took the head. The men marched forward, stooping. At a signal the rope was dropped, and each man went to digging a pit where he stood, throwing the earth over the rope. These pits were connected, and good cover was soon obtained.
Sand-bag loop-holes were built in the third parallel for the use of the sharpshooters, who occupied it next day.
*See Note 14, p. 323.