OFFICE OF CHIEF ENGINEER, DEPT. OF THE SOUTH,

Hilton Head, S. C., August 15, 1864.

[General J. G. FOSTER.]

GENERAL: In compliance with your instructions I have the honor to submit the following extract from a report which I made to General Gillmore last fall relative to placing a battery on Paine's Wharf. The report was made after a careful inspection of the locality:

I found it (Paine's Wharf) to consist essentially of a floor of heavy planking resting on some foundation of which I could not ascertain the nature, and inclosed by a crib-work of heavy square timbers about 4 feet high, except on the side toward Moultrie and Gregg, where it has been turned away down to the flooring. About 12 feet inside the crib-work is another inclosed space about 1 1/2 feet high, also composed of square timbers. Its sides are parallel to those to the exterior crib-work. This inclosed space is filled up flush with oyster shells.

In shape it (the wharf) is a hexagon equilateral, but not equiangular. The sides are about 70 feet long; those of the interior polygon about 54 feet long. It lies on the left side of the mouth of the creek and detached about 30 feet from shore. At high tide the water overflows the flooring in those places where the parapet was burned. Spring tides overflow the greater part of the area filled with shells.

In conclusion, I beg leave to state that in my opinion the results to be attained by placing a battery in this location are entirely incommensurate with the time and labor required for its construction. Besides, when completed, it will be often open to a surprise party, as it cannot be supported.

In addition I will state that the distance to Sumter from Paine's Wharf is 1 2/3 miles; from the Marsh Battery to Sumter 2 1/3 miles. The line of fire from the Marsh Battery is nearly perpendicular to the gorge wall of Sumter.

Paine's Wharf lies considerably to the right of this line of fire. The line of communication to Paine's Wharf is about one-third longer than to the Marsh Battery, and being by water is often impassable at low tide.

The space available on this wharf would be mostly occupied by the battery, as will be seen by the accompanying sketch. The direction indicated for the battery is necessary, otherwise the work would be seen in reverse from James Island. There will be little or no room for building bomb-proof shelters for the supports, hence the difficulty of holding the work.

The shore of the harbor to the left of this point is good and firm, so that a surprise party might easily creep along there and surprise the work.

Finally, I am afraid the foundation would not be reliable for firing heavy guns. It would probably settle unequally and necessitate continual alternations. I think the Marsh Battery decidedly the best location. A 100-pounder would compensate sufficiently the increased range (two-thirds of a mile).

The battery may be increased in area by pulling Paine's Dock to pieces and towing the timbers to the Marsh Battery; also by using marsh mud in making parapets. I think a magazine and bomb-proof could be constructed there.

I am, general, very respectfully, your obedient servant,

CHAS. R. SUTER,

Chief Engineer, Department of the South.