HDQRS. DEPT. SOUTH CAROLINA, GEORGIA, AND FLORIDA, Savannah, October 28, 1862.

Brigadier General H. W. MERCER,
Commanding District of Georgia, Savannah, Ga.:

GENERAL: Before leaving on my return to Charleston I think it and visible to leave with you a summary of the additions and changes I have ordered to the works intended for the defense of this city, and which ought to be executed as promptly as practicable, commencing with those on the river and at Carston's Bluff.

1st. The magazines of several of the river batteries must be thoroughly drained at once and repaired. They are now unfit for use on account of their dampness, and the one at Battery Lawton has not yet been commenced. The position selected for it is too far to the rear. It should be closer to the battery, and well draimed. Not a moment should be lost in its construction. The service magazine should have its entrance enlarged and strengthened at the top. The magazine doors at Fort Jackson do not open freely; this defect must be corrected.

2nd. Good and strong traverses must be constructed as directed in the naval battery to prevent enfilading.

3rd. The two 8-inch columbiads on Fort Jackson must be separated, and one of the barbette 32-pounders removed for a traverse to be constructed in its place; must be put in position outside, in rear of the glaces, to fire down the river.

4th. Those river works when garrisoned must always be provided with several days' provisions on hand.

5th. The mortar chamber in Captain Lama's battery is too small; the mortar should be mounted as soon as practicable and the men drilled to it.

6th. It would be important, if practicable, to lay a boom obstruction across the river at or near Hutchinson Island under the guns of its battery and of Fort Boggs, and a three or four gun battery should also be constructed at Screven's Ferry Landing.

7th. Carston's Bluff must be made an inclosed work, with two mortars and four additional heavy guns added to its armament. Two of these guns must be placed so as to bear up the Augustine River.

8th. A three-gun battery must be constructed at Greenwich Point, on Augustine River, to cross fire with the two guns just referred to and enfilade the enemy's batteries on Whitemarsh Island, constructed against Carston's Bluff.

9th. One rifled 32-pounder must be added to the Thunderbolt Battery, and one of its 8-inch shell guns must be changed in position as ordered, and the embrasure of its 8-inch columbiad must be reduced in size. Several traverses must be raised and lengthened. The upper slope of the battery in front of several of its guns must be increased.

10th. A new battery for four 24-pounder howitzers on siege carriages, with some rifle pits, must be constructed to command the Isle of Hope Causeway.

11th. Several of the guns of Fort Boggs and battery at Beaulieu are in want of elevating screws, and some in the latter battery require smaller trunnion plates, and the upper slope of its parapet must be lowered in several places.

12th. A new battery and rifle must be constructed on Rosedew Island for five or six pieces, of which one or two should be rifled guns, so as to command the Little Ogeechee. One rifled 24-pounder is already on its way to this city from Atlanta for said work.

13th. Two rifled guns (one 32-pounder and one 24-pounder) must be

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