CIRCULAR.] HEADQUARTERS FIRST MILITARY DISTRICT, Month Pleasant, November 8, 1863.

In view of the possibility of an attempt on the part of the enemy to effect a landing on Sullivan's Island or the Mouth Pleasant shore, by a coup de main, the following general instructions are given, and will be carefully studied by commanders of positions, regiments, batteries, and companies. The whole shores of Sullivan's Island, from Breach Inlet to the wester wade of Fort Moultire, will continue to be heavily picketed every night, at intervals not exceeding 100 yards. These intervals will be reduced to 50 on that part of the shore from in front of the ruins of the Pinckney House to Battery Rutledge. Three men will be kept on each post, and a reserve will be kept in hand at a distance of about 50 yards from the center of the line of pickets furnished by each command. The picket duty will be performed by each regiment of Brigadier-General Clingman's and Colonel Hamilton's commands in the front of their respective positions, in order that in case of retiring each advanced party will rally on its own command without confusion. Brigadier-General Clingman's pickets will extended to the front of the covered way between Battery Rutledge and Fort Moultrie.

The artillery on duty at the several batteries will keep a strict guard on their batteries, and their commanders will be in communication each night with the commanders of the pickets i in the front. They will receive instructions form the commanding officers of the brigades or commands whence they come, to insure such communications. The whole remaining strength of the forces on Sullivan's Island will be held in readiness for instant service; and so soon as the instructions are given to that effect, each regiment and battalion will take up its position in line of battle, just after dark, and sleep upon its arms. The horses of the light artillery will be kept harnessed in readiness during the night, and when the infantry sleeps upon its arms, the guns will also be in position. The troops of Colonel Hamilton's command will be kept harnessed in readiness during the night, and when the infantry sleeps upon its arms, the guns will also be in position. The troops of General Clingman's command will occupy the ground on the west, and extend to Battery Rutledger, he giving particular attention to the full support of Battery Beauregard and the defense of the curlew ground between that battery and the sand-hills.

When the troops sleep on their arms in line of battle, their position will be in advance, and between the fixed batteries and the position of light artillery, care being taken not to mask the direct fire of those batteries. Commanding officers must keep in communication with the operations of our own troops. Three hundred men or more from Colonel L. M. Keitt's command at Mount Pleasant, will continue to report, and take position nightly for the support of the works west of and including Battery Rutledge. So soon as possible, a light battery and a regiment or battalion will be added to General Clingman's command, and the force from Colonel Keitt's west of Fort Moultrie will be increased upon an emergency, so far as means will permit. Meantime, should occasion require it, Brigadier-General Clingman is authorized to call on Colonel Hamilton for a section of Captain Jeter's battery.

The commanding officers of batteries will be furnished with rockets for signals. Commanders of pickets will also be furnished with blue