Gregg, and a mile south of this Fort Wagner, an extensive sand battery of the most powerful construction. Finally, at Light-house Inlet, which divides Morris Island from Folly Island, was another fortification covering the landing at that place. Within a few days of the attack the enemy also erected a new sand work between the two last mentioned. The number of guns mounted on these works was estimated at several hundred, comprising the heaviest smooth bore ordnance, and many rifled pieces of English manufacture; and as an additional means of protection, the channel between Fort Sumter and Sullivan’s Island was obstructed by rows of floating casks supporting torpedoes and other submarine obstacles, and in that between Sumter and Cummings’ Point were no less than four rows of piles extending nearly up to Charleston. Upon the 6th of April the whole National fleet crossed the Charleston Harbor bar, intending to reduce Fort Sumter at once, and proceed thence direct to the city; but the day turned out to be particularly foggy, and the attack was necessarily deferred until the following day. About noon, upon the 7th, the signal was given by Admiral Dupont from his flagship for the vessels to weigh anchor. According to the plan of attack the vessels were to form in the following order ahead, at intervals of one cable’s length: 1. Weehawken, Captain John Rogers; 2. Passaic, Captain Percival Drayton; 3. Montauk, Commander John L. Worden; 4. Patapsco, Commander Daniel Ammen; 5. New Ironsides, Commodore Thomas Turner; 6. Catskill, Commander George W. Rodgers; 7. Nantucket, Commander Donald McN. Fairfax; 8. Nahant, Commander John Downes; 9. Keokuk, Lieutenant-Commander Alexander C. Rhind. The squadron was then to pass up the main ship channel without returning the fire of the batteries on Morris Island, unless signalized to do so, and was to take up a position to the northward and westward of Fort Sumter, and engage its northwest face at a distance of from one thousand to eight hundred yards. A squadron of reserve, consisting of the Canandaigua, Unadilla, Housatonic, Wissahickon, and Huron, under the command of Captain Joseph H. Green, of the Canandaigua, was ordered to remain outside the bar, and be in readiness to support the iron-clads, when they should attack the batteries on Morris Island, which would be subsequent to the reduction of Fort Sumter.