batteries on both Cooper and Ashly Rivers; for the iron steamers at least may pass by Castle Pickney without much damage. Still, to possess the harbor, it would be necessary to take that work, and it would be easy to do so by an attack on all sides after the capture of the works above mentioned. Fort Johnson and the other works around Charleston would, I think, be abandoned by the enemy.

I will now briefly discuss the modus operandi and the details, premising that all our knowledge of the channels and of the adjacent harbors is derived from the charts and notes of the Coast Survey and from the excellent map of Colonel Hartman Bache, of the Topographical Engineers, published in 1825. I have myself, as light-house inspectors, been somewhat familiar with Charleston Harbor, and have passed through the inner channel from that harbor to Bull's Bay.

BASE OF OPERATIONS-ADJUTANT HARBORS.

Bull's Bay, 21 miles est of Fort Moultrie, is an excellent harbor, of easy entrance, with 13 feet on the bar at low water and 18 feet at high water. This place is said to be fortified. There are sand hills, immediately behind the light-house, some 50 feet above the water, with a counter-slope and ravines affording excellent cover for infantry.

If the fortifications have been placed on these hills, which are according to my recollection, about one-fourth mile from the beach, it will be necessary, probably in order to seize, to assail by land as well as by water. Troops may be landed from boats on the beach, as Professor Bache states, about 3 miles from the northeast bluff. I am disposed to think the enemy would abandoned this place, if they have not already done so, as soon as they perceived that they an attack was to be made in force. If they make a stand, the entire garrison ought to be captured. With one or more iron-clad vessels and some vessels of small draught and armed barges we can, I think, take possession of the entire channel around Bull Island. Escape by water would be impossible. Escape by land could only be made at low water through the marshes at the divide, and this I think would be very difficult. The next of any importance, proceeding towards Charleston, is

Dewees' Inlet, 9 miles from Fort Mountrie, with 7 feet on the bar at low water and 12 feet at high water, and a good anchorage inside.

Beach Inlet, at the eastern end of Sullivan's Island, about 3 miles from Fort Moultrie, can be entered by boats and barges at high water Passing by Charleston Harbor, the first inlet west is.

Light-House Inlet, 4 1\2 miles west of Fort Sumer and less than 1 mile from Charleston light. Boats entering here can pass through interior channels to Stono River and to Charleston.

Stono Inlet, about 8 miles westerly from Charleston main bar, has about 8 feet any low water and probably 13 feet at high water. It is said to be fortified.

North Edisto Inlet, 18 miles south westerly from Charleston Bar, has 13 feet at low water and 19 feet at high water. It is, or has recently been, in our possession.

CHANNELS OF CHARLESTON HARBOR.

Sullivan's Island Channel, recently obstructed by "stone ships," has 11 feet at low water, 16 or 17 feet at high water.

North Channel, still open, 8 feet at low water, 13 or 14 feet at high water.