guns on the channel side, commencing with Numbers 4, inclusive, are en barbette, although well protected from our fire, and also from flank fire, by high traverses. From Numbers 4 to Numbers 7, inclusive, 17 guns were seen, apparently very heavy, most of them.

Captain T. Talbot goes to Washington with dispatches. No supplies came from the city yesterday.

Very respectfully, your obedient servant,

J. G. FOSTER,

Captain, Engineers.

P. S.-The revenue cutter still lies off the left shoulder angle, and during the firing ran up the Confederate flag and kept it flying.

J. G. F.

NAVY DEPARTMENT, Washington, April 5, 1861.

Captain SAMUEL MERCER,

Commanding U. S. S. Powhatan, New York:

SIR: The United States steamers Powhatan, Pocahontas, and Harriet Lane will compose a naval force, under your command, to be sent to the vicinity of Charleston, S. C., for the purpose of aiding in carrying out the objects of an expedition of which the War Department has charge.

The primary object of the expedition is to provision Fort Sumter, for which purpose the War Department will furnish the necessary transports. Should the authorities at Charleston permit the fort to be supplied, no further particular service will be required of the force under your command, and after being satisfied that supplies have been received at the fort, the Powhatan, Pocahontas, and Harriet Lane will return to New York, and the Pawnee to Washington.

Should the authorities at Charleston, however, refuse to permit or attempt to prevent the vessel or vessels having supplies on board from entering the harbor, or from peaceably proceeding to Fort Sumter, you will protect the transports or boats of the expedition in the object of their mission-disposing of your force in such manner as to open the way for their ingress and afford, so far as practicable, security to the men and boats, and repelling by force, if necessary, all obstructions towards provisioning the fort and re-enforcing it; for in case of resistance to the peaceable primary object of the expedition a re-enforcement of the garrison will also be attempted. These purposes will be under the supervision of the War Department, which has charge of the expedition. The expedition has been intrusted to Captain G. V. Fox, with whom you will put yourself in communication, and co-operate with him to accomplish and carry into effect its object.

You will leave New York with the Powhatan in time to be off Charleston Bar, ten miles distant from and due east of the light-house, on the morning of the 11th instant, there to await the arrival of the transport or transports with troops and stores. The Pawnee and Pocahontas will be ordered to join you there at the time mentioned, and also the Harriet Lane, which latter vessel has been placed under the control of this Department for this service.

On the termination of the expedition, whether it be peaceable or otherwise, the several vessels under your command will return to the