The gun-boat Selma was chased up the bay 4 miles by the Metacomet and captured, the gun-boat Gaines disabled and run ashore at Fort Morgan. The Phillipp, a small dispatch steamer of ours, attempting to follow the fleet, was burned by the enemy's shells.

From the monitor Tecumseh only 2 officers and 13 men were saved; the gallant Captain Craven lost with all the rest. In addition to this loss, the casualties in our fleet were about 60 killed and wounded.

Admiral Buchanan, with his right leg badly shattered at the knee, was brought in, with 55 other wounded from both sides, to the navy-yard hospital; the brave Captain Mullany, commanding the Oneida, among them, with his right arm shot off. The rebel gun-boat Morgan escaped and put to sea.

Captain Jouett delivered to the commander of Fort Morgan this morning the written demand of Admiral Farragut of surrender the fort, and will call for the answer to-morrow morning.

By this brilliant victory our gallant navy have obtained great advantages, and, separating Forts Morgan, Gaines, and Powell, secured for themselves a safe anchorage, with full control of the forts and bay up to the city. The chartered steam transport Merrimac, Captain Frederick A. Sampson commanding, arrived this morning with one battalion of the Second Maine Cavalry, Colonel Woodman commanding, and is disembarking at the navy-yard. The steam transport Mississippi, with the Second Battalion on board, was left behind yesterday evening, aground at the Southwest Pass of the Mississippi River. I expect her in to-night, and as soon as the Second Battalion is disembarked will start to cross the Perdido and control the east shore of Mobile Bay. The horses of the Second Maine Cavalry are in poor condition and the men very sickly, but there is no time at present for recuperation; they will have to move at once.

I am, major, very respectfully, your obedient servant,

ASBOTH,

Brigadier-General.

HEADQUARTERS DEPARTMENT OF THE SOUTH,
Hilton Head, S. C., August 8, 1864.

Major General H. W. HALLECK,

Chief of Staff of Armies of United States, Washington, D. C.:

GENERAL: The balance of Brigadier General William Birney's brigade leaves here to-night and to-morrow morning, having just arrived from Florida. It is stronger than I thought, looking at the returns, for now that the extra-duty men are in it numbers 3,000 effectives. It is a good brigade. I shall do whatever can be done in the way of small raids with the troops that remain. The enemy is strengthened by the arrival of the battalions of militia which have been called out in South Carolina by General Samuel Jones and in Georgia by Governor Brown. This body of militia, or at least that portion of it that is now daily reporting at Savannah and Charleston, is reported by deserters as being considerable in point of numbers, 500 arriving daily, but very inferior in all that goes to make good soldiers. I have no fears of anything they can do against us. They are fearing an attack from us. The health of the department continues good.

Very respectfully, your obedient servant,

J. G. FOSTER,

Major-General, Commanding.