HDQRS. DEPT. OF THE GULF, NINETEENTH ARMY CORPS,
Vicksburg, Miss., August 1, 1863.

Major General H. W. HALLECK,

General-in-Chief, U. S. Army:

GENERAL: I have the honor to acknowledge the receipt of your telegram of the 27th July, transmitted to me by General Grant. I have already informed you of the condition of this department. The views I expressed in reference to other movements are strengthened by the occurrences of the day. The advantage of immediate operations against Mobile consists in the fact that its fortifications thus far are upon the Gulf and the bay. The rear of the city is unprotected except by a line of incomplete works, with few guns mounted, and is unprepared for an assault on the land side. In a short time these works will be completed, the guns mounted, the city provisioned, and the garrison strengthened. The army and people are now in such panic from the fall of Vicksburg and Port Hudson, that of attacked on the land side, where assault is not anticipated, and re-enforcements are not sent from the east at once, the place will probably be surrendered without serious contest. The approach by land from Portersville, on Mississippi Sound, is 25 miles; from Pascagoula, 65 miles. The country to Mobile is level and sandy. Roads can be made in any direction without labor.

From Pensacola they way is open to the rear of Mobile, from which all supplies can be cut off. The condition of troops on the Mississippi is such that rapid or long marches are impracticable. The movement against Mobile can be made by water, except a single march of 25 miles. Attacked from land, the water defenses are unavailable, and the forts will fall with the city.

The co-operation of the naval force now here is all that is required. Twenty-five thousand men, one corps of General Grant's army, with the available forces at New Orleans, are sufficient for the work. It is believed that Western Louisiana is free from any considerable force of the enemy.

The possession of Mobile gives the Government the control of the Alabama River and the line of railways east and west from Charleston and Savannah to Vicksburg, via Montgomery, and places the whole of Mississippi and Southern Alabama in position to resume at will their place in the Union. If the rebel Government loses this position, it has no outlet to the Gulf except Galveston. The operation need not last more than thirty days, and can scarcely interfere with any other movements east or west. I understand it to meet with General Grant's approval, if it be consistent with the general plans of the Government, upon which condition only I urge it. I send this from Vicksburg, having arrived here at 9 o'clock this morning, and return to New Orleans this evening.

I have the honor to be, with respect, your obedient servant,

N. P. BANKS,

Major-General, Commanding.

HDQRS. DEPT. OF THE GULF, NINETEENTH ARMY CORPS,
New Orleans, August 1, 1863.

Commanding Officer at Baton Rouge:

SIR: General Emory directs that you send the Fourth Wisconsin across the river to rive off and disperse some 200 of the enemy's cavalry, said to be at Madame Seager's plantation, 14 miles above