HDQRS. DEPT. OF THE GULF, NINETEENTH ARMY CORPS, New Orleans, July 19, 1863.

Major-General HALLECK,
Commander-in-Chief, &c.:

GENERAL: I left Port Hudson Wednesday, the 15th instant, reaching this city on the 18th, for the purpose of expediting the movements of the gunboats into Berwick Bay. They said to-day, not in season, I fear, to prevent the enemy's passage across the bay with whatever material he may have in this possession. It is reported, and I believe correctly, that they were crossing as early as Wednesday, having brought two or that they were crossing as early as Wednesday, having brought two or three steamers from Red River to aid them. It was impossible to prevent this, excepting by the occupation of the bay by the gunboats, and Admiral Farragut assures me that he has made every effort to facilitate their movement; but it has been unavailing till now. We have but four boats that can cross the bar at the present low stage of water, and these were so much out of repair, after long service, that they could not be at once moved.

Everything remains quiet at Port Hudson. The troops are stationed at that point, at Baton Rouge, and at Donaldsonville. We shall soon reoccupy the La Fourche district.

The nine-months' regiments will be sent home at once by sea, the expense to the Government being much less that way.

The officers of the garrison at Port Hudson are in confinement here. The men have been paroled.

The city of New Orleans is perfectly quiet, and has been in no danger whatever during the campaign, notwithstanding the representations made to the public. The departure of so many troops leaves my force quite small, and I hope the Government may now be able to re-enforce the army here, where it is so much needed.

The news of the repulse of Lee's army up the 7th has filled us all with joy, and we believe that if the victories of the east are confirmed with joy, and we believe that if the victories of the east are confirmed the war must be considered near its end. I have the honor to acknowledge the receipt of your letter covering intercepted dispatches from Jefferson Davis.

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

N. P. BANKS,

Major-General, Commanding.

HEADQUARTERS DEFENSES OF NEW ORLEANS, July 20, 1863.

Major General N. P. BANKS:

GENERAL: In the absence of your [chief of] staff, I take the liberty of addressing you directly upon a subject which I think of sufficient interest to present directly to your attention without passing it through the adjutant-general's office, still at Port Hudson.

The defenses of this city are essentially those projected by the enemy, and are based upon three considerations, none of which exist at this time.

1. Upon the presence of a large defending force, say, at least, 10,000 men.

2. Upon a population supposed to be in the main friendly, if not wholly so.

3. Upon a high stage of water and the filling of the swamps, which at that season are impossible.