the armies in the field anticipates an attack, and from the rear, and the major-general commanding enjoins strict vigilance on the part of all the troops, but especially upon the cavalry. Please let me know with some detail the line of cavalry pickets, and have them pushed out as far as practicable, particularly on the west and southwest. The various attacks on the cavalry pickets a few days ago may have been for the purpose of ascertaining the best mode of approaching and attacking our rear, and the pickets should, therefore, be pushed out farther. Please enjoin upon all the necessity of prompt and rapid communication of intelligence of the enemy.

A. A. HUMPHREYS,

Major-General and Chief of Staff.

HEADQUARTERS ARMY OF THE POTOMAC,
September 4, 1864.

Brigadier-General GREGG,

Commanding Cavalry:

In the evening of an attack by the enemy on our rear, it is probable their cavalry would endeavor to cross the Blackwater at some points below where we hold, and come up upon our trains between City Point and our lines. Please keep this in view as among the contingencies.

A. A. HUMPHREYS,

Major-General and Chief of Staff.

SPECIAL ORDERS,
HDQRS. ARMIES OF THE UNITED STATES,

Numbers 87.
City Point, Va., September 4, 1864.

* * * * *

IV. On surgeon's certificate of disability, leave of absence for fifteen days is hereby granted Major General E. O. C. Ord, commanding Eighteenth Army Corps.

V. Major General John Gibbon, U. S. Volunteers, is hereby temporarily assigned to the command of the Eighteenth Army Corps.

By command of Lieutenant-General Grant:

T. S. BOWERS,

Assistant Adjutant-General.

HEADQUARTERS TENTH ARMY CORPS,
September 4, 1864.

Brigadier General SETH WILLIAMS,

Assistant Adjutant-General:

I have the honor to transmit the following report received from the signal officer:

3.50 P. M.

The lookout at Friend's house reports a column of troops 2,500 strong, with four stand of colors, coming from Richmond toward Petersburg.

D. B. BIRNEY,

Major-General.