In my rear it is impossible to prevent hostile forces from crossing the Tennessee and taking positions of annoyance in the country above me, from which they have to be dislodged by cavalry from La Grange and Corinth.

The forces in the District of Columbus are of no use for offensive purposes, and barely so for defensive, under their present officers. There seems to be a continual fight in that command. Under these circumstances, there is no possibility of sending any force from the remnant of the SIXTEENTH Army Corps now here to Arkansas, without serious peril to our hold upon this line.

I have requested General Grant to return me a DIVISION, and have forwarded the telegram of the General-in-Chief to him. Memphis requires as garrison, to cover its immense stores, to protect its hospitals, and, not least, to prevent smuggling, at least eight regiments, and this necessity will exist until the operations of the army below shall destroy the basis upon which the advanced line of the enemy now rests.

I await this time hopefully, and as soon as I learn that fact shall throw all my cavalry and mounted infantry, supported by a brigade from Corinth, first upon Roddey at Bear Creek, and thence on Okolona.

I am, colonel, your obedient servant,

S. A. HURLBUT.

HDQRS. DEPT. OF THE TENN., Vicksburg, MISS., July 19, 1863.

Major General STEPHEN A. HURLBUT, Memphis, Tenn.:

GENERAL: The major-general commanding directs me to respectfully inform you that General Joe Johnston has evacuated Jackson, after destroying most of the place, and retreated east. Pursuit was found impracticable. Sherman has captured between 500 and 600 prisoners, destroyed the railroad beyond the hope of repair in every direction, and burned a large number of locomotives and cars. A considerable amount of rolling-stock was sent to Grenada.

I have the honor to be, general, very respectfully, your obedient servant,
JNO. A. RAWLINS,

Assistant Adjutant-General.

Vicksburg, MISS., July 20, 1863.

General WASHBURN, Snyder's Bluff:

General Kimball's DIVISION in readiness to be moved up the river as soon as possible. Boats will be ordered as soon as coal arrives to furnish fuel. Full instructions will be given before the troops leave.

U. S. GRANT.

Vicksburg, MISS., July 20, 1863.

General WILLIAM T. SHERMAN:

The heat and dust being suffocating, you may take your own time returning. You can locate your forces on Big Black, or return to your former position at your own option. By scattering the troops on high ground it may be more healthy than having them close together. No eastern news.

U. S. GRANT.