U. S. GUNBOAT FAIRPLAY, February 22, 1863.

Brigadier General Greenville M. DODGE,

Corinth, MISS.:

GENERAL: I have just received your letter of the 21st instant. I am sorry to say that Van Dorn had already crossed the river; most of his force crossed above Big Muscle Shoals, where we could not reach him with gunboats. He has about 5,000 cavalry, and is now with Wheeler and Forrest at Columbia. There are some guerrillas on the opposite side of the river from Florence, back from the river about 2 or 3 miles. I have destroyed all flats or ferries as high up as I could get-about 6 miles above Florence.

Very respectfully, your obedient servant,

LE ROY FITCH,

Commanding Gunboats.

CORINTH, MISS., February 23, 1863.

Major General U. S. GRANT,

Opposite Vicksburg:

SIR: There are some matters south of this that may be of interest to you, and perhaps I may be excused for communicating them direct. They have been sent, part of them, to my immediate commanders. The scouts posted at Mobile, Meridian, and Jackson have sent in long reports, and the substance of those that can be relied upon are about as follows:

1. No troops have come to Pemberton's army since Smith's 10,000 joined him about Christmas.

2. All troops from Mobile up the road, and from Grenada, have gone to Vicksburg and Port Hudson, leaving a few thousand at Mobile, some 600 at Meridian, and two regiments at Jackson, and about three regiments of militia at Grenada. A portion that left Grenada are posted on Black River. Everything in the shape of cavalry, even to the partisan rangers as low down as Port Hudson, joined Van Dorn in his move to Tennessee, leaving perhaps a regiment or two north of Grenada, a few at Okolona, and a few companies just south of me. Everything in the shape of Government property has been taken away form the country bordering the Yazoo and adjacent streams, and all prominent points, such as Jackson, Grenada, Columbus, &c. At Jackson the foundries are running and a cotton-mill or two, and perhaps a Government shoe and clothing shop, but every preparation is being made to take them away. WEST Mississippi is being entirely stripped of stock, provisions, forage, &c., and everything indicates that they are getting ready for a quick move.

In the last ten days some 3,000 negroes have been pressed and put to work at Columbus, MISS., and one or two points near Meridian, while the great stock of cars and engines at Meridian are being taken east and south. I appears to be the opinion of the scouts that the enemy are making preparations to take up the line of the Tombigbee for the go up Big Black, when their army will have to take position to save Selma and Mobile.

The trains go loaded from Vicksburg daily with sick and discharged soldiers. They say that they average 12 cars a day. Last week two heavy steamboat engines and the prow to a ram went up the road to Jackson; said to be placed in some boat in the Yazoo.

Deserters and conscripts are flocking into my lines daily, and, so far