WASHINGTON, D. C. May 18, 1863-11 a. m.

General BURNSIDE, Cincinnati, Ohio, and

General ROSECRANS, Murfreesborough, Tenn.:

Dispatches just received say that General Joe Johnston, with a considerable force, has left Tennessee to re-enforce Vicksburg. To cover this movement, the enemy will probably threaten an advance, and attempt raids into Kentucky and Tennessee. The best way to counteract this is to concentrate your forces and advance against the enemy in Tennessee, moving, if possible, in such a manner as to threaten East Tennessee.

H. W. HALLECK.

MEMPHIS, TENN., May 18, 1863-11 p. m.

Major General H. W. HALLECK, General-in-Chief:

Scouts report all the cars on Mobile and Ohio Railroad below Okolona drawn off south to transport troops to Jackson. Mobile papers of the 14th admit defeat of Gregg and Walker, but say heavy re enforcements are moving on General Grant from South Carolina, Georgia, and Tennessee, and that he will be crushed. Estimated his force at 50,000. General Grant has taken Jackson; capitol burned. From 6,000 to 10,000 mounted men are concentrating near Okolona, threatening advance in the direction of this railroad. A citizen just up from Jackson reports that the enemy abandoned Vicksburg on Saturday, marching on the ridge northeast to Lexington.

S. A. HURLBUT.

UNITED STATES Mississippi SQUADRON,

Flag-ship Black Hawk, near Vicksburg, May 18, 1863.

Major General STEPHEN A. HURLBUT,

Commanding, &c., Memphis, Tenn.:

GENERAL: I am not in any way authorized to say so, but my opinion is that General Grant should be re-enforced with all dispatch, and with every man that can be sent him from all directions.

He will have the hardest fight ever seen during this war. The attention of the nation should now be devoted to Vicksburg.

I received your communication in relation to Dr. Dickenson, and have referred the matter to the honorable Secretary of the Navy.

Captain Breese sent Dr. Dickenson to Memphis to collect evidence.

Very respectfully, your obedient servant.

DAVID D. PORTER

JACKSON, May 18, 1863.

Lieutenant-Colonel BINMORE, Assistant Adjutant-GENERAL:

Three men in from Meridian last night report railroad in running order to Jackson for last ten days. Confirms tenor of last dispatches from that quarter. Roddey is reported crossing Big Bear Creek, and Forrest at Clifton, crossing. I hardly believe this can be true to any extent. Dodge is watching every point closely. One man was killed yesterday by shell thrown across from Savannah.

R. J. OGLESBY.