WASHINGTON, July 15, 1863-7.30 a.m.

General PRENTISS, Helena:

It is reported that Price is moving north. All available forces should immediately move on his rear so as to cut off his retreat. The forces in Missouri will prevent his penetrating far into that State, and, if he is cut off in rear, his forces must disperse or surrender. Apply to the naval commander for co-operation with gunboats on White River. No time should be lost.

H. W. HALLECK,

General-in-Chief.

WAR DEPARTMENT,

Washington, July 15, 1863-10 a.m.

Major-General SCHOFIELD, Saint Louis, MO.:

General Prentiss has been ordered to move on Price's rear. If properly resisted in Missouri by General Davidson, he must either disperse or surrender.

H. W. HALLECK,

General-in-Chief.

SAINT LOUIS, MO.,

July 15, 1863-10.30 p.m.

Major-General HALLECK,

General-in-Chief:

General Davidson will move forward immediately, and assist the forces from Helena. Please inform me if Eastern Arkansas is to be restored to this department. With your approval, I wish to go there myself soon.

J. M. SCHOFIELD,

Major-General.

CAPE GIRARDEAU, MO.,

July 15, 1863-8.30 a.m.

Major-General SCHOFIELD:

I rode over here last night, as my line is not working yet,to talk with you. I sent Captain [Byron O.] Carr up for more transportation. Our roads were horrible. It is impossible to get to New Madrid until the water in the swamps subsides, and then it will take great labor to repair the roads. Harding is safe from the enemy at New Madrid with a platoon. I think the Twenty-fourth Missouri ought to be sent to the Cape. I am working the road to Poplar Bluff, and have troops at Saint Francisville; also troops at Saint Luke, and repairing the road to Chalk Bluff. I am throwing up works at Bloomfield for a permanent garrison. The Cairo and Fulton Railroad ought to be repaired by the Government. I have written you fully on this and other subjects by Captain Carr. Glenn thinks his scouts are all captured. I telegraphed you the last information I had from a prisoner. Price, I believe, is on the Ridge. If you will give me some infantry I will be glad to go down either on the Ridge or to Batesville. I leave here at 12 m. to-day. Carr will carry you full information.

J. W. DAVIDSON,

Brigadier-General.