Headquarters Eights Army Corps, Baltimore, Md.,

June 21, 1863-11. 15 p. m.

Captain M. V. WOODHULL, Harper's Ferry:

Train leaves here to-morrow morning. You know how it is between the Monocacy and the Ferry. There is nothing between the Monocacy and here. Be careful.

WM. H. CHESEBROUGH,

Assistant Adjutant-General.

BLOODY RUN, June 21, 1863.

Major-General COUCH:

One of my most reliable scouts, sent yesterday morning toward Hagerstown, sent back a dispatch this morning, stating that the rebel infantry force at Hagerstown is estimated at 40, 000, with eighteen pieces of artillery. There were 300 rebel cavalry at Mercersburg yesterday, gathering horses and cattle.

R. H. MILROY,

Major-General.

WAR DEPARTMENT, Washington, June 21, 1863-11. 30 a. m.

Major-General Couch, Harrisburg, Pa.:

Movements of the enemy indicate a raid against the Northern Central Railroad. Forces should be sent down to assist General Schenck in its protection. Block-houses and stockades should be erected at all the bridges. See the officers of the road, and get the assistance of their operatives in building block-houses, and defending bridges.

H. W. HALLECK,

General-in-Chief.

War DEPARTMENT, Washington, June 21, 1863-12 noon.

Major-General SCHENCK, Baltimore, Md.:

General Couch has been directed to assist in the defense of the Northern Central Railroad. Block-houses and palisades should be immediately constructed to protect the bridges. Railroad operatives and militia forces should be employed in their construction and defense. See railroad officers, and get their co-operation.

H. W. HALLECK,

General-in-Chief.

Harrisburg, June 21, 1863-6. 30 p. m.

Major-General HALLECK, Washington:

I have expected the Northern Central Railroad to be cut. However, I will try and protect five of the important bridges north of the Maryland line.

D. N. COUCH,

Major-General.