4th. That the force to be left to cover Washington shall be such as to give an entire feeling of security for its safety from menace. (Unanimous.)

II. If the foregoing cannot be, the army should then be moved against the enemy, behind the Rappahannock, at the earliest possible moment, and the means for reconstructing bridges, repairing railroads, and stocking them with materials sufficient for supplying the army should at once be collected for both the Orance and Alexandria and Aquia and Richmond Railroads. (Unanimous.)

N. B. - That with the forts on the right bank of the Potomac fully garrisoned and those on the left bank occupied a covering force in front of the Virginia line of 25,000 men would suffice. (Keyes, Heintzelman, and McDowell.) A total of 40,000 men for the defense of the city would suffice. (Sumner.)

This was assented to by myself and immediately communicated to the War Department. The following reply was received the same day:

WAR DEPARTMENT, March 13, 1862.

The President having considered the plan of operations agreed upon by yourself and the commanders of army corps, makes no objection to the same, but gives the following directions as to its execution:

1. Leave such force at Manassas Junction as shall make it entirely certain that the enemy shall not reposes himself of that position and line of communication.

2. Leave Washington entirely secure.

3. Move the remainder of the force down the Potomac, choosing a new base at Fortress Monroe, or anywhere between here and there, or, at all events, move such remainder of the army at once in pursuit of the enemy by some route.

EDWIN M. STANTON,

Secretary of War.

Major General GEORGE B. MCCLELLAN.

My preparations were at once begun in accordance with these directions, and on the 16th of March the following instructions were sent to Generals Banks and Wadsworth:

HEADQUARTERS ARMY OF THE POTOMAC,
March 16, 1862.

SIR: You will post your command in the vicinity of Manassas, intrench yourself strongly, and throw cavalry pickets well out to the front.

Your first care will be the rebuilding of the railway from Washington to Manassas and to Strasburg, in order to open your communication with the valley of the Shenandoah. As soon as the Manassas Gap Railway is in running order, intrench a brigade of infantry, say four regiments, with two batteries, at or near the point where the railway crosses the Shenandoah. Something like two regiments of cavalry should be left in that vicinity to occupy Winchester and thoroughly scour the country south of the railway and up the Shenandoah Valley, as well as through Chester Gap, which might perhaps be advantageously occupied by a detachment of infantry, well entrenched. Block-houses should be built at all the railway bridges. Occupy by grand guards Warrenton Junction and Warrenton itself, and also some little more advanced point ton the Orange and Alexandria Railroad as soon as the railway bridge is repaired..

Great activity should be observed by the cavalry. Besides the two regiments at Manassas, another regiment of cavalry will be at your disposal to scout towards the Occoquan, and probably a fourth towards Leesburg.

To recapitulate, the most important points which should engage your attention are as follows:

1. A strong force, well entrenched, in the vicinity of Manassas - perhaps even Centreville; and another force (a brigade), also well entrenched, near Strasburg.

2. Block-houses at the railway bridges.

3. Constant employment of the cavalry well to the front.

4. Grand guards at Warrenton Junction, and in advance as far as the Rappahannock, if possible.

5. Great care to be exercised to obtain full and early information as to the enemy..

6. The general object is to cover the line of the Potomac and Washington.

The above is communicated by command of Major-General McClellan.

S. WILLIAMS,

Assistant Adjutant-General.

Major General N. P. BANKS,

Commanding Fifth Corps, Army of the Potomac.