the column exposed to attack from their advanced positions, and on getting as far to the right as Vienna, have our line exposed to interruption, for Vienna is nearer to the enemy than it is to Falls Church or the camps on the Georgetown road.

To go farther to the right could not safely be done, even by a force superior to that the enemy can bring against us. I think a glance at the map will show this. Any reverse happening to this raw force, pushed farther along, with the enemy on the flank and rear and an impassable river on the right, would be fatal. I do not think, therefore, it safe to risk anything from this position in the direction of Leesburg farther than Vienna, seven miles by the Leesburg turnpike from Falls Church, and even togo there the force should be large. Vienna could be supplied or re-enforced-

1st. By the Leesburg road from Falls Church.

2st. By the railroad from Alexandria.

3rd. By the dirt road from Ball's Cross-Roads.

The first two are liable to interruption unless strongly guarded, and the third is an indifferent road and a long one. The force, then, to go as far as Vienna should be large enough to hold the position for several hours, and should be well supplied with artillery and cavalry and strengthened by such defenses as could be readily thrown up. Vienna being held in force, and offensively, would cover the country from the Difficult Creek well towards Goose Creek from any force of the enemy operating from Manassas Junction or its dependencies, and I have never heard of there being over 500 men, mostly local troops, at Leesburg. As it would be constantly liable to be attacked by all the available force of the enemy and is only a few hours' march from him, it would be necessary to have strong reserves ready at either Falls Church or the camp of the Ohio brigade.

The force sufficient to hold Vienna cannot well be stated, because of the changes which are taking place in front of us. I do not think it prudent to go there with less than 8,000 infantry, a battery of field regular rifled artillery, with some guns in position, and six companies of cavalry, and the line from Fort Corcoran to General Tyler to be held as strong as at present, and a reserve on that line of 3,000 men; some of the force to be organized into small field brigades, as heretofore proposed, under regular colonels.

I have the honor to be, very respectfully, your obedient servant,

IRVIN McDOWELL,

Brigadier-General, Commanding.

HDQRS. DEPARTMENT NORTHEASTERN VIRGINIA, Arlington, June*-, 1861.

Lieutenant Colonel E. D. TOWNSEND,

Asst. Adjt. General, Headquarters of the Army:

COLONEL: I have the honor to submit the following plan of operations, and the composition of the force required to carry it into effect, in compliance with the verbal instructions of the General-in-Chief:

The secession forces at Manassas Junction and its dependencies are supposed to amount at this time to-

Infantry......................................... 23,000

Cavalry.......................................... 1,500

Artillery........................................ 500

25,000

*About June 24, 1861?