Cavalry: First U. S. Cavalry, Eight Pennsylvania Cavalry, Colonel Gregg, now serving with Porter's division, Third Army Corps; Barker's squadron of Illinois Cavalry; Captain Mann's Fifth Company of Oneida Cavalry. The Third Indiana, now with Hooker's division, Third Army Corps, to report for duty to Brigadier General James S. Wadsworth, Military Governor of the District of Columbia. Such of the above-named regiments and detachments as are not now serving with the commands to which they are assigned will be immediately reported by letter to the commanderes indicated, but will continue on duty as at present until further orders. A full report of the strength and condition of each regiment and detachment of cavalry will be immediately forwarded to these headquarters through the chief of cavalry.

By command of Major-General McClellan:

S. WILLIAMS,

Assistant Adjutant-General.

[11 and 12.]

HEADQUARTERS ARMY OF THE POTOMAC, March 24, 1862.

General R. B. MARCY,
Chief of Staff:

Please have operator at Winchester keep me constantly informed as to state of affairs. Ascertain how many troops are left at Harper's Ferry, and what went from there to the front. The railroad and bridge should not be left entirely unguarded.

GEO. M. McCLELLAN,

Major-General.

[12.]

HEADQUARTERS ARMY OF THE POTOMAC, Seminary, March 24, 1862-10.30 a. M.

General J. G. BARNARD,
Chief Engineer, Washington:

I am endeavoring to get some accurate data as to width of streams. It seems to me a necessity that we should have at least enough bateau with Third and Fourth Corps to form a bridge for heavy artillery; all beyond that should go to First Corps. The fact as sending train to Third Corps does not make it necessary to land them all there; they will be available for First Corps, while if they remain here with the First Corps, the Third and Fourth may be tied fast.

GEO. B. McCLELLAN,

Major-General.

[11.]

WAR DEPARTMENT, Washington City, D. C., March 26, 1862.

His Excellency Governor SPRAGUE:

SIR: It is the desire of this Department that you should accompany the forces of the United States now operating from the Potomac, and render assistance in the care and comfort of the troops from your State, and make report to this Department. You are authorized to receive your necessary transportation, forage, and subsistence, and the officers