These troops will be instructed to report on their arrival at Manassas to Brigadier-General Sumner, or, in the event of his having left, to Brigadier-General Abercrombie. They will be employed as long as their services may be required for the purpose of constructing the field works to be thrown up at Manassas, which will be laid out by Lieutenant Colonel B. S. Alexander, aide-de-camp, and constructed under the superintendence of Captain Munther, aide-de-camp and engineer.

The commanding general also directs that you send with the least possible delay a regiment of infantry to Budd's Ferry, to relieve Hooker's division, to arrive before the last of the division leaves, and it will embark on Thursday or Friday of the present week.

The regiment of infantry to be sent to Budd's Ferry will report to Colonel Carter, Third Indiana Cavalry, and be guided by such instructions as that officer may give.

The order heretofore in force in General Hooker's command respecting the intercourse with the Virginia shore will be fully carried out.

I am, very respectfully, your obedient servant,

S. WILLIAMS,

Assistant Adjutant-General.

STEAMER COMMODORE, April 1, 1862. (Received April 2, 1 a.m.)

Honorable E. M. STANTON,

Secretary of War:

Have instructed General Sumner to move two brigades of Blenker on Strasburg as soon as he learns that 4,000 men will join him promptly from Wadsworth's command. Please expedite this. My letter explains fully.

GEO. B. McCLELLAN,

Major-General.

HEADQUARTERS ARMY OF THE POTOMAC, April 1, 1862.

Brigadier-General WADSWORTH,
Mil. Gov. of the Dist. of Columbia, Washington, D. C.:

If the cavalry under General Hatch has not all left Washington, please direct him to send two regiments to report to General Abercrombie at Warrenton Junction. If General Hatch has left with the four regiments, please send directions for the two regiments in rear to proceed to Warrenton Junction by the shortest route.

The intention is that two of the hour regiments are to go to Winchester and two to Warrenton Junction. The regiments assigned to General Hatch are the First Vermont, First New England, Fifth New York, and First Maine Cavalry Regiments.

GEO. B. McCLELLAN,

Major-General, Commanding.

HEADQUARTERS ARMY OF THE POTOMAC,
Steamer Commodore, Midnight, April 1, 1862.

Brigadier General E. V. SUMNER,

Warrenton:

If you learn of 4,000 men being about to join you from General Wadsworth, you can detach two brigades of Blenker's division, under General