The position of the troops of our army is as follows at this time: Sixth Corps, at Franklin's Crossing; Second Corps, near Falmouth; Twelfth Corps, near Brooks' and Aquia; Birney's (Third), on your right; Reynolds', moving to-day to vicinity of Bealeton; Howard, Hartwood last night, and to-day moving to Catlett's. In case of withdrawal, the orders will be sent you as speedily as possible. Should I telegraph you to "Send the wagon, " you will understand that the movement is ordered, the details being made up to send you; and send your teams off to the right, if it can be dome to-day without indicating the movement. All surplus wagons and impediments not absolutely necessary for movements should be sent off as per circular order issued a few days since. In the event of this wing of the army withdrawing by the Occoquan and Dumfries, on an inner line, General Reynolds will command the right.

Very respectfully,

DANL. BUTTERFIELD,

Major-General, Chief of Staff.

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CIRCULAR.] HEADQUARTERS Army of the Potomac, Camp near Falmouth, Va., June 13, 1863.

This army will be transferred from this line to the Orange and Alexandria Railroad. General Slocum will move with [his] corps at once, via Dumfries and the Occoquan, toward Alexandria. He will remain at Dumfries, on the Telegraph road, until the column of General Sedgwick has come up and passed, when he will resume his march across the Occoquan River, at Occoquan, and there await orders. General Sedgwick will move, via Dumfries, Greenwood, and Wolf Run Shoals, recrossing the Rappahannock soon after dark to-night, covering the withdrawal of the bridges, and furnishing any assistance necessary to General Benham for their withdrawal. The major-general commanding the Second Corps will cover the transfer of the portion of the army that moves via Dumfries in advance of General Sedgwick's column. The movements will be made so as to escape the notice of the enemy. The trains of each corps will precede it, and move on rapidly and without delay. General Meade will withdraw under the orders of General Reynolds. The point of concentration for the corps will be in the vicinity of Centreville. The Eight Pennsylvania Cavalry will withdraw their pickets after dark to-night, and the regiment will report to General Hancock for such service as he may require. General Hancock will send a strong cavalry picket to Banks' Ford, to guard that, after General Meade's infantry is withdrawn. General Reynolds will withdraw the forces on the right, making Manassas Junction by forced marches, and, if not ordered to the contrary, proceed to Centreville, and take position. The Engineer Brigade, with the Twentieth New York and Colonel Root's Ninety-fourth New York, will, under the command of

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, cover the withdrawal of the sick, supplies, &c., from the depots at Potomac Creek and Aquia, and be removed on transports.