WAR DEPARTMENT, Washington City, November 5, 1862.

Major-General BURNSIDE,

Commanding, &c.:

GENERAL: Immediately on assuming command of the Army of the Potomac you will report the position of your troops and what you purpose doing with them.

Very respectfully, your obedient servant,

H. W. HALLECK,

General-in-Chief.

After some consultation, it was decided that General Buckingham and myself should proceed to the headquarters of General McClellan, then at Rectortown, where the order relieving General McClellan was delivered to him; after which it was decided that the orders which had already been issued by General McClellan, directing the movement of the army for concentration near Warrenton, with a view to accumulating supplies, and for other purposes, should be carried out, and that he should remain in command of the army until we reached Warrenton.

It was understood that the army was then moving, as near as possible, under certain general instruction contained in a letter from the President to General McClellan, a copy of which was sent to me under cover of the following letter, and is marked A in the appendix:

HEADQUARTERS OF THE ARMY, Washington, D. C., December 11, 1862.

Major-General BURNSIDE,
Commanding,&c.:

GENERAL: Your dispatch of the 7th was received last evening at 9 o'clock. I telegraphed to you this morning to arrange a meeting for to-morrow. I hope to hear from you to-night.

I inclose you herewith a copy of a letter from the President to General McClellan, dated the 13th of last month. I wish you to carefully consider the President's views, as contained in that letter, so that we may talk it over understandingly to-morrow. General Meigs and General Haupt will accompany me.

Yours, truly,

H. W. HALLECK,

General-in-Chief.

On the 9th day of November General McClellan issued an order relinquishing the command of the army, after which an order was issued from my headquarters assuming command.

The positions of the different corps of the army were as follows: The First, Second, Ninth Corps, with Stoneman's and Whipple's divisions, on both sides of the river, in the neighborhood of Waterloo; Eleventh Corps at Gainesville, New Baltimore, and the gaps; Pleasonton at Jefferson and Amissville, with advance on Hazel River; Bayard at Rappahannock Station and neighborhood; Slocum was still at Harper's Ferry and Fayetteville. There were no pontoons with the moving army at this time, and our supplies had run very low. It will be observed that directions were given in the order from General Halleck to me, dated November 5, to report at once a plan for the future operations of the army, which was done, and is marked B in the appendix. This plan had been fully matured, and was at the time understood to be in accordance with the views of most of the prominent general officers in accordance with the views of most of the prominent general officers in the command. It had been written out and was sent to Washington by Major E. M. Neill on November 10, and delivered to General Halleck telegraphed me that he would meet me at Warrenton on the next day [the 12th], which he did, accompanied by Generals Meigs and Haupt. During that night and the next morning we had long consultations. General Halleck was strongly in favor of continuing the movement of