From this it will be seen that the positions selected by the enemy at Centreville and Manassas were naturally very strong, with impassable streams and broken ground, affording ample protection for their flanks, and that strong lines of entrenchments swept all the available approaches.

Although the history of every former war has conclusively shown the great advantages which are possessed by an army acting on the defensive and occupying strong positions, defended by heavy earthworks, yet at the commencement of this war but few civilians in our country, and indeed not all military men of rank, had a just appreciation of the fact.

New levies that have never been in battle cannot be expected to advance without cover under the murderous fire from such defenses and carry them by assault. This is work in which veteran troops frequently falter and are repulsed with loss. That an assault of the enemy's positions in front of Washington, with the new troops composing the Army of the Potomac, during the winter of 1861 - '62, would have resulted in defeat and demoralization, was too probable.

The same army, though inured to war in many battles, hard-fought and bravely won, has twice, under other generals, suffered such disasters as it was no excess of prudence then to avoid. My letter to the Secretary of War, dated February 3, 1862, and given above, expressed the opinion that the movement to the Peninsula would compel the enemy to retire from his position at Manassas and free Washington from danger. When the enemy first learned of that plan, they did thus evacuate Manassas. During the Peninsular campaign, as at no former period, Northern Virginia was completely in our possession and the vicinity of Washington free from the presence of the enemy. The ground so gained was not lost, nor Washington again put in danger, until the enemy learned of the orders for the evacuation of the Peninsula, sent to me at Harrison's Bar, and were again left free to advance northward and menace the national capital. Perhaps no one now doubts that the best defense of Washington is a Peninsula attack on Richmond.

My order for the organization of the army corps was issued on the 13th of March. It has been given above.

While at Fairfax Court-House, on March 12, I as informed through the telegraph by a member of my staff that the following document had appeared in the National Intelligence of that morning:

PRESIDENT'S WAR ORDER, EXECUTIVE MANSION,

Washington, March 11, 1862.

Numbers 3.

Major-General McClellan having personally taken the field at the head of the Army of the Potomac, until otherwise ordered he is relieved from the command of the other military departments, he retaining command of the Department of the Potomac.

Ordered further, That the departments now under the respective commands of Generals Halleck and Hunter, together with so much of that under General Buell as lies west of a north and south line indefinitely drawn through Knoxville, Tenn., be consolidated and designated the Department of the Mississippi, and that, until otherwise ordered, Major-General Halleck have command of said department.

Ordered also, That the country west of the Department of the Potomac and east of the Department of the Mississippi be a military department, to be called the Mountain Department, and that the same be commanded by Major-General Fremont.

That all the commanders of departments, after the receipt of this order by them, respectively report severally and directly to the Secretary of War, and that prompt, full, and frequent reports will be expected of all and each of them.

ABRAHAM LINCOLN.

Though unaware of the President's intention to remove me from the position of General-in-Chief, I cheerfully acceded to the disposition he.