EXECUTIVE MANSION, WASHINGTON, March 8, 1862. ORDERED, That no change of the base of operations of the Army of the Potomac shall be made without leaving in and about Washington such a force as, in the opinion of the General-in-chief and the commanders of army corps, shall leave said city entirely secure. That no more than two army corps (about fifty thousand troops) of said Army of the Potomac shall be moved en route for a new base of operations until the navigation of the Potomac, from Washington to the Chesapeake Bay, shall be freed from the enemy's batteries, and other obstructions, or until the President shall hereafter give express permission. That any movement as aforesaid, en route for a new base of operations, which may be ordered by the General-in-chief, and which may be intended to move upon Chesapeake Bay, shall begin to move upon the bay as early as the 18th of March, instant, and the General-in-chief shall be responsible that it moves as early as that day. ORDERED, That the Army and Navy coöperate in an immediate effort to capture the enemy's batteries upon the Potomac between Washington and the Chesapeake Bay. L. THOMAS, Adjutant-General. ABRAHAM LINCOLN. On the 9th of March, the steamer Merrimac, which had been taken possession of by the insurgents at Norfolk, after the abandonment of that post in the spring of 1861, and converted into a formidable iron-clad vessel, re-named the Virginia, attacked and destroyed the Government sailing frigates Cumberland and Congress. The Minnesota, in coming to their assistance, ran aground. For awhile, all the shipping in the harbor seemed at the mercy of the Rebel monster. But the timely arrival of Ericsson's Monitor, just completed, and hitherto regarded as a doubtful experiment, ended the work of destruction, and caused the Merrimac to retire within shelter at Norfolk. These hurried and startling events caused great sensation at the time, both in this country and abroad, and have had a marked influence in regard to naval armaments every-where. McClellan having now taken the field, so that a supervision of all the armies of the nation was clearly out of his power, the President made public a change that was no secret to the General commanding the Army of the Potomac, through the following order-in which, also, two separate departments were created in the West, to be commanded by Gens. Halleck and Buell, and a third intermediate department, under the command of Gen. Fremont: EXECUTIVE MANSION, WASHINGTON, President's War Order, No. 3.] } Maj.-Gen. 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 Poto mac. ORDERED, FURTHER, That the two departments now under the respective commands of Gens. Halleck and Hunter, together with so much of that under Gen. Buell as lies west of a north and south line indefinitely drawn through Knoxville, Tennessee, be consolidated and designated the Department of the Mississippi, and that until otherwise ordered Maj.-Gen. 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 Maj.-Gen. Fre mont. 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. Gen. McClellan telegraphed to the Secretary of War from Fairfax Court House, on the 13th of March, that a council of the commanders of army corps had "unanimously agreed upon a plan of operations," which Gen. McDowell would lay before him. To this the Secretary, on the same day, replied: "Whatever plan has been agreed upon, proceed at once to execute, without losing an hour for any approval." The plan which, in answer to a question of Mr. Stanton, Gen. McClellan stated that "the council, together with himself," were unanimous in forming--was given in these words: HEADQUARTERS ARMY OF THE POTOMAC, } FAIRFAX COURT HOUSE, March 13, 1862. A council of the Generals commanding army corps, at the headquarters of the Army of the Potomac, were of the opinionI. That the enemy having retreated from Manassas to Gordonsville, behind the Rappahannock and Rapidan, it is the opinion of the Generals commanding army corps that the operations to be carried on will be best undertaken from Old Point Comfort, between the York and James rivers: Provided, 1st. That the enemy's vessel, Merrimac, can be neutralized. 2d. That the means of transportation, sufficient for an immediate transfer of the force to its new base, can be ready at at Washington and Alexandria to move down the Potomac ; and, 3d. That a naval auxiliary force can be had to silence, or aid in silencing, the enemy's batteries on the York river. 4th. That the force to be left to cover Washington shall be such as to give an entire feeling of security for its safety from menace. (Unanimous.) II. If the foregoing can not be, the army should then be moved against the enemy, behind the Rappahannock, at the earliest possible moment, and the means for reconstructing bridges, repairing railroads, and stocking them with materials sufficient for supplying the army, should at once be collected, for both the Orange and Alexandria and Acquia and Richmond Railroads. (Unanimous.) NOTE. That with the forts on the right bank of the Potomac fully garrisoned, and those on the left bank occupied, a covering force in front of the Virginia line of twenty-five thousand men would suffice. (Keyes, Heintzelman and McDowell.) A total of forty thousand men for the defense of the city would suffice. (Sumner.) The scheme having been promptly submitted to the President, the following dispatch was immediately returned: WAR DEPARTMENT, March 13, 1862. The President having considered the plan of operations agreed upon by yourself and the commanders of army corps, makes no objection to the same, but gives the following directions as to its execution: 1. Leave such force at Manassas Junction as shall make it entirely certain that the enemy shall not repossess himself of that position and line of communication. 2. Leave Washington entirely secure. 3. Move the remainder of the force down the Potomac, choosing a new base at Fortress Monroe, or any-where between here and there, or, at all eveuts, move such remainder of the army at once in pursuit of the enemy by some route. EDWIN M. STANTON, Maj.-Gen. GEORGE B. MCCLELlan. Secretary of War. McClellan replied that this would "be at once carried into effect." Transportation was rapidly provided, under the direction of the War Department, this work having really commenced as early as the middle of February, and the other preparations for departure, on the part of the force intended for the Peninsula, were soon in readiness. The following statement of the numerical strength of this portion of the Army, on the 1st of April, is taken from the official report of the Adjutant General: Provost Guards, U. S. Engineer forces, and Head quarters Cavalry escort, 1,144 Total, 158,419 From the same authority, it appears that the total force left (according to the intention of Gen. McClellan) under command of Brig.-Gen. James S. Wadsworth, now appointed Military Governor of the District of Washington, was 22,410, of whom less than 20,000 were present for duty. How far this number fell short of all McClellan's previous estimates of the necessary force for the defense of the city, need not be suggested to the reader of the preceding pages. Gen. Wadsworth promptly called the attention of the War Department to this striking deficiency. The plan of the Peninsular movement as submitted for Executive approval, the special order of the President consenting to this plan, on condition that the capital should be rendered secure, and the letter of Gen. Wadsworth on this subject, were referred to Adj.-Gen. Thomas and Maj.-Gen. E. A. Hitchcock, who were required to report whether the President's order, in this matter, had been carried out. Those officers, after full consideration, reported that the force proposed to be left, in execution of that order, was "entirely inadequate." They further said: In view of the opinion expressed by the council of the commanders of army corps of the force necessary for the capital, though not numerically stated, and of the force represented by Gen. McClellan as left for that purpose, we are of opinion that the requirement of the President that this city shall be left entirely secure, not only in the opinion of the General-inchief, but that of the commanders of all the army corps, also, has not been fully complied with. Meanwhile, the movement of troops from Alexandria to Fortress Monroe had commenced. Gen. Hamilton's division, of the Third Corps, embarked on the 17th of March, and was followed by Fitz John Porter's division, of the same corps, on the 22d. Other troops followed at intervals, as transports were ready. Gen. McClellan himself left Alexandria on the 1st of April, and reached Fortress Monroe the next day. There still remained two army corps which had not yet been transferred to the Peninsula, when the report of Gens. Thomas and Hitchcock was made. The only remedy for McClellan's intended disregard alike of the conditions of his own plan and of the President's requirement, respecting the force to be left at Washington and in its vicinity, was such as the President applied in the first part of the following order, the wisdom of which was soon fully demonstrated: } EXECUTIVE MANSION, WASHINGTON, April 3, 1862. The Secretary of War will order that one or the other of the corps of Gen. McDowell and Gen. Sumner remain in front of Washington until further orders from the Department, to operate at, or in the direction of, Manassas Junction, or otherwise as the occasion may require; that the other corps, not so ordered to remain, go forward to Gen. McClellan as speedily as possible; that Gen. McClellan commence his forward move |