3d. Volunteer engineer troops, General Woodbury: 15th New York volunteers; 50th New York volunteers.

Regular engineer troops, Captain Duane: Companies A, B, and C, United States engineers.

Artillery troops, with siege trains: 1st Connecticut heavy artillery, Colonel Tyler.

4th. Infantry reserve, (regular brigade,) General Sykes: 9 companies 2d United States infantry, 7 companies 3d United States infantry, 10 companies 4th United States infantry, 10 companies 6th United States infantry, 8 companies 10th and 17th United States infantry, 6 companies 11th United States infantry, 8 companies 12th United States infantry, 9 companies 14th United States infantry, and 5th New York volunteers, Colonel Warren.

SECOND CORPS, GENERAL SUMNER.

Cavalry. 8th Illinois cavalry, Colonel Farnsworth, and one squadron 6th New York cavalry.

RICHARDSON'S DIVISION.

Artillery-Clark's battery A and G, 4th United States, 6 Napoleon guns; Frank's battery G, 1st New York, 6 10-pounder Parrott guns; Pettit's battery B, 1st New York, 6 10-pounder Parrott guns; Hogan's battery A, 2d New York, 6 10-pounder Parrott guns.

Infantry.-Howard's brigade: 5th New Hampshire, 81st Pennsylvania, and 61st and 64th New York volunteers. Meagher's brigade: 69th, 63d, and 88th New York volunteers. French's brigade: 52d, 57th, and 66th New York, and 53d Pennsylvania volunteers.

SEDGWICK'S DIVISION.

Artillery.-Kirby's battery I, 1st United States, 6 Napoleon guns; Tompkins's battery A, 1st Rhode Island, 6-4 10-pounder Parrott and 2 12-pounder howitzer-guns; Bartlett's battery B, 1st Rhode Island, 6-4 10-pounder Parrott and 2 12-pounder howitzer-guns; Owen's battery G, 6 3-inch ordnance guns.

Infantry.-Gorman's brigade: 2d New York State militia, and 15th Massachusetts, 34th New York, and 1st Maine volunteers. Burns's brigade: 69th, 71st, 72d, and 106th Pennsylvania volunteers. Dana's brigade: 19th and 20th Massachusetts, 7th Michigan, and 42d New York volunteers.

NOTE.-Blenker's division detached and assigned to the mountain depart

ment.

THIRD CORPS, GENERAL HEINTZELMAN.

Cavalry.—3d Pennsylvania cavalry, Colonel Averill.

PORTER'S DIVISION.

Artillery.-Griffin's battery K, 5th United States, 6 10-pounder Parrott guns: Weeden's battery C, Rhode Island; Martin's battery C, Massachusetts, 6 Napoleon guns; Allen's battery E, Massachusetts, 6 3-inch ordnance guns.

Infantry.-Martindale's brigade: 2d Maine, 18th and 22d Massachusetts, and 25th and 13th New York volunteers. Morell's brigade: 14th New York, 4th Michigan, 9th Massachusetts, and 62d Pennsylvania volunteers. Butterfield's brigade: 17th, 44th, and 12th New York, 83d Pennsylvania, and Stockton's Michigan volunteers.

First Berdan sharpshooters.

HOOKER'S DIVISION.

Artillery. Hall's battery H, 1st United States, 6-4 10-pounder Parrott and 2 12-pounder howitzer-guns; Smith's battery, 4th New York, 6 10-pounder Parrott guns; Bramhall's battery, 6th New York, 6 3-inch ordnance born's battery D, 1st New York artillery, 4 3-inch ordnance guns.

guns; Os

Infantry.-Sickles's brigade: 1st, 2d, 3d, 4th, and 5th Excelsior, New York. Naglee's brigade: 1st and 11th Massachusetts, 26th Pennsylvania, and 2d New Hampshire volunteers. Colonel Starr's brigade: 5th, 6th, 7th, and 8th New Jersey volunteers.

HAMILTON'S DIVISION.

Artillery. Thompson's battery G, 2d United States, 6 Napoleon guns; Beam's battery B, New Jersey, 6-4 10-pounder Parrott and 2 Napoleon-guns; Randolph's battery E, Rhode Island, 6-4 10-pounder Parrott and 2 Napoleonguns.

Infantry.-Jameson's brigade: 105th, 63d, and 57th Pennsylvania, and 87th New York volunteers. Birney's brigade: 38th and 40th New York, and 3d and 4th Maine volunteers. brigade: 2d, 3d, and 5th Michigan, and 37th

New York volunteers.

FOURTH CORPS, GENERAL KEYES.

COUCH'S DIVISION.

Artillery-McCarthy's battery C, 1st Pennsylvania, 4 10-pounder Parrott guns; Flood's battery D, 1st Pennsylvania, 4 10-pounder Parrott guns; Miller's battery E, 1st Pennsylvania, 4 Napoleon guns; Brady's battery F, 1st Pennsylvania, 4 10-pounder Parrott guns.

Infantry.-Graham's brigade: 67th (1st Long Island) and 65th (1st United States chasseurs) New York, 23d, 31st, and 61st Pennsylvania volunteers. Peck's brigade: 98th, 102d, and 93d Pennsylvania, and 62d and 55th New York volbrigade: 24 Rhode Island, 7th and 10th Massachusetts, and 36th New York volunteers.

unteers.

SMITH'S DIVISION.

Artillery.-Ayre's battery F, 5th United States, 6-4 10-pounder Parrott and 2 Napoleon-guns; Mott's battery, 3d New York, 6-4 10-pounder Parrott and 2 Napoleon-guns; Wheeler's battery E, 1st New York, 4 3-inch ordnance guns; Kennedy's battery, 1st New York, 6 3-inch ordnance guns.

Infantry.-Hancock's brigade: 4th Wisconsin, 49th Pennsylvania, 43d New York, and 6th Maine volunteers. Brooks's brigade: 2d, 3d, 4th, 5th, and 6th Vermont volunteers. Davidson's brigade: 33d, 77th, and 49th New York, and 7th Maine volunteers.

CASEY'S DIVISION.

Artillery-Regan's battery, 7th New York, 6 3-inch ordnance guns; Fitch's 8th New York, 6 3-inch ordnance guns; Bates's battery A, 1st New York, 6 Napoleon guns; Spratt's battery H, 1st New York, 4 3-inch ordnance guns. Infantry.-Keim's brigade: 85th, 101st, and 103d Pennsylvania, and 96th New York volunteers. Palmer's brigade: 85th, 98th, 92d, 81st, and 93d New York volunteers. brigade: 104th and 52d Pennsylvania, 56th and

100th New York, and 11th Maine volunteers.

5th. Provost guard: 2d United States cavalry; battalions 8th and 17th United States infantry.

At general headquarters: 2 companies 4th United States cavalry; 1 company Oneida cavalry, (New York volunteers;) and 1 company Sturges's rifles, (Illinois volunteers.)

The following troops of the army of the Potomac were left behind, or detached on and in front of the Potomac for the defence of that line, April 1,1862. Franklin's and McCall's divisions, at subsequent and different dates, joined the active portion of the army on the Peninsula. Two brigades of Shields's division joined at Harrison's landing :

FIRST CORPS, GENERAL MCDOWELL.

Cavalry-1st, 2d, and 4th New York, and 1st Pennsylvania.
Sharpshooters.-2d regiment Berdan's sharpshooters.

FRANKLIN'S DIVISION.

Artillery-Platt's battery D, 2d United States, 6 Napoleon guns; Porter's battery A, Massachusetts, 6-4 10-pounder Parrott and 2 12-pounder howitzer-guns; Hexamer's battery A, New Jersey, 6-4 10-pounder Parrott and 2 12-pounder howitzer-guns; Wilson's battery F, 1st New York artillery, 4 3-inch ordnance guns.

Infantry-Kearney's brigade: 1st, 2d, 3d, and 4th New Jersey volunteers. Slocum's brigade: 16th and 27th New York, 5th Maine, and 96th Pennsylvania volunteers. Newton's brigade: 18th, 31st, and 32d New York, and 95th Pennsylvania volunteers.

M'CALL'S DIVISION.

Artillery.-Seymour's battery C, 5th United States, 6 Napoleon guns; Easton's battery A, 1st Pennsylvania, 4 Napoleon guns; Cooper's battery B, 1st Pennsylvania, 6 10-pounder Parrott guns; Kein's battery C, 1st Pennsylvania, 6-2 10-pounder and 4 12-pounder Parrott-guns.

Infantry.-Reynolds's brigade: 1st, 2d, 5th, and 8th Pennsylvania reserve regiments. Meade's brigade: 3d, 4th, 7th, and 11th Pennsylvania reserve regiments. Ord's brigade: 6th, 9th, 10th, and 12th Pennsylvania reserve regi

ments.

1st Pennsylvania reserve rifles.

KING'S DIVISION.

Artillery.-Gibbon's battery B, 4th United States, 6 Napoleon guns; Monroe's battery D, 1st Rhode Island, 6 10-pounder Parrott guns; Gerrish's battery A, New Hampshire, 6 Napoleon guns; Durrell's battery, Pennsylvania, 6 10pounder Parrott guns. Infantry.-- brigade: 2d, 6th, and 7th Wisconsin, and 19th Indiana volunteers. Patrick's brigade: 20th, 21st, 23d, and 25th New York State militia. Augur's brigade: 14th New York State militia, and 22d, 24th, and 30th New York volunteers.

FIFTH CORPS, GENERAL BANKS.

Cavalry-1st Maine, 1st Vermont, 1st Michigan, 1st Rhode Island, 5th and 8th New York, Keyes battalion of Pennsylvania, 18 companies of Maryland, 1 squadron of Virginia.

Unattached.-28th Pennsylvania volunteers, and 4th regiment Potomac home brigade, (Maryland volunteers.)

WILLIAMS'S DIVISION.

Artillery-Best's battery F, 4th United States, 6 Napoleon guns; Hampton's battery, Maryland, 4 10-pounder Parrott guns; Thompson's battery, Maryland, 4 10-pounder Parrott guns; Mathews's battery F, Pennsylvania, 6 3-inch ordnance guns; battery M, 1st New York, 6 10-pounder Parrott guns; Knapp's battery, Pennsylvania, 6 10-pounder Parrott guns; McMahon's battery, New York, 6 3-inch ordnance guns.

Infantry-Abercrombie's brigade: 12th and 2d Massachusetts, and 16th Indiana, 1st Potomac home brigade, (Maryland,) 1 company Zouaves D'Afrique, (Pennsylvania) volunteers. brigade: 9th New York State militia, and 29th Pennsylvania, 29th Indiana, and 3d Wisconsin volunteers. brigade: 28th New York, 5th Connecticut, 46th Pennsylvania, 1st Maryland, 12th Indiana, and 13th Massachusetts volunteers.

SHIELDS'S DIVISION.

Artillery.-Clark's battery E, 4th United States, 6 10-pounder Parrott guns; Jenks's battery A, 1st Virginia, 4 10-pounder Parrott and 2 6-pounder guns; Davy's battery B, 1st Virginia, 2 10-pounder Parrott guns; Huntington's battery A, 1st Ohio, 6 13-pounder James's guns; Robinson's battery L, 1st Ohio, 2 12-pounder howitzers and 4 6-pounder guns; and battery, 4th Ohio

artillery.

Infantry

brigade 14th Indiana, 4th, 8th, and 67th Ohio, 7th brigade 5th, 62d, and

brigade 7th

:

Virginia, and 84th Pennsylvania volunteers. 66th Ohio, 13th Indiana, and 39th Illinois volunteers. and 29th Ohio, 7th Indiana, 1st Virginia, and 11th Pennsylvania volunteers. Andrew sharpshooters.

GENERAL WADSWORTH'S COMMAND.

Cavalry-1st New Jersey cavalry, at Alexandria, and 4th Pennsylvania cavalry, east of the Capitol.

Artillery and infantry-10th New Jersey volunteers, Bladensburg road; 104th New York volunteers, Kalorama heights; 1st Wisconsin heavy artillery, Fort Cass, Virginia; 3 batteries of New York artillery, Forts Ethan Allen and Marcy; depot of New York light artillery, Camp Barry; 2d District of Columbia volunteers, Washington city; 26th Pennsylvania volunteers, G street wharf; 26th New York volunteers, Fort Lyon; 95th New York volunteers, Camp Thomas; 94th New York and detachment of 88th Pennsylvania volunteers, Alexandria; 91st Pennsylvania volunteers, Franklin Square barracks; 4th New York artillery, Forts Carroll and Greble; 112th Pennsylvania volunteers, Fort Saratoga; 76th New York volunteers, Fort Massachusetts; 59th New York volunteers, Fort Pennsylvania; detachment of 88th Pennsylvania volunteers, Fort Good Hope; 99th Pennsylvania volunteers, Fort Mahon; 2d New York light artillery, Forts Ward, Worth, and Blenker; 107th and 54th Pennsylvania volunteers, Kendall Green; Dickerson's light artillery, 86th New York, and detachment of 88th Pennsylvania volunteers, east of the Capitol; 14th Massachusetts (volunteers) heavy artillery and 56th Pennsylvania volunteers, Forts Albany, Tillinghast, Richardson, Runyon, Jackson, Barnard, Craig, and Scott; detachments of 4th United States artillery and 37th New York volunteers, Fort Washington; 97th, 101st, and 91st New York, and 12th Virginia volunteers, Fort Corcoran.

In camp near Washington.-6th and 10th New York, Swain's New York, and 2d Pennsylvania cavalry, all dismounted.

These troops (3,359 men) were ordered to report to Colonel Miles, commanding railroad guard, to relieve 3,306 older troops ordered to be sent to Manassas to report to General Abercrombie.

GENERAL DIX'S COMMAND, BALTIMORE.

Cavalry-1st Maryland cavalry and detachment of Purnell Legion cavalry. Artillery-Battery I, 2d United States; battery, Maryland; battery L, 1st New York, and two independent batteries of Pennsylvania artillery.

Infantry.-3d and 4th New York, 11th, 87th, and 111th Pennsylvania, detachment 21st Massachusetts, 2d Delaware, 2d Maryland, 1st and 2d Eastern Shore (Maryland) home guards, and Purnell Legion (two battalions) Maryland volunteers.

In a staff charged with labors so various and important as that of the army of the Potomac, a chief was indispensable to supervise the various departments and to relieve the commanding general of details. The officer of chief of staff, well known in European armies, had not been considered necessary in our small peace establishment. The functions of the office were not defined, and, so far as exercised, had been included in the Adjutant General's department. The small number of officers in this department, and the necessity for their employment in other duties, have obliged commanding generals, during this war, to resort to other branches of the service to furnish suitable chiefs of staff.

On the 4th of September, 1861, I appointed Colonel R. B. Marcy, of the inspector general's department, chief of staff, and he entered upon service immediately, discharging the various and important duties with great fidelity, industry, and ability, from this period until I was removed from command at Rectortown. Many improvements have been made during the war in our system of staff administration, but much remains to be done.

Our own experience, and that of other armies, agree in determining the necessity for an efficient and able staff. To obtain this, our staff establishment should be based on correct principles, and extended to be adequate to the necessities of the service, and should include a system of staff and line education.

The affairs of the Adjutant General's department, while I commanded the army of the Potomac, were conducted by Brigadier General S, Williams, assisted by Lieutenant Colonel James A. Hardie, aide-de-camp. Their management of the department during the organization of the army in the fall and winter of 1861, and during its subsequent operations in the field, was excellent. They were, during the entire period, assisted by Captain Richard B. Irwin, aide-de-camp, and during the organization of the army by the following-named officers: Captains Joseph Kirkland, Arthur McClellan, M. T. McMahon, William P. Mason, and William F. Biddle, aides-de-camp.

My personal staff, when we embarked for the Peninsula, consisted of Colonel Thomas M. Key, additional aide-de-camp; Colonel E. H. Wright, additional aide-de-camp and major, 6th United States cavalry; Colonel T. T. Gantt, additional aide-de-camp; Colonel J. J. Astor, jr., volunteer aide-de-camp; Lieutenant Colonel A. V. Colburn, additional aide-de-camp and captain, Adjutant General's department; Lieutenant Colonel N. B. Sweitzer, additional aide-decamp and captain, 1st United States cavalry; Lieutenant Colonel Edward McK. Hudson, additional aide-de-camp and captain, 14th United States infantry; Lieutenant Colonel Paul Von Radowitz, additional aide-de-camp; Major H. Von Hammerstein, additional aide-de-camp; Major W. W. Russell, United States marine corps; Major F. LeCompte, of the Swiss army, volunteer aidede-camp; Captains Joseph Kirkland, Arthur McClellan, L. P. D'Orleans, R. D'Orleans, M. T. McMahon, William P. Mason, jr., William F. Biddle, and E. A. Raymond, additional aides-de-camp.

To this number I am tempted to add the Prince de Joinville, who constantly