For convenience of reference the strength of the Army of the Potomac at subsequent periods is given:

+ Including McCall, not Dix.

: Including two brigades of Shields' division, absent, 5,354 men.

In organizing the Army of the Potomac and preparing it for the field, the first step taken was to organize the infantry into brigades of four regiments each, retaining the newly-arrived regiments on the Maryland side until their armament and equipment were issued and they had obtained some little elementary instruction before assigning them permanently to brigades. When the organization of the brigades was well established and the troops somewhat disciplined and instructed, divisions of three brigades each were gradually formed, as is elsewhere stated in this report. Although I was always in favor of the organization into army corps as an abstract principle, I did not desire to form them until the army had been for some little time in the field, in order to enable the general officers first to acquire the requisite experience as division commanders on active service and that I might be able to decide from actual trial who were best fitted to exercise these important commands. For a similar reason I carefully abstained from making any recommendations for the promotion of officers to the grade of majorgeneral.

When new batteries of artillery arrived, they also were retained in Washington until their armament and equipment were completed and their instruction sufficiently advanced to justify their being assigned to divisions. The same course was pursued in regard to cavalry. I regret that circumstances have delayed the chief of cavalry, General George Stoneman, in furnishing his report upon the organization of that arm of service. It will, however, be forwarded as soon as completed, and will doubtless show that the difficult and important duties intrusted to him were efficiently performed. He encountered and overcame, as far as it was possible, continual and vexatious obstacles arising from the great deficiency of cavalry arms and equipments and the entire inefficiency of many of the regimental officers first appointed. This last difficulty was, to a considerable extent, overcome in the cavalry, as well as in the infantry and artillery, by the continual and prompt action of courts-martial and boards of examination.

As rapidly as circumstances permitted every cavalry soldier was armed with a saber and revolver, and at least two squadrons in every regiment with carbines.

It was intended to assign at least one regiment of cavalry to each division of the active army, besides forming a cavalry reserve of the regular regiments and some picked regiments of volunteer cavalry. Circumstances beyond my control rendered it impossible to carry out

this intention fully, and the cavalry force serving with the army in the field was never as large as it ought to have been.

It was determined to collect the regular infantry to form the nucleus of a reserve. The advantage of such a body of troops at a critical moment, especially in an army constituted mainly of new levies, imperfectly disciplined, has been frequently illustrated in military history, and was brought to the attention of the country at the first battle of Manassas. I have not been disappointed in the estimate formed of the value of these troops. I have always found them to be relied on. Whenever they have been brought under fire they have shown the utmost gallantry and tenacity. The regular infantry, which had been collected from distant posts and which had been recruited as rapidly as the slow progress of recruiting for the regular service would allow, added to the small battalion with McDowell's army which I found at Washington on my arrival, amounted on the 30th of August to 1,040 men; on the 28th of February, 1862, to 2,682, and on the 30th of April, to 4,603. On the 17th of May, 1862, they were assigned to General Porter's corps for organization as a division, with the Fifth Regiment New York Volunteers, which joined May 4, and the Tenth New York Volunteers, which joined subsequently. They remained from the commencément under the command of Brig. Gen. George Sykes, major Third Infantry, U. S. Army.

ARTILLERY.

The creation of an adequate artillery establishment for an army of so large proportions was' a formidable undertaking, and had it not been that the country possessed in the regular service a body of accomplished and energetic artillery officers, the task would have been almost hopeless.

The charge of organizing this most important arm was confided to Major (afterwards Brig. Gen.) William F. Barry, chief of artillery, whose industry and zeal achieved the best results. The report of General Barry is appended among the accompanying documents. By referring to it it will be observed that the following principles were adopted as the basis of organization:*

*

The zeal and services of Maj. A. S. Webb, assistant to General Barry, entitle him to especial praise. At the close of the Peninsular campaign General Barry assumed the duties of chief of artillery of the defenses of Washington, and was relieved in his former position by Col. Henry J. Hunt, who had commanded the artillery reserve with marked skill, and brought to his duties as chief of artillery the highest qualifications. The services of this distinguished officer in reorganizing and refitting the batteries prior to and after the battle of Antietam, and his gallant and skillful conduct on that field, merit the highest encomium in my power to bestow. His assistant, Major Doull, deserves high credit for his services and gallantry throughout both campaigns. The designations of the different batteries of artillery, both regular and volunteer, follow within a few pages.

The following distribution of regiments and batteries was made, as a preliminary organization of the forces at hand, shortly after my arrival in Washington. The infantry, artillery, and cavalry, as fast as collected and brought into primary organization, were assigned to brigades and divisions, as indicated in the subjoined statements:

* For portion here omitted see Report No. 2, paragraphs numbered 1 to 7, and [13], [15], and [16], pp. 67-69.

Organization of the Division of the Potomac, August 4, 1861.

Brigadier-General Hunter's brigade.-Twenty-third, Twenty-fifth, Thirty-fifth, and Thirty-seventh Regiments New York Volunteers.

Brigadier-General Heintzelman's brigade.-Fifth Regiment Maine Volunteers, Sixteenth, Twenty-sixth, and Twenty-seventh Regiments New York Volunteers, and Tidball's battery (A), Second U. S. Artillery.

Brig. Gen. W. T. Sherman's brigade.-Ninth and Fourteenth Regiments Massachusett's Volunteers, De Kalb [Forty-first] Regiment New York Volunteers, Fourth Regiment Michigan Volunteers, Hamilton's battery (E), Third U. S. Artillery, and Company I, Second U. S. Cavalry.

Brigadier-General Kearny's brigade.-First, Second, and Third Regiments New Jersey Volunteers, Greene's battery (G), Second U. S. Artillery, and Company G, Second U. S. Cavalry.

Brigadier-General Hooker's brigade-First and Eleventh Regiments Massachusetts Volunteers, Second Regiment, New Hampshire Volunteers, and Twenty-sixth Regiment Pennsylvania Volunteers.

Colonel Keyes brigade.-Twenty-second, Twenty-fourth, and Thirtieth Regiments New York Volunteers, and Fourteenth Regiment New York State Militia [Eightyfourth Volunteers].

Brigadier-General Franklin's brigade.-Fifteenth, Eighteenth, Thirty-first, and ThirtySecond Regiments New York Volunteers, Platt's battery (M), Second U. S. Artillery, and Company C [First], New York (Lincoln) Cavalry.

Colonel Blenker's brigade.-Eighth and Twenty-ninth Regiments New York Volunteers, Twenty-seventh Regiment Pennsylvania Volunteers, and Garibaldi Guard [Thirty-ninth], New York Volunteers.

Colonel Richardson's brigade.-Twelfth Regiment New York Volunteers and Second and Third Regiments Michigan Volunteers.

Brigadier-General Stone's brigade.-Thirty-fourth and Tammany [Forty-second] Regiments New York Volunteers, First Regiment Minnesota Volunteers, and Second Regiment New York State Militia [Eighty-second Volunteers].

Col. William F. Smith's brigade.-Second and Third Regiments Vermont Volunteers, Sixth Regiment Maine Volunteers, Thirty-third Regiment New York Volunteers, Company H, Second U. S. Cavalry, and Captain Mott's New York battery.

Colonel Couch's brigade.-Second Regiment Rhode Island Volunteers, Seventh and Tenth Regiments Massachusetts Volunteers, and Thirty-sixth Regiment New York Volunteers.

The Second Regiment Maine, the Second Regiment Wisconsin, and the Thirteenth Regiment New York Volunteers, stationed at Fort Corcoran.

The Twenty-first Regiment New York Volunteers, stationed at Fort Runyon. The Seventeenth Regiment New York Volunteers, stationed at Fort Ellsworth.

By October the new levies had arrived in sufficient numbers, and the process of organization so far carried on that the construction of divisions had been effected.

The following statement exhibits the composition of the Army, October 15, 1861:

Organization of the Army of the Potomac, October 15, 1861.

1. Brig. Gen. George Stoneman's cavalry command.-Fifth U. S. Cavalry, Fourth Pennsylvania Cavalry, Oneida Cavalry (first company), Eleventh Pennsylvania Cavalry (Harlan's), and Barker's Illinois Cavalry (one company).

2. Col. H. J. Hunt's artillery reserve.-Batteries L, A, and B, Second U. S. Artillery; Batteries K and F, Third U. S. Artillery; Battery K, Fourth U. S. Artillery; Battery H, First U. S. Artillery, and Battery A, Fifth U. S. Artillery.

3. CITY GUARD, BRIG. GEN. ANDREW PORTER.

Caralry.-Companies A and E, Fourth U. S. Cavalry.

Artillery.-Battery K, Fifth U. S. Artillery.

Infantry.-Second and Third battalions U. S. Infantry, Company Company - First U. S. Infantry, and Sturges' rifles (Illinois Volunteers).

4. BANKS' DIVISION.

Eighth and

Cavalry.-Four companies Third Regiment New York Cavalry (Van Alen's). Artillery.-Best's battery (F), Fourth U. S. Artillery; detachment Ninth New York

Artillery; Matthews' battery (F), First Pennsylvania Artillery; Tompkins' battery (A), First Rhode Island Artillery.

Infantry.-Abercrombie's brigade: Twelfth Massachusetts, Twelfth and Sixteenth Indiana, and Thirtieth Pennsylvania Volunteers. Stiles' brigade: Third Wisconsin, Twenty-ninth Pennsylvania, and Thirteenth Massachusetts Volunteers, and Ninth New York State Militia [Eighty-third Volunteers]. Gordon's brigade: Second Massachusetts, Twenty-eighth and Nineteenth New York, Fifth Connecticut, Forty-sixth and Twenty-eighth Pennsylvania, and First Maryland Volunteers.

M'DOWELL'S DIVISION.

Cavalry. Second New York Cavalry (Harris' Light), Colonel Davies.
Artillery.-Battery M, Second, and Battery G, First, U. S. Artillery.

Infantry.-Keyes' brigade: Fourteenth New York State Militia [Eighty-fourth Volunteers], and Twenty-second, Twenty-fourth, and Thirtieth New York Volunteers. Wadsworth's brigade: Twelfth, Twenty-first, Twenty-third, and Thirty-fifth New York Volunteers. King's brigade: Second, Sixth, and Seventh Wisconsin, and Nineteenth Indiana Volunteers.

HEINTZELMAN'S DIVISION.

Cavalry.-First New Jersey Cavalry, Colonel Halsted.
Artillery.-Thompson's battery (G), U. S. Artillery.

Infantry.-Richardson's brigade: Second, Third, and Fifth Michigan, and Thirtyseventh New York Volunteers. Sedgwick's brigade: Third and Fourth Maine and Thirty-eighth and Fortieth New York Volunteers. Jameson's brigade: Thirty-second, Sixty-third, Sixty-first, and Forty-fifth Pennsylvania Volunteers, and Wild Cat Reserves (Pennsylvania Volunteers).

F. J. PORTER'S DIVISION.

Calvary. Third Pennsylvania Cavalry, Colonel Averell, and Eighth Pennsylvania Cavalry, Colonel Gregg.

Artillery.-Battery E, Second, and Battery E, Third, U. S. Artillery.

Infantry.-Morell's brigade: Thirty-third Pennsylvania, Fourth Michigan, Ninth Massachusetts, and Fourth New York Volunteers. Martindale's brigade: Thirteenth New York, Second Maine, and Eighteenth Massachusetts Volunteers, and De Kalb [Forty-first] Regiment New York Volunteers. Butterfield's brigade: Fiftieth New York, Eighty-third Pennsylvania, Seventeenth and Twenty-fifth New York Volunteers, and Stockton's Independent Michigan [Sixteenth] Regiment.

FRANKLIN'S DIVISION.

Cavalry.-First New York Cavalry, Colonel McReynolds.

Artillery.-Batteries D and G, Second U. S. Artillery, and Hexamer's battery (New Jersey Volunteers).

Infantry.-Kearny's brigade: First, Second, Third, and Fourth New Jersey Volunteers. Slocum's brigade: Sixteenth, Twenty-sixth, and Twenty-seventh New York, and Fifth Maine Volunteers. Newton's brigade: Fifteenth, Eighteenth, Thirty-first, and Thirty-second New York Volunteers.

STONE'S DIVISION.

Cavalry.-Six companies Third New York (Van Alen) Cavalry.

Artillery.-Kirby's battery (I), First United States; Vaughn's battery (B), First Rhode Island Artillery, and Bunting's Sixth New York Independent Battery. Infantry.-Gorman's brigade: Second New York State Militia [Eighty-second Volunteers], First Minnesota, Fifteenth Massachusetts, and Thirty-fourth New York Volunteers, and Tammany [Forty-second] Regiment New York Volunteers. Lander's brigade: Nineteenth and Twentieth Massachusetts, and Seventh Michigan Volunteers, and a company of Massachusetts Sharpshooters. Baker's brigade: Pennsylvania Volunteers (First, Second, and Third California).

BUELL'S DIVISION.

Artillery.-Batteries D and H, First Pennsylvania Artillery.

Infantry.-Couch's brigade: Second Rhode Island, Seventh and Tenth Massachnsetts, and Thirty-sixth New York Volunteers. Graham's brigade: Twenty-third and

Thirty-first Pennsylvania, and Sixty-seventh (First Long Island) and Sixty-fifth (First U. S. Chasseurs) New York Volunteers. Peck's brigade: Thirteenth and Twenty-first Pennsylvania and Sixty-second (Anderson Zouaves) and Fifty-fifth New York Volunteers.

M'CALL'S DIVISION.

Cavalry-First Pennsylvania Reserve Cavalry, Colonel Bayard.

Artillery.-Easton's battery (A), Cooper's battery (B), and Kerns' battery (G), First Pennsylvania Artillery.

brigade: brigade: Tenth,

Infantry.-Meade's brigade: First Rifles, Pennsylvania Reserves, Fourth, Third, Seventh, Eleventh, and Second Pennsylvania Reserve Infantry. Fifth, First, and Eighth Pennsylvania Reserve Infantry. Sixth, Ninth, and Twelfth Pennsylvania Reserve Infantry.

HOOKER'S DIVISION.

Cavalry.-Eight companies Third Indiana Cavalry, Lieutenant-Colonel Carter. Artillery.-Elder's battery (E), First U. S. Artillery.

Infantry.-- brigade: First and Eleventh Massachusetts, Second New Hampshire, Twenty-sixth Pennsylvania, and First Michigan Volunteers. Sickles' brigade: First, Second, Third, Fourth, and Fifth Regiments Excelsior Brigade [Seventieth, Seventy-first, Seventy-second, Seventy-third, and Seventy-fourth], New York Vol

unteers.

BLENKER'S BRIGADE.

Cavalry.-Fourth New York Cavalry (mounted rifles), Colonel Dickel.

Artillery.-One battery.

Infantry.-Eighth and Twenty-ninth New York, Twenty-seventh and Thirty-fifth Pennsylvania Volunteers, Garibaldi Guard, and Cameron Rifles ([Thirty-ninth and Sixty-eighth] New York Volunteers).

SMITH'S DIVISION.

Cavalry.-Fifth Pennsylvania Cavalry (Cameron Dragoons), Colonel Friedman. Artillery.-Ayres' battery (F), Fifth U. S. Artillery; Mott's Second New York Independent battery, and Barr's battery (E), First Pennsylvania Artillery.

Infantry.brigade: Second, Third, Fourth, and Fifth Vermont Volunteers. Stevens' brigade: Thirty-third and Forty-ninth New York and Sixth Maine Volunteers, and Seventy-ninth New York State Militia [Seventy-ninth Volunteers]. Hancock's brigade: Forty-seventh and Forty-ninth Pennsylvania, Forty-third New York, and Fifth Wisconsin Volunteers. Companies B and E, Berdan Sharpshooters.

Casey's Provisional Brigades.-Fifth, Sixth, and Seventh New Jersey Volunteers, Roundhead Regiment ([One hundredth] Pennsylvania Volunteers), Battalion District of Columbia Volunteers, Fortieth Pennsylvania, Eighth New Jersey, and Fourth New Hampshire Volunteers.

5. GARRISONS.

Alexandria.-Brigadier-General Montgomery, military governor. Cameron Guard ([Eighty-eighth] Pennsylvania Volunteers).

Fort Albany.-Fourteenth Massachusetts Volunteers.

Fort Richardson.-Fourth Connecticut Volunteers.

Fort Washington.-Company D, First U. S. Artillery; Companies H and I, Thirtyseventh New York Volunteers, and United States recruits unassigned.

6. DIX'S DIVISION, BALTIMORE.

Cavalry.-Company of Pennsylvania cavalry.

Artillery.-Battery I, Second U. S. Artillery, Second Massachusetts Light Battery, and a battery of New York artillery.

Infantry.-Third, Fourth, and Fifth New York, Seventeenth and Twenty-fifth Massachusetts, Twenty-first Indiana, Sixth Michigan, Fourth Wisconsin, Seventh Maine, Second Maryland Battalion, and Reading City Guard, volunteers.

[Battery E, Third U. S. Artillery, the Seventy-ninth New York State Militia, the Forty-seventh Pennsylvania Volunteers, and the Roundhead Regiment were transferred to General Sherman's expedition.]

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