been considered necessary in our small peace establishment. The func tions 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 Col. 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 Brig. Gen. S. Williams, assisted by Lieut. Col. 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 Capt. Richard B. Irwin, aide-de-camp, and during the organization of the Army by the following-named officers: Capts. 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 Col. Thomas M. Key, additional aide-de-camp; Col. E. H. Wright, additional aide-de-camp and major Sixth U. S. Cavalry; Col. T. T. Gantt, additional aide-de-camp; Col. J. J. Astor, jr., volunteer aide-de-camp; Lieut. Col. A. V. Colburn, additional aide-de-camp, and captain Adjutant-General's Department; Lieut. Col. N. B. Sweitzer, additional aidede-camp, and captain First U. S. Cavalry; Lieut. Col. Edward McK. Hudson, additional aide-de camp, and captain Fourteenth U. S. Infantry; Lieut. Col. Paul Von Radowitz, additional aide-de-camp; Maj. H. von Hammerstein, additional aide-de-camp; Maj. W. W. Russell, U. S. Marine Corps; Maj. F. LeCompte, of the Swiss Army, volunteer aide-de-camp; Capts. George A. Custer, Joseph Kirkland, Arthur McClellan, L. P. D'Orleans, R. D'Orleans, M. T. McMahon, William P. Mason, jr., William F. Biddle, and E. Á. Raymond, additional ades-de

camp.

To this number I am tempted to add the Prince de Joinville, who constantly accompanied me through the trying campaign of the Peninsula, and frequently rendered important services. Of these officers Captain McMahon was assigned to the personal staff of Brigadier-General Franklin, and Captains Kirkland and Mason to that of Brig. Gen. F. J. Porter during the siege of Yorktown. They remained subsequently with those general officers. Major LeCompte left the Army during the siege of Yorktown; Colonels Gantt and Astor, Maj. Russell, Capts. L. P. D'Orleans, R. D'Orleans, and Raymond, at the close of the Peninsular campaign. Before its termination Capts. W. S. Abert and Charles R. Lowell, of the Sixth U. S. Cavalry, joined my staff as aidesde-camp, and remained with me until I was relieved from the command of the Army of the Potomac. All of these officers served me

with great gallantry and devotion; they were ever ready to execute any service, no matter how dangerous, difficult, or fatiguing.

INSPECTOR-GENERAL'S DEPARTMENT.

The highly important duties of this department were performed by Col. D. B. Sacket and Maj. N. H. Davis to my entire satisfaction. They introduced many valuable changes in the system of inspections and in the forms of reports, and so systematized the labors of the inspectors of corps and divisions that excellent results were obtained. The intelligent and energetic performance of their duties by these officers enabled me to keep myself well informed of the condition of the troops and to correct evils promptly.

ENGINEERS.

When I assumed command of the Army of the Potomac I found Maj. J. G. Barnard, U. S. Engineers, subsequently brigadier-general of volunteers, occupying the position of chief engineer of that army. I continued him in the same office, and at once gave the necessary instructions for the completion of the defenses of the capital, and for the entire reorganization of the department. Under his direction the entire system of defenses was carried into execution. This was completed before the army departed for Fort Monroe, and is a sufficient evidence of the skill of the engineers and the diligent labor of the troops.

For some months after the organization of the Army of the Potomac was commenced there were no engineer troops with it. At length, however, three companies were assigned. Under the skillful management of Capt. J. C. Duane, U. S. Engineers, these new companies rapidly became efficient, and, as will be seen, rendered most valuable service during the ensuing campaigns.

The number of engineer troops being entirely inadequate to the necessities of the army, an effort was made to partially remedy this defect by detailing the Fifteenth and Fiftieth New York Volunteers, which contained many sailors and mechanics, as engineer troops. They were first placed under the immediate superintendence of Lieut. Col. B. S. Alexander, U. S. Engineers, by whom they were instructed in the duties of pontoniers, and became somewhat familiar with those of sappers and miners. Previous to the movement of the army for the Peninsula this brigade was placed under the command of Brig. Gen. D. P. Woodbury, major U. S. Engineers.

The labor of preparing the engineer and bridge trains devolved chiefly upon Captain Duane, who was instructed to procure the new model French bridge train, as I was satisfied that the India-rubber pontoon was entirely useless for the general purposes of a campaign.

The engineer department presented the following complete organization when the army moved for the Peninsula:

Brig. Gen. J. G. Barnard, chief engineer; First Lieut. H. L. Abbot, Topographical Engineers, aide-de-camp. Brigade volunteer engineers, Brigadier General Woodbury commanding; Fifteenth New York Volunteers, Col. J. McLeod Murphy; Fiftieth New York Volunteers, Col. C. B. Stuart. Battalion three companies U. S. Engineers, Capt. J. C. Duane commanding; companies respectively commanded by First Lieuts. C. B. Reese, C. E. Cross, and O. E. Babcock, U. S. Engineers. The chief engineer was ably assisted in his duties by Lieut. Col. B. S. Alexander, and First Lieuts. C. B. Comstock, M. D. McAlester, and Merrill, U. S.

Engineers. Capt. C. S. Stewart and Second Lieut. F. U. Farquhar, U. S. Engineers, joined after the army arrived at Fort Monroe.

The necessary bridge equipage for the operations of a large army had been collected, consisting of bateaux with the anchors and flooring material (French model), trestles, and engineer's tools, with the necessary wagons for their transportation.

The small number of officers of this corps available rendered it impracticable to detail engineers permanently at the headquarters of corps and divisions. The companies of regular engineers never had their proper number of officers, and it was necessary, as a rule, to follow the principle of detailing engineer officers temporarily whenever their services. were required.

TOPOGRAPHICAL ENGINEERS.

To the corps of topographical engineers was intrusted the collection of topographical information and the preparation of campaign maps. Until a short time previous to the departure of the army for Fort Monroe Lieut. Col. John N. Macomb was in charge of this department, and prepared a large amount of valuable material. He was succeeded by Brig. Gen. A. A. Humphreys, who retained the position throughout the Peninsula campaign. These officers were assisted by Lieuts. H. L. Abbot, O. G. Wagner, N. Bowen, John M. Wilson, and James H. Wilson, Topographical Engineers. This number, being the greatest available, was so small that much of the duty of the department devolved upon parties furnished by Professor Bache, Superintendent of the Coast Survey, and other gentlemen from civil life.

Owing to the entire absence of reliable topographical maps the labors of this corps were difficult and arduous in the extreme. Notwithstanding the energy and ability displayed by General Humphreys, LieutenantColonel Macomb, and their subordinates, who frequently obtained the necessary information under fire, the movements of the army were sometimes unavoidably delayed by the difficulty of obtaining knowledge of the country in advance. The result of their labors has been the preparation of an excellent series of maps, which will be invaluable to any army traversing the same ground.

During the campaign it was impossible to draw a distinct line of demarkation between the duties of the two corps of engineers, so that the labors of reconnaissance of roads, of lines of intrenchments, of fields for battle, and of the position of the enemy, as well as the construction of siege and defensive works, were habitually performed by details from either corps, as the convenience of the service demanded.

I desire to express my high appreciation of the skill, gallantry, and devotion displayed by the officers of both corps of engineers, under the most trying circumstances.

During the Maryland campaign I united the two corps under Capt. J. C. Duane, U. S. Engineers, and found great advantages from the arrangement.

MEDICAL DEPARTMENT.

For the operations of the medical department I refer to the reports, transmitted herewith, of Surg. Charles S. Tripler and Surg. Jonathan Letterman, who, in turn, performed the duties of medical director of the Army of the Potomac, the former from August 12, 1861, until July 1, 1862, and the latter after that date. The difficulties to be overcome in

organizing and making effective the medical department were very great, arising principally from the inexperience of the regimental medical officers, many of whom were physicians taken suddenly from civil life, who, according to Surgeon Tripler, "had to be instructed in their duties from the very alphabet," and from the ignorance of the line officers as to their relations with the medical officers, which gave rise to confusion and conflict of authority. Boards of examination were instituted, by which many ignorant officers were removed, and by the successive exertions of Surgeons Tripler and Letterman the medical corps was brought to a very high degree of efficiency. With regard to the sanitary condition of the army while on the Potomac, Dr. Tripler says that the records show a constantly increasing immunity from disease. "In October and November, 1861, with an army averaging 130,000 men, we had 7,932 cases of fever of all sorts. Of these about 1,000 were reported as cases of typhoid fever. I know that errors of diagnosis were frequently committed, and therefore this must be considered as the limit of typhoid cases. If any army in the world can show such a record as this, I do not know when or where it was assembled." From September, 1861, to February, 1862, while the army was increasing, the number of sick decreased from 7 per cent. to 6.18 per cent. Of these the men sick in the regimental and general hospitals were less than onehalf; the remainder were slight cases, under treatment in quarters. "During this time, so far as rumor was concerned, the army was being decimated by disease every month." Of the sanitary condition of the army during the Peninsular campaign, up to its arrival at Harrison's Landing, Dr. Tripler says:

During this campaign the army was favored with excellent health. No epidemic disease appeared. Those scourges of modern armies-dysentery, typhus, cholerawere almost unknown. We had some typhoid fever and more malarial fevers, but even these never prevailed to such an extent as to create any alarm. The sick reports were sometimes larger than we cared to have them, but the great majority of the cases reported were such as did not threaten life or permanent disability. I regret that I have not before me the retained copies of the monthly reports, so that I might give accurate satistics. I have endeavored to recover them, but have been unsuccessful. My recollection is that the whole sick report never exceeded 8 per cent. of the force, and this including all sorts of cases, the trivial as well as the severe. Army of the Potomac must be conceded to have been the most healthy army in the service of the United States.

The

His remarks at the conclusion of his report upon our system of medical administration and his suggestions for its improvement are especially worthy of attention.

The service, labors, and privations of the troops during the seven days' battles had of course a great effect on the health of the army after it reached Harrison's Landing, increasing the number of sick to about 20 per cent. of the whole force. The nature of the military operations had also unavoidably placed the medical department in a very unsatisfactory condition. Supplies had been almost entirely exhausted or necessarily abandoned, hospital tents abandoned or destroyed, and the medical officers deficient in numbers and broken down by fatigue. All the remarkable energy and ability of Surgeon Letterman were required to restore the efficiency of his department, but before we left Harrison's Landing he had succeeded in fitting it out thoroughly with the supplies it required, and the health of the army was vastly improved by the sanitary measures which were enforced at his suggestion.

The great haste with which the army was removed from the Peninsula made it necessary to leave at Fort Monroe, to be forwarded afterwards, nearly all the baggage and transportation, including medical stores and ambulances, all the vessels being required to transport the

troops themselves and their ammunition; and when the Army of the Potomac returned to Washington after General Pope's campaign, and the medical department came once more under Surgeon Letterman's control, he found it in a deplorable condition. The officers were wornout by the labors they had performed, and the few supplies that had been brought from the Peninsula had been exhausted or abandoned, so that the work of reorganization and resupplying had to be again performed, and this while the army was moving rapidly, and almost in the face of the enemy. That it was successfully accomplished is shown by the care and attention which the wounded received after the battles of South Mountain and Antietam.

Among the improvements introduced into his department by Surgeon Letterman, the principal are the organization of an ambulance corps, the system of field hospitals, and the method of supplying by brigades, all of which were instituted during the Maryland campaign, and have since proved very efficient.

QUARTERMASTER'S DEPARTMENT.

On assuming command of the troops in and around Washington I appointed Capt. S. Van Vliet, assistant quartermaster (afterwards brigadier-general), chief quartermaster to my command, and gave him the necessary instructions for organizing his department and collecting the supplies requisite for the large army then called for.

The disaster at Manassas had but recently occurred, and the army was quite destitute of quartermaster's stores. General Van Vliet with great energy and zeal set himself about the task of furnishing the sup plies immediately necessary, and preparing to obtain the still larger amounts which would be required by the new troops, which were moving in large numbers towards the capital. The principal depot for supplies in the city of Washington was under charge of Col. D. H. Rucker, assistant quartermaster, who ably performed his duties. Lieut. Col. R. Ingalls, assistant quartermaster, was placed in charge of the department on the south side of the Potomac. I directed a large depot for transportation to be established at Perryville, on the left bank of the Susquehanna, a point equally accessible by rail and water. Capt. C. G. Sawtelle, assistant quartermaster, was detailed to organize the camp, and performed his duties to my entire satisfaction. Capt. J. J. Dana, assistant quartermaster, had immediate charge of the transportation in and about Washington, as well as of the large number of horses purchased for the use of the artillery and cavalry. The principal difficulties which General Van Vliet had to encounter arose from the inexperience of the majority of the officers of his department in the new regiments and brigades. The necessity of attending personally to minor details rendered his duties arduous and harassing in the extreme. All obstacles, however, were surmounted by the untiring industry of the chief quartermaster and his immediate subordinates, and when the army was prepared to move, the organization of the department was found to be admirable.

When it was determined to move the army to the Peninsula, the duties of providing water transportation were devolved by the Secretary of War upon his assistant, the Hon. John Tucker. The vessels were ordered to Alexandria, and Lieutenant-Colonel Ingalls was placed in immediate charge of the embarkation of the troops, transportation, and material of every description. Operations of this nature on so extensive a scale had no parallel in the history of our country.