Washington I organized a secret-service force, under Mr. E. J. Allen, a very experienced and efficient person. This force, up to the time I was relieved from command, was continually occupied in procuring from all possible sources information regarding the strength, positions, and movements of the enemy. (Mr. Allen Pinkerton was the trustworthy and efficient chief of the secret-service corps mentioned under the assumed name of E. J. Allen.)
All spies, "contrabands," deserters, refugees, and many prisoners of war coming into our lines from the front were carefully examined, first by the outpost and division commanders, and then by my chief of staff and the provost-marshal-general. Their statements, taken in writing, and in many cases under oath, from day to day, for a long period, previous to the evacuation of Manassas, comprised a mass of evidence which, by careful digests and collations, enabled me to estimate with considerable accuracy the strength of the enemy before us. Summaries showing the character and results of the labors of the secret-service force accompany this report, and I refer to them for the facts they contain, and as a measure of the ignorance which led some journals at that time, and persons in high office, unwittingly to trifle with the reputation of an army, and to delude the country with quaker-gun stories of the defenses and gross understatements of the numbers of the enemy.
The following orders were issued for the examination of persons coming from the direction of the enemy:
CIRCULAR.] HEADQUARTERS ARMY OF THE POTOMAC,
Washington, December 16, 1861.
The Major-General Commanding directs that hereafter all deserters, prisoners, spies, "contrabands," and all other persons whatever coming or brought within our lines from Virginia shall be taken immediately to the quarters of the commander of the division within whose lines they may come or be brought, without previous examination by any one, except so far as may be necessary for the officer commanding the advance guard to elicit information regarding his particular post; that the division commander examine all such persons himself, or delegate such duty to a proper officer of his staff, and allow no other persons to hold any communication with them; that he then immediately send them, with a sufficient guard, to the provost-marshal in this city for further examination and safe-keeping, and that stringent orders be given to all guards having such persons in charge not to hold any communication with them whatever; and, further, that the information elicited from such persons shall be immediately communicated to the major-general commanding or to the chief of staff, and to no other person whatever.
The Major-General Commanding further directs that a sufficient guard be placed around every telegraph station pertaining to this army, and that such guards be instructed not to allow any person, except the regular telegraph corps, general officers, and such staff officers as may be authorized by their chief, to enter or loiter around said stations within hearing of the sound of the telegraph instruments.
By command of Major-General McClellan:
GENERAL ORDERS, HEADQUARTERS ARMY OF THE POTOMAC,
Washington, February 26, 1862.
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All deserters from the enemy, prisoners, and other persons coming within our lines will be taken at once to the provost-marshal of the nearest division, who will examine them in presence of the division commander, or an officer of his staff designated for the purpose. This examination will only refer to such information as may affect the division and those near it, especially those remote from general headquarters.
As soon as this examination is completed - and it must be made as rapidly as possible - the person will be sent, under proper guard, to the provost-marshal-general, with a statement of his replies to the questions asked. Upon receiving him the provost-marshal-general will at once send him, with his statement, to the chief of staff.