The inducement for this raid, as I some time since reported, was so great that I am surprise that the enemy have so long resisted the temptation.

very respectfully, your obedient servant,

JNO. C. TIDBALL,

Colonel Fourth New York Artillery.

Captain THOMPSON,

Assistant Adjutant-General.

[Indorsement.]

HEADQUARTERS DEPARTMENT OF WASHINGTON,
October 2, 1863.

Captain Carroll H. Potter, assistant adjutant-general, with sufficient escort, will proceed without delay to the scene of the within reported surprise, make a thorough and rigid examination into the circumstances attending it. In his report he will specify on whom the blame should fall.

By command of Major-General Heintzelman:

J. H. TAYLOR,

Chief of Staff, and Assistant Adjutant-General.

Numbers 2. Report of Captain Carroll H. Potter, Assistant Adjutant-General, U. S. Army.

HEADQUARTERS DEPARTMENT OF WASHINGTON,
October 3, 1863.

SIR: I have the honor to report, in accordance with your order indorsed upon the report of Colonel J. C. Tidball, Fourth New York Artillery, reporting the capture of the guard near Lewinsville at Camp Beckwith (one of the government farms), that I left Washington the 2nd instant, at about 1.30 O'clock p. m., with 1 commissioned officer and 25 men from Scott's Nine Hundred Cavalry, and proceeded on my way to Lewinsville to make a thorough examination of the circumstances attending the capture of the guard and public property at that post.

When I arrived at Lewinsville, 5.30 p. m., I found First Lieutenant W. J. Keays, Company B, Sixteenth New York Cavalry, in command of the cavalry detachment at Camp Beckwith, composed, before the attack of the enemy, of 1 commissioned officer, Second Lieutenant H. S. Larned, with 1 acting lieutenant, H. Cary, really a quartermaster sergeant, and 40 men, 30 of whom were fit for duty at the time of the attack, and Second Lieutenant P. H. Welch, in command of the infantry guard, composed, before the attack, of 17 men, all fit for duty.

Lieutenant W. J. Keays was placed there with his detachment of cavalry to scout the country, cover the camp of the infantry, and to notify them of any advance of the enemy. To perform this duty he stationed at night a picket of 3 men on the road leading from the camp toward the Alexandria and Leesburg pike, which it intercepts near Difficult Run; 3 men on a wood road leading toward the