Numbers 13. Report of Lieutenant Colonel Ira Spaulding, Fiftieth New York Engineers, including operations April 29-June 30.

HDQRS. DETACH. 50TH NEW YORK VOL. ENGINEERS, Near Petersburg, Va., August 30, 1864.

MAJOR: In compliance with Special Orders, Numbers 209, headquarters Army of the Potomac, dated August 5, 1864, I have the honor to submit the following report of the operations of this command since the opening of the opening of the campaign to the assault on the enemy's position in front of Petersburg, July 30, 1864:

To make this report intelligible, I should premise that the command consists of eleven companies of this regiment, numbering in all an average of about 40 officers and 1,500 enlisted men present; that small details from these companies and the twelfth company of the regiment were at the opening of the campaign with Colonel Pettes at the depot of the Engineer Brigade in Washington, and that a short time previous to the beginning of the campaign this command was divided into the First, Second, Third, and Reserve Battalions. The First Battalion, composed of Companies B, F and G, commanded by Major Wesley Brainerd, had in charge a pontoon train of fourteen boats (French pontoons) together with the entrenching tools of the Second Corps, to which it was assigned for duty. The Second Battalion, composed of Companies E, H and L, commanded by Major E. O. Beers, had in charge a pontoon train of thirteen French pontoons together with the entrenching tools of the Sixth Corps, to which it was assigned. The Third Battalion, compassed of Companies D, K, and M. commanded by Captain J. H. Mcdonald, Major Ford not having joined, had in charge a pontoon train of thirteen French pontoons, and also the entrenching tools of the Fifth Corps to which it was assigned. The Reserve Battalion, under my own immediate command, consisted of Companies C and I, having in charge two pontoon trains of twelve canvas boats each and two wing trestles each, Captain W. W. Folwell commanding pontoon train Numbers 4, and Captain M. Van Brocklin, Company C, commanding pontoon train Numbers 5. Al these pontoon trains were arranged under my directions, acting under the general orders of the chief engineer, and the whole of the above battalions and trains were to operate under my immediate supervision and inspection.

On the 28th of April, 1864, Major Brainerd was encamped with the First Battalion and trains near Stevensburg; Major Beers with the Second Battalion and trains at Welford's Ford, having a bridge in use over Hazel River; Captain McDonald, whit Third Battalion and trains, was at my winter camp near Rappahannock Station. My headquarters were also at the same camp with the Reserve Battalion and trains.

FIRST EPOCH.

Reserve Battalion.

On the 29th of April I sent Captain Folwell whit his company and pontoon train Numbers 4 to Kelly's Ford to bridge the Rappahannock for the passage of Gregg's division of cavarly. The brigade was completed in short bays of 16 feet at 1 p. m.; length of bridge, 180