to me the charge of the siege operations on the Fifth Corps front, by details from the Fifth and Second Corps, and Fiftieth New York Volunteer Engineers, and Fourth New York Heavy Artillery:

First Batteries constructed for forty-four guns, parapets generally fifteen feet thick at top, and not less than ten in any case; four magazines.

Second. The large battery on the left of the Fifth Corps was turned over to me with the parapet up alone. it was thoroughly traversed, two large bomb-proof magazines built, eight platforms constructed and laid by Fourth New York Heavy Artillery, embrasures for seventeen guns cut and revetted.

Third. Two mortar batteries, one for ten 10-inch mortars and one for six 8-inch mortars were constructed, three magazines built, the platforms laid.

Fourth. Seventeen thousand two hundred feet of boyau constructed, averaging nine feet in width and three feet and a half in depth.

In addition to the above the following has been done under Lieutenant Benyaurd's direction on the Ninth Corps front, viz: A fourteen-gun siege battery with two magazines and the necessary platforms, with an approach 600 yards long; a magazine and platform were placed in another siege battery, and platforms placed in the six-gun battery near the Taylor house. Lieutenant Benyaurd also repaired about 300 yards of the approach to the mining gallery, and kept his company employed in instructing in making gabions and fascines.

The officers of the battalion at the opening of the campaign were the following: Captain C. N Tunbull, commanding Company D; First Lieutenant R. S. Mackenzie, commanding Company A; First Lieutenant W. H. H. Benyaurd, commanding Company C; First Lieutenant C. W. Howell. Since that time Captain Turnbull and Lieutenant Mackenzie have been relieved, and Capts. F. Harwood and George L. Gillespie, and Lieutenants Cuyler and Heap, have Joined the battalion. A large portion of the services of these officers in this campaign have been performed while detached on the staff of corps commanders and elsewhere, under direction of the chief engineer, of which no reports have been made to me.

It is hoped that their services will be recognized in other reports.

I is scarcely necessary for me to say that all the officers of the command have manifested the utmost willingness, energy, and efficiency in the performance of the arduous duties that have fallen upon them, and the value and importance of their services deserve recognition. The enlisted men of the battalion have always done credit to themselves and to their officers by the earnestness, rapidity, and thoroughness of their labor, and I take pleasure in stating my belief that no better body of enlisted men can be found in any army.

The accompanying drawings* represent the character of some of the works constructed on the Fifth Corps front.

I am, major, very respectfully, your obedient servant,

G. H. MENDELL,

Captain of Engineers, Commanding U. S. Engineer Battalion.

Major J. C. DUANE,

Chief Engineer, Army of the Potomac.

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*Not found.

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