was connected with Fort Davis. He also located on the map the second line in rear of that fort, to be taken up in the event of its being blown up by the enemy. He also had charge of Fort McMahon until relieved by Captain Hine; assisted Captain Harwood in planning Forts Blaisdell and Kelly, and accompanied him in the reconnaissance in the neighborhood of Prince George Court-House and along the Blackwater. Captain Paine has been engaged in examining and mapping the roads between the Jerusalem plank road and the Weldon railroad as far toward the south as he was able to go. In the topographical department I directed my principal assistant, Major Weyss, assisted by Mr. Theilkuhl, to survey the new line of works extending from Fort Dushane, on the Weldon railroad, to Fort Bross, near the Blackwater Swamp. The survey has been completed and plotted and added to the large 8-inch map of the operations in front of Petersburg. The new line from Fort Sedgwick to Fort Haskell was also surveyed yesterday. The construction and drawing of the large map of Petersburg have been progressing with every prospect of completing it by the end of the next week. Detailed measurements and sketches preliminary to preparing accurate plans and profiles have been made within the last few days of Forts Sedgwick, Wadsworth, Rice, Alexander Hays, Dushane, Howard, Meikel, Morton, and Haskell. Tracings from the original drawings* have been made, and are now respectfully submitted with this report, of Forts Davis and Prescott (redoubts on the plank road); of the eighteen-gun battery (now part of Fort Sedgwick); of the 10-inch mortar battery (now forming one face of Fort Rice), and of the field battery for eighteen guns (located near the Norfolk railroad, but recently demolished). A map of Dinwiddie County (scale one inch to the mile) has also been completed and photographed and copies forwarded for the use of the lieutenant-general. Campaign maps (scale one inch to the mile) are als in course of compilation from the Rapidan to the Appomattox. The Culpeper, Spotsylvania Court-House, and Fredericksburg sheets are already finished, and those of Hanover Court-House, Richmond, and Petersburg are far advanced toward completion; the construction and compilation have been going on during the week. A "copy of section of photogaph map captured from the enemy, showing the country adjacent to Richmond and lines of defensive works surrounding the city," is also being made in the office; part of it is already completed and photographed, and the other part will probably be finished in the course of several days. A sketch (two inches to the mile) giving the relative positions of the different forts, redoubts, and batteries, and the infantry parapets connecting them, of the entire line from the Appomattox to the Blackwater Swamp has just been prepared to show the names, numbers, or letters of the respective works. Sign-boards have also been painted to designate each fort and battery. A list has been prepared to be printed, giving the arnament, garrison, name, and locality of each work. The line is sixteen miles in length, and along it have been constructed or are in course of construction nineteen forts and redoubts and forty-one batteries.

I have the honor to be, colonel, very respectfully, your obedient servant,

N. MICHLER,

Major of Engineers.

Lieutenant Colonel T. S. BOWERS,

Assistant Adjutant-General,

Hdqrs. Armies of the United States, City Point, Va.

[42.]

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*On file in Engineer Bureau.

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