all on the Louisville and Nashville Railroad, and mainly intended for the defense of important bridges, though Bowling Green and Munfordville are strategic points, and the works at these points are correspondingly more extended and important. The same may be said of the work at Glasgow, 12 miles southeast of the railroad from Cave City.

I have also visited the forts at Frankfort and Lexington (armament of these forts on the ground), and in every case left directions for such extensions and improvements as circumstances required.

All the works mentioned, except those at Bowling Green (which were thrown up by the rebels), were projected by Captain Miles D. McAlester, Corps of Engineers, and have been pushed forward as rapidly as the strength of the garrisons would allow. Those at Munfordville and Glasgow are about ready for their armament, which, as also for all the other works, have been required by the chief of ordnance of this department.

I am preparing a tabular statement of the forts and batteries, their location and armament, at the request of the Ordnance Department, a copy of which I hope to send you.

SURVEYS FOR MILITARY DEFENSES.

The surveyed and mapping of the country intervening [between] this city and Lexington have been continued, the total length of roads measured and topography given during the month of April being 167 miles.

The direct road from Crab Orchard toward Cumberland Gap I have had, by direction of General Burnside, examined as far as a point 18 miles beyond London, with a view, if possible, to its being metalloid or planked.

Between the 27th and 29th of April, by direction of Major-General Burnside, I, with Captain Dickerson, chief quartermaster, selected a site for a large depot, 6 miles beyond Nicholasville, between a bend of the Kentucky River and Hickman Creek, on its west side, distant from Lexington on the Danville pike 18 miles. Lieutenant-Colonel [O. E.] Babcock, assistant inspector-general and chief engineer, District of Central Kentucky, has been directed by me, under instructions from Major-General Burnside, to fortify the area, embracing about 4 1/4 square miles.

Captain T. B. Brooks, volunteer engineer, I have sent to aid Lieutenant-Colonel Babcock in the examination of the area, and afterward to examine the wagon roads between that point and the Cumberland, about Somerset, and thence to Jamestown, Columbia, Campbellsville, and Lebanon, with a view to ascertain the best route for forwarding supplies.

Lieutenant-Colonel Babcock has made a survey of the country immediately about Louisville, with a view, if required, to its fortification, and submitted a tracing of map and reports to this office.

Captain Poe, Corps of Engineers, is chief engineer of Twenty-third Army Corps, Brigadier-General Hartsuff commanding, at present in Louisville and about to take the field.

I inclose a statement of money received and expended up to April 30. The accounts for the month were made out, but under the circular of April 10, Treasury Department, they will be withheld till the close of the present quarter.

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

J. H. SIMPSON,

Major of Engineers.