along the summit of the highlands southeast of the Eastern Branch the ground is very much cut by wooded ravines perpendicular to the direction of the roads. Hence, this single work exercises a powerful influence in preventing an enemy, coming from the direction of Bladensburg, from reaching the margin of the Eastern Branch opposite Washington . It should be capable of holding out for a few days without external aid. The work is well built and sufficiently large. The Commission recommend the construction of bomb-proofs for the garrison, and to contain, besides five days' provisions, reversed casemates at three of the angles of counterscarp and a few more platforms for field guns on east and west faces; also a stockaded redan, to cover the entrance and flank the gorge. It should be remarked that Benning's Bridge itself is guarded by a tete-de-pont for infantry.

The chain of works (ten in all) from Fort Meigs to Fort Greble occupies the summit of the ridge between the Eastern Branch and Oxen Creek from almost all points at which, in this distance of 6 miles,an enemy can bring batteries to bear upon the navy-yards or arsenal.

Fort Meigs occupies a key-point to the ridge. It is the extreme point in this direction from which the arsenal and the navy-yard can be seen and reached by an enemy's batteries. To reach this point from Bladensburg, an enemy must taken the Eastern Branch and Benning's Bridge roads, or, by a considerable detour, strike the Marlborough road to the eastward. Obstructed at Fort Meigs, if he would reach the ridge at a lower point, he must make a more extensive detour, cross the valley of Oxen Creek above Fort Meigs, and recross it again; the only public road available being the one ascending the ridge at Fort Wagner and leading to the Navy-Yard Bridge. Fort Meigs should be a work capable of resisting a vigorous assault. It is not so (no isolated small field-work can be so), and no single large work on this difficult ground, even if the topography permitted, can be made so without numerous outworks. The object can only be attained by a congeries of works, which shall sustain and flank each other, and, from numerous points of view, see and guard all the ravines and otherwise hidden surfaces. To accomplish this-to a great degree, at least-several auxiliary works are necessary-say, a work some 300 yards distant, on the Marlborough road (under construction); a battery in connection therewith,near the road, to command a ravine of gentle slopes which extends from near Fort Meigs southward to Oxen Creek; a small work (under construction) on a knob a few hundred yards north of Fort Meigs (of much lower elevation), to see, in reverse, the steep slopes and ravines which approach the fort from the northward. These works, with Fort Du Pont, will form a congeries, which may be considered a single fortifications of fortified camp, in which the garrison must sustain itself for a few days. The various ravines and inequalities of the ground furnish ample against direct or covered fires, and, as vertical fires are not to be apprehended, bombproof are unnecessary, except for the ground of the forts themselves and for storage of provisions. The guns of Fort Meigs are all sea-coast 32s, and in barbette. As these guns will be useful for their distant fire, the light guns of surrounding works being depended on for flanking purposes, it may be well to let them remain as they are.

Fort Du Pont, after what has been said, requires no especial remark. A deep ravine to the westward may, perhaps, be best defended by a block-house, which can be pretty well screened from an enemy's artillery. The system we have just spoken of may require two or three of these structures.

Fort Davis requires no especial remark. It may be regarded as an

58 R R-VOL XXI