on which the enemy could plant artillery to bear upon these works, and upon the marginal spurs on which batteries could be established, to bear on the aqueduct of Chain Bridge. Considering how important these functions are, the Commission recommend the substitution of 100-pounders for the rifled 42s in Battery Comeron, and the addition of another 100-pounder to each of the other batteries.

Battery Vermont was constructed before the other shore of the Potomac was occupied. It has a good view of the Leesburg turnpike, and the Commission recommend the substitution of rifled guns for the 32-pounders, to bear on that approach.

Battery Martin Scott sweeps the Chain Bridge. It now contains field 6-pounders. Two 8-inch siege howitzers are recommended.

Returning now to the principal line, and proceeding from Fort De Russy eastward, near Rock Creek, on the heights, on the east side, is a battery for field guns, on the line of rifle-pits, intended to command the broad ravine which crosses the interval between Rock Creek and Fort Massachusetts.

Fort Massachusetts, in conjunction with Forth Slocum, commands one of the principal avenues of approach to Washington. The original work was entirely inadequate to its important purpose. It has recently been judiciously enlarged, and, with the addition, is a powerful and satisfactory work. The Commission recommend that melons be raised on the exposed front of the old work, which will, at the same time, defilade the rear and lateral faces; that the parapet of the exposed front be thickened; that bomb proofs for garrison and casemates for reverse fire at the southeast angel of the old work and at the north angle of new work be constructed.

Fort Slocum.--From two-thirds of a mile to 1 mile in advance of Forts Massachusetts and Slocum the country rises to heights say 20 to 30 feet higher than the crests to those works, furnishing to an enemy most advantageous emplacements for artillery. Along the dividing ridge of this high ground, between Rock Creek and the Eastern Branch, leads the Seventh street turnpike road. These two works are, therefore, exposed to the most powerful efforts of the enemy. Fort Slocum, though originally of more respectable dimensions than Fort Massachusetts, was, nevertheless, a small work, and quite inadequate in strength, armament, and bomb-proof. The work is undergoing a considerable and judicious enlargement. The Commission recommend melons and traverses on the exposed fronts of the old work, by which the work will be defiladed and the guns better protected. The high ground spoken of in advance of these works will be under the fire of the 100-pounders and other rifled guns of Forts De Russy and Totten, besides that of the powerful batteries of the works themselves.

Fort Totten occupies a most commanding and strong position, and exercises a powerful influence upon the approaches from the northward and those through the valley between it and Fort Lincoln. It is well adapted to its position, well built and well armed, and amply provided with magazines and bomb-proofs. The 100-pounder here placed will sweep the sector from Fort De Russy to Fort Lincoln. Melons and traverses are not called for in this work. The position is so strong that reverse fires are not considered necessary for the ditches. No recommendations made.

Fort Slemmer. - A well-placed battery for three 32-pounder guns. No recommendations made.

Fort Bunker Hill occupies a very commanding position, but it is deficient in interior space. It should contain at least two rifled guns, and needs additional fire upon its capital. An advanced battery for field