Second. Precautions should be taken against fire. Two or tree men could burn this bridge any night and without danger to themselves. Once on the flats under the bridge they could lodge fire balls on the piers and under the flooring by means of poles. The guard would not know it until the bridge was on fire, and then, as things now are, they would have no means of extinguishing the flames. Hogsheads or barrels filled with water ought to be placed at intervals on the bridge with ropes, buckets, axes, &c.

Third. A couple of rope ladders down the side of the pier under the gate would enable the guard at this point to escape if too strongly attacked so that the batteries could instantly open without danger to our own men.

Fourth. Some twenty-fire or thirty feet of the brigade flooring ought to be taken up every night. In case danger is apprehended the flooring of the sidewalks ought also to be taken up.

Aqueduct Bridge. - Besides the tete-de-pont of Forts Corcoran and Haggerty, there are three block-houses near the south end of this bridge, but the latter are not occupied. The immediate defense of this bridge consists of a stockade with gates across the approach to the bridge at the south or Virginia end. Captain Blanchard, of the Veteran Reserves, commands the bridge. Has one officer and thirty men at the south end, and two officers and twenty-five men at the north end. He has no means of putting out fire no means of patrolling the river to prevent an enemy from floating down and firing the bridge from the under side. Has applied for boats and thinks he ought to have at least two. If a sudden attack was apprehended would close the gates and man the stockade. Did not know whether the bars for securing the gates were on hand or not; did not know whether the bars, if on hand, would fit the staples. Had never tried them. Upon examination, at my request, these were found to be in perfect readiness. No arrangements have been made for taking up the flooring of this bridge as it would involve cutting away the bottom sheathing of the aqueduct. This can be done at some little expense with time to do it, but could not be done promptly in a sudden emergency without previous preparation.

I remark:

First. That the guard ought to be increased so as to afford a patrol both on and under this bridge, and the same remark applies to both the other bridges. The guard should be supplied with one or two boats.

Second. Precautions should be taken to guard against fire. Hogsheads or barrels of water should be kept on the bridge, and perhaps an engine kept on hand and in readiness for this purpose.

Third. Additional security could be given to this bridge by putting up a battery for a section of artillery on the bank at this end of the bridge.

Fourth. The three block-houses at the south end could be better disposed by removing them nearer to the end of the bridge. They would then afford the necessary quarters for the guard, and the guard be in the right place at the end of the bridge, whereas now it is on the bridge.

Long Bridge. - Mr. Childs reports as follows: Captain Sims, of the Veteran Reserves, commands the guard at the north end of this bridge. He has sixty-four men. To guard against fire, barrels of water and buckets are placed on the bridge at intervals of thirty or forty yards. There is also a water-tank at the Washington end of the bridge, but