to a gun-boat, should such passage at any time become of pressing importance. My experience in the Western Department convinced me that all movable obstructions were not reliable or safe in the Cumberland, Tennesse, or Mississippi Rivers; for instance, heavy chains, supported by buyos, rafts, or boats; nor can the most massive rafts, secured to the firmest anchors, be depended upon. Such works proved deceptive at New Orleans, Columbus, Ky., and in the Cumberland River. I am decidedly of the opinion that no pass-way should be left through the obstructions at Drewry's Bluff, and that all parts of the work shoul be fixed in position. If no passage be left, it may be asked, why build iron-clad gun-boats and floating batteries at the shipyards of Richmond? Simply because such defense will be of invaluable aid to the land batteries at the Bluff, if placed just above the obstructions, while they will be safe from the attacks of any of the enemy's steam rams in the river. Having the fixed, insurmoutable barrier between them and the enemy's fleet, they can be maneuvered in safety and with certainty, bringing the guns first of one side to bear, then of the other. Should a bodl, dashing advance enable the enemy to come right up to the obstructing works, some of the guns mounted on the land batteries would have to be fired at a considerabel depression to reach their gun-boats. At such a moment the guns of our floating batteries and gun-boats would tell with deadly effect. Without their presence, an advance such as I have supposed might give the enemy serious advantage.

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

J. F. GILMER,

Lieutenant Colonel, and Chief Engineer, Dept. of Northern Virginia.

[First indorsement.]

Respectfully submitted to the President.

In addition to the considerations here presented, I would suggest that the estimated speed of the Richmond being five knots, it will be well to test her capacity for maneuvering before weakening the barrier. It is possible that experiment may demonstrate her unfitness for operations below the barrier.

G. W. RANDOLPH,

Secretary of War.

[Second indorsement.]

Postpone decision until the Richmond is shown to have the needful locomotion.

J. D.

[18.]

WARRENTON, September 10, 1862.

President JEFFERSON DAVIS:

I have just arrived here. Left Frederick City at noon yesterday. General Lee expected that I would meet you and Governor Lowe, and gave me dispatches in addition to verbal instructions. The latter would be useless, since you have returned to Richmond. I shall return to the army and forward the dispatches by mail, unless ordered otherwise.

W. H. TAYLOR,

Major and Aide-de-Camp.

[19.]