FORT PICKENS, FLA., March 30, 1861.

The ASSISTANT ADJUTANT-GENERAL, Headquarters of the Army:

SIR: I have the honor to report that matters have not assumed a hostile attitude. Everything appears quiet. Troops are being quietly concentrate ed and preparations made for an immediate movement should the present amicable agreement be interrupted. From all I can learn, there are not nearly one thousand enlisted men occupying the various posts and batteries in the vicinity and five thousand expected. Since my last report the redoubt between Fort Barrancas and the bayou has been occupied and made an ordnance depot. Nearly all the powder has been transferred from the navy-yard to that post. The troops are organized and apparently under good discipline, a marked difference existing between them and the volunteers who first occupied these positions. Guns are being mounted at Fort McRee. The light-house battery had four 8-inch columbiads which bear directly on this work. Another battery of four 8-inch columbiads is situated to the east and front of the naval hospital. Report says that another battery has been constructed at the old light-house. I cannot distinguish any signs of it, however. If made, it is effectually masked.

Fort Barrancas is fully armed. Guns are mounted in the navy-yard for its protection. These works are being strengthened and completed each day, and soon the position will be one which will be very difficult to reoccupy, and one which will prove a serious annoyance to this post. Shot and shells can be thrown from each of these works into Fort Pickens. I have protested against the prosecution of these works, but have continued them ont eh plea of being for defensive purposes. With one or two batteries established on Santa Rosa Island, Fort Pickens would be in almost as bad a position as Fort Sumter. Fort McRee and these batteries would be able to drive off any shipping and prevent the introduction of re-enforcements and provisions. I have thus far succeeded in preventing any lodgment on the island, and will consider any such movement a breach of the agreement.

It is very necessary that we should be informed as to passing events, and would, therefore, most respectfully call the attention of the Commanding General to the fact that form the 23rd February until the 29th March no important communication has been received. We receive nothing but from the sufferance of the opposing forces, which at any moment may be stopped should anything occur contrary to their desires. I am now left without an officer, but will request the transfer of Lieutenant Langdon to the fort during the absence of Lieutenant Gilman.

Fresh provisions are now denied us. If it is the intention of the Government to hold his fort, I would most respectfully suggest that the stores and supplies necessary for the effective defense of the work be forwarded immediately, with definite instructions as to their being landed.

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

A. J. SLEMMER,

First Lieutenant, First Artillery, Commanding.

HEADQUARTERS OF THE ARMY,
Washington, April 1, 1861.

Bvt. Colonel HARVEY BROWN,

U. S. Army, Washington, D. C.:

SIR: You have been designated to take command of an expedition to re-enforce and hold Fort Pickens, in the harbor of Pensacola. You will