The rebels are engaged in establishing new batteries, and are busy all night long in hammering, chopping, sawing, and driving on heavy timber. From my examination to-day, I am satisfied that it will require an immense expenditure of time, labor, and material to silence the batteries now erected by the rebels to dispute the navigation of the Potomac at this point, and, if my opinion was asked, would not advise it. Directly above the main work of the enemy, that at Quantico, is high ground on the edge of the river, which could be readily taken possession of, and in one night, with the necessary supply of entrenching tools, could be put in condition of defense against three times my number which commands their batteries, and with field artillery would compel them to abandon their guns the first day we opened fire on them. With these means at our disposal, the Navy, and a plenty of scows, my command can be transferred to that side of the river very quietly any night. I can see no other speedy and successful mode of opening the navigation of the Potomac and keeping it open. I am aware of the presence of large bodies of troops in the neighborhood, but they need not know it until the next morning, when it will be too late. If my command is insufficient, which I do not believe, sufficient force is close at hand, with water communication, to place the result beyond peradventure. I write of this with great confidence, for the reason that I feel no doubt of its absolute and complete success.

The enemy were discharging their guns more or less almost every hour during the day without any apparent object-certainly with no effect. The steamer arrived to-day, and will be discharged so as to return to-morrow. I inclose my morning report of yesterday, which is the first one I have been able to prepare since my arrival.

I have dispatched a messenger to the telegraph people, to inform them of the direction to run the wires to my camp.

I have continued to address all my communications to Brigadier General S. Williams. If this is incorrect, please inform me.

Very respectfully,

JOSEPH HOOKER,

Brigadier-General, Commanding Division.

HEADQUARTERS ARMY, October 30, 1861.

General ROSECRANS,
U. S. A., Camp Tompkins, W. Va.:

General Scott says detach Brigadier-General Benham and his brigade to Romney, to report to General Kelley, as soon as possible.

E. D. TOWNSEND,

Assistant Adjutant-General.

WASHINGTON, October 31, 1861.

General ROSECRANS,

Camp Tompkins, W. Va.:

Telegram [of] T. T. Eckert was right, but is countermanded, as you desire. Object is to re-enforce Kelley at Romney as soon as possible. If you can spare troops to do it, send them.

E. D. TOWNSEND,.

Assistant Adjutant-General.