fire. The Monitor them at once and opened her fire, when all the enemy's vessels retired excepting the Merrimac. These two iron-clads fought, part of the time touching each other, from 8 a. m. to noon, when the Merrimac retired. Whether she is injured or not it is impossible to say. Lieutenant J. L. Worden, who commanded the Monitor, handled her with great skill, and was assisted by Chief Engineer Stimers. Lieutenant Worden was injured by the cement from the pilots-house being driven into his eyes, but I trust not seriously. The Minnesota kept up a continuous fire, and is herself somewhat injured. She was moved considerably to-day, and will probably be off to-night. The Monitor is uninjured and ready at any moment to repel another attack.

G. V. FOX,

Assistant Secretary.

WASHINGTON NAVY-YARD, March 9, 1862-9-p. m .

Honorable GIDEON WELLES, Secretary of the Navy:

The proposed measures for guarding the Potomac are in progress. i am informed from the Quartermaster's Department that eight canalboats, loaded with stone, were about to leave, and eight more would leave during the night. I have sent instructions to the commandant of the flotilla as to the disposition and use at the three places where the channel has the least depth of water.

The only 11-inch gun and 50-pounder which I have will be landed on Giesborough Point before midnight. The platforms will be laid and the guns in position to-morrow morning. The mortars will also be placed. Shot are being cast for all of them, and a full supply will be ready tomorrow.

The Secretary of War has visited the defensive points and given me authority to draw on any of the regiments or forts for men, guns or munitions. He has also authorized me to take for the while the private steamers plying on the river present use of the Government, and I nave sent around for them. It there should be any use at all for a battery o Giesborough, there ought to be twenty of the heaviest cannon. Shot of 170 pounds at 50 or 100 yards will be apt to do something. A smart steamer has been dispatched to the mouth of the Potomac to observe it.

JNO. A. DAHLGREN, Commandant.

BUDD'S FERRY, March 9, 1862-9.15 p. m.

Captain DAHLGREN:

I was absent when your telegram for Captain Wyman reached this office; it was, however, duly communicated.

Captain Wyman is of the opinion that the Merrimac cannot ascend the Potomac.

HOOKER, Brigadier-General.

EXECUTIVE MANSION, Washington, March 9, 1862.

Colonel INGALLS, Quartermaster, Annapolis:

Should the Merrimac, which did so much damage at Newport News, attempt anything at Annapolis, it is believed that the best defense would be an attack by a number of swift steamers, full of men, who