In spite of the heat of the day, the Union troops reached the entrenched camp at about half past four o’clock, and were in possession at twenty minutes before five. The entrenchments were strongly fortified with earthworks, on the top of which were found twenty-nine pieces of artillery. When just about to enter the city the troops were met by a flag of truce. The Mayor of the city, who had come out under the flag, was met by General Wool and Secretary Chase. They entered a cottage by the road side, for the purpose of conferring together, and there the Mayor of Norfolk informed General Wool of the purport of his visit, explaining that he had come to surrender the city into the hands of the United States, and to ask protection for the persons and property of the citizens. General Wool’s reply was that the request was granted in advance. He then immediately took possession of the city, and appointed Brigadier-General Egbert L. Viele to be Military Governor, with directions to see that the citizens were protected in all their civil rights. At this point it is necessary to look backward for a few days at the doings of the rebels, in order to explain the burning of the Merrimac. DESTRUCTION OF THE MERRIMAC. Commodore Tatnall, early in May, received orders to take up his position upon the James river, in such a way as would entirely prevent the Union forces from ascending it. On the next day he was ordered to endeavor to protect Norfolk, too, which placed him in his original position. On the day following, Commodore Hollins reached Norfolk with orders from the rebel Secretary of the Navy, Honorable S. R. Mallory, to communicate with Commodore Tatnall and such officers as he might select, in regard to the best disposition to be made of the rebel steamer Virginia—better known at the North as the Merrimac. On the 8th of May the Union forces attacked the Sewell’s Point battery; and Commodore Tatnall immediately undertook its defence, with the Merrimac. Six of our vessels, including the Monitor and Naugatuck, were actively engaged in the bombardment of the rebel batteries on Sewell’s Point and Craney Island. The Merrimac evinced a decided disinclination to come out into the roadstead; and, as the National vessels were equally disinclined to go up to her, the combat ceased. The Monitor had orders to engage the Merrimac, in only such a position as would enable the Union iron-clad, and other vessels engaged, to run her down.