It has been stated that early in the war the Norfolk navy yard was burned to prevent its falling into the possession of the Confederates. Among the vessels sunk was the frigate _Merrimac_, which went down before much injury was done to her. She was a formidable craft of 3,500 tons, 300 feet in length, and had mounted 40 guns. The Confederates succeeded in raising her, and proceeded to work marvelous changes in her structure, by which she was turned into the first real armor-clad ever constructed. She was protected by layers of railroad iron, which sloped like the roof of a house, and was furnished with a prow of cast iron which projected four feet in front. Pivot guns were so fixed as to be used for bow and stern chasers, and the pilot-house was placed forward of the smoke-stack and armored with four inches of iron. She carried ten guns, one at the stern, one at the bow, and eight at the sides, and fired shells. Her iron armor sloped down at the sides, so that she looked like an enormous mansard-roof moving through the water. Her commanding officer was Commodore Franklin Buchanan, formerly of the United States navy, while under him were Lieutenant Catesby R. Jones, the executive officer, six other lieutenants, six midshipmen, surgeons, engineers, and subordinate officers, in addition to a crew of 300 men. She was rechristened the _Virginia_, but will always be remembered as the _Merrimac_. [Illustration: SECRETARY STANTON'S OPINION ABOUT THE MERRIMAC. "The whole character of the war will be changed."] Of necessity this craft, being the pioneer of its kind, had many defects. She could move only very slowly, and her great length of 300 feet and poor steering apparatus required a half-hour for her to make a complete turn, while her draft of 22 feet confined her to the narrow channel of the Roads. Still she could go faster than an ordinary sailing vessel, and her resistless momentum and iron prow enabled her to crush any vessel afloat as if it were an egg-shell. Great pains were taken by the Confederates to keep secret the particulars of her building; but it was known in Washington that a strange craft was in course of construction at Norfolk, with which it was expected to capture Washington and devastate the leading cities along the Atlantic seaboard. Ericsson, the famous Swedish inventor, was engaged near New York in building a smaller vessel upon the same principle, and he was pressed to make all possible haste in finishing it; for, though the government did not suspect the terrible effectiveness of the _Merrimac_, they meant to take all reasonable precautions against it. AWFUL WORK OF THE MERRIMAC.