single-turreted monitors was ten inches thick, and that of the river monitors eight and a half inches. The Tennessee, to which these were to be opposed, was a vessel of different type, and one to which the few ironclads built by the Confederates for the most part conformed--called commonly the broadside ironclad, because the guns, like those of ships-of-war generally, were disposed chiefly along the sides. Her hull was built at Selma, on the Alabama River, and thence towed to Mobile to be plated; it being desirable to take her down the river while as light as possible. She was two hundred and nine feet long and forty-eight feet wide, drawing, as has been said, fourteen feet when loaded. Upon her deck, midway between the bow and the stern, was a house seventy-nine feet long, whose sides and ends sloped at an angle of thirty-four degrees and were covered with iron plating, six inches thick on the forward end and five inches thick on the other end and the sides. With the inclination given, a cannon ball striking would be likely to be turned upward by the iron surface, instead of penetrating. The sloping sides of the house were carried down beyond the point where they met those of the vessel, until two feet below the water. There they turned and struck in at the same angle toward the hull, which they again met six or seven feet under water. Thus was formed all round the ship a knuckle, which, being filled-in solid and covered with iron, was a very perfect protection against any but the most powerful ram. The Tennessee herself was fitted with a beak and intended to ram, but, owing to the slender resources of the Confederacy, her engines were too weak to be effective for that purpose. She could only steam six knots. Her battery, however, was well selected and powerful. She carried on each side two six-inch rifles, and at each end one seven-inch rifle--six guns in all. There were, besides the Tennessee, three wooden gunboats, and Farragut was informed that there were also four ironclads; but this, as regards the lower bay at least, was a mistake.