“Mr. Brooke attended daily to the iron armor, constructed targets, ascertained by actual tests the resistance offered by inclined planes of iron to heavy ordnance, and determined interesting and important facts in connection therewith, and which were of great importance in the construction of the ship; devised and prepared the models and drawings of the ship’s heavy ordnance, being guns of a class never before made, and of extraordinary power and strength.” Porter having got the hull in the dry dock, cut it down to where the berth deck had been. Then he laid a heavy timber deck over the entire hull, and on this, amidships, he erected a casemate, with its walls inclined in at an angle of “about thirty-six degrees,” according to one of her officers, and forty-five according to another. This casemate was two feet thick, and was made of twelve-inch timbers standing on end, covered with eight-inch timbers laid horizontally, which were in turn covered with oak plank four inches thick. On these were laid iron plates two inches thick and eight inches wide, placed horizontally, with another layer of the same dimensions over them placed vertically. The side-walls of this casemate projected down and out over the sides of the hulk, like the eaves of a country house, to protect the water-line, and the hull itself was plated with one-inch iron for two feet below the deck, although the design called for three-inch iron. The inclined sides were carried up high enough to give seven feet head room inside, and then a heavy flat deck twenty feet wide, with hatches in it, was laid across. On the bow, two feet below the water-line, was bolted a cast-iron wedge that projected two feet from the stem, and was for use as a ram. [Illustration: Franklin Buchanan.] The battery of the _Merrimac_ contained six of the nine-inch Dahlgrens found in the Norfolk Navy Yard, and four rifles designed by Brooke. Two of these rifles were mounted as pivots at bow and stern, and two smaller ones were in the broadside. The pivots were cast-iron muzzle-loading rifles of seven-inch calibre, and they weighed 14,500 pounds each. The reader will appreciate the weight of the gun when it is told that the best gun in the British navy at that time was the 68-pounder, having a calibre of eight inches and weighing 9,500 pounds. Moreover, Brooke’s heavy casting was reinforced by wrought-iron bands shrunk on. The broadside guns were of the same construction, but weighed 9,000 pounds and were of four-inch calibre. Brooke’s guns were far and away the best then afloat.