At the outbreak of the Civil War in the United States, the government appointed a special naval committee to report upon types of ironclads. The conclusions of this board are of interest, in showing the state of armor development at that period. They required rolled armor of solid iron, whose minimum thickness was 4½ inches. Ericsson’s Monitor, however, carried laminated plating from 3 to 5 inches thick on her low sides, and 11 layers, each one inch thick, on her turret. This construction, which the difficulties in the manufacture of solid plate necessitated, made the record of endurance of this type far from good. The defect lay mainly with fastening bolts, which broke frequently, thus loosening or detaching the side armor, and the heads or nuts of which, flying off with violence when the armor was struck by shot, became sometimes fatal missiles against those within the turrets. In contrast with this, the behavior of the New Ironsides, clothed with solid armor, was most excellent. She was a casemated ironclad frigate with unarmored ends, her plating was 4½ inches thick, and inclined throughout the citadel, at an angle of 30° from the perpendicular. For two years she was subjected to the most severe test that a war-vessel must meet, the tossing and straining of blockade duty and the fiery ordeal of close action with fortifications. In one engagement, she sustained alone a fight against the combined fire of the forts in Charleston harbor, and, although struck on her side-armor sixty times, came out of the struggle unhurt. The record of this ship is one which does honor to the flag. The achievement of the Confederacy during this war, in the matter of armor, was remarkable. With iron worth almost its weight in gold, and with most limited facilities for manufacturing, they yet succeeded in constructing some of the most formidable ironclads of their day. The Merrimac, for instance—with 3-inch armor, in two layers of narrow bars, at an angle of 30° with the horizontal—sustained no material damage to her plating from the fire of the Monitor; although had the full charge of 30 lbs. of powder been used in the 11-inch smooth-bores of the latter, the story would have been different. Every fair blow would have smashed a hole completely through the armor, and driven a shower of splinters about the battery-deck. Again, the armor of the Atlanta and the Tennessee—both casemated ships, with the sides of the citadel inclined at a sharp angle to the horizontal—was sufficiently strong, with the former vessel, to withstand, at 500 yards, the 11-inch projectile fired with a 20-lbs. charge, and, with the latter, the same shot practically at the muzzle, although the 15-inch projectile broke through completely in both cases.