The attitude of the Admiralty in regard to steam had hitherto been that in many respects it must be auxiliary to sail. The _Black Prince’s_ armour, though only 4½ inches thick, was considered to offer an adequate resistance to the 68-pounder gun’s projectile, and this, too, after the experience gained in the Crimean War; besides which no allowance whatever was made for the probability that more powerful guns, firing heavier projectiles than any yet known, would shortly be in existence, especially as they were already being designed. Although called an ironclad, the _Black Prince_ would be better described as “armour-patched,” for only 213 feet on each side was armour-protected. The rest of the hull, including even the steering gear, was as unarmoured and unprotected as that of any sailer of a century before. The ends of the armoured belts, however, were united by iron plated bulkheads, so that the armoured portion of the ship formed a central or box battery. In order to add to the safety of the ship, in case of its penetration by a hostile shot, a number of watertight compartments was built into her, thereby ensuring a certain amount of buoyancy. This vessel, like the _Warrior_, was “unhandy,” to use a sailor’s phrase, as were all her class, their length making them difficult to steer, on account of the amount of room required in which to turn. Indeed, they were so awkward that in manœuvres it was necessary to keep them four cables’ lengths apart instead of the two cables’ lengths customary with other vessels. The _Black Prince_ carried four 9-ton guns and twenty 6½-ton guns, all muzzle-loaders. These ships were unquestionably most impressive from the spectacular point of view, and, compared with the wooden ships they superseded, their fighting value was great. They were practically the forerunners of the class represented by the three iron sisters, _Agincourt_, _Minotaur_, and _Northumberland_. The last named, a ship-rigged, armoured, first-class cruiser, was begun in 1865, by the Millwall Ironworks and Shipbuilding Company, and completed in 1868, the designs being prepared by the Admiralty. At first it was proposed that she should have only three masts, and as many as fifty-eight guns, but during the process of construction, it was decided to increase the number of masts to five and to reduce the number of guns to twenty-eight more powerful than those originally intended. Her design, and that of her sisters, represented a curious adherence to a belief in the necessity of sail, tempered by a desire to a compromise in the matter of more modern artillery. When launched, she had four 12-ton muzzle-loading rifle guns and twenty-two 9-ton 8-inch muzzle-loading rifles on the main deck, while on her upper deck were two 6.5-ton 7-inch breech-loading rifle guns. Her armour was 5½ inches thick, with 9 inches of teak backing, and was extended throughout her entire length with the double purpose of protecting the