Of the various types of modern war-vessels, the most formidable yet devised are undoubtedly the _steam-rams_ and _turret-ships_. The steam-ram is armed with a strong steel beak, with which it charges an enemy in much the same way as the war-galleys of ancient times charged a foe, or as a sword-fish attacks its adversary. The turret-ship carries one or more shot-proof circular turrets, in which one or more guns are worked by the crew, the guns being capable of being turned and pointed in any direction. Both turret-ships and steam-rams are, of course, iron plated. Vessels of this description were first employed by the Americans in the great civil war. The careers of the _Merrimac_ and _Monitor_ may be said to have become a part of American national history. The _Merrimac_ was the first iron-plated steam-ram. She was originally a wooden frigate; was cut down, coated with iron, and furnished with a ram. In her famous encounter with the _Congress_ and the _Cumberland_, two wooden frigates of the Federals, she steamed alongside the former, delivered a raking fire, and then, turning upon the _Cumberland_, attacked that vessel with her ram. Of the _Cumberland_ she made quick work; for having torn a gaping rent in her side, she poured a damaging fire into the gap, hanging on by the sharp iron beak with which steam-rams are furnished. Then withdrawing to a short distance, she again charged her adversary, and delivered a second terrible fire, until the _Cumberland_ finally sank. The Merrimac then turned her attention to the _Congress_, whose fate she sealed in about half an hour. The first shot caused fearful destruction, killing every man at one of the guns, blowing away the bulk-heads, strewing the deck with a carnage too horrible to dwell upon, and finally setting the ship on fire. The _Congress_ at last struck her colours, but during the night she blew up. This formidable vessel had subsequently to haul down her colours before the _Monitor_--in a figurative sense, that is, for she did not actually surrender, but retreated after a contest of some hours. In this notable struggle the _Merrimac_ sustained much damage, without succeeding in inflicting on her enemy anything like the same amount of injury; in fact, the _Monitor_ came out of the action scathless. The changes that are taking place in the construction of war-ships are so various and so rapid, that we cannot attempt to do more here than take note of a few of the principal; and even what are mentioned as novelties now, before these pages appear may have ceased to be novelties.