en used, but instead of carrying the
armour right up to the upper deck, to save weight it was in the form of
a narrow belt protecting a few feet above and below the water line only,
except amidships, where it was carried up to the upper deck, forming a
"citadel," inside which her ten 18-ton and 12-ton guns were well
protected. In this way her guns, waterline, and engines--or "vitals,"
as these are known for short--were fully protected at the expense of
less vital parts of the ship. Though smaller and less expensive than
the _Minotaur_ she was a far more efficient ship. Her broadside was
1818 pounds. The _Sultan_, another ship of much the same type, had a
broadside of 1964 pounds. During the early sixties another type of
vessel came to the front. Captain Coles had invented the "turret,"
which consisted of a turn-table or revolving platform, round which was a
shield of thick armour, turning with it: the top was also closed in. In
the shield was a very small port for the gun--which was aimed by
revolving the turret till it pointed at the required object. The crew
was thus completely protected from the enemy's fire.

In the American Civil War the Federals or Northerners, had provided two
of their wooden frigates with these turrets and sent them to attack the
_Merrimac_, a cut-down wooden frigate which had been armoured and
provided with a ram. The _Merrimac_ steamed up to the _Congress_,
delivering her fire with awful effect, and then proceeding towards the
_Cumberland_, ran into her near the bow, ripping an enormous rent in her
side, and hung on by her own sharp prow while she fired into the
fractured chasm. She then backed out and repeated her tremendous
onslaught, suffering little from the fire of her enemy, till the latter
went down. She next attacked the _Congress_ with shells, which killed
the greater number of the Federal crew, and in half-an-hour the few
survivors hauled down their colours.

Later on the _Merrimac_ was attacked by the armoured _Monitor_. The two
ships hammered away at one another for many hours without result; only
five men were killed after a five hours action, for the armour beat the
gun.

The result of these actions made it clear that turret-ships to be of any
use must be armoured, and as a first experiment it was decided to
cut-down the _Royal Sovereign_, a ship of the size of the _Duke of
Wellington_. Her masts and her three upper decks were taken off, her
lower-deck alone remai