IRON-HORSE. The iron rail of the head; the horse of the fore-sheet or boom-sheet traveller.
IRON-PLATED SHIPS. See [Armour-clad].
IRONS. A ship is said to be in irons when, by mismanagement, she is permitted to come up in the wind and lose her way; so that, having no steerage, she must either be boxed off on the former tack, or fall off on the other; for she will not cast one way or the other, without bracing in the yards. Also, [bilboes] (which see). Also, the tools used by the caulkers for driving oakum into the seams. (See also [Boom-irons].)
IRON-SICK. The condition of vessels when the iron work becomes loose in the timbers from corrosion by gallic acid, and the speeks or sheathing nails are eaten away by rust.
IRON-SIDES. Formerly a sobriquet for favourite veteran men-of-war, but latterly applied to iron and iron-clad ships.
IRON WEDGES. Tapered iron wedges on the well-known mechanical principle, for splitting out blocks and for other similar purposes.
IRON-WORK. A general name for all pieces of iron, of whatever figure or size, which are used in the construction and equipment of ships.
IRREGULAR BASTION. One whose opposite faces or flanks do not correspond; this, as well as the constant irregularity of most real fortification, is generally the result of the local features of the neighbourhood.
ISLAND. May be simply described as a tract of land entirely surrounded with water; but the whole continuous land of the Old World forms one island, and the New World another; while canals across the isthmuses of Suez and Panama would make each into two. The term properly only applies to smaller portions of land; and Australia, Madagascar, Borneo, and Britain are among the larger examples. Their materials and form are equally various, and so is their origin; some having evidently been upheaved by volcanic eruption, others are the result of accretion, and still more revealing by their strata that they were formerly attached to a neighbouring land. The sudden emergence of Sabrina, in the Atlantic, has occasioned wonder in our own day. So has that of Graham's Island, near the south coast of Sicily; and the Archipelago is daily at work.
ISLAND HARBOUR. That which is protected from the violence of the sea by one or more islands or islets screening its mouth.