Irregular. Not regular; not according to common form or rules; as, an irregular building or fortification. See [Fortification, Irregular].
Irregular Cavalry. A term now almost obsolete. It applied a few years ago to regiments of horsemen raised under certain conditions in the East Indies. These conditions were that each man should provide his own horse, arms, accoutrements, and clothing, receiving in return a monthly sum, which also included his pay. To these regiments only three English officers were appointed, the other officers being natives. These regiments are still paid in the same way, but they are clothed, armed, and equipped in a uniform manner; the number of British officers is increased, and they are no longer styled irregular cavalry.
Irregularity. A violation of the customs of service,—a delinquency which is subject to censure but not serious enough to be brought before a court-martial.
Irun. A town of Spain, near the left bank of the Bidassoa. It is a place of great antiquity, having been in existence in the time of the Romans. The Carlists were defeated by the British Legion, under Gen. Sir de Lacy Evans, in the battle of Irun, May 16, 1837.
Isabella the Catholic, Order of. A Spanish order of knighthood, founded by Ferdinand VII., March 24, 1815, as a reward of loyalty, for the defense of the possessions of Spanish America. At present, it is conferred for all kinds of merit. The sovereign is the head of the order, which is divided into the three classes of Grand Crosses, Commanders, and Knights.
Isauria. A province in Asia Minor, the inhabitants of which were a wild and semi-barbarous race, who lived by rapine and plunder. The Romans surrounded Isauria with a chain of fortresses, but the Isaurians broke through them and remained as untamable as before. Under the empire, army after army was sent against Isauria, which stood to Rome, and afterwards to Constantinople, very much in the relation that Circassia now does to Russia. In the 8th century their national vanity was gratified by a countryman of their own being appointed to the throne. From this date they gradually ceased to be formidable.
Ischia. An island in the Gulf of Naples, 6 miles from the coast, and 17 miles west from Naples. In 1807, Ischia was taken by a British and Sicilian force.
Isernia. A place in Southern Italy, on the west slope of the Apennines, where the Sardinian general Cialdini defeated the Neapolitans, October 17, 1860.
Isle of France. See [Mauritius].
Ismail, or Ismailov. A strong town of Turkey in Europe, on the north side of the Kilia arm of the Danube. This place was long in the possession of the Turks; it was stormed by the Russians, under Suwarrow, in 1790. It remained in the possession of Russia until 1856, when it was restored to Turkey by the removal of the Russian frontier.