ADJUTANT. [From Lat. _adjuvo_, to help.] A military assistant to field-officers. The term has been applied to an assistant captain of a fleet. It is indeed the duty performed by first lieutenants. ADMEASUREMENT. The calculation of proportions according to assumed rules, often ignorantly practised in estimating the tonnage of a ship. ADMIRAL. The derivation of this noble title from the Greek _almyros_, from the Latin _admirabilis_, from the Saxon _aenmereeal_, and from the French _aumer_, appear all fanciful. It is extensively received that the Sicilians first adopted it from _emir_, the sea, of their Saracen masters; but it presents a kind of unusual etymological inversion. The term is most frequent in old Romance; but the style and title was not used by us until 1286; and in 1294, William de Leybourne was designated "Amiral de la Mer du Roy d'Angleterre;" six years afterwards Viscount Narbonne was constituted Admiral of France; which dates nearly fix the commencement of the two states as maritime powers. The _admiral_ is the chief commander of a fleet, but of this rank there are three degrees, distinguished by a flag at the fore, main, or mizen mast, according to the title of _admiral_, _vice-admiral_, or _rear-admiral_. These were again subdivided according to their colour of red, white, or blue, which had to be likewise borne by the squadrons they respectively commanded. (_See_ FLAG.) In 1865 the colours were omitted, and the only flag now hoisted by ships of war is the white St. George's ensign, and for admirals the white St. George's cross at the main, fore, or mizen. The _admiral of the fleet_ is the highest officer under the admiralty of Great Britain; it is rather an honorary distinction, and usually attained by seniority and service: when this officer serves afloat, he hoists the proud distinction of the Union flag at the main. The _lord high-admiral_ was one of the principal officers of the state, who formerly decided all cases relating to the sea: he wore a gold call and chain, similar in form to that which has descended to the boatswain and his mate. This dignity has been extinct for many years, and the duty merged into that of the lords-commissioners and admiralty court; in 1827, it was revived for a short time in the person of His Royal Highness the Duke of Clarence. The epithet of _admiral_ was also formerly applied to any large or leading ship, without reference to flag; and is still used for the principal vessel in the cod and whale fisheries. That which arrives first in any port of Newfoundland retains this title during the season, with certain rights of beach in flakes. The master of the second ship becomes the vice-admiral, and the master of the third the rear-admiral. ADMIRAL. A beautiful and rare shell of the genus _Conus_; the varieties are designated the grand-admiral, the vice-admiral, the orange-admiral, and the extra-admiral.