sed height,--the invention of that wonderful
man. It is also used to remove grain in breweries from a lower to a
higher level. The name has been recently applied to the very important
introduction in steam navigation--the propelling screw. (_See_
SCREW-PROPELLER.)

ARCHING. When a vessel is not strongly built there is always a tendency
in the greater section to lift, and the lower sections to fall; hence
the fore and after ends droop, producing arching, or _hogging_ (which
see).

ARCHIPELAGO. A corruption of Aegeopelagus, now applied to clusters of
islands in general. Originally the AEgean Sea. An archipelago has a great
number of islands of various sizes, disposed without order; but often
contains several subordinate groups. Such are the AEgean, the Corean, the
Caribbean, Indian, Polynesian, and others.

ARCHITECTURE. _See_ NAVAL ARCHITECTURE.

ARCTIC. Northern, or lying under _arktos_, the Bear; an epithet given to
the north polar regions comprised within the _arctic circle_, a lesser
circle of the sphere, very nearly 23 deg. 28' distant from the north pole.

ARCTIC OCEAN. So called from surrounding the pole within the imaginary
circle of that name.

ARCTIC POLE. The north pole of the globe.

ARCTURUS. {a} Booetis. A star of the first magnitude, close to the knee
of Arctophylax, or Booetes. One of the nautical stars.

ARD, OR AIRD. A British or Gaelic term for a rocky eminence, or rocks on
a wash: hence the word _hard_, in present use. It is also an
enunciation.

ARDENT. Said of a vessel when she gripes, or comes to the wind quickly.

ARE. The archaism for _oar_ (which see). A measure of land in France
containing 100 square metres.

AREA. The plane or surface contained between any boundary lines. The
superficial contents of any figure or work; as, the _area_ of any square
or triangle.

ARENACEOUS. Sandy; partaking of the qualities of sand; brittle; as,
_arenaceous_ limestone, quartz, &c.

ARENAL. In meteorology, a cloud of dust, often so thick as to prevent
seeing a stone's-throw off. It is common in South America, being raised
by the wind from adjoining shores. Also off the coast of Africa at the
termination of the desert of Zahara.

ARENATION. The burying of scorbutic patients up to the neck in holes in
a sandy beach, for cure; also spreading hot sand over a diseased person.

AREOMETER. An instrument for measuring the specific gravity of fluids.

ARGIN. An old word for an _embankment_.

ARGO. A