lexicon describes the
crocodile as "partly aquatil, partly terrestrial."

AQUATITES. The law-term for everything living in the water.

AQUE. Wall-sided flat-floored boats, which navigate the Rhine.

AQUEDUCT. Conduits or canals built for the conveyance of water.

AQUILA. The constellation Aquila, in which {a} Aquilae is an important
star of the first magnitude: used by seamen in determining the latitude
and longitude; also in lunar distances. (_See_ ALTAIR.)

AQUILON. The north-east wind, formerly much dreaded by mariners.

ARAMECH. The Arabic name for the star Arcturus.

ARBALIST [from _arcus_ and _balista_]. An engine to throw stones, or the
cross-bow used for bullets, darts, arrows, &c.; formerly arbalisters
formed part of a naval force.

ARBITER. The judge to whom two persons refer their differences; not
always judicial, but the arbiter, in his own person, of the fate of
empires and peoples.

ARBITRAGE. The referring commercial disputes to the arbitration of two
or more indifferent persons.

ARBITRATION. The settlement of disputes out of court.

ARBOR. In chronometry, a shaft, spindle, or axis.

ARBY. A northern name for the thrift or sea-lavender.

ARC, OR ARCH. The segment of a circle or any curved line, by which all
angles are measured.

ARC DIURNAL. _See_ DIURNAL ARC.

ARC NOCTURNAL. _See_ NOCTURNAL ARC.

ARC OF DIRECTION OR PROGRESSION. The arc which a planet appears to
describe when its motion is direct or progressive in the order of the
signs.

ARC OF VISION. The sun's depth below the horizon when the planets and
stars begin to appear.

ARCH-BOARD. The part of the stern over the counter, immediately under
the knuckles of the stern-timbers.

ARCH OF THE COVE. An elliptical moulding sprung over the cove of a ship,
at the lower part of the taffrail.

ARCHED SQUALL. A violent gust of wind, usually distinguished by the
arched form of the clouds near the horizon, whence they rise rapidly
towards the zenith, leaving the sky visible through it.

ARCHEL, ARCHIL, ORCHILL. _Rocella tinctorum fucus_, a lichen found on
the rocks of the Canary and Cape de Verde groups; it yields a rich
purple. Litmus, largely used in chemistry, is derived from it.

ARCHES. A common term among seamen for the Archipelago. (_See_ also
GALLEY-ARCHES.)

ARCHI-GUBERNUS. The commander of the imperial ship in ancient times.

ARCHIMEDES' SCREW. An ingenious spiral pump for draining docks or
raising water to any propo