under the hoops.

ARITHMETIC. The art of computation by numbers; or that branch which
considers their powers and properties.

ARK. The sacred and capacious vessel built by Noah for preservation
against the flood. It was 300 cubits in length, 50 in breadth, and 30 in
height; and of whatever materials it was constructed, it was pitched
over or pay'd with bitumen. _Ark_ is also the name of a mare's-tail
cloud, or cirrhus, when it forms a streak across the sky.

ARLOUP. An archaism for the deck, now called _orlop_ (which see).

ARM. A deep and comparatively narrow inlet of the sea. That part of an
anchor on which the palm is shut. The extremity of the bibbs which
support the trestle-trees. Each extremity or end of a yard, beam, or
bracket.--_To arm_, to fit, furnish, and provide for war; to cap and set
a loadstone; to apply putty or tallow to the lower end of the lead
previous to sounding, in order to draw up a specimen of the bottom.--_To
arm a shot_, is to roll rope-yarns about a cross-bar-shot, in order to
facilitate ramming it home, and also to prevent the ends catching any
accidental inequalities in the bore.

ARMADA. A Spanish term signifying a royal fleet; it comes from the same
root as army. The word _armado_ is used by Shakspeare.

ARMADILLA. A squadron of guarda-costas, which formerly cruized on the
coasts of South America, to prevent smuggling.

ARMADOR. A Spanish privateer.

ARMAMENT. A naval or military force equipped for an expedition. The
arming of a vessel or place.

ARMAMENTA. The rigging and tackling of an ancient ship. It included
shipmen and all the necessary furniture of war.

ARMATAE. Ancient ships fitted with sails and oars, but which fought under
the latter only.

ARM-CHEST. A portable locker on the upper deck or tops for holding arms,
and affording a ready supply of cutlasses, pistols, muskets or other
weapons.

ARMED. Completely equipped for war.--_Armed at all points_, covered with
armour.--_Armed "en flute," see_ FLUTE.--_Armed mast_, made of more than
one tree.--_Armed ship_, a vessel fitted out by merchants to annoy the
enemy, and furnished with letters of marque, and bearing a commission
from the Admiralty to carry on warlike proceedings.

ARMED STEM. _See_ BEAK.

ARMILLARY SPHERE. An instrument composed of various circles, to assist
the student in gaining a knowledge of the arrangement and motions of the
heavenly bodies. A brass _armilla tolomaei_ was one of the instruments