The Sailor's Word-Book
Chapter 16 : ASTEROIDS. The name by which the minor planets between the orbits of Jupiter and Mars w

ASTEROIDS. The name by which the minor planets between the orbits of Jupiter and Mars were proposed to be distinguished by Sir W. Herschel.

They are very small bodies, which have all been discovered since the commencement of the present century; yet their present number is over eighty.

ASTRAGAL. A moulding formerly round a cannon, at a little distance from its breech, the _cascabel_, and another near the muzzle. It is a half round on a flat moulding.

ASTRAL. Sidereal, relating to the stars.

ASTROLABE. An armillary sphere.--_Sea-astrolabe_, a useful graduated bra.s.s ring, with a movable index, for taking the alt.i.tude of stars and planets: it derived its name from the armillary sphere of Hipparchus, at Alexandria.

ASTROMETRY. The numerical expression of the apparent magnitudes of the so-called fixed stars.

ASTRONOMICAL CLOCK. A capital bit of horology, the pendulum of which is usually compensated to sidereal time, for astronomical purposes. (_See_ SIDEREAL TIME.)

ASTRONOMICAL HOURS. Those which are reckoned from noon or midnight of one natural day, to noon or midnight of another.

ASTRONOMICAL OBSERVATIONS. There have been occasional slight records of celestial phenomena from the remotest times, but the most useful ones are those collected and preserved by Ptolemy. Since 1672, science has been enriched with a continued series of astronomical observations of accuracy and value never dreamed of by the ancients.

ASTRONOMICAL PLACE OF A STAR OR PLANET. Its longitude or place in the ecliptic, reckoned from the first point of Aries, according to the natural order of the signs.

ASTRONOMICAL TABLES. Tables for facilitating the calculation of the apparent places of the sun, moon, and planets.

ASTRONOMICALS. The s.e.xagesimal fractions.

ASTRONOMY. The splendid department of the mixed sciences which teaches the laws and phenomena of the universal system. It is _practical_ when it treats of the magnitudes, periods, and distances of the heavenly bodies; and _physical_ when it investigates the causes. In the first division the more useful adaptation _nautical_ is included (which see).

ASTROSCOPIA. Skill in examining the nature and properties of stars with a telescope.

ASTRUM, OR ASTRON. Sirius, or the Dog-star. Sometimes applied to a cl.u.s.ter of stars.

ASWIM. Afloat, borne on the waters.

ASYLUM. A sanctuary or refuge; a name given to a benevolent inst.i.tution at Greenwich, for 800 boys and 200 girls, orphans of seamen and marines.

The Royal Military Asylum is also an excellent establishment of a similar nature at Chelsea, besides numerous others.

ASYMMETRY. A mathematical disproportion. The relation of two quant.i.ties which have no measure in common.

ASYMPTOTES. Lines which continually approximate each other, but can never meet.

ATABAL. A Moorish kettle-drum.

ATAGHAN. _See_ YATAGHAN.

AT ANCHOR. The situation of a vessel riding in a road or port by her anchor.

ATAR. A perfume of commerce, well known as atar-of-roses; atar being the Arabic word for fragrance, corrupted into _otto_.

A'TAUNTO, OR ALL-A-TAUNT-O. Every mast an-end and fully rigged.

ATEGAR. The old English hand-dart, named from the Saxon _aeton_, to fling, and _gar_, a weapon.

ATHERINE. A silvery fish used in the manufacture of artificial pearls; it is 4 or 5 inches long, inhabits various seas, but is taken in great numbers in the Mediterranean. It is also called _argentine_.

ATHILLEDA. The rule and sights of an astrolabe.

ATHWART. The transverse direction; anything extending or across the line of a s.h.i.+p's course.--_Athwart hawse_, a vessel, boat, or floating lumber accidentally drifted across the stem of a s.h.i.+p, the transverse position of the drift being understood.--_Athwart the fore-foot_, just before the stem; s.h.i.+ps fire a shot in this direction to arrest a stranger, and make her bring-to.--_Athwart s.h.i.+ps_, in the direction of the beam; from side to side: in opposition to _fore-and-aft_.

ATHWART THE TIDE. _See_ ACROSS THE TIDE.

ATLANTIC. The sea which separates Europe and Africa from the Americas, so named from the elevated range called the Atlas Mountains in Morocco.

ATLANTIDES. The daughters of Atlas; a name of the Pleiades.

ATLAS. A large book of maps or charts; so called from the character of that name in ancient mythology, son of Ura.n.u.s, and represented as bearing the world on his back. Also the Indian satin of commerce.

ATMOSPHERE. The ambient air, or thin elastic fluid which surrounds the globe, and gradually diminis.h.i.+ng in gravity rises to an unknown height, yet by gravitation partakes of all its motions.

ATMOSPHERIC OR SINGLE-ACTION STEAM-ENGINE. A condensing machine, in which the downward stroke of the piston is performed by the pressure of the atmosphere acting against a vacuum.

ATMOSPHERICAL TIDES. The motions generated by the joint influence of the sun and moon; and by the rotatory and orbital course of the earth,--as developed in trade-winds, equinoctial gales, &c.

ATOLLS. An Indian name for those singular coral formations known as lagoon-islands, such as the Maldive cl.u.s.ter, those in the Pacific, and in other parts within the tropics, where the apparently insignificant reef-building zoophytes reside.

ATRIE. To bring the s.h.i.+p to in a gale.

A-TRIP. The anchor is _a-trip_, or a-weigh, when the purchase has just made it break ground, or raised it clear. Sails are _a-trip_ when they are hoisted from the cap, sheeted home, and ready for tr.i.m.m.i.n.g. Yards are _a-trip_ when swayed up, ready to have the stops cut for crossing: so an upper-mast is said to be _a-trip_, when the fid is loosened preparatory to lowering it.

ATTACHED. Belongs to; in military parlance an officer or soldier is attached to any regiment or company with which he is ordered to do duty.

ATTACK. A general a.s.sault or onset upon an enemy. Also the arrangement for investment or battle. (_See_ FALSE ATTACK.)

ATTEMPT, TO. To endeavour to carry a vessel or place by surprise; to venture at some risk, as in trying a new channel, &c.

ATTENDANT MASTER. A dockyard official. (_See_ MASTER-ATTENDANT.)

ATTENTION. A military word of command, calling the soldier from the quiescent position of "at ease" into readiness for any exercise or evolution. Also the erect posture due to that word of command, and which is a.s.sumed by a private soldier in the presence of an officer. The attending to signals.

ATTERRAGE. The land-fall, or making the land. Usually marked on French charts and plans to show the landing-place.

ATTESTATION. In Admiralty courts the attestation of a deed signifies the testifying to the signing or execution of it.

ATTESTED. Legally certified; proved by evidence.

ATTILE. An old law term for the rigging or furniture of a s.h.i.+p.

ATTORNEY. _See_ SEA-ATTORNEY.

ATTRACTION. The power of drawing, or the principle by which all bodies mutually tend towards each other; the great agent in nature's wonderful operations.--_Attraction of mountains_, the deviating influence exercised on the plumb-line by the vicinity of high land. But exerting also a marvellous effect on all floating bodies, for every seaman knows that a s.h.i.+p stands insh.o.r.e faster than she stands out, the distances being similar.

ATWEEN, OR ATWIXT. Betwixt or between, shortened into _'tween_, that is, in the intermediate s.p.a.ce. The word _'tween decks_ is usually applied to the lower deck of a frigate, and _orlop_ to that of a line-of-battle s.h.i.+p.