The Sailor's Word-Book Part 74

DELL. A narrow valley, ravine, or small dale.

DELTA. A name given by the Greeks to the alluvial tract inclosed between the bifurcating branches of the Nile and the sea-line. It is well known that rivers which deposit great quant.i.ties of matter, do also very often separate into two or more branches, previous to their discharge into the sea; thus forming triangular s.p.a.ces, aptly called _deltas_ from their resemblance to the Greek letter ?.

All deltas appear by their section to be formed of matter totally different from that of the adjacent country. They are the creation of the rivers themselves, which, having brought down with their floods vast quant.i.ties of mud and sand from the upper lands, deposit them in the lowest place, the sea; at whose margin, the current which has. .h.i.therto impelled them ceasing, they are deposited by the mere action of gravity.

This is particularly ill.u.s.trated on the western coast of Africa by the shoals off the Rio Grande, Rio Nunez, and others. The coast, as well as the embouchures of the rivers, exhibit a deposit of deep mud, and yet far at sea banks of clean siliceous sand arise.

DEMAND. The official paper by which stores are desired for a s.h.i.+p, the making out of which is the duty of the officer in whose charge the stores will be placed: they must be approved by the captain and admiral before being presented to the dockyard authorities. Also, whence from?

where bound?

DEMI-BASTION. In fortification, a bastion which has a flank on one side only.

DEMI-CANNON. An ancient name for a gun carrying a ball of 33 pounds weight, with a length of from 12 to 14 feet, and a diameter of bore of 6-1/2 inches; its point-blank range was estimated at 162 paces, and its random one at 2000.

DEMI-CULVERIN. An ancient cannon which threw a ball of 9 pounds weight, was about 9 feet long, and 4 inches in diameter of bore; its point-blank range was called 174 paces, and its random one about 1800.

DEMIHAG. A long pistol, much used in the sixteenth century.

DEMILANCE. A light horseman, who carried a light lance.

DEMILUNE. In fortification, the outwork, more properly called a _ravelin_ (which see).

DEMI-REVETMENT. In fortification, that form of retaining wall for the face of a rampart which is only carried up as high as cover exists in front of it, leaving above it the remaining height, in the form of an earthen mound at its natural slope, exposed to, but invulnerable by shot.

DEMONSTRATION-s.h.i.+PS. Those kept in a certain state of preparation for war, though on a peace establishment.

DEMURRAGE. The compensation due to a s.h.i.+p-owner from a freighter for unduly delaying his vessel in port beyond the time specified in the charter-party or bill of lading. It is in fact an extended freight. A s.h.i.+p unjustly detained, as a prize, is ent.i.tled to demurrage. Vessels chartered to convey government stores have a term given for discharge by government aid. If not delivered within that period, demurrage, as stated in the doc.u.ment, is paid per diem for any "unavoidable delay."

DEN. A sandy tract near the sea, as at Exmouth and other places.

DEN AND STROND. A liberty for s.h.i.+ps or vessels to run or come ash.o.r.e.

Edward I. granted this privilege to the barons of the Cinque Ports.

DE NAUTICO FNORE. Of nautical usury; bottomry.

DENE. The Anglo-Saxon _daene_; implying a kind of hollow or ravine through which a rivulet runs, the banks on either side being studded with trees.

DENEB. The bright star in the constellation Cygnus, well known as a standard nautical star.

DENSITY. The weight of a body in comparison with its bulk.

DENTICE. An excellent fish, so named from being well furnished with teeth. It is of the _Sparidae_ family, and frequents the Adriatic.

DEPARTMENT. A term by which the divisions in the public services are distinguished, as the civil, the commissariat, the military, the naval, the victualling, &c.

DEPARTURE. The bearing of an object on the coast from which a vessel commences her dead-reckoning and takes her departure. The distance of any two places lying on the same parallel counted in miles of the equator.

DEPOT. A magazine in which military stores are deposited. Also, a company left in England for the purpose of recruiting when regiments are ordered abroad.

DEPRESS. The order to adjust the quoin in great-gun exercise; to depress the muzzle to point at an object below the level, in contradistinction to elevate.

DEPRESSED POLE. That end of the earth's axis which is below the horizon of the spectator according to his being in the northern or southern hemisphere. Also applied to the stars. (_See_ POLAR DISTANCE.)

DEPRESSION, OF THE HORIZON. (_See_ DIP.) In artillery, the angle below the horizon at which the axis of a gun is laid in order to strike an object on a lower level. The depression required in batteries of very elevated site (those of Gibraltar for example), for the laying the guns on near vessels, is so great as to necessitate a peculiar carriage.

DEPTH OF A SAIL. The extent of the square sails from the head-rope to the foot-rope, or the length of the after-leech of a staysail or boom-sail; in other words, it is the extent of the longest cloth of canvas in any sail.

DEPTH OF HOLD. The height between the floor and the lower-deck; it is therefore one of the princ.i.p.al dimensions given for the construction of a s.h.i.+p. It varies, of course, according to the end for which she is designed, trade or war.

DERELICT [Lat. _derelictus_, abandoned]. Anything abandoned at sea. A s.h.i.+p is derelict either by consent or by compulsion, stress of weather, &c., and yet, to save the owner's rights, if any cat, dog, or other domestic animal be found on board alive, it is not forfeited. The owner may yet recover, on payment of salvage, within a year and a day--otherwise the whole may be awarded. (_See_ SALVAGE.)

DERIVATION. In artillery, the constant deflection of a rifled projectile. (_See_ DEFLECTION.)

DERRICK. A single spar, supported by stays and guys, to which a purchase is attached, used in loading and unloading vessels. Also, a small crane either inside or outside of a s.h.i.+p.

DERRICK, TO. A cant term for setting out on a small not over-creditable enterprise. The act is said to be named from a Tyburn executioner.

DERRING-DO. A Spenserian term for deeds of arms.

DESCENDING NODE. _See_ NODES.

DESCENDING SIGNS. Those in which the sun appears to descend from the north pole, or in which his motion in declination is towards the south.

DESCENDING SQUALL. A fitful gust of wind issuing from clouds which are formed in the lower parts of the atmosphere. It is usually accompanied with heavy showers, and the weatherwise observe that the squall is seldom so violent when it is followed as when it is preceded by rain.

(_See_ WHITE SQUALL as a forerunner.)

DESCENSION. The same as _oblique ascension_ (which see).

DESCENT. The landing of troops for the purpose of invading a country.

The pa.s.sage down a river.

DESCRIPTION-BOOK. A register in which the age, place of birth, and personal description of the crew are recorded.

DESERT. An extensive tract, either absolutely sterile, or having no other vegetation than small patches of gra.s.s or shrubs. Many portions of the present deserts seem to be reclaimable.

DESERTER. One that quits his s.h.i.+p or the service without leave. He is marked R (_run_) on the books, and any clothes or other effects he may have left on board are sold by auction at the mast, and the produce borne to account.

DESERTION. The act of quitting the Army or Navy without leave, with intention not to return.

DESERTION-MONEY. The sum of three pounds paid to him who apprehends a deserter, which is charged against the offender's growing pay--his wages for previous service having become forfeited from his having _run_.

DESTROYING PAPERS. A ground of condemnation in the Admiralty court.

DETACHED. On detached service. A squadron may be detached under a commodore or senior officer.

DETACHED BASTION. A bastion cut off by a ditch about its gorge from the body of the place, which latter is thus rendered in a degree independent of the fall of the former.

DETACHED ESCARP. An escarp wall, originally invented by Carnot, and revived by the Prussians, removed some distance to the front of the rampart; which latter, being finished exteriorly at the natural slope of the earth, remains effective after the destruction of the wall by a besieger. It was at first intended, being kept low and covered by a near counterguard, to offer extraordinary difficulties to the besieger's breaching batteries; but improved artillery has nullified that supposed advantage.