DETACHED WORKS. Works included in the scheme of defence of a fortress, but separated from it, and beyond the glacis.
DETACHMENT. A force detached from the main body for employment on any particular service.
DETAIL OF DUTY. The captain"s night orders.
DETENTION OF A VESSEL: on just ground, as supposed war, suspicious papers, undue number of men, found hovering, or cargo not in conformity with papers or law.
DETONATING HAMMER. A modern introduction into the Royal Navy for firing the guns. With the aid of an attached laniard, it is made to descend forcibly upon the percussion arm of the tube, and fires the piece instantaneously. It is, however, already generally superseded by the use of the _friction-tube_ (which see).
DEVIATION. A voluntary departure from the usual course of the voyage, without any necessary or justifiable cause: a step which discharges the insurers from further responsibility. Liberty to touch, stay, or trade in any particular place not in the usual course of the voyage must be expressly specified in the contract, and even this is subordinate to the voyage. The cases of necessity which justify deviation are--1, stress of weather; 2, urgent want of repairs; 3, to join convoy; 4, succouring ships in distress; 5, avoiding capture or detention; 6, sickness; 7, mutiny of the crew. It differs from a _change_ of voyage, which must have been resolved upon before the sailing of the ship. (_See_ CHANGE.)--_Deviation_ is also the attraction of a ship"s iron on the needle. It is a term recently introduced to distinguish a sort of second variation to be allowed for in iron vessels.
DEVIL. A sort of priming made by damping and bruising gunpowder.
DEVIL-BOLTS. Those with false clenches, often introduced into contract-built ships.
DEVIL-FISH. The _Lophius piscatorius_, a hideous creature, which has also obtained the name of fish-frog, monk-fish, bellows-fish, sea-devil, and other appellatives significant of its ugliness and bad manners.
There is also a powerful _Raia_, which grows to an immense size in the tropics, known as the devil-fish, the terror of the pearl-divers.
_Manta_ of Spaniards.
DEVILRY. Spirited roguery; wanton mischief, short of crime.
DEVIL"S CLAW. A very strong kind of split hook made to grasp a link of a chain cable, and used as a stopper.
DEVIL"S SMILES. Gleams of sunshine among dark clouds, either in the heavens or captain"s face!
DEVIL"S TABLE-CLOTH. _See_ TABLE-CLOTH.
DEVIL TO PAY AND NO PITCH HOT. The seam which margins the water-ways was called the "devil," why only caulkers can tell, who perhaps found it sometimes difficult for their tools. The phrase, however, means service expected, and no one ready to perform it. Impatience, and naught to satisfy it.
DEW-POINT. A meteorological term for the degree of temperature at which the moisture of the atmosphere would begin to precipitate; it may be readily ascertained by means of the hygrometer.
DHOLL. A kind of dried split pea supplied in India to the navy.
DHONY, OR DHONEY. A country trading-craft of India from 50 to 150 tons; mostly flat-bottomed. (_See_ DONEY.)
DHOW. The Arab dhow is a vessel of about 150 to 250 tons burden by measurement--grab-built, with ten or twelve ports; about 85 feet long from stem to stern, 20 feet 9 inches broad, and 11 feet 6 inches deep.
Of late years this description of vessel has been well built at Cochin, on the Malabar coast, in the European style. They have a great rise of floor; are calculated for sailing with small cargoes; and are fully prepared, by internal equipment, for defence--many of them are sheathed on 2-1/2-inch plank bottoms, with 1-inch board, and the preparation of chunam and oil, called _galgal_, put between; causing the vessel to be very dry and durable, and preventing the encroachments of the worm or _Teredo navalis_. The worm is one of the greatest enemies in India to timber _in_ the water, as the white ant (_termites_) is out of it. On the outside of the sheathing board there is a coat of whitewash, made from the same materials as that between the sheathing and planks, and renewed every season they put to sea. They have generally one mast and a lateen sail. The yard is the length of the vessel aloft, and the mast rakes forward, for the purpose of keeping this ponderous weight clear in raising and lowering. The tack of the sail is brought to the stem-head, and sheets aft in the usual way. The halyards lead to the taffrail, having a pendant and treble purchase block, which becomes the backstay, to support the mast when the sail is set. This, with three pairs of shrouds, completes the rigging, the whole made of _coir_ rope. Several of these vessels were fitted as brigs, after their arrival in Arabia, and armed by the Arabs for cruising in the Red Sea and Arabian Gulf, as piratical vessels. It was of this cla.s.s of vessel that Tippoo Sultan"s navy at Onore consisted. The large dhows generally make one voyage in the season, to the southward of Arabia; taking advantage of the north-east monsoon to come down, and the south-west to return with an exchange cargo. The Arabs who man them are a powerful well-grown people, and very acute and intelligent in trade. They usually navigate their ships to Bengal in perfect safety, and with great skill. This was well known to Captain Collier and his officers of the _Liverpool_ frigate, when they had the trial cruise with the Imam of Muscat"s fine frigate in 1820.
DIACLE. An old term for a boat-compa.s.s.
DIAGONAL BRACES, knees, planks, &c., are such as cross a vessel"s timbers obliquely. (_See_ DIAGONAL TRUSSING.)
DIAGONAL RIBBAND. A narrow plank made to a line formed on the half-breadth plan, by taking the intersections of the diagonal line with the timbers. (_See_ RIBBANDS.)
DIAGONALS. A line cutting the body-plan diagonally from the timbers to the middle line. Diagonals are the several lines on the draughts, delineating the station of the harpings and ribs, to form the body by.
DIAGONAL TRUSSING. A particular method of binding and strengthening a vessel internally by a series of riders and truss-pieces placed diagonally.
DIAMETER. In geometry, a right line pa.s.sing through the centre of any circular figure from one point of its circ.u.mference to another.
DIAMETER, APPARENT. The angle which the diameter of a heavenly body subtends at any time, varying inversely with its distance. The true is the real diameter, commonly expressed in miles.
DIAMOND-CUT. _See_ RHOMBUS.
DIAMOND-KNOT. An ornamental knot worked with the strands of a rope, sometimes used for bucket-strops, on the foot-ropes of jib-booms, man-ropes, &c.
DIBBS. A galley term for ready money. Also, a small pool of water.
DICE. _See_ DYCE.
DICHOTOMIZED. A term applied to the moon, when her longitude differs 90 from that of the sun, in which position only half her disc is illuminated.
d.i.c.kADEE. A northern name for the sand-piper.
d.i.c.k-A-DILVER. A name for the periwinkle on our eastern coasts.
d.i.c.kER-WORK. The timbering of tide-harbours in the Channel. Wattling between piles.
d.i.c.kEY. An officer acting in commission.--_It"s all d.i.c.key with him._ It"s all up with him.
DIDDLE, TO. To deceive.
DIEGO. A very strong and heavy sword.
DIE ON THE FIN, TO. An expression applied to whales, which when dying rise to the surface, after the final dive, with one side uppermost.
DIET. The regulated food for patients in sick-bays and hospitals.
DIFFERENCE. An important army term, meaning firstly the sum to be paid by officers when exchanging from the half to full pay; and, secondly, the price or difference in value of the several commissions.
DIFFERENCE OF LAt.i.tUDE. The distance between any two places on the same meridian, or the difference between the parallels of lat.i.tude of any two places expressed in miles of the equator.
DIFFERENCE OF LONGITUDE. The difference of any place from another eastward or westward, counted in degrees of the equator: that is, the difference between two places is an arc of the equator contained between their meridians, but measured in s.p.a.ce on the parallel. Thus the difference of a degree of longitude in miles of the meridian would be--
At 20 lat. 564 miles " 40 " 386 "
" 60 " 300 "
" 80 " 104 "
DIFFERENTIAL OBSERVATION. Taking the differences of right ascension and declination between a comet and a star, the position of which has been already determined.
DIFFICULTY. A word unknown to true salts.
DIGHT [from the Anglo-Saxon _diht_, arranging or disposing]. Now applied to dressing or preparing for muster; setting things in order.
DIGIT. A twelfth part of the diameter; a term employed to denote the magnitude of an eclipse; as, so many _digits eclipsed_.
DIKE. _See_ d.y.k.e.
DILL. An edible dark brown sea-weed, torn from the rocks at low-water.