NUTION OF OBLIQUITY. A slow approximation of the planes of the
ecliptic and the equator, at the present rate of 0.485" annually.

DIMSEL. A piece of stagnant water, larger than a pond and less than a
lake.

DING, TO. To dash down or throw with violence.

DING-DONG. Ships firing into each other in good earnest.

DINGHEY. A small boat of Bombay, propelled by paddles, and fitted with a
settee sail, the mast raking forwards; also, the boats in use on the
Hooghly; also, a small extra boat in men-of-war and merchant ships.

DINGLE. A hollow vale-like space between two hills. A clough; also, a
sort of boat used in Ireland, a coracle.

DINNAGE. _See_ DUNNAGE.

DIP. The inclination of the magnetic needle towards the earth. (_See_
DIPPING-NEEDLE.) Also, the smallest candle formerly issued by the
purser.

DIP, TO. To lower. An object is said to be dipping when by refraction it
is visible just above the horizon. Also, to quit the deck suddenly.

DIP OF THE HORIZON. The angle contained between the sensible and
apparent horizons, the angular point being the eye of the observer; or
it is an allowance made in all astronomical observations of altitude for
the height of the eye above the level of the sea.

DIPPED. The limb of the sun or moon as it instantly dips below the
horizon.

DIPPER. A name for the water-ousel (_Cinclus aquaticus_). A bird of the
Passerine order, but an expert diver, frequenting running streams in
mountainous countries.

DIPPING-LADLE. A metal ladle for taking boiling pitch from the cauldron.

DIPPING-NEEDLE. An instrument for ascertaining the amount of the
magnet's inclination towards the earth; it is so delicately suspended,
that, instead of vibrating horizontally, one end _dips_ or yields to the
vertical force. This instrument has been so perfected by Mr. R. W. Fox
of Falmouth, that even at sea in the heaviest gales of wind the dip
could instantly, by magnetic deflectors, be ascertained to _minutes_,
far beyond what heretofore could be elicited from the most expensive
instruments, observed over 365 days on shore.

DIPPING-NET. A small net used for taking shad and other fish out of the
water.

DIPS. _See_ LEAD-LINE.

DIP-SECTOR. An ingenious instrument for measuring the true dip of the
horizon, invented by Dr. Wollaston, and very important, not only where
the nature and quantity of the atmospherical refraction are to be
examined, but for ascertaining the rates of chronometers, and the exact
l