off.

NIPPERS. Are formed of clean, unchafed yarns, drawn from condemned rope,
unlaid. The yarns are stretched either over two bolts, or cleats, and a
fair strain brought on each part. They are then "marled" from end to
end, and used in various ways, viz. to bind the messenger to the cable,
and to form slings for wet spars, &c. The nipper is passed at the
manger-board, the fore-end pressing itself against the cable; after
passing it round cable and messenger spirally, the end is passed twice
round the messenger, and a foretop-man holds the end until it reaches
the fore-hatchway, when a maintop-man takes it up, and at the
main-hatchway it is taken off, a boy carrying it forward ready coiled
for further use.--_Selvagee nippers_ are used when from a very great
strain the common nippers are not found sufficiently secure; selvagees
are then put on, and held fast by means of tree-nails. (_See_ SELVAGEE
and TREE-NAILS.)--_Buoy and nipper._ Burt's patent for sounding. By this
contrivance any amount of line is loosely veered. So long as the lead
descends, the line runs through the nipper attached to a canvas inflated
buoy. The instant it is checked or the lead touches bottom, the back
strain nips the line, and indicates the vertical depth that the lead has
descended.

NIPPLE. In ship-building. Another name for _knuckle_ (which see). Also,
the nipple of a gun or musket lock; the perforated projection which
receives the percussion-cap.

NISSAK. The Shetland name for a small porpoise.

NITRE. _Potassae nitras_, a salt formed by the union of nitric acid with
potash; the main agent in gunpowder.

NITTY. A troublesome noise; a squabble.

NOAH'S ARK. Certain clouds elliptically parted, considered a sign of
fine weather after rain.

NOB. The head; therefore applied to a person in a high station of life.
(_See_ KNOB.)

NOCK. The forward upper end of a sail that sets with a boom. Also, a
term used for _notch_.

NOCTURNAL, NOCTURLABIUM. An instrument chiefly used at sea, to take the
altitude or depression of some of the stars about the pole, in order to
find the latitude and the hour of the night.

NOCTURNAL ARC. That part of a circle, parallel to the equator, which is
described by a celestial object, between its setting and rising.

NODDY. The _Sterna solida_, a dark web-footed sea-bird, common about the
West Indies. Also, a simpleton; so used by Shakspeare in the _Two
Gentlemen of Verona_.

NODES. Those points in the orbi