m beat of the drum, without variation, for a considerable
time. The divisions are summoned by roll of drum, one roll for each.
(_See_ MUSTER-ROLL.)

ROLLER. A mighty oceanic swell said to precurse the northers of the
Atlantic, and felt in great violence at Tristan d'Acunha, where H.M.S.
_Lily_ foundered with all hands in consequence, and several vessels at
St. Helena have been driven from their anchors and wrecked. These waves
roll in from the north, and do not break till they reach soundings, when
they evince terrific power, rising from 5 to 15 feet above the usual
level of the waters. A connection with volcanoes has been suggested as a
cause.

ROLLERS. Cylindrical pieces of timber, fixed either horizontally or
vertically in different parts of a ship above the deck, so as to revolve
on an axis, and prevent the cables, hawsers, and running rigging from
being chafed, by lessening their friction. The same as _friction-roller_.
Also, movable pieces of wood of the same figure, which are occasionally
placed under boats, pieces of heavy timber, &c.

ROLLING. That oscillatory motion by which the waves rock a ship from
side to side. The larger part of this disturbance is owing to the depth
of the centre of gravity below the centre of figure, the former
exercising a violent reaction when disturbed from its rest by passing
seas; therefore it is diminished by raising the weights, and must by no
means be confounded with heeling.

ROLLING-CHOCK, OR JAW-PIECE. Similar to that of a gaff, fastened to the
middle of an upper yard, to steady it.

ROLLING-CLEAT. Synonymous with _rolling-chock_.

ROLLING DOWN TO ST. HELENA. Running with a flowing sheet by the
trade-wind.

ROLLING-HITCH. Pass the end of a rope round a spar or rope; take it
round a second time, riding the standing part; then carry it across, and
up through the bight.

ROLLING-SWELL. That heaving of the sea where the waves are very distant,
forming deep troughs between.

ROLLING-TACKLES. Used to prevent the yards from swaying to and fro under
heavy rolling motion.

ROLLSTER, OR ROSTER. A rotation list of officers.

ROLL UP A SAIL, TO. To hand it quickly.

ROMAN CEMENT. A cement which hardens under water; used for piers, docks,
&c., as pozzolana, Aberthaw limestone, &c.

ROMBOWLINE, OR RUMBOWLINE. Condemned canvas, rope, and the like. Also
the coarse rope used to secure new coils.

RONDEL. An old term for a light, round shield.

RONE. A northern term for the