RADIUS. The semi-diameter of a circle, limb of a sextant, &c.
RADIUS-BAR OF PARALLEL MOTION. An intervening lever for guiding the
side-rods of a steam-engine.
RADIUS-VECTOR. An imaginary line joining the centres of the sun and a
planet or comet in any point of its orbit.
RADUS. A term used for the constellation Eridanus.
RAFT. A sort of float formed by an assemblage of casks, planks, or
pieces of timber, fastened together with swifters and raft-dogs side by
side, as well as tier upon tier. The timber and plank with which
merchant ships are laden in the different ports of the Baltic, are
attached together in this manner, in order to float them off to the
shipping; but the rafts of North America are the most gigantic in the
world. Also, a kind of floating bridge of easy construction for the
passage of rivers by troops, &c.
RAFT-DOG. A broad flat piece of iron, having a sharp point at each end,
with the extremities bent at right angles. There are also _dog-hooks_,
having the shoulder bent into a hook, by which the raft-chains are
secured, or suddenly thrown off and released.
RAFTING. Conveying goods by floating, as by raft-chains, lashings, &c.
RAFT-PORT. A large square hole, framed and cut through the buttocks of
some ships, immediately under the counter--or forward between the
breast-hooks of the bow--to load or unload timber.
RAG-BOLTS. Those which are jagged or barbed, to prevent working in their
holes, and to make them hold more securely. The same as _barb-bolts_.
RAILS. Narrow pieces of wood, with mouldings as ornaments, mortised into
the heads of stanchions, or nailed for ornament on several parts of a
ship's upper works.
RAILS OF THE HEAD. Curved pieces of timber extending from the bows on
each side to the continuation of the ship's stem, to support the knee of
the head, &c.