rock-bound 
The breaking waves dash'd high 
On a stern and rock-bound coast. 
Mrs. Hemans, Landing of the Pilgrim Fathers. 
rock-brake (rok'brak), n. Same as parsley-fern. 
rock-breaker (rok'bra"ker), n. A machine for 
breaking rock and stones, in which the material 
to be broken passes between two jaws, one or 
both of which are movable. It is by machin- 
ery of this kind that stones are usually broken 
for road-metal. 
rock-butter (rok'but'er), n. In mineral. See 
butter*. 
rock-candy (rok'kan'di), n. Pure sugar in co- 
hering crystals of considerable size and hard- 
ness. Also called candy-sugar, and sometimes 
Gibraltar rock. 
rock-cavy (rok'ka'vi), n. A South American 
quadruped of the family Caviidse, Kerodon moco 
or Cavia rupestris ; the moco. 
rock-cist (rok'sist), n. [Shortened from rock- 
cistus (the plants were once included in the 
genus Cistus)."} A book-name for plants of the 
genus Helianthemum. 
rock-cod (rok'kod), n. See corf 2 and rockfish. 
rock-cook (rok'kuk), n. The small-mouthed 
wrasse, Centrolabrus cxoletus, about 4 inches 
long. [Cornwall, Eng.] 
rock-cork (rok'kdrk), >i. Mountain-cork, a 
white- or gray-colored variety of asbestos : so 
called from its lightness and fibrous structure. 
Also called rock-leather. 
rock-crab (rok'krab), . One of several differ- 
ent crabs found on rocky sea-bottoms, as the 
5206 
out the western part of the Palearctic region, and is the 
reputed wild stock or original of the domestic pigeon. 
The commonest varieties of the latter retain close resein- 
California Rock-crab ( Cancer arttcnnar, 
common Carcinvs msenas, Cancer irroratus, C. 
antennarius, Panopseus depressus, and related 
species. [Eng. and TJ. S.] 
rock-cress (rok'kres), n. See Arabia. 
rock-crowned (rok'kround), n. Crowned or 
surmounted with rocks: as, a rock-crowned 
height. 
rock-crusher (rok'krush'er), n. A stone- 
breaker or stone-crusher. 
rock-crystal (rok'kris'tal), n. See crystal, and 
cut under pokal. 
Rock-day (rok'da), . [< rocW + day*.] A 
popular name for St. Distaffs day, or the day 
after Twelfth Day. 
rock : demon (rok'de'mon), . One of certain 
spirits or demons worshiped by the Huron In- 
dians, and conceived of as dwelling in some 
famed, renowned, or dangerous rock. 
An early missionary account of a rock-demon worshipped 
by the Huron Indians will show with what absolute per- 
sonality savages can conceive such a being. 
E. B. Tylor, Prim. Culture, II. 188. 
rock-doet (rok'do), . A species of Alpine deer. 
The rock-dee breeds chiefly upon the Alps : a creature 
of admirable swiftness. S. Grew, Museum. 
rock-dolphin (rok'doFfin), . A local name 
at Brighton, England, of the sea-scorpion, Cot- 
tits scorpiits. 
rock-doo (rok'dS), . A Scotch form of rock- 
dove. 
rock-dove (rok'duv), . 1. The rock-pigeon 
or blue-rock, Columba livia : in distinction from 
the other two British pigeons of the same ge- 
nus, the ring-dove (C.palmnbus) and the stock- 
dove (C. cenas). It is widely distributed through- 
Kock-dove (Coltimba Irt'ia). 
blance to the wild bird, as may be seen by comparing the 
figure here given with that under pigeon. 
2. The sea-dove, sea-pigeon, or black guille- 
mot, Uria grylle : so called because it breeds in 
the rocks. [Ireland.] 
rock-drill (rok'dril), n. A machine-drill; a 
drill worked by steam-, water-, or horse-power: 
distinguished from a drill worked by hand, in 
the accompanying figures A, A are the legs which support 
the working parts shown in the section. The legs form 
a tripod stand which is pivoted at C to the bed-plate D. 
Rock-drill. 
Rock-drill (section). 
The legs are weighted at B to hold the machine firmly 
when at work. The bed-plate has guideways K formed on 
its upper surface, one of which is shown in the section. 
To these ways are fitted guides on the cylinder P. A 
standard G is bolted to the back of the bed-plate, and at 
its upper end has a fixed bearing I for the feed-screw H. 
A winch 3 is used to turn the feed-screw, which, as the 
latter cannot move vertically, operates in the nut I' to 
raise or lower the cylinder F together with all its attach- 
ments; K is the steam-chest and valve-box with bonnets 
K'. Steam is supplied to K by a steam-hose I. : M (in the 
section) is the steam-thrown induction-valve, which also 
controls exhaust after the manner of the common slide- 
valve, but is cylindrical in form and is moved by the 
action of the steam admitted to K ; N is the piston . N', 
the piston-rod ; N", the drill, fitted to a socket in the 
exterior end of N; P and P* are parts of the mechanism 
which turns the piston, piston-rod, and drill a short dis- 
tance on their vertical axis at each stroke of the piston. 
rock-duck (rok'duk), . The harlequin duck. 
J. H. Langille. [Nova Scotia.] 
rock-eel (rok'el), w. A fish, Murxnoidcs giin- 
ncllus, of the family Xipliidiontidie, with an 
elongated smooth body, nearly eighty dorsal 
spines, and two spines and thirty-eight rays in 
dorsal. It inhabits the northern seas. 
rockelt, . [Of. roquelawe.'] A woman's cloak. 
Halliwell. [Prov. Eng.] 
rockelay (rok'e-la), . Same as roquelaure. 
rock-elm (rok'elm), . An American elm, VI- 
mu.t racemosa, highly valued for its heavy, hard, 
and strong timber, which is used in making 
agricultural implements, for railroad-ties, etc. 
Also cork-elm, hickory-elm, etc. 
rocker 1 (rok'er), . [< rock 1 + -e-r 1 .] The rock- 
dove, Columba livia. Montagu. Also rockier, 
rock. 
rocker 2 (rok'er), n. [< ME. rokker; < rod*. i\. 
+ -!.] One who or that which rocks. Specifi- 
cally (a) One who rocks a cradle. 
His majesty was graciously pleased that there should 
neither be nurse, rocker, nor any other officer belonging to 
the queen's nursery . . . save only Protestants. 
Court and Times of Charles I., II. 03. 
His fellow, who the narrow bed had kept, 
Was weary, and without a rocker slept. 
Dryden, Cock and Fox, 1. 228. 
rocket 
(6) The curved piece of wood on which a cradle or rock- 
ing-chair rocks, (c) A rocking-horse. 
There were beasts of all sorts; horses, in particular, of 
every breed, from the spotted barrel on four pegs ... to 
the thoroughbred rocker on his highest mettle. 
Dickens, Cricket on the Hearth, ii. 
(d) A rocking-chair, (e) In engramny, same as cradle, 4 
(e). (f) A rocker-shaft, (y) In mining, same as cradle 
4 (i) (1). (A) In an electric-lamp regulator, a lever, pivoted 
in the middle, carrying at its extremities the armatures 
of two electromagnets, by the alternate attraction of 
which the carbon rods are made to separate or to approach 
each other. 
The armatures of the two electro-magnets were placed 
at the two extremities of a rocker, carrying a lever for 
the release of the mechanisms used for the approach or 
withdrawal of the carbons. 
Hospitaller, Electricity (trans.), p. 170. 
(i) A boat or yacht having a rocker keel. 
When a fast sloop of the straight-keel type came out, 
the rockers were beaten. Tribune Book ojf Sports, p. 251. 
(jt A skate in which the bottom of the runner is not 
straight, but is convex from toe to heel, (*) A vessel 
for freezing chemical mixtures, essentially a freezer 
mounted on rockers. (I) In a railway gravel tip-car, a 
curved iron casting which supports the car-body, and on 
which the body rocks when the load is dumped, (m) One 
of two beams used in the body-frame of a carriage to sup- 
port the floor-boards. See cut under barouche. Boston 
rocker, a rocking-chair with a plain wooden seat shaped 
slightly to the person, and back and arms supported on 
slender uprights, usually turned. This form has persist- 
ed nearly unchanged for two centuries. [U. S.] Rocker 
keel, a keel curved upward both forward and. aft of the 
midship line. 
rocker-cam (rok'er-kam), M. A cam keyed to a 
rock-shaft . It does not make successive complete revo- 
lutions, but has a reciprocating rotary movement through 
an arc of generally less than 180. Such cams are much 
used in the valve-gear of steam-engines on river-boats 
propelled by paddle-wheels, In the valve-gear of some 
stationary engines, and also in the construction of other 
machinery. Also called wiper. 
rockered (rok'erd), a. [< rocker 2 + -ed 1 .] 
Shaped like a rocker: curved or bellied down- 
ward : as, a rockered keel. 
rocker-shaft (rok'er-shaft), H. Same as rock- 
shaft. 
rocker-sleeve (rok'er-sley), n. A part of the 
breech-action of a magazine-gun. 
rockery (rok'er-i), n. ; pi. rockeries (-iz). [< 
rock 1 + -ery.~\ An artificial mound formed of 
stones or fragments of rock, earth, etc., for the 
cultivation of particular kinds of plants, as 
ferns. 
rocket 1 (rok'et), n. [= D. raket = G. rakete 
= Dan. Sw. raket = F. roquet, roquette, rac- 
quette (> Sp. raquete), < Olt. rocchetto (ML. 
rochetus, rocheta), a rocket, so named from its 
shape, lit. 'a bobbin,' It. rocchetto, a bobbin 
(rochetta, a distaff) (= F. rochet, roquet, a bob- 
bin), dim. of rocca, a distaff: see rock 3 .} 1. 
A cylindrical tube of pasteboard or metal 
filled with a mixture of niter, sulphur, char- 
coal, etc., which, on being 
ignited at the base, pro- 
pels the tube forward by 
the impact of the liberated 
gases against the atmo- 
sphere. Rockets are used for 
various purposes, (a) In war, 
when the apparatus generally 
consists of a sheet-iron case filled 
with a composition such as is de- 
scribed above, and a head which 
maybe solid, or hollow and filled 
with a bursting-charge, (ft) Life- 
rockets, used for carrying a line 
over a wreck, and thus estab- 
lishing communication between 
the ship and the shore. The 
Russian rocket has a short stick 
attached to the base and armed 
with a hook which slides in 
a groove on the under side of 
the rocket-stand and engages 
the ring of the chain attached 
to the line as the rocket leaves 
the stand. The German sys- 
tem comprises five-centime- 
ter and eight-centimeter rock- 
ets and eight-centimeter an- 
chor-rockets, all of which have 
long chains attached to the 
rocket-stick at one end and to 
the line at the other. The Eng- ro<;Kel pru[ra . ._ 
Hsh system consists of double metal rod connecting rocket 
Boxer rockets placed end to end with a float rf carrying a 
in a single metallic case, having ^e'^ock^s'tnkes'tnew'i' 
a stick fastened to one side of tcr> showing at nig ht posi^ 
the case. The Hooper rocket is tion of line /, g, rod to 
a. modification of the Hale war- which line / is attached; 
rocket, and was very tinsatis- *. f - f .- 2 : Rock ?' af ' 
factory in its results. All these 
Life-saving Rocket. 
Fig. i. Rocket before fir- 
ing 1 <*, rocket proper; c. 
terfirinn: lettering as above. 
,. Rocket proper : 
rockets have metallic cases, and metallic shell filled 
ith a 
are flred by means of fuses. The slow-burning composition 
uncertainty of their flight and ^SS^ASSKtSSSsS& 
their liability to deterioration H^^2rt?58^ 
by transportation and storage fig. 4. 
have prevented their adoption 
for life-saving purposes in the United States, (c) Signal- 
or sky-rockets, pasteboard cylinders tilled with nearly 
