CRA 
is technically termed, the wire-drawing) of 
the oil impedes the motion of the wheels, so 
as to low'er the greatest w'eights with any 
velocity required. A portion of the circle 
m is fastened to the cock, with fine teeth 
cut in it : a click takes into these teeth to 
hold the cock at any opening it may be set 
to. This contrivance is described in Gre- 
gory’s Mechanics, published in 1806, ap- 
plied to a different kind of crane, but the 
invention is ascribed to Mr. David Hardie. 
We consider it a contrivance of great utility, 
and likely to prove extremely useful. 
Fig. 4 is an elevation of a crane at Queen- 
hithe wharf, London. A B is a very strong 
upright beam, firmly bolted to beams run- 
ning inland, and further secured by curved 
stays D ; « d e is a cast-iron frame, bolted 
to the beam at one end, and the stays D at 
the other. This forms the frame for the 
wheelwork, which is the same as fig. 1 ; 
the chain, after going round the roll, goes 
over a large wheel f, and passes through the 
beam to the jib. E is a cast-iron frame, 
bolted to the top of the beam A B ; to re- 
ceive the upper pivot of the jib g is one of 
the small pulleys, round which the chain 
bends when the jib is turned overland to 
raise or lower goods. F is another cast-iron 
frame, to support the lower pivot of the 
jib, and G is a pile bolted to it to assist. A 
few boards nailed over the two stays D 
forms a cover for the whole machinery, and 
defends the wheel-work. Tlie jib and its 
iron-vVork will be understood by inspection 
of the figure. All cranes where’ chains are 
used for hoisting the goods should have bar- 
rels, with a spiral groove cut in them, and 
the lower half of the chain lay in the groove, 
as in fig. 5. This was applied, in 1789, by 
Mr. John Smeaton ro a crane designed by 
him, and executed c the Wool-quay, Cus- 
tom-house, and foimd to be a great advan- 
tage. In 1805 Mr. Gilbert Gilpin received 
the Silver Medal of the Society of Arts for 
the same invention, without perhaps know- 
ing it had been used before. The pulleys 
should also be grooved to receive tire lower 
half of the links of the chain in the same 
manner. 
CRANICHIS, in botany, a genus of the 
Gynandria Diandria class and order. Na- 
tural order of Orchidem. Essential charac- 
ter : nectary galeated. There are five spe- 
cies, all natives of Jamaica. 
CRANIOLARIA, in botany, a genus of 
the Didynamia Angeospermia class and or- 
der. Natural order of Personatae. Big- 
noniae, Jussieu. Essential character : calyx 
CRA 
double of the flower ; perianth four-leaved 
spathe one leaved ; corolla tube very long ; 
capsule of martynia. There is but one spe- 
cies, viz. C. annua, found in the neighbour- 
hood of Carthagena in New Spain. 
CRANIUM. See Anatomy. 
CRANK, a contrivance in machines, in 
manner of an elbow, only of a square form, 
projecting from a spindle, and serving by its 
rotation, to raise and fall the pistons of en- 
gines. 
Crank likewise denotes the iron support 
for a lantern, or the like ; 2dso the iron made 
fast to a stock of a bell for ringing it. 
In the sea-language, a ship is said to be 
crank-sided when she can bear but small 
sail, for fear of over-setting ; and when a ship 
cannot be brought on the ground without 
danger, she is said to be crank by the 
ground. 
CRANZIA, in botany, a genus of the 
Pentandria Monogynia class and order. 
Essential character : calyx five parted ; pe- 
tals five ; nectary none ; berried capsule. 
There is but oiie species, viz. C. aculeata, a 
prickly shrub; leaves ternate with pellucid 
dots ; fruit dotted like the orange. Native 
of the East Indies. 
, CRAPE, in commerce, a kind of stuff 
made in tlie manner of gauze, with raw silk, 
gummed and twisted on the mill. 
CRASPEDIA, in botany, a genus of the 
Syngenesia Polygamia Segregata. Essen- 
tial character : calycle none ; calyx imbri- 
cate ; florets in depressed bundles, all her- 
maphrodite, tubular ; down feathered ; re- 
ceptacle chaffy. One species, viz. C. uni- 
flora, a native of New Zealand. 
CRASSULA, in botany, a genus of the 
Pentandria Pentagynia class and order. 
Natural order of Succulent®. Semper- 
viv®, Jussieu. Essential character; calyx 
one leafed, five cleft ; petals five ; nectare- 
ous scales five at the base of the germ ; 
capsule five, many-seeded. There are six- 
ty-four species. 
CRATAEGUS, in botany, a genus of the 
Icosandria Digynia class and order. Natu- 
ral order of Pomac®. Rosace®, Jussieu. 
Essential character : calyx five cleft ; petals 
five ; berry inferior, two seeded. There are 
twenty-three species. This genus consists 
chiefly of shrubs or trees, hardy and deci- 
duous ; leaves simple, undivided, or lobed ; 
peduncles in most species many flowered ; 
corymbed terminating, and solitary from 
the axils ; corollas white, appearing in May 
and June, and succeeded by red berries in, 
autumn. 
