450 
C R A 
C R A 
C R A 
anthera only on one point of each ; the fruit 
is a dry, globose, and deciduous berry. There 
are six species, three of them herbaceous 
esculents with perennial roots, producing 
annually large leaves resembling those of 
cabbage spreading on the ground, with 
strong flower-stalks and yellowish flowers. 
Only one of the species is a native of Bri- 
tain. it grows wild on the shores of many 
of the maritime counties of England, but i’s 
cultivated in many gardens as a choice es- 
culent ; and the young robust shoots of its 
leaves and flower-stalks, as they issue forth 
from the earth after the manner of asparagus- 
shoots, are then in the greatest perfection 
for use. At this period, if covered when they 
rise with a garden-pot, they appear white 
as if blanched, and when boiled eat exceed- 
ingly sweet and tender. Its principal season 
for use is in April and May. This plant 
may also be employed in the pleasure- 
ground as a flowering perennial, for the 
stalks divide into line branchy heads of flow- 
ers. It is propagated by seeds sown in any 
common light earth in autumn or spring, 
where the plants are to remain, which, when 
two years old, will produce shoots lit for 
use, will multiply exceedingly by the roots, 
and continue for many years. The crambe 
fruticosa is a greenhouse plant. 
CRAMP, in medicine, a convulsive con- 
traction of a muscular part of the body. It 
affects all parts indifferently ; but the hams 
calves, feet, and toes, oftener than the arms 
and hands. 
Cramp-iron, or Cramps, a piece of iron 
bent at eacii end, which serves to fasten to- 
gether pieces of wood, stones, or other 
things. 
CRAMPON E'E, in heraldry, an epithet 
given to a cross which has at each end a 
cramp or square piece coining from it ; that 
from the arm in chief towards the sinister 
angle, that from the arm on that side down- 
wards, that from the arm in base towards 
the dexter side, and that from the dexter 
arm upwards. 
CRANE. See Grus. 
Crane, a machine used in building, on 
wharfs, and in warehouses, for raising and 
lowering huge stones, ponderous weights, 
packages, &c. 
Cranes, until of late years, were common- 
ly constructed as follows : The principal mem- 
ber is a strong upright beam or arbor, firmly 
fixed in the ground, and sustained by eight 
arms, coming from the extremities of four 
pieces of wood laid across, through the 
middle of which passes the foot of the beam. 
About the middle of the arbor the arms 
meet, and are mortised into it: its top ends 
in an iron pivot, on which is borne a trans- 
verse piece, advancing out to a good dis- 
tance, something after the manner of a crane’s 
neck, whence the machine lias its name. 
This projecting piece is now more common- 
ly called the jib or gibbet. The middle and 
extremities of this are again sustained by 
arms from tiie middle of the arbor : and 
over it comes a rope or cable, to one end of 
which the weight is fixed ; the other is wound 
about the spindle of a wheel, which when 
turned (commonly by means of men walking 
upon the inside of the rim of the wheel) 
draws the rope, and that heaves up the 
weight ; which may afterwards be applied 
to any side or quarter by the mobility of the 
transverse piece on the pivot. These cranes 
have usually been made of two kinds: in the 
first, called the rat-tailed crane, the whole 
machine with the load turns upon a strong 
axis: in the second kind the gibbet alone 
moves on its axis. But in either kind, if the 
machinery is put into motion by men walk- 
ing within the wheel, as lias been till late- 
ly the almost universal practice in this coun- 
try, the labourers employed are exposed to 
extreme danger, and have frequently met 
with the most shocking and fatal accidents. 
It is not then to be wondered at, that skilful 
mechanists should at length have devised 
cranes that are not only more safe, but more 
powerful in their operation, than the com- 
mon walking crane. 
The late Mr. Ferguson invented a crane 
which has three trundles, with different num- 
bers of staves, that may he applied to the 
cogs of a horizontal wheel with an upright 
axle ; round which is coiled the rope that 
draws up the weight. This wheel has 96 
cogs ; 'the largest trundle 24 staves, the next 
12, and the smallest 6 ; so that the largest 
revolves 4 times for one revolution of the 
wheel, the next 8, and the smallest 16. 
A winch is occasionally fixed on the axis of 
either of these trundles for turning it ; and 
is applied to the one or the other according 
as the weight to be raised is smaller or larger. 
While this is drawing up, the ratch-teeth of 
a wheel slip round below a catch that falls 
into them, prevents the crane from turning 
backwards, and detains the weight in any 
part of its ascent, if the man who works at 
the winch should accidentally quit his hold, 
or wish to rest himself before the weight is 
completely raised. Making a due allowance 
for friction, a man may raise by such a crane, 
from three times to twelve times as much 
in weight as would balance his effort at the 
winch, viz. from 90 to 360 lbs. taking the 
average labour. 
But several cranes which are preferable to 
the common walking-crane, while they are 
free from the dangers attending that ma- 
chine, lose at the same time one of its advan- 
tages ; that is, they do not avail themselves 
of that addition to the moving power which 
the weight of the men who are employed 
may furnish. Yet this advantage has been 
long since ensured by the mechanists on the 
continent, who cause the labourers to walk 
upon an inclined plane, turning upon an 
axis. The same principle has been lately 
brought- into notice, probably without ever 
knowing it had been adopted before, by Mr. 
James White, of Chevening, in Kent : his 
crane is exhibited in fig. 1 . as it was describ- 
ed in the Transactions of the Society for the 
Encouragement of the Arts. See PI. Cranes. 
A (fig. 1.) is a circular inclined plane, 
moving on a pivot underneath, and carrying 
round with it the axis E. A person walking, 
on this plane, and pressing against the lever 
B, throws off the gripe D, by means of an 
iron rod C ; and thus admits the plane and 
its axis to move freely, and raise the weight 
G by the coiling of the rope F round the axis 
To shew more clearly the construction 
and action of the lever and gripe, a plan of 
the circular inclined plane, with the lever 
and gripe, is added, (see fig. 2.) where B 
represents the lever, D the spring or gripe. 
In this plan, where the lever B is in the situ- 
ation in which it now appears, the spring or 
gripe D presses against the periphery of the 
plane, as shewn by the double line, and the 
machine cannot move ; but when the lever 
B is pressed out to the dotted line H, the 
gripe is also thrown off to the dotted line I, 
and the whole machine left at liberty to 
move. One end of a rope or cord, of a pro- 
per length, is fixed near the end of the lever 
B, and the other end made fast to one of the 
uprights, serving to prevent the lever mov- 
ing too far when pressed by the man. 
4 lie supposed properties of this crane, for 
which the premium of 40 guineas was adjudg- 
ed by the society to the inventor, are as 
follows: 
1. It is simple, consisting merely of a 
wheel and axle. 2. It has comparatively 
little friction, as is obvious from the bare in- 
spection of the figure. 3. It is durable, as 
is evident from the two properties above- 
mentioned. 4. It is safe ; for it cannot move 
but during the pleasure of a man, and while 
he is actually pressing on the gripe-lever. 
5. This crane admits of an almost infinite va- 
riety of different powers, and this variation 
is obtained without the least alteration of 
any part of the machine. If, in unloading 
a vessel, there should be found goods of any 
weight, from a few hundreds to a ton and 
upwards, the man that does the work will 
be able so to adapt his strength to each as 
to raise it in a space of time proportionate 
to its weight ; he walking always with the 
same velocity as nature and his greatest ease 
may teach him. 
It is a great disadvantage in some cranes, 
that they take as long time to raise the small- 
est as the largest weight, unless the man 
who works them turns or walks with such ve- 
locity as must soon tire him. In other cranes, 
perhaps, two or three different powers may 
be procured ; to obtain which, some pinion 
must be shifted, or fresh handle applied or 
resorted to. In this crane, on the contrary, 
if the labourer finds his load so heavy as to 
permit him to ascend the wheel without its 
turning, let him only move a step or two 
towards the circumference, and he will be 
fully equal to the task. Again, if the load 
is so light as scarcely to resist the action of 
his feet, and thus to oblige him to run 
through so much space as to tire him beyond 
necessity, let him move laterally towards the 
centre, and lie will soon feel the place where 
his strength will suffer the least fatigue by 
raising the load in question. One man’s 
weight applied to the extremity of the wheel 
would raise upwards of a ton ; and it need 
not be added, that a single-sheaved block 
would double that power. Suffice it to say, 
that the size may be varied in any required 
ratio; and that this wheel will give as great 
advantage at any point of its plane as a com- 
mon walking-wheel of equal diameter, as 
the inclination can be varied at pleasure, as 
far as expediency may require. It may be 
necessary to observe, that what in the figure 
is the frame, and seems to form a part of 
the crane, must be considered as a part of 
the house in which it is placed; since it 
would be mostly unnecessary should such 
cranes be erected in houses already built. 
With respect to the horizontal part, by walk- 
ing on which the man who attends the jib 
occasionally assists in raising the load, it is 
not an essential part of this invention, where 
