COK 
other. Being thus edged, tlie impression 
is given them by the mill, which is so con- 
trived that the metal receives at once an 
impression on each side, and becomes mo- 
ney as soon as it has been examined and 
weighed. The process for coining medals 
is nearly the same with that of money ; there 
is, however, this difference, that money Ifom 
the smallness of the relievo receives its im- 
pression at once, whereas medals require 
several strokes. The figures of tl>e coin- 
ing-mill have been so frequently given, that 
it seemed to us needless to insert them 
here, especially as a new method of coining 
has been iptrodiiced by Messrs. Bolton and 
Watt, which is shortly to be the only mode 
used in this country. For this purpose 
buildings are erecting on Tower-Hill. This 
machinery invented by these able mecha- 
nicians has been long used in the manufac- 
ture of copper money ; it works the screw- 
presses for cutting out the circular pieces of 
copper, and coins both the edges and faces 
of the money at the same time, with such 
superior excellence and cheapness of work- 
manship as will prevent clandestine imita- 
tion. By this machinery, four boys are 
capable of striking 30,000 pieces of money 
in an hour ; and the machine acts at the 
same time as a register, and keeps an un- 
erring account of the number of pieces 
struck. 
Coining, in the tin-works, is the weigh- 
ing and stamping the blocks of tin with a 
lion rampant, performed by the king’s offi- 
cer; the duty for eVery hundred weight 
being four shillings. 
COIX, in botany, a genus of the Monoe- 
cia Triandria class and order. Natural or- 
der of grasses. Essential character : males 
in remote spikes ; calyx glume two-flowered 
awnless ; corolla glume awnless ; female, 
calyx glume two-flowered ; corolla glume 
awnless ; style two parted ; seeds covered 
by the calyx ossified. There are three spe- 
cies. 
COKE, a preparation of fossil coal, 
whereby it is deprived of the naptha, 
bitumen, or asphaltum it may contain, so 
that when applied to certain purposes, it 
may not communicate a ,bad flavor or bad 
qualities. Coke is made in very large 
ovens, principally from the refuse or bnish- 
eoal, with which some pits abound ; the 
coal in them being extremely brittle, and 
rarely coming away in large pieces. The 
ovens have vents and mouths that are occa- 
sionally stopped, in part, for the purpose of 
regulating the heat, which, in no case 
COL 
should be such as to consume, but merely 
to char. The ovens being closed, at a pro- 
per time, the fire is gradually extinguished, 
and the coke is compacted into large masses, 
requiring to be broken before they can be 
taken out. In this state it will burn with 
a clear and steady heat, free from fumes, 
and consequently without occasioning malt 
(which is usually dried with coke, wbere 
coal pits are at hand) to partake of a bitu- 
menous or smoky flavor. Good coke should 
be light, rather little, and more close than 
cellular ; that which is of a deep ash colour 
is in general preferable : when black, or at 
all glossy, it is a certain sign of the want of 
due preparation ; it ought to be equally 
charred, and in large lumps, from the size 
of a quartern loaf to a bushel : the small 
refuse is not profitable, and often is too 
much burnt. 
COLCHICUM, in botany, meadow saf- 
fron, a genus of the Hexandria Trigynia 
class and order. Natural order of Spatha- 
cesE. Junci, Jussieu. Essential character : 
spathe; corolla six-parted, with a rooted 
tube ; capsule three, connected, inflated. 
There are three species. 
COLD. When we leave a room at the 
temperature of 60°, and go into the air in 
a frosty day at the temperature of 30°, we 
say it is cold ; or w'hen the hand is held in 
water at the temperature of 100° for a few 
minutes, and then suddenly plunged into 
water at the temperature of 40°, the latter 
is said to be cold. This, however, is 
merely an expression of the sensation ex- 
cited in the body, which depends solely on 
tlie abstraction of its heat. This may be 
proved by the following experiment. If 
tlwee quantities of water ai-e taken, the 
first at the temperature of 30°, the second 
at the temperature of 50°, and the third at 
the temperature of 98°. Immerse tlie 
right hand into tlie water at the tempera- 
ture of 98°, and the left into tlie water at 
the temperature of 30°. Let them both re- 
main for a minute, and then suddenly 
plunge both hands into the water at the in- 
termediate temperature of 50°, to the right 
hand it will feel cold, and to the left warm : 
thus different sensations are produced by 
the same body at the same time, and at 
the same temperature. But this depends 
entirely on the previous state of tlie hands, 
and on the absorption or abstraction of the 
caloric. The right, which was placed in 
the water at the temperature of 98° ab- 
sorbed caloric, because the temperature of 
the water is above that of the body. This 
