COIN, laws relating to. Counterfeiting the king's money, or bringing false money into the realm counterfeit to the money of England, clipping, washing, rounding, filing, impairing, diminishing, falsifying, scaling, lightening, edging, colouring, gilding, making, mending, or having in one's possession, any puncheon, counter puncheon, matrix, stamp, dye, pattern, mould, edger, or cutting engine all these incur the penalty of high treason. And if any person shall counterfeit any such kind of gold or silver, as are not the proper coin of the realm, but current therein by the king's consent, he shall be guilty of high trea

son.

If any person shall tender in payment any counterfeit coin, he shall, for the first offence, be imprisoned six months; for the second offence, two years; and for the third offence shall be guilty of felony without benefit of clergy.

Blanching copper or other base metal, or buying or selling the same; and receiving or paying money at a lower rate than its denomination doth import; and also the offence of counterfeiting copper half-pence and farthings; incur the penalty of felony, but within clergy. Counterfeiting coin not the proper coin of this realm, not permitted to be current therein, is misprision of treason. A person buying or selling, or having in his possession, clippings or filings, shall for feit 5001. and be branded in the cheek with the letter R. And any person having in his possession a coining-press, or casting bars or ingots of silver, in imitation of Spanish bars or ingots, shall for

feit 5001.

VOL. III.

A reward of 401. is given for convicting a counterfeiter of the gold or silver coin; and 10. for a counterfeiter of the copper coin.

COINING, the art of making money, which has hitherto been performed by the hammer or the mill. The first operations are the mixing and melting of the metal, because there is no species of coin of pure gold or silver but requires a quantity of alloy. See ALLOY. For gold coin the alloy is a mixture of silver and copper, as silver alone would make the coin too pale, and the copper alone would give it too high a colour. The alloy is used for the purpose of rendering the coins harder, and less liable to wear, or to be diminished by art. When the gold and silver are completely melted and mixed, they are cast into long, flat bars, nearly of the thickness of the coin to be cast. In coining by the mill, which has been the only method in use for the last 250 years, the bars are taken out of the moulds, and scraped, brushed, flattened in a mill, and brought to the proper thickness of the species to be coined. The plates, thus reduced as nearly as possible to the proper thickness, are cut into round pieces, called blanks, or planchets, with an instrument fastened to the lower end of an arbor, whose upper end is formed into a screw, which, being turned by an iron handle, turns the arbor, and lets the steel, well sharpened in form of a punch-cutter, fall on the plates; and thus a piece is punched out. The pieces are now to be brought to the standard weight by filing or rasping, and what remains of the plate between the circles is melted again. The pieces are next weighed in Hh

an accurate balance, and those that prove too light are re-melted; but those that are too heavy are filed to the standard weight. When the blanks are adjusted, they are carried to the blanching-house, where the blanks are brought to their proper colour. They are next milled, by means of a machine which consists of two plates of steel in form of rulers, on which the edging is engraved, half on the one and half on the other. Being thus edged, the impression is given them by the mill, which is so contrived, that the metal receives at once an impression on each side, and becomes money 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, from the smallness of the relievo, receives its impression at once, whereas medals require several strokes. The figures of the coining-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 introduced by Messrs. Bolton and Watt, which is shortly to be the only mode used in this country. For this purpose build. ings are erecting on Tower-Hill. This machinery, invented by these able mechanicians, has been long used in the manufacture 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 workmanship as will prevent clandestine imitation. By this machinery, four boys are capable of striking 30,000 pieces of money in an bour and the machine acts at the same time as a register, and keeps an unerring account of the number of pieces struck.

COINING, in the tin-works, is the weighing and stamping the blocks of tin with a lion rampant, performed by the king's officer; the duty for every hundred weight being four shillings.

COIX, in botany, a genus of the Monoecia Triandria class and order. Natural order 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 twoparted; seeds covered by the calyx ossified. There are three species.

COKE, a preparation of fossil coal, whereby it is deprived of the naphtha,

bitumen, or asphaltum, it may contain, so that, when applied to certain purposes, it may not communicate a bad flavour or bad qualities. Coke is made in very large ovens, principally from the refuse or brush-coal, with which some pits abound; the coal in them being extremely brittle, and rarely coming away in lage pieces. The ovens have vents and mouths that are occasionally stopped, in part, for the purpose of regulating the heat, which in no case should be such as to consume, but merely to char. The ovens being closed at a proper 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, where coal pits are at hand) to partake of a bituminous or smoky flavour. 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 Spathaceæ. Junci, Jussieu. Essential character: spathe; corolla six-parted, with a rooted tube; capsule three, connected, inflated. There are three species. One of them, viz. C. autumnale, has been supposed by Mr. Want to be the base of the Eau medicinale d'Hussor.

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 when 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, excited in the body, which depends solely on the abstraction of its heat. This may be proved by the following experiment. If three quantities of water are taken, the first at the temperature of 30°, the second at the temperature of 50°, and the third at the temperature of 98°. Immerse the right hand into the water at the temperature of 98°, and the left into the water at the

temperature of 30°. Let them both remain for a minute, and then suddenly plunge both hands into the water at the intermediate 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 the hands, and on the absorption or abstraction of the caloric. The right, which was placed in the water at the temperature of 98°, absorbed caloric, because the temperature of the water is above that of the body. This excites the sensation of heat: but when the same hand is placed in the water at the temperature of 50°, it is deprived of caloric, because the surrounding medium is far below its temperature, and thus the sensation of cold is produced. But from the left, placed in the water at 30°, caloric is abstracted, which gives the sensation of cold, and the same hand placed in the water at 50°, receives caloric, and this entering the body, excites the sensation of heat Thus the term cold is expressive of the relative temperature of two bodies. There have, however, been persons who would account for the phenomena of cold by the existence of frigorific particles, supposed to be floating in the air, and by mixing with liquid bodies convert them to solids, and there are facts which seem to support this doctrine.

Nothing appears at first sight more directly contradictory to the common opinion of cold being only relative, and only a negative term implying the abstracttion of heat, than the facts which shew the apparent radiation, absorption, and reflexion of cold; the evidence of which stands on the same ground as the corresponding motions of heat, namely, on the rise or fall of the thermometer. If the rise of the liquor on the scale of a thermometer, whose bulb is placed in the focus of a mirror, be considered as a proof of the propulsion of certain calorific rays from a distant heated surface, and their subsequent reflexion according to the laws of catoptrics, the sinking of the same thermometer liquor under similar circumstances of position, when the surface, which before was sensibly hotter than the atmosphere, is now sensibly colder, would seem, from a parity of reasoning, to indicate the propulsion and reflexion of frigorific rays. Nor can we consider this question as at all determined, though an ingenious hypothesis has

been advanced by M. Prevost, which goes a considerable way to reconcile the apparent contradiction of the doctrine of the unity of heat and cold.

It is singular, that the reflection of cold should have been accidentally discovered, and decidedly announced about the year 1667, by the members of the Florentine Academy del Cimento, without any further prosecution of so curious a fact. The experiment is the following: a mass of ice of about 500lb, was set some distance before a concave glass mirror, and the bulb of a spirit thermometer put in the focus, to try whether cold would be reflected. Immediately the spirit of the thermometer began to sink, and fell several degrees. To prove that this was not merely owing to the contiguity of the ice, the surface of the mirror was covered with a cloth, to prevent the reflexion, and the thermometer again rose. No further inference is drawn from this experiment, and the author of it seemed even to doubt of the reality of the reflexion, and to be disposed to impute it to some other unknown cause. This experiment was repeated in a much more accurate way by M. Pictet. The apparatus which he used was the same as that before described, as employed for the reflection of heat; that is, two tin mirrors placed directly opposite each other at some distance, in the focus of one of which was placed the bulb of a very sensible thermometer, and in the other, the vessel intended to produce the heat or cold. In this instance, this latter was a mattrass full of snow: the mirrors were separated to the distance of 104 feet. At the instant the mattrass was placed in one focus, the thermometer in the opposite focus began to sink, and descended several degrees. When stationary, nitrous acid was poured on the snow, which produced a cold of much greater intensity, and the thermometer in consequence immediately descended several degrees lower. When taken out of the focus, it again rose to the common temperature.

Mr. Leslie also found, not only the same effect in this experiment, but that the action of a cold radiating surface upon the tin reflector produced exactly the same proportional effect upon the differential thermometer as the hot radiating surface, only in the opposite direction of the scale. The differential thermometer, which is always at zero when both bulbs are equally heated, is beatifully calculated to shew this striking experi