For other information respecting clock-work, see the articles BALANCE, PENDULUM, and SCAPEMENT, in this volume.

Some very simple contrivances for clocks, by Mr. Ferguson, and Dr. Franklin, may be seen in Ferguson's Select Exercises. In the fourth century an artist named James Dondi constructed a clock for the city of Padua, which was long considered as the wonder of that period. Besides indicating the hours, it represented the motion of the sun, moon, and planets, as well as pointed out the different festivals of the year. On this account Dondi obtained the surname of Horologio, which became that of his posterity. A little time after, William Zelander constructed for the same city a clock still more complex; which was repaired in the sixteenth century by Janellus Turrianus, the mechanist of Charles V.

But the clocks of the cathedrals of Strasburgh and of Lyons are much more celebrated. That of Strasburgh was the work of Conrad Dasypodius, a mathematician of that city, who finished it about 1573. The face of the basement of this clock exhibits three dial-plates; one of which is round, and consists of several concentric circles; the two interior ones of which perform their revolutions in a year, and serve to mark the days of the year, the festivals and other circumstances of the calendar. The two lateral dial-plates are square, and serve to indicate the eclipses both of the sun and the moon. Above the middle dialplate, and in the attic space of the basement, the days of the week are represented by different divinities, supposed to preside over the planets from which their common appellations are derived. The divinity of the current day appears in a car rolling over the clouds, and at midnight retires to give place to the succeeding one. Before the basement is seen a globe, borne on the wings of a pelican, around which the sun and moon revolved; and which in that manner represented the motion of these planets: but this part of the machine, as well as several others, has been deranged for a long time. The ornamental turret, above this basement, exhibits chiefly a large dial in the form of an astrolabe; which shews the annual motion of the sun and moon through the ecliptic, the hours of the day, &c. The phases of the moon are seen also marked out on a particular dial-plate above. This work is remarkable also for a considerable assemblage of bells and figures, which perform different motions. Above the dial-plate last mentioned, for example, the four ages of man are represented by symbolical figures: one passes every quarter of an hour, and marks the quarter by striking on small bells: these figures are followed by Death, who is expelled by Jesus Christ risen from the grave: who, however, permits it to sound the hour, in order to warn man that time is on the wing.

Two small angels perform movements also; one striking a bell with a sceptre, while the other turns an hour-glass at the expiration of an hour. In the last place, this work was decorated with various animals, which emitted sounds similar to their natural voices; but none of them now remains, except the cock, which crows immediately before the hour strikes, first stretching out its neck and clapping its wings. Indeed it is to be regretted that a great part of this machine is now entirely deranged.

The clock of the cathedral of Lyons is of less size than that of Strasburgh, but is not inferior to it in the variety of its move ments; it has the advantage also of being in a good condition. It is the work of Lippius de Basle, and was exceedingly well repaired in the last century by an ingenious clock-maker of Lyons named Nourisson. Like that of Strasburgh, it exhibits on different dial-plates the annual and diurnal progress of the sun and moon, the days of the year, their length, and the whole calendar, civil as well as ecclesiastic. The days of the week are indicated by symbols more analogous to the place where the clock is erected the hours are announced by the crowing of a cock, three times repeated after it has clapped its wings, and made various other movements. When the cock has done crowing, angels appear, who, by striking various bells, perform the air of a hymn; the annunciation of the Virgin is represented also by moving figures, and by the descent of a dove from the clouds; and after this mechanical exhibition the hour strikes. On one of the sides of the clock is seen an oval dial-plate, where the hours and minutes are indicated by means of an index, which lengthens or contracts itself, according to the length of the semidiameter of the ellipsis over which it moves.

A very curious clock, the work of Martinot, a celebrated clock-maker of the seventeenth century, was formerly to be seen in the royal apartments at Versailles. Before it struck the hour, two cocks on the corners of a small edifice crowed alternately, clapping their wings: soon after two lateral doors of the edifice opened, at which appeared two figures bearing cymbals, beat upon by a kind of guards with clubs. When these figures had retired, the centre door was thrown open, and a pedestal, supporting an equestrian statue of Louis XIV. issued from it, while a group of clouds separating, gave a passage to a figure of Fame, which came and hovered over the statue. An air was then performed by bells: after which the two figures re-entered; the two guards raised up their clubs, which they had lowered as if out of respect for the presence of the king, and the hour was then struck.

While, however, we have thought it right to describe these ingenious performances of foreign artists, we must not neglect

to mention the equally ingenious workmanship of some of our own countrymen. We now refer to two clocks made by Euglish artists, as a present from the East-India Company to the emperor of China. These two clocks are in the form of chariots, in each of which a lady is placed in a fine attitude, leaning her right hand upon a part of the chariot, under which appears a clock of curious workmanship, little larger than a shilling, that strikes and repeats, and goes for eight days. Upon the lady's finger sits a bird, finely modelled, and set with diamonds and rubies, with its wings expanded in a flying posture, and actually flutters for a considerable time on touching a diamond button below it: the body of the bird, in which are contained part of the wheels that animate it as it were, is less than the 16th part of an inch. The lady holds in her left-hand a golden tube little thicker than a large pin, on the top of which is a small round box, to which is fixed a circular ornament not larger than a sixpence, set with diamonds, which goes round in near three hours in a constant regular motion. Over the lady's head is a double umbrella, supported by a small fluted pillar not thicker than a quill, and under the larger of which a bell is fixed, at a considerable distance from the clock, with which it seems to have no connection; but from which a communication is secretly conveyed to a hammer, that regularly strikes the hour, and repeats the same at pleasure, by touching a diamond button fixed to the clock below. At the feet of the lady is a golden dog.

COINAGE, or COINING, the art or act of making money. Coining is either performed by the hammer or the mill. The first method is now little used in Europe, especially in England, France, &c. though the only one known till the year 1553, when a new machine, or coining-mill, invented by an engraver, one Antoine Brucher, was first tried in the French king's palace at Paris, for the coining of counters; though some attribute the invention of the mill to Varin, a famous engraver, who, in reality, was no more than an improver of it; and others to Aubrey Olivier, who had only the inspection of it.

The mill has met with various fate since its first invention; being now used, and again laid by, and the hammer resumed: but it has at length got that footing, by the neatness and perfection of the species struck with it, that there appears no great probability of its ever being again disused.

In either kind of coining, the pieces of metal are stamped or struck with a sort of punchions or dyes, wherein are engraven the prince's effigies, with the arms, legends, &c.

Coining by the mill, or milled money.-The bars or plates being taken out of the mould, and scraped and brushed, are

passed several times through a mill, to flatten them further, and bring them to the just thickness of the species to be coined; with this difference, however, that the plates of gold are heated again in a furnace, and quenched in water, before they undergo the mill; which softens and renders them more ductile: whereas those of silver pass the mill just as they are, without any heating; and when afterwards they are heated they are left to cool again of themselves, without water.

The plates, whether gold, silver, or copper, thus reduced as near as possible to their thickness, are cut into round pieces, cailed blanks or planchets, near the size of the intended species, with a cutting instrument fastened to the lower extremity 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 is a piece punched out.

These pieces are now given to be adjusted, and brought by filing, or rasping, to the weight of the standard, whereby they are to be regulated: and what remains of the plate between the circles is melted again, under the denomination of sizel.

The pieces are adjusted in a fine balance: and those which prove too light are separated from those too heavy; the first to be melted again, and the second to be filed down. For it may be observed, that the mill through which the plates are passed can never be so just but there will be some inequality, whence will arise a difference in the blanks. And this inequality, indeed, may be owing to the quality of the matter as well as of the machine; some parts being more porous than others.

When the blanks are adjusted they are carried to the blanching or whitening-house, i. e. the place where the gold blanks have their colour given them, and the silver ones are whitened; which is done by heating them in the furnace, and, when taken out and cooled, boiling them successively in two copper vessels, with water, common salt, and tartar: and, after that, scouring them well with sand, and washing them with common water, drying them over a wood fire, in a copper sieve, wherein they are put when taken out of the boilers.

Formerly the planchets, as soon as blanched, were carried to the press, to be struck, and receive their impressions; but now they are first marked with letters or graining on the edges, to prevent the clipping and paring of the species, which is one of the ways wherein the ancient money used to be damaged. The machine used to mark the edges is very simple, yet ingeni

it consists of two plates of steel, in form of rulers, about the thickness of a line, on which the legend or edging is engraven, half on the one, and half on the other. One of these

plates is immoveable, being strongly bound with screws to a copper plate; and that again to a strong board, or table: the other is moveable, and slides on the copper plate by means of a handle, and a wheel, or pinion of iron, the teeth whereof catch in a kind of other teeth, on the surface of the sliding plate. Now, the planchet, being placed horizontally between these two plates, is carried along by the motion of the moveable one; so as by that time it has made half a turn it is found marked all round. See fig. 1. pl. XIV.

This machine is so easy, that a single man is able to mark twenty thousand planchets in a day. Savang pretends it was invented by the sieur Castagin, engineer to the French king, and first used in 1685. But it is certain we had the art of lettering the edges in England long before that time; witness the crowns and half-crowns of Oliver Cromwell struck in 1658, which for beauty and perfection far exceed any French coins we have ever seen.

Lastly, the planchets, being thus edged, are to be stamped, i. e. their impression is to be given them in a sort of mill, or press, by the French called a balancier, invented towards the latter end of the sixteenth century. See its figure in fig. 2. pl. XIV.

Its chief parts are a beam, screw, arbor, &c. all contained in the body of the machine, except the first, which is a long iron bar, with a heavy ball of lead at each end, and rings, to which are fastened cords, which give it motion: this is placed horizontally over the body of the machine. In the middle of the beam is fastened a screw, which, by turning the beam, serves to press the arbor underneath it; to the lower extremity of which arbor, placed perpendicularly, is fastened the dye, or matrice, of the reverse, or arm side, in a kind of box, or case, wherein it is retained by screws: and under this is a box, or case, containing the dye of the image-side, firmly fastened to the lower part of the engine, fig. 3.

Now when a planchet is to be stamped it is laid on the image-matrice, upon which two men draw, each on his side, one of the ropes of the beam, and turn the screw fastened in it; which by this motion lowers the arbor to which the dye of the arms is fastened: by which means the metal being in the middle, at once receives an impression on each side, from either dye. As to the press formerly used, it has all the essential parts of a balancier, except the beam, which is here, as it were, divided, and only drawn one way.

The blanks having now all their marks and impressions, both on the edges and faces, become money; but they have not currency till they have been weighed and examined.