the most valuable of all the metals, is of a bright yellow colour when pure, but becomes more or less white in proportion as it is alloyed with other metals. It is the heaviest of all known bodies, platinum only excepted. See Chemistry and Mineralogy Index.

Method of Recovering Gold from Gilt Works. The solubility of gold, and the indissolubility of silver, in aqua regia, affords a principle on which gold may be separated from the surface of silver; and, on this foundation, different processes have been contrived, of which the two following appear to be the best.—Some powdered sal ammoniac, moistened with aquafortis into the consistence of a paste, is spread upon the gilt silver, and the piece heated till the matter smokes and becomes nearly dry: being then thrown into water, it is rubbed with a scratch brush composed of fine brass wire bound together; by which the gold easily comes off. The other way is, by putting the gilt silver into common aqua regia, kept so hot as nearly to boil, and turning the metal frequently till it becomes all over black; it is then to be washed with a little water, and rubbed with the scratch brush, to get off what gold the aqua regia may have left. This last method appears preferable to the other; as the same aqua regia may be made to serve repeatedly till it becomes saturated with the gold, after which the gold may be recovered pure by precipitation with sulphate of iron.

For separating gold from gilt copper, some direct a solution of borax to be applied on the gilt parts, but nowhere else, with a pencil, and a little powdered sulphur to be sprinkled on the places thus moistened; the principal use of the solution of borax seems to be to make the sulphur adhere; the piece being then made red hot, and quenched in water, the gold is said to be so far loosened as to be wiped off with a brush. Others mix the sulphur with nitre and tartar, and form the mixture with vinegar into a paste, which is spread upon the gilt parts.

Schlutter recommends mechanical means, as being generally the least expensive, for separating gold from the surface both of silver and copper. If the gilt vessel is round, the gold is conveniently got off by turning it in a lathe, and applying a proper tool, a skin being placed underneath for receiving the shavings: he says it is easy to collect into two ounces of shavings all the gold of a gilt vessel weighing thrice as many pounds. Where the figure of the piece does not admit of this method, it is to be properly fixed, and scrapers applied of different kinds according to its size and figure; some large, and furnished with two handles, one at each end; others small and narrow, for penetrating into depressed parts. If the gold cannot be got off by either of these ways, the file must be had recourse to, which takes off more of the metal underneath than the turning tool or the scraper, particularly than the former. The gold scrapings or filings may be purified from the silver or copper they contain, by the methods described under the article Metallurgy.

The editors of the Encyclopédie give a method of recovering the gold from wood that has been gilt on a water size: this account is extracted from a memoir of the same subject, presented to the Academy of Sciences by M. de Montamy. The gilt wood is steeped for a quarter of an hour in a quantity of water sufficient to cover it, made very hot: the size being thus softened, the wood is taken out, and scrubbed piece by piece, in a little warm water, with short stiff bristle brushes of different sizes, some small for penetrating into the carvings, and others large for the greater dispatch in flat pieces. The whole mixture of water, size, gold, &c., is to be boiled to dryness, the dry matter made red hot in a crucible to burn off the size, and the remainder ground with mercury, either in a mortar, or, where the quantity is large, in a mill.

Gold-Coast. See Guinea.

Gold-Wire, a cylindrical ingot of silver, superficially gilt or covered with gold at the fire, and afterwards drawn successively through a great number of little round holes, of a wire-drawing iron, each less than the other, till it be sometimes no bigger than a hair of the head. See Wire-Drawing.

It may be observed that, before the wire be reduced to this excessive fineness, it is drawn through above 150 different holes; and that each time they draw it, it is rubbed afresh over with new wax, both to facilitate its passage, and to prevent the silver's appearing through it.

Gold-Wire flatted, is the former wire flatted between two rollers of polished steel, to fit it to be spun on a stick, or to be used flat, as it is, without spinning, in certain stuffs, laces, embroideries, &c. See Stuff, &c.

Gold-Thread, or Spun-gold, is flatted gold, wrapped or laid over a thread of silk, by twisting it with wheel and iron bobbins.

To dispose the wire to be spun on silk, they pass it between two rollers of a little mill: these rollers are of nicely polished steel, and about three inches in diameter. They are set very close to each other, and turned by means of a handle fastened to one of them, which gives motion to the other. The gold wire, in passing between the two, is rendered quite flat, but without losing any thing of its gilding; and is rendered so exceedingly thin and flexible, that it is easily spun on silk-thread, by means of a hand-wheel, and so wound on a spool or bobbin. See Wire-Drawing.

Gold-Leaf or Beaten Gold, is gold beaten with a hammer into exceeding thin leaves, so that it is computed, that an ounce may be beaten into 1600 leaves, each three inches square, in which state it takes up more than 159,052 times its former surface.

The preparation of gold leaf, according to Dr Lewis, is as follows:

"The gold is melted in a black-lead crucible, with some..." Gold some borax, in a wind furnace, called by the workmen a wind hole: as soon as it appears in perfect fusion, it is poured out into an iron ingot mould, six or eight inches long, and three quarters of an inch wide, previously greased, and heated, so as to make the tallow run and smoke, but not to take flame. The bar of gold is made red hot, to burn off the unctuous matter, and forged on an anvil into a long plate, which is further extended by being passed repeatedly between polished steel rollers, till it becomes a ribbon as thin as paper. Formerly the whole of this extension was procured by means of the hammer, and some of the French workmen are still said to follow the same practice; but the use of the flatting mill both abridges the operation, and renders the plate of more uniform thickness. The ribbon is divided by compasses, and cut with sheers into equal pieces, which consequently are of equal weights: these are forged on an anvil till they are an inch square; and afterwards well sealed, to correct the rigidity which the metal has contracted in the hammering and flating. Two ounces of gold, or 960 grains, the quantity which the workmen usually melt at a time, make 150 of these squares, whence each of them weighs six grains and two-fifths; and as 902 grains of gold make a cubic inch, the thickness of the square plates is about the 766th part of an inch.

"In order to the further extension of these pieces into fine leaves, it is necessary to interpose some smooth body between them and the hammer, for softening its blow, and defending them from the rudeness of its immediate action: as also to place between every two of the pieces some proper intermedium, which, while it prevents their uniting together, or injuring one another, may suffer them freely to extend. Both these ends are answered by certain animal membranes.

"The goldbeaters use three kinds of membranes; for the outside cover, common parchment made of sheep skin; for interlaying with the gold, first the smoothest and closest vellum, made of calf skin; and afterwards the much finer skins of ox gut, stript off from the large straight gut slipt open, curiously prepared on purpose for this use, and hence called goldbeater's skin. The preparation of these last is a distinct business, practised by only two or three persons in the kingdom, some of the particulars of which I have not satisfactorily learned. The general process is said to consist, in applying one upon another, by the smooth sides, in a moist state, in which they readily cohere and unite inseparably; stretching them on a frame, and carefully scraping off the fat and rough matter, so as to leave only the fine exterior membrane of the gut; beating them between double leaves of paper, to force out what unctuousness may remain in them; moistening them once or twice with an infusion of warm spices; and lastly, drying and pressing them. It is said, that some calcined gypsum, or plaster of Paris, is rubbed with a hare's foot both on the vellum and the ox gut skins, which fills up such minute holes as may happen in them, and prevents the gold leaf from sticking, as it would do to the simple animal-membrane. It is observable, that, notwithstanding the vast extent to which the gold is beaten between these skins, and the great tenacity of the skins themselves, yet they sustain continual repetitions of the process for several months, without extending or throwing thinner. Our workmen find, that, after 70 or 80 repetitions, the skins, though they contract no flaw, will no longer permit the gold to extend between them; but that they may be again rendered fit for use by impregnating them with the virtue which they have lost, and that even holes in them may be repaired by the dexterous application of fresh pieces of skin: a microscopical examination of some skins that had been long used plainly showed these repairs. The method of restoring their virtue is said in the Encyclopédie to be, by interlaying them with leaves of paper moistened with white wine vinegar, beating them for a whole day, and afterwards rubbing them over as at first with plaster of Paris. The gold is said to extend between them more easily, after they have been used a little, than when they are new.

"The beating of the gold is performed on a smooth block of black marble, weighing from 200 to 600 pounds, the heavier the better; about nine inches square on the upper surface, and sometimes less, fitted into the middle of a wooden frame, about two feet square, so as that the surface of the marble and the frame form one continuous plane. Three of the sides are furnished with a high ledge; and the front, which is open, has a leather flap fastened to it, which the gold-beater takes before him as an apron, for preserving the fragments of gold that fall off. Three hammers are employed, all of them with two round and somewhat convex faces, though commonly the workman uses only one of the faces: the first, called the cutch hammer, is about four inches in diameter, and weighs 15 or 16 pounds, and sometimes 20, though few workmen can manage those of this last size: the second, called the shoddering hammer, weighs about 12 pounds, and is about the same diameter: the third, called the gold hammer, or finishing hammer, weighs 10 or 11 pounds, and is nearly of the same width. The French use four hammers, differing both in size and shape from those of our workmen: they have only one face, being in figure truncated cones. The first has very little convexity, is near five inches in diameter, and weighs 14 or 15 pounds: the second is more convex than the first, about an inch narrower, and scarcely half its weight: the third, still more convex, is only about two inches wide, and four or five pounds in weight: the fourth or finishing hammer is near as heavy as the first, but narrower by an inch, and the most convex of all. As these hammers differ so remarkably from ours, I thought proper to insert them, leaving the workmen to judge what advantage one set may have above the other.

"A hundred and fifty of the pieces of gold are interlaid with leaves of vellum, three or four inches square, one vellum leaf being placed between every two of the pieces, and about 20 more of the vellum leaves on the outsides; over these is drawn a parchment case, open at both ends, and over this another in a contrary direction, so that the assemblage of gold and vellum leaves is kept tight and close on all sides. The whole is beaten with the heaviest hammer, and every now and then turned upside down, till the gold is stretched to the extent of the vellum; the case being from time to time opened for discovering how the extension goes on, and the packet, at times, bent and rolled..." rolled as it were between the hands, for procuring sufficient freedom to the gold, or, as the workmen say, to make the gold work. The pieces taken out from between the vellum leaves, are cut in four with a steel knife; and the 600 divisions, hence resulting, are interlaid, in the same manner, with pieces of the ox-gut skins five inches square. The beating being repeated with a lighter hammer till the golden plates have again acquired the extent of the skins, they are a second time divided in four: the instrument used for this division is a piece of cane cut to an edge, the leaves being now so light, that the moisture of the air or breath condensing on a metallic knife would occasion them to stick to it. These last divisions being so numerous, that the skins necessary for interposing between them would make the packet too thick to be beaten at once, they are parted into three parcels, which are beaten separately, with the smallest hammer, till they are stretched for the third time to the size of the skins: they are now found to be reduced to the greatest thinness they will admit of; and indeed many of them, before this period, break or fail. The French workmen, according to the minute detail of this process given in the Encyclopaedic, repeat the division and the beating once more; but as the squares of gold, taken for the first operation, have four times the area of those used among us, the number of leaves from an equal area is the same in both methods, viz. 16 from a square inch. In the beating, however simple the process appears to be, a good deal of address is requisite, for applying the hammers so as to extend the metal uniformly from the middle to the sides: one improper blow is apt not only to break the gold leaves, but to cut the skins.

"After the last beating, the leaves are taken up by the end of a cane instrument, and, being blown flat on a leather cushion, are cut to a size, one by one, with a square frame of cane made of a proper sharpness, or with a frame of wood edged with cane: they are then fitted into books of 25 leaves each, the paper of which is well smoothed, and rubbed with red hole to prevent their sticking to it. The French, for sizing the leaves, use only the cane knife; cutting them first straight on one side, fitting them into the book by the straight side, and then paring off the superfluous parts of the gold about the edges of the book. The size of the French gold leaves is from somewhat less than three inches to three and three quarters square; that of ours, from three inches to three and three-eighths.

"The process of gold-beating is considerably influenced by the weather. In wet weather, the skins grow somewhat damp, and in this state make the extension of the gold more tedious: the French are said to dry and press them at every time of using; with care not to overdry them, which would render them unfit for farther service. Our workmen complain more of frost, which appears to affect the metallic leaves themselves: in frost, a gold leaf cannot easily be blown flat, but breaks, wrinkles, or runs together.

"Gold leaf ought to be prepared from the finest gold; as the admixture of other metals, though in too small a proportion to affect sensibly the colour of the leaf, would dispose it to lose of its beauty in the air. And indeed there is little temptation to the workman to use any other; the greater hardness of alloyed gold occasioning as much to be lost in point of time and labour, and in the greater number of leaves that break, as can be gained by any quantity of alloy that would not be at once discoverable by the eye. All metals render gold harder and more difficult of extension. Even silver, which in this respect seems to alter its quality less than any other metal, produces with gold a mixture sensibly harder than either of them separately, and this hardness is in no art more felt than in the goldbeater's. The French are said to prepare what is called the green gold leaf, from a composition of one part of copper and two of silver with eighty of gold. But this is probably a mistake: for such an admixture gives no greenness to gold: and I have been informed by our workmen, that this kind of leaf is made from the same fine gold as the highest gold-coloured sort, the greenish hue being only a superficial tinct induced upon the gold in some part of the process: this greenish leaf is little otherwise used than for the gilding of certain books.

"But though the goldbeater cannot advantageously diminish the quantity of gold in the leaf by the admixture of any other substance with the gold, yet means have been contrived for some particular purposes, of saving the precious metal, by producing a kind of leaf, called party-gold, whose basis is silver, and which has only a superficial coat of gold upon one side: a thick leaf of silver and a thinner one of gold, laid flat on one another, heated and pressed together, unite and cohere; and being then beaten into fine leaves, as in the foregoing process, the gold, though its quantity is only about one-fourth of that of the silver, continues everywhere to cover it, the extension of the former keeping pace with that of the latter."

But it is to be observed by Mr Nicholson, that pure gold is too ductile to be worked between the goldbeater's skin. The newest skins will work the finest gold, and make the thinnest leaf, because they are the smoothest. Old skins, being rough or foul, require coarser gold. The finer the gold, the more ductile; insomuch, that pure gold, when driven out by the hammer, is too soft to force itself over the irregularities, but would pass round them, and by that means become divided into narrow slips. The finest gold for this purpose, has three grains of alloy in the ounce, and the coarsest twelve grains. In general the alloy is six grains, or one-eightieth part. That which is called pale gold contains three pennyweights of silver in the ounce. The alloy of gold leaf is silver, or copper, or both, and the colour is produced of various tints accordingly. Two ounces and two pennyweights of gold is delivered by the master to the workman, who, if extraordinarily skillful, returns two thousand leaves, or eighty books of gold, together with one ounce and six pennyweights of waste cuttings. Hence one book weighs 4.8 grams; and as the leaves measure 3.3 inches in the side, the thickness of the leaf is one two hundred and eighty-two thousandth part of an inch.

The yellow metal called Dutch gold is fine brass. It is said to be made from copper plates, by cementation with calamine, without subsequent fusion. Its thickness, compared with that of leaf gold, proved as 19 to 4, and under equal surfaces it is considerably more than twice as heavy as the gold. Jour. vol. i. It must be observed, however, that gold is beaten more or less, according to the kind or quality of the work it is intended for; that for the gold-wire-drawers to gild their ingots withal, is left much thicker than that for gilding the frames of pictures, &c. See Gilding.

Gold Brocade. See Brocade.

Fulminating Gold. See Chemistry Index.

Mosaic Gold, is gold applied in panels on a proper ground, distributed into squares, lozenges, and other compartments; part of which is shadowed to raise or heighten the rest. See Mosaic.

Gold Plates for Enamelling are generally made of ducat gold, whose fineness is from $23\frac{1}{2}$ to $23\frac{3}{4}$ carats; and the finest gold is the best for this purpose, unless where some parts of the gold are left bare and unpolished, as in watch-cases, snuff-boxes, &c., for which purpose a mixture of alloy is necessary, and silver is preferred to copper, because the latter disposes the plates to tarnish and turn green. See Enamelling.

Shell-Gold is that used by the gilders and illuminers, and with which gold letters are written. It is made by grinding gold leaves, or gold-beaters fragments, with a little honey, and afterwards separating the honey from the powdered gold by means of water. When the honey is washed away, the gold may be put on paper or kept in shells; whence its name. When it is used, it is diluted with gum-water or soap-suds.

The German gold-powder, prepared from the Dutch gold leaf in the same manner, is generally used; and when it is well scoured with varnish, answers the end in japanners gilding as well as the genuine.

Gold Size for burnished gilding is prepared of one pound and a half of tobacco-pipe clay, half an ounce of red chalk, a quarter of an ounce of black lead, forty drops of sweet oil, and three drams of pure tallow; grind the clay, chalk, and black lead, separately, very fine in water; then mix them together, add the oil and tallow, and grind the mixture to a due consistence.

Gold size of japanners may be made by pulverizing gum animi and asphaltum, of each one ounce; red lead, litharge of gold, and umber, of each one ounce and a half, mixing them with a pound of linseed oil, and boiling them, observing to stir them till the whole be incorporated, and appears on growing cold of the consistence of tar; strain the mixture through a flannel, and keep it stopped up in a bottle for use. When it is used, it must be ground with as much vermilion as will give it an opaque body, and diluted with oil of turpentine, so that it may be worked freely with the pencil. A simple preparation consists of one pound of linseed oil and four ounces of gum animi; powder the gum, and mix it gradually with the boiling oil; let it continue to boil till it becomes of the consistence of tar; strain it through a coarse cloth; keep and use it as the other.

Gold-Finch. See Fringilla, Ornithology Index.

Gold Fish. See Cyprinus, Ichthyology Index.

Golden, something that has a relation to gold or consists of gold.

Golden-Calf, was a figure of a calf, which the Israelites cast in that metal, and set up in the wilderness to worship during Moses's absence in the mount; and which that legislator at his return burnt, grinded to powder, and mixed with the water the people were to drink off; as related in Exod. xxxii. The commentators have been divided on this article; the pulverizing of gold, and rendering it potable, is a very difficult operation in chemistry. Many, therefore, suppose it done by a miracle; and the rest, who allow of nothing supernatural in it, advance nothing but conjectures as to the manner of the process. Moses could not have done it by simple calcination, nor amalgamation, nor antimony, nor calcination; nor is there one of those operations that quadrates with the text.

M. Stahl has endeavoured to remove this difficulty. The method Moses made use of, according to this author, was by dissolving the metal with hepar sulphuris only, instead of the vegetable alkali, he made use of the Egyptian natron, which is common enough throughout the east.

Golden-Fleece, in the ancient mythology, was the skin or fleece of the ram upon which Phryxus and Hella are supposed to have swam over the sea to Colchis; and which being sacrificed to Jupiter, was hung upon a tree in the grove of Mars, guarded by two brazen-hoofed bulls, and a monstrous dragon that never slept; but was taken and carried off by Jason and the Argonauts.

Many authors have endeavoured to show that this fable is an allegorical representation of some real history, particularly of the philosophers stone. Others have explained it by the profit of the wool trade to Colchis, or the gold which they commonly gathered there with fleeces in the rivers. See Argonauts.

Order of the Golden Fleece, is a military order instituted by Philip the Good, duke of Burgundy, in 1429. It took its denomination from a representation of the golden fleece, borne by the knights on their collars, which consisted of flints and steels. The king of Spain is now grand-master of the order, in quality of duke of Burgundy: the number of knights is fixed to thirty-one.

It is usually said to have been instituted on occasion of an immense profit which that prince made by wool; though others will have a chemical mystery couched under it, as under that famous one of the ancients, which the adepts contend to be no other than the secret of the elixir, wrote on the fleece of a sheep.

Oliver de la Marche writes, that he had suggested to Philip I. archduke of Austria, that the order was instituted by his grandfather Philip the Good duke of Burgundy, with a view to that of Jason; and that John Germain bishop of Chalons, chancellor of the order, upon this occasion made him change his opinion, and assured the young prince that the order had been instituted with a view to the fleece of Gideon, William bishop of Tournay, chancellor likewise of the order, pretends that the duke of Burgundy had in view both the golden fleece of Jason and Jacob's fleece; i.e. the speckled sheep belonging to this patriarch, according to agreement made with his father-in-law Laban. Which sentiment gave birth to a great work of this prelate in two parts: in the first, under the symbol of the fleece of Jason, is represented the virtue of magnanimity, which a knight ought to possess; and under the symbol of the fleece of Jacob he represents the virtue of justice. Paradin is of the same mind; and tells us, that the duke designed to insinuate that the fabulous conquest which Jason is said to have made of the golden fleece in Colchis, was nothing else but the conquest of virtue, which gains a victory over those horrible monsters vice and our evil inclinations.