GOLD.— Gilding.

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The packet is now opened, and the leaves of gold,being spread on a cushion, are again subdivided intofours, by means of two pieces of cane cut to verysharp edges, and fixed down crosswise on a board.This rectangular cross being applied on each leaf,with slight pressure, divides it into four equal por-tions, and is preferable to a steel knife, to which thegold, in its now attenuated state, would be liable toadhere. The 2400 squares thus formed are sepa-rated into three parcels of 800 each, and the squaresof each parcel are placed in another shoder or mouldcomposed of gold-beater’s skin, inclosed in the parch-ment cases, and beaten as before. This is the lastand most difficult stage of the process. The mouldmust be made of the finest skins, about 5 inchessquare; and on the fineness of the skin, and thejudgment and dexterity of the workman, the per-fection and thinness of the leaf of gold depend. A7 lb. hammer is now employed, and after two hours’beating the gold is reduced to the of an

inch in thickness, and begins to transmit the rays oflight. When the gold is quite pure, or but slightlyalloyed, it transmits the green rays, but in goldhighly alloyed with silver, the pale violet rays aretransmitted. After being hammered another twohours, the leaves acquire the tenuity of ordinaryleaf-gold, and average from 3 to 3^ inches square.The three beatings and two quarterings expand thegold to an area about 190 times greater than ithad in the form of a riband, and 100 square feetof it weigh only an ounce. It is true that anounce might be hammered to cover an area of 100feet; but in this case the gold would be too muchattenuated for common use, and the extra labourand care required would not be compensated byany corresponding advantage. After the last beat-ing, the leaves are lifted one by one with a delicatepair of long pincers, made of white wood, and arespread out on a leathern cushion by blowing themflat with the mouth. Broken or blemished leavesare rejected; the good ones have the ragged edgescut off with a square frame of sharp cane, whichreduces them all to a uniform size, and are thenplaced in a book, the leaves of which have beenrubbed with red ochre, to prevent the gold fromadhering. Each book is capable of holding 25leaves, and in this form the gold-leaf is sold forgilding picture - frames and books, and for thevarious ornamental purposes to which it is appliedin the arts.

In this country the art of gold-beating was long .,confined to London , where it has been carried tohigher perfection than in any other part of theworld; but of late years efforts have been madeon the Continent, with the aid of English gold-beaters’ skin, to emulate the beauty and finenessof the English product; and the art is now prac-tised successfully in different large cities in Eng-land, as well as in Scotland and Ireland . At theGreat Exhibition of 1851 machines were exhibitedfor superseding the arduous operation of beatinggold by band; but the success of these -was verypartial, and no material change has taken place inVOL. II.

the process as above described since that date, thegold-leaf at the present day being made almostentirely by hand.

Gilding. — This consists in applying a superficialcovering of gold to articles of wood, metal, &c.,chiefly for the purpose of ornament, but sometimesalso for utility, as when it is essential that the articleshould be preserved from tarnishing. Gilding ispractised by various methods, the principal of whichmay be classified under the following heads, namely:—1. Mechanical gilding with gold-leaf for wood,leather, &c.; 2. Chemical gilding, properly so called,which is practised on metallic substances, and in-cludes wash-gilding, or gilding by amalgamation ;gilding by immersion and various other processes; 3.Electro-gilding, or the deposition of gold by theelectrolysis of its solution.

1. Mechanical Gilding , or gilding on wood witligold-leaf, is of two kinds, distinguished as burnish-gilding and oil-gilding.

The process of burnish-gilding may be exemplifiedas applied to a picture - frame. In this case thegilder receives from the joiner a bevelled moulding12 feet in length, which he prepares for gilding by anumber of preliminary coatings of size, mixed withdifferent substances. He first gives it a priming ofhot size, and whiting, this mixture being laid on in asomewhat fluid state, and therefore termed thin-white. It is prepared by melting the size in anearthen pipkin, and stirring in the whiting in finepowder by small portions at a time. When thisfirst coating is dry the surface is examined, and allholes and irregularities axe filled up with a mixtureof whiting and size, made of the consistence of putty,but containing no oil. The moulding then receives4 or 5 layers of a mixture similar to the first, butof greater consistence, and therefore termed thick-white, allowing time between each layer for the workto dry. While each of these last coatings is stillwet, the fine work of the moulding is kept open bymeans of chisels, gouges, and other tools for thepurpose. Sometimes two thick-whites are laid onsuccessively, without allowing the first to dry, andare then worked into the shape of the moulding byhard stones of the required form. The whiting isnow from one-sixteenth to one-twelfth of an inch inthickness, and is trimmed to remove unevennessat the edges, after which the entire surface of themoulding is smoothed with pumice-stone, formed tofit exactly into the various parts, which are slightlywetted to promote the smoothing effect. A finalpolish is given to the whiting by glass-paper.

The moulding is now ready to receive the gold-size, which consists of pipe-clay, red chalk, blacklead, suet, and bullock’s blood. Of this mixture,which is sold to the gilder in a tenacious mass,rather softer than butter, a portion is melted withcommon clear thin size; and while still slightlywarm is laid on with a brush, and with great nicetyof hand.

The next operation is the gilding, for whichseveral tools are required—a leathern cushion toreceive the gold-leaf, a knife for cutting it into14