being exhausted. In practice the average degree of tenuity to which the gold is reduced is not nearly so great as the example above quoted. A “book of gold” containing 25 leaves measuring each 31} inches, equal to an area of 264
square inches, generally weighs from 4 to 5 grains.The gold used by the goldbeater is variously alloyed, according to the variety of colour required. Fine gold is commonly supposed to be incapable of being reduced to thin leaves. This, however, is not the case, although its use for ordinary purposes is undesirable on account of its greater cost. It also adheres on one part of a leaf touching another, thus causing a waste of labour by the leaves being spoiled; but for work exposed to the weather it is much preferable, as it is more durable, and does not tarnish or change colour. The external gilding on many public build- ings, such, e._r/., as the Albert Memorial in Hyde Park, London, is done with pure gold. The following is a list of the principal classes of leaf recognized and ordinarily prepared by British beaters, with the proportions of alloy per ounce they contain.
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=*'=""° 0‘ 1”‘ ’).’§‘r’‘’a‘’('§i.'1‘.’‘' §i°s‘i?5t-'9." l(if08(?}lit;)ltl')Il‘i Grains. Grains Grains. Red .............................. .. -156460 20-24 Pale red ......................... .. 46-1 16 Extra deep ..................... .. 456 12 12 Deep ............................. .. 4-14 24 1'2 Citron ........... . .............. .. -140 30 10 Yellow........ ................... .. 408 72 Pale yellow ..................... .. 384 96 Lemon ........................... .. 360 1:20 Green or pale ................... .. 312 1 (18 White .......................... .. ‘.240 240
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The fine membrane called goldbeaters’ skin, used for
making up the shoder and mould, is the outer coat of the
caecum or blind gut of the ox. It is stripped off in lengths
about 25 or 30 inches, and freed from fat by dipping in a
potash solution and scraping with a blunt knife. It is
afterwards stretched on a frame ; two membranes are glued
together, treated with a solution of aromatic substances or
camphor in isinglass, and subsequently coated with white
of egg. Finally they are cut into squares of 5 or 5% inches ;
and to make up a mould of 950 pieces the gut of about 380
oxen is required, about skins being got from each animal.
A skin will endure about 200 beatings in the mould, after
which it is fit for use in the shoder alone.}}
The dryness of the cutch, shoder, and mould is a matter of extreme delicacy. They require to be hot-pressed every time they are used, although they may be used daily, to remove the moisture which they acquire from the atmo- sphere, except in extremely frosty weather, when they acquire so little moisture that then a difiiculty arises from their over-dryness, whereby the brilliancy of the gold is diminished, and it spreads very slowly under the hammer. On the contrary, if the cutch or shoder be damp, the gold will become that which is technically termed hollow or sieve-like; that is, it is pierced with innumerable micro- scopical holes; and in the moulds in its more attenuated state it will become reduced to a pulverulent state. This condition is more readily produced in alloyed golds than in fine gold. It is necessary that each skin of the mould should be rubbed over with calcined gypsum (the fibrinated variety) each time the mould may be used, in order to pre- vent the adhesion of the gold to the surface of the skin in beating. Dentist gold is gold leaf carried no further than the cutch stage, and should be perfectly pure gold.
By the above process also silver is beaten, but not so . thin, the inferior value of the metal not rendering it com- mercially desirable to bestow so much labour upon it. Copper, tin, zinc, palladium, lead, cadmium, platinum, and aluminium can be beaten into thin leaves, but not to the same extent as gold or silver.
general account may be given of the use of the precious metals in textiles of all descriptions into which they enter. That these metals were used largely in the sumptuous textiles of the earliest periods of civilization there is abund- ant testimony; and to this day, in the Oriental centres whence a knowledge and the use of fabrics inwoven, orna- mented, and embroidered with gold and silver first spread, the passion for such brilliant and costly textiles is still most strongly and generally prevalent. The earliest mention of the use of gold in a woven fabric occurs in the description of the ephod made for Aaron (Exod. xxxix. 2, 3)—“ And he made the ephod of gold, blue, and purple, and scarlet, and fine twined linen. And they did beat the gold into thin plates, and cut it into wires (strips), to work it in the blue, and in the purple, a11d in the scarlet, and in the fine linen. with cunning work.” In both the Iliad and the 0:./yssey distinct allusion is frequently made to inwoven and embroidered golden textiles. Many circumstances point to the conclusion that the art of weaving and embroidering with gold and silver originated in India, where it is still principally prosecuted, and that from one great city to another the practice travelled westward,—Babylon, Tarsus,
Baghdad, Damascus, the islands of Cyprus‘ and Sicily, Con-.
