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Fire Gilding

This was extensively done before the discovery of the art of workmanship has come down to us from an. cient Rome and Greece, gilded, and probably in the same way as we do it now, under the name of fire-gilding. It requires more gold, the coating being thicker, and is therefore more expensive; but it will last longer, and is the No. 3588) boiling hot, and moved about there- more convenient way for gilding coins and in, when, in from a few seconds to a minute, small articles. Clean the silver piece, by depending on the newness and strength of means of a brush and a little ammonia water, the liquid, the requisite coating of gold will until the surface is evenly bright and shows be deposited on them. By a little practice no tarnish. Take a small piece of gold and the time to withdraw the articles is readily dissolve it in about 4 times its volume of meknown; the duration of the immersion re- tallic mercury, which will in a short time bo quired to produce any given effect gradually accomplished and an amalgam formed. (Sec increases as the liquid weakens by use.

When properly gilded, the articles are withdrawn from the solution of gold, washed in Nos. 3533 and 3534.) Put a little of this ama!gam on a piece of dry cloth, and rub the silver piece with it on all sides; then place it on clean water, and dried; after which they un- a clean stone in a furnace, and heat to the dergo the usual operation of coloring, &c. A beginning of redness. After cooling it must dead appearance is produced by the applica- be cleaned again with a brush and a little tion to the articles of a weak solution of cream of tartar, when it will be found beautinitrate of mercury previously to the immer- fully and lastingly gilded. sion; or the deadening may be given by applying a solution of the nitrate to the gilded surface and then expelling the mercury by heat.

3588. Elkington's Patent Gilding Liquid. Fine gold, 5 ounces (troy); nitromuriatic acid (aqua regia), 52 ounces (avoirdupois); dissolve by heat, and continue the heat until red or yellow vapors cease to be evolved; decant the clear liquid into a suitable vessel; add distilled water, 4 gallons; 3595. To Remove the Gilding from Old China. The following method is recommended for removing the remains of gilding from old china: Take soft water, 8 parts by measure; nitric acid, 8 parts; common salt, 4 parts; sal-ammoniac, 1 part. Let it boil, put the china into it, and rub with a stiff brush. 3596. Wernicke's Method of Gilding Glass. The following are the ingredients required: 1st. Solution of gold. Pure gold, free from silver, is dissolved in aqua regia, the pure bicarbonate of potassa, 20 pounds; and solution evaporated, and the residue taken up boil for 2 hours. The nitro-muriatic acid is with water, so that 120 cubic centimeters made with pure nitric acid (specific gravity (1 gill) contain 1 gramme (15.4 grains) of 1.45) , 21 ounces; pure muriatic acid (specific gold. 2d. Solution of sodic hydrate (which gravity 1.15), 17 ounces; and distilled water, need not be absolutely pure) of 1.06 specific 11 ounces.