GILDING. 



GiLDiXG on Wood. See the three fiift articles in Gild- 

 ing. 



(JiLDiNG on Mcicils ly ihe Fire. There are two ways of 

 jfikliiig by lire ; -viz. that with liquid gold, and that with 

 leaf gold. For the latter, fee Gilding of Metals, fupra. 



The former, technically called " water-gilding,"' is pcr- 



efFcftual iv.cde of gildir, j, as we perceive in the manufaiflure 

 of gilt filver and copper wire. The bar, before it is comn-.it- 

 ted to th.e wire-drawer, is plated with gold, by having fevcral 

 leaves of gold fucceiTively burniflicd dow ii upon it, and be- 

 ing then fubjccted to the llrong comprefTion lliat takes place 

 in wire-drawing, the gold and the other metal become fo 



perfectly united, as to form, in a manner, one fubftance. See formed with gold amalgamated with mercury, in the pro 

 Gold IVlre. 



Some metals, and particularly filver, may be gilt in the 

 following manner : dip pieces of linen in thefolution of gold 

 by aijuaVegia, and then burn them to aflics ; rub thefe adies 

 on the furfacc of the fdver, well cleanfed from any undtuous 

 matter, with a wet linen rag, dipped in fait water, and the 

 particles of gold contained in them will thu? be -■:;)plied to 

 the iilver, and adhere to it, v.ithout the apphcation of heat, 

 or intervention of any other body. Burniih the filver with 

 a blood-ftone, till it acquires the colour of gold. Mod gilt 

 ornaments on fans, fnuft-boxes, and other toys of much flievv 

 and little value, are nothing but filver gilt in this manner. 

 Beclcmann (Hift. of Inventions, vol. i ) fuggells, that this 



portion of about fix or eight parts of mercury to one of 

 gold. 



In order to tliis operation, they heat fome pure quickfil- 

 ver in a clean crucible, and, wlieu it is nearly boiling, put 

 about a fixth of its weight of fine gold in thin plates heated 

 red-hot, and ftir ihem gently about, till the gold be found 

 melted and incorporated into a rnafs with the mercury. It 

 if- then allowed to cool ; and when cold, it is to be put in a 

 piece of foft leather ; and by j;radual prefTure, the fluid part 

 of the amalgam, confifting alinoll wholly of mercury, may- 

 be forced through the pores of the leather, while the gold, 

 combined with about twice its weight of mercury, will re- 

 main behind, forming a yellowifli filvery mafs, of the con- 

 jnethod of gilding, fometimes called dry. and fometimes cold fiftence of foft butter. This, after having been bruifcd in a 

 o-ilding, is a German invention ; and that foreigners, at leatl mortar, or {haken in a ftrong phial with repeated portions of 

 the Englifli, were firft made acquainted with it about the end fait and water, till the water ccafes to be fouled by it, is fit 

 of the I 'jth century ; for Robert Southwell defcribes it in the for ufe, and may be kept for any length of time, without in- 

 Pliil. Tranf. for 1698, and fays, that it was known to very jury, in a corked phial. It is of indifpenfible importance 

 few goldfmiths in Germany. See Gilding cf Melals by that the materials of this amalgam fliould be perfeftly pure; 

 the fire. and therefore, the mercury- employed in the preparation of it 



Gilding on paper, parehmenl, and vellum. Thei-e are va*' fliould be procured from the diftillation of the red precipitate 

 rious methods uled for this purpofe, according to the feveral (nitrous red oxyd of mercury), either alone, or mixed with 

 ends which the gilding is defigned to anfwer. But for the a little charcoal po^vder, 



jnoll part, fize, properly fo called, and gum-water, are ufed 

 as the cements, and the powders are more generally employ- 

 See the three firft articles in GiLD- 



ed than the leaf gold 



The gilding proper to be ufed with water-colours may be 

 either with the leaf-gold or powder ; the leaf-gold may be 

 laid on the defigned ground by means either of gum-water, 

 or ifinglafs fize ; obierving, that the gum-water or fize be 

 of the weaker kind, and laid fparingly on the ground, and 

 that proper time be allowed for it to be dry ; and then the gold 



When filver is the metal to be gilt, it is prepared for the 

 operation by foaking it in warm dilute muriatic acid, fo that 

 the furface may be rendered perfeftly clean ; it is next walh- 

 ed in clean water, which (hould be two or three times chang- 

 ed, in order to free it from the whole of the acid ; and being 

 afterwards dried, and made moderately warm, a little gcjld- 

 amalgam, alto warm, is to be evenly fpread upon the iilver, 

 to which it will immediately adhere. In applying the am.al- 

 gam, the operator ufcs a little knife, or a brufli made of 

 brafs wire, for the purpofe ; and giving the work a gentle 



is applied to it, as in the articles above recited ; and it may heat before the fire, he dabs or fpreads the amalgam with the 



be polifhed, if neceflary, by the dog's tooth, or other kind 

 of burnifher. In gilding larger furfaces, it will be found 

 iifeful to colour the ground with the gall-ftone ; and when 

 colours are to be laid on the gilding, the gall of any beaft 

 brullied over the gold will adapt it for receiving the colours. 

 When the gold powders are ufed along with paintings in 

 water-colours, they are previoufly formed into fliell-gold. 

 The gilding proper for the coloured paper ufed in binding 

 books, and for other fuch purpofes, is performed much in 

 the fame manner : only that the gum-water and fize may be 

 much ftronger, and that they are generally conveyed to the 

 ground by means of a wooden plate or print, or by an en- 

 graved roller, which make an impreflioii of the intended 

 figure or defign. In this kind of gilding, the japanner's gold- 

 fize may be alfo commodioufly employed ; and this iTiould 

 be always ufed when the embofled appearance is wanted in 

 the greateft degree ; and for this purpofe it Ihould be thick- 

 ened with yellow ochre, mixed with as much red-lead as the 

 proper working of the print will admit. Inftead of the ge- 

 nuine leaf-gold, or gold powder, the German powder, form- 

 ed of the leaves called Dutch gold, is commonly ufed in this 

 iind of gilding. The edges of books or paper are gilt in 

 the manner direfted under the article BooK-linJin^ and 

 tjILDING of looks. 



Gilding on Thread and IFire. See CoLo-thread, and 



brufh farther and more evenly upon it. 



Thus far advanced, the metal is fet over the fire, upon a 

 grate, or in a fort of cage, under which is a pan of char- 

 coal, yielding a heat juft luflicient for e\'aporating the mer- 

 cury ; by which means the mercury is raifed in fumes, and 

 leaves the gold alone adhering to the work ; in propor- 

 tion as the mercury, evaporating and flying ofF, difcovers 

 places where gold is wantiiig, they take care to fupply 

 them, by adding new pieces of amalgam with the knife or 

 brufli. 



If a thicker gilding be required than can refult from fo 

 much of the amalgam as is applied at once, the metal, after 

 the firft quantity has left its gold fixed on the furface, has 

 more of the amalgam fpread upon it. After the evapora- 

 tion of the mercury from this, another quantity may be ap- 

 plied in the fame manner. When the mercury- is evaporated, 

 fo that the furface becomes uniformly of a pale yellow colour, 

 the metal is made to undergo other operations, by Avhich its 

 colour and luftie are heightened. For this purpofe, it is firft 

 rubbed with a fcratch brufli, compofed of fine brafs wire, till 

 its furface is made clean and fmooth, but the pale yellow 

 colour ftill remains ; then it is covered over with a compo- 

 fition called gilding wax, and again expofed to the fire till 

 the wax be burnt off" ; and this application is i-epeated till the 

 gold appears of a proper colour. This gilding wax is com- 

 pofed of bees' ivax; mixed with the following fubftanccs ; 



5 ^''^ 



