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tili their colouring matter is transferred into the liquor:on boiling the strained liquor, the colouring matter is saidto be thrown up to the surface in form of scum, which isafterwards exsiccated by itself, and formed into masses,which, as brought to us, are moderately hard and dry, ofa brown colour on the outside, and a dull red within. Boththese substances dissolve very readily in the spirit: the gam-boge communicates a high yellow colour, and the annottoa deep reddish yellow. The solution of the gamboge ismixed with about half its quantity of that of the annotto,and trial made of the mixture on some silver leaf: if thecolour inclines too much to the yellow or the red, moreof the one or the other liquor is added, till the true goldencolour is obtained. There are sundry other materials, froma due mixture of which a like colour may be produced,as turmeric, saffron, dragons-blood, &c.

The silver leaf being fixed on the subject, in the samemanner as gold leaf, by the interposition of proper gluti-nous matters ■, the varnish is spread upon the piece with abrush or pencil. The first coat being dry, the piece isagain and again washed over with the varnish till the colourappears sufficiently deep.

What is called gilt leather, and many picture frames,have no other than this counterfeit gilding. Waffiingthem with a little rectified spirit of wine affords a proof ofthis; the spirit dissolving the varnish, and leaving the silverleaf of its own whiteness.

For plain frames, thick tin foil may be used instead ofsilver. The tin leaf, fixed on the piece with glue, is to beburnished, then polished with emery and a fine linen cloth,and afterwards with putty applied in the fame manner :being then lackered over with the varnish five or six times,it looks very nearly like burnished gold.

The fame varniffi, made with a less proportion of thecolouring materials, is applied also on works of brass; both

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