Modern curiosities of art & nature extracted out of the cabinets of the most eminent personages of the French court : together with the choicest secrets in mechanicks, communicated by the most approved artists of France / composed and experimented by the Sieur Lemery, apothecary to the French king ; made English from the original French.

CHAP. XXII.

To discover Gold under a black Colour with an Ivory Point, a great Secret, and as beautiful as those things gilt in China.

HAving well burnisht your Gold without fault, grind Lamb-black with Linseed Oyl or Oyl of Nuts, adding as much Um∣ber as Black to make it dry; then as much Spike-Oyl as Linseed Oyl; make tryal with one Leaf of Gold burnisht; lay the Black upon the Gold very smooth and even, then dry about a day, more or less accord∣ing to the time; if dry enough, 'twill not stick to your Fingers; then take a Point of Ivory or Stags-Horn well sharpned, rub it on a piece of Glass to take off the ruffness, that it scratch not the Gold or the White; then draw what you please with the Point, discovering the Gold; if it appear bright and shining, and that the Black be not une∣ven and slovenly about the edges of the Stroaks you have made, then is your Black in good temper, but if in discovering the Gold it seem tarnish't, your Black is not dry enough; if the Black be troublesome to get off, and cannot be easily done with an unslit Pen, then mix Spike-Oyl till it comes to

work easily, clean and bright; then may you easily draw the finest hair Stroaks: your Black thus made, cover your burnish't Gold all over with a soft Pencil, then with the Feather of a Turky Cocks Tail, paste over the Black as even and smooth as you can, free from all manner of Dust or Filth; be∣ing dry, and having made your Draught or Figure as large as the Work, follow the Tract of the Line with the Point, and dis∣cover or lay open the Gold.

If you would have the Figures of Birds or little Beasts, or whatsoever else, find out the strong Lights of them, discover them by hatching with a Pen, or the point of a Pin, if not too sharp, but if by the Stroaks ap∣proaching too near each other, you make a Fault, you may mend it by laying on a lit∣tle Black, letting it dry; if the way of making great Lights be not profitable, or that Shadows are more easie and pleasing to you, discover the Gold with a point of soft Wood, that it may not scratch the Gold, which you must discover or lay open to the bigness of your whole Figure, shadowing the proper places, as the Nose, Eyes, Hair, &c. leaving it to dry; then hatch it with a point according to the Judgment of him that draws it; to know when 'tis dry e∣nough to hatch, always at the same time you cover your Work, cover a little waste piece for tryals, to prevent the spoiling your

Work; being finished, leave it three or four days to dry, and varnish it with drying Varnish twice, if you see cause; when you lay on the Black, do but one piece at a time, because some, by being too dry, will be troublesome to discover the Gold; take care also that in the first laying on of the Varnish, that you spread it gently, for fear of defacing.

For the same after a more easie manner.

Your Work being covered with burnisht Gold or Silver (it matters not which) mix and grind Lamp-black and Umber together very well with Water, taking care you put not so much Umber as to destroy the Black; then add some of the Yolk of an Egg, which grind with it, and lay it on your Work with a soft Pencil or Brush very smooth, when dry (if you find cause) give a second laying of the same Black, and with an Ivory Point very smooth, discover your Work; if the Black come not easily off, then there was too little of the Yolk; if the Stroaks be too broad and ragged, then there was too much Yolk of Egg; this way of discovering the Gold, is more shining than the other, but be sure to be careful that in varnishing, you pull not off the Black, nor cause it to fully, to that end, be sure to work with a soft Pen∣cil and smooth Stroak; you need not much

fear the laying on the Varnish the second time, provided it be not too thick, and that it be Oyl of Spike Varnish.

To do the same another way.

Having laid your Black on the burnisht Gold, as aforesaid, mix equal parts of Lin∣seed Oyl, and Oyl of Spike, which lay lightly on with a large Pencil, let it dry four or five days, more or less, according as you find the Gold more or less easie to ap∣pear bright and shining; by this way you may allow almost what time you will, always remembring to make a tryal before you fall to work; for Blew, take Azure; for Red, fine Lake; for Green, Verdigreece; and so in all other Colours, being mixt and ground with the Yolk of an Egg, as before directed.