The art of glass shewing how to make all sorts of glass, crystal and enamel : likewise the making of pearls, precious stones, china and looking-glasses : to which is added, the method of painting on glass and enameling : also how to extract the colours from minerals, metals, herbs and flowers ... : illustrated with proper sculptures / written originally in French, by Mr. H. Blancourt, and now first translated into English ; with an appendix, containing exact instructions for making glass-eyes of all colours.

CHAP. LIV. The way to make Aqua Regalis for the solution of Gold and other Metals, except Silver.

AQua Regalis, is nothing but a common Aqua∣Fortis, wherein you dissolve ¼ of its weight of Sal-Armoniac. But to have a good and strong Aqua-Regalis you must take one pound of Aqua-Fortis prepared as in Chap. 52. put it in a Glass Matrass, and add to it only 2 Ounces of Sal Armoniac, then put the Matrass into a warm Bath or Pan, of warm Water, and stir it often, that the Sal armo∣niac may be well dissolved in the Aqua-Fortis, which

will be tinged of a yellow Colour. Then you must add as much Sal-Armoniac to it as the Aqua∣Fortis can dissolve, then let it settle a little; and the Sal-Armoniac will leave at the bottom all its Terrestreity. After that decant it gently off into another Vessel, so that you don't trouble the settling at bottom, or rather filter it through whited-brown Paper. This Water will dissolve Gold and other Metals, far better than the com∣mon Aqua Regalis, except Silver, which it toucheth not at all, for reasons which Chymists are ac∣quainted with.