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. CCXXVIII. To make a Liquid for Moistning and Grinding the Powder withal, &c.

TIS impossible to give all the Preparations for the Lapis-Lazuli in one Chapter, they are too ••edious for that purpose, and can't be so confined without Confusion; this we intimate to justifie our ••ivision thereof into several Chapters.

For moistening and grinding your aforesaid Pow∣••er of the Stone, take a Pound and half of running ••ater, and put this into a new Earthen-Pot, add 〈◊〉〈◊〉 it an Egg-shell full of raw Honey, boil it until it ••ave no more Scum; take the Pot off, and keep this ••ydromel, or Liquid for use in Bottles, as we shall ••ve occasion for hereafter.

This done, take four Scruples of the best Gum∣••ragon, grind it on your Marble, with some of the ••ydromel, and then put it into a Glass; add thereto 〈◊〉〈◊〉 much Hydromel as you find convenient, to bring it 〈◊〉〈◊〉 a Violet-colour, so cover it, and preserve it for 〈◊〉〈◊〉: This Liquid is good for your Powder of Lapis-Lazuli;

if the Colour be too Violet, add the less hereof, if otherwise the more, as your Judgment, or Experience shall direct.

Put half a Pound of Powder at a time into a small Porphyry, or Marble Vessel, the larger the Mortar the worse, for you'll lose more, and be longer a grinding; pour leisurely by little and little thereon, some of your Violet Liquid, grind these together for a full Hour, still wetting it; you may use three or four Ounces of Liquid to the half Pound of Pow∣der, and you'll have it very good; you must take care of grinding it too long, for then it will lose its colour.

When 'tis thus ground, dry it on a Marble or Flat-stone, where the Sun does not come at all, co∣ver it well to preserve it from Dust; when 'tis dry, 'twill Powder easily between your Fingers, if it be rightly done; if so, let it alone on the Marble, but if it be clammy, or stick, take it off, for it has still some unctuosity of the Honey in it, which must be cleansed away by a Cement.

Your Lapis being thus dry, wash it well before you put it to the Cement, for which you must use a glazed Earthen Bason round above like a Bar∣ber's, and well glazed within, put your Lapis there∣in, and pour thereon some of the mild Lixivium in the next Chapter, as much as will rise above the Surface four Inches; wash the Lapis very well with your Hands, and then let it settle, and 'twill preci∣pitate: The Liquid being clear'd again, decant it into a large Copper, or Earthen-Vessel, then let the Lapis dry in a Shade in the same Vessel 'twas washed in, and spread it afterwards on the flat Marble, or Porphyry, and there let it lie until quite dry: Thus 'tis prepared for mixing with the Cement, of which we will give the Preparation in Chap. 231. and those next succeeding it.