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. CCXXVII. How to make Ultra-marine, of Lapis-Lazuli.

THIS Rich and Noble Blue drawn from an A∣zure-Stone, commonly called Lapis-Lazuli; 'tis 〈◊〉〈◊〉 Opaque-Stone, of a fine Sky-colour, or Turkish-••lue, or like the Blue-Flowers which grow in Corn∣••••lds, 'tis embellished with small Streaks and Spar∣••es of Gold-colour; the best is that which is fixt, ••••at is, can endure Fire without altering colour, ••nd comes from Persia and the greater I dies; it is ••••so supposed it may be had from Africk, as well as ••sia, but questionless, there does not come that ••enty thence as from the other places.

There is also found in Germany, and Hungary, a kind of Lapis-Lazuli, but not fixt, tho as hard as the former; they call it Lesurstein, and its colour Asurbleau; but its colour changes in some time, and becomes Greenish; 'tis used however by Painters.

The sixt Lapis-Lazuli has great Vertues in Phy∣sick, and much more excellent ones than are ascri∣bed to it by most Persons, who indeed are ignorant of them, and so are many of the Learned too; but we'll pass these over here, and reserve them for a∣nother time in some other place. This hint however may serve to advise the Curious to pry into the Mat∣ter, and possibly discover its further Excellencies and Vertue.

'Tis called Vltra-marine, because brought to us from beyond Sea; or rather, because the first tha•• ever came into France, was out of the Kingdom o•• Cyprus, a Maritime Country; for so are those Coun∣tries called, which border on the Sea-Coasts.

Before you proceed to Extract your Vltra-marine take some account of the Manner, to know whethe•• the Stone be good, for unless it is singularly so, you'•••• lose your labour: Put pieces thereof on live Coal•• and blow them continually for an Hour, if they r••¦tain their first hardness and colour afterwards, yo•• may conclude them good, but if they crumble b••¦tween your Fingers, they are naught: It may 〈◊〉〈◊〉 tried otherwise in an Iron-Ladle put into a Furna•••• with some of the Stone to heat, and so quench it•• strong Vinegar; if the Colour remains still uncha••••ged and splendid, you may assure your self '•• good.

When you have made this Tryal, calcine 〈◊〉〈◊〉 which to do the easier, break the stone to piec•• as small Hazel-Nuts, wash them afterwards in wa•••• Water, and set them in a Crucible, on a Win•• Furnace, or into an Iron-Ladle to re-unite; th••

cast them into a glazed Earthen Vessel of distilled Vinegar to quench them in, do thus seven times, to prepare them by Calcination for Powdering, and to prevent their sticking to the Mortar.

Thus calcined, dry 'em well, and so powder them in a Stone-Mortar well cover'd, and accordingly searce it with the same caution, as Perfumers do their most delicate and finest Powders, lest the best should go off, and dispel its self in the Air: And thus pre∣serve this precious Powder with all imaginable care.