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.

OF THE ART OF GLASS. (Book 3)

BOOK III. (Book 3)

CHAP. LXI. The Way of making Glass of the colour of Gold Yellow, of Granat, Amethist, Saphir, Velvet Black, Milk White, Marble, Peach Flower, and deep Red: Also to make Fritt with Natural Crystal, to colour Glass of a Pearl Colour, Viper, Ruby, Topaz, Opal, Sun-flower and others, with several other particulars in this Art.

THERE are several Ways of giving Glass the Colour of Gold, of Amethist, of Sa∣phir and others; which are not unknown to the Curious in this Art; and as there is generally some one way more particular and finer than the rest, several may be ignorant of that; for that rea∣son this Third Book is destin'd to that end, viz. to

shew the best, and also to make Fritt of Natural (or Rock) Crystal, the way and Process whereof we will lay down so distinctly, that it shall be impossible for any one to miss his aim in doing it, that observes these Rules: To that end we caution those who em∣ploy themselves in making them, that they must be very punctual in the Dose, Time, and Circumstan∣ces, and Materials: For if you err in any one, the whole will be spoil'd and come to nothing, for you will have quite different Colours from what you pro∣posed to your self. We will endeavour to make our Descriptions in the following Chapters, so clear and plain, that we hope they will prove to the Reader's Satisfaction.

CHAP. LXII. To make a Gold-Yellow in Glass.

GOld-colour being one of the most noble and fi∣nest we can make, by reason of its imitating the most perfect Metal in Nature, as we have said in Chap. 8. must be made with the purest Materials, and great precaution.

Take two parts of Crystal Fritt, made with Tar∣so, and not with Sand, which is not so good; and one part of Fritt composed of two thirds of Tarso, and one third of fine Salt of Polverine, prepared as in Chap. 7, pound and mix them well, and to each hundred Pound of this Composition, add one Pound of Tartar purified, pounded and searced fine; and one Pound of Manganese of Piedmont, prepared as in Chap. 18, mixing well these Powders with the two Fritts, because you must not cast them on the melted Glass as in other Colours: Then put the whole little by little into a Pot, and put them into a Furnace,

wherein let them stand at an ordinary Fire four Days, for fear the Glass rising, should run over. When that Matter is well purified, you may use it for making Vessels, and what other Works you please, which will be of a fair colour. If you would have the Co∣lour yet clearer, you must add more Powder, and you will have a very fine Golden-colour. If you would have it yet finer, take fine Crystal Fritt made of Polverine of Rochetta, and the Golden-colour will be yet more fair.

CHAP. LXIII. Granat-Colour in Glass.

THE beauty of this Colour is to express the Yel∣lowish-red of Fire, when it is exposed to the Sun: We will treat more largely of it in the fifth Book, in shewing the way to counterfeit this Stone, as also several others.

To give Granat-colour to Glass: Take of Crystal Frit, of Fritt of Rochetta, each an equal quantity, mix them well, and to an hundred Pound of these Materials, add one Pound of Manganese of Piedmont, prepared as in Chap. 18, one Ounce of Zaffer, pre∣pared as in Chap. 17, mix them well with the Fritts, then put them little by little into an Earthen Pot made red-hot in the Furnace, because the Glass is apt to rise and run over. After four Days the Glass be∣ing well tinged and purified, you may work it; you may encrease or diminish the Colour as much as you please, that depends on the Discretion of the Work∣man who puts in the Powders, which ought to be orderly put in, that the Matter be not spoiled.

CHAP. LXIV. To make an Amethist-Colour in Glass.

AMethist being of a Violet Colour, proceeding from Red and Blue, must be well imitated to look beautiful. For this Colour, take Crystal Fritt well made, with Tarso and not Sand, this Colour re∣quiring no other; to which add to each Pound one Ounce of the following Powder, which mix well to∣gether before they be put into the Pot. After that you must set the Pot to the Fire in the Furnace little by little, otherwise the violence of the Powder would cause it to break. When this Glass has been well purified for the space of four Days, and it has the colour of Amethist, you may work it. This Colour may be augmented or diminished by means of the Fritt, or Powder, according to the Discretion of the Workman.

This is the Powder which produces the Amethist Colour in Glass. Take one Pound of Manganese of Piedmont, prepared as in Chap. 18, and an Ounce and half of Zaffer, prepared as in Chap. 17; mix them well together, and put the Dose we have shewn to each Pound of Fritt, to have a true Ame∣thist-Colour.

Porta in his sixth Book, Chap. 5. only allows one Drachm of Manganese to each Pound of Metal, to make the Glass of an Amethist Colour; but that Dose is too weak, and you must follow that we have shewn.

CHAP. LXV. To make Glass of a Saphir-Colour.

TO imitate the Colour of Saphir in Glass, which is of a clear and transparent Blue; you must put to each hundred Pound of Fritt of Rochetta, one Pound of Zaffer prepared, with an Ounce of Manga∣nese of Piedmont, also prepared as we have shewn. Well mix these Powders with the Fritt, then put the whole into a Pot in a Furnace, letting the Glass be well melted and purified: For the longer it remains on the Fire it becomes so much the siner, if you take care to take it out from time to time. Then mix it very well, and make an Essay of the Colour, and if it be not full enough, augment or diminish it as much as you think fit; then the Glass may be wrought, and you will have a Saphir of the Colour of the Dou∣ble Violet of Constantinople, which the small Dose of Manganese produces.

CHAP. LXVI. Another way of giving Glass a finer Saphir-Colour.

GLASS will have a far fairer Saphir-Colour, if in room of Fritt of Rochetta, you take good Cry∣stal Fritt, and add to it the same Dose of Powder, as in the preceding Chapter. Of this Glass thus tinged you may make what Works you please. You must not put the Powder of Manganese and Zaffer on the melted Glass, but mix it with the Fritt as we have noted: For the Colour the melted Glass takes, is not so fine as when the Materials are first mixed.

CHAP. LXVII. To give Glass a Velvet Black.

ALTHO' this Black Colour look mournful, yet it is not without its Beauty: To make it, take pieces of Glass of several Colours, to which add a little less than half the quantity of Manganese as Zaf∣fer, and put the whole into a Pot in the Furnace. This Glass being well purify'd may be wrought, and it will give a Black like Velvet, fit for many things.

CHAP. LXVIII. Another Way of giving Glass a much fairer Velvet Black.

ANOTHER Way of giving a Black Velvet Co∣lour to Glass, much fairer than the former, is to take twenty Pound of Crystal Fritt in Powder, with four Pound of Calx of Lead and Tin, of each an equal quantity; mix the whole well together, and put them into a Pot heated in the Furnace; and when this Glass is well melted and purified, you must cast in three Ounces of Steel calcined and powder'd, and three Ounces of Scales of Iron from the Smiths Forge, powder'd and mixed with the Steel; mix the whole well as you cast them in, that the Glass may not rise, and the better to incorporate them. Then let all rest twelve Hours, during which time, stir them sometimes; then you may work it: And you will have a Velvet Black Colour very fair, wherewith you may work as you please.

CHAP. LXIX. Another Velvet Black fairer than the precedent.

THIS last Way of making a Black, surpasses in Beauty the preceding. Take one hundred Pound of Rochetta Fritt, two Pound of Tartar, six Ounces of Manganese prepared, reduce all to Pow∣der, mix them together, put them into a Pot, which you must put into the Furnace leisurely, that the Matter don't rise too much. Then let it melt and purifie during the space of four Days or thereabouts; mix the Materials well, cast them into Water the better to purifie, and then melt them again; and you'll have a Black of an extraordinary Beauty, which may be wrought as you please.

CHAP. LXX. To make a Milk White Colour in Glass.

THE Milk White to be done well, requires no less exactness than the Blue. To succeed in it, take twelve Pound of good Crystal Fritt, two Pound of Calx of Lead and Tin, one of each, and half an Ounce of Manganese of Piedmont prepared, as we have shewn: The whole pulverized and mixed toge∣ther, and put them into a Pot heated in the Furnace, where let them stand twelve Hours, then mix the whole well, and make an Essay of it. If the Colour don't please you, add to it some Calx of the two Me∣tals before mentioned, which incorporate with the Glass, well mixing it. Eight Hours after the Glass will be fit to work, and white as Milk.

CHAP. LXXI. Another Fairer and Whiter Colour.

THIS second way of giving Milk White to Glass, is much better than the precedent, and the Working more exquisite. We only make use of the Calx of Tin, without mixing any Lead; and we put sixty Pound of that Calx, to four hundred Pound of pure Crystal Fritt, with two Pounds and an half of Manganese of Piedmont prepared; the whole being well pulverized and mixed, must be put in a Pot heated in the Furnace, there to purifie during eight Days: Then cast the Matter into the Water the bet∣ter to purifie it, then put it to melt again in the same Pot, after having dry'd it. If it be transpa∣rent, you must add to it fifteen Pound of the same Calx of Tin as before, mixing it well with the melt∣ed Metal, to make it the better incorporate; twen∣ty four Hours afterward, it will be finer and whiter than Snow, and ready to work.

CHAP. LXXII. The Way to give Glass the Colour of Lapis Lazuli.

LAPIS LAZVLI, which is a fine Blue, and full of Veins of Gold, will not be easie to imitate, without a great deal of Care and Industry in its Pre∣paration.

To make this fine Colour, we must make use of the same Matter of the fine White in the preceding Chapter, and when it is in fusion in the Pot, you must add to it little by little the Blue Enamel in Powder, that the Painters make use of, mixing well the whole together each time, and that as often as there is oc∣casion to make this Colour. Then try if it please you, and when it is to your Mind, let it stand two full Hours, then stir it well and make a second Essay of it. If the Colour be perfect, let it stand ten Hours and then mix it again. If it keeps in the same State without changing colour, you may employ it in ma∣king what Vessels you please, which will be of the true colour of Lapis Lazuli. If in working this Glass it chances to rise, you may cast in a little Leaf-Gold, which will make the Glass approach yet nearer to Lapis Lazuli, and which will in a moment stop the rising of the Metal, as Sugar will do in boiling Oyl.

CHAP. LXXIII. The Way to make a Marble-Colour in Glass.

WHITE Marble being very simple, it is easie to imitate, the way of doing it only requires Crystal Fritt, which must be worked as soon as it is melted, before it be purified, for so it will give a very fair Marble Colour.

CHAP. LXXIV. The Way of making a Peach-Colour in Glass.

TO make this Colour, which is a very agreeable one, take Glass prepared, and tinged of a Milk White, whereof we have spoken in the prece∣dent Chapters; and when it is in good fusion, put in some Manganese of Piedmont, prepared as in Chap. 18, and that little by little, stirring the Matter well at each time, till the Colour become as fine and per∣fect as you desire it; but you must work the Glass in time, otherwise the Colour will be lost; and you will have a very fair Peach Colour.

CHAP. LXXV. The Way of tinging Glass of a deep Red.

OPAQUE Colours have a Body, but the Tran∣sparent ones none; wherefore this deep Red must be mixed with Matters that give it one, as we will shew.

You must take twenty Pound of Crystal Fritt, one Pound of pieces of White Glass, and two Pounds of calcined Tin; mix the whole well together, and put it in a Pot in a Furnace that it may purifie. That being well melted, cast in an Ounce of calcin'd Steel well pounded; and an Ounce of Skales of Iron from the Anvil, well pulveriz'd and mixed together, stir∣ring well the Glass with an Iron Stirrer, when you are putting in the Powder, to hinder it from rising too much. You must take care not to put in too

much of the Powder, for that would make the Glass black, whereas it ought to be clear, shining, and of an obscure yellow Colour. Then take about six Drachms of calcined Copper, prepared as in Chap. 32, cast it upon the melted Glass, often mixing it, to three or four times, and the Glass will be as red as Blood. If the Workman like the Colour, he must presently work it, for fear it should become black, and the Colour be lost, wherein you must take great care. If notwithstanding this the Colour comes to be lost, you must add more Scales of Iron in Pow∣der, and it will return. This Work seems somewhat wearisom, but you must not think of that, but pre∣pare and finish the business carefully, otherwise you will not succeed.

CHAP. LXXVI. The Way of Calcining Natural (or Rock) Crystal, to make an Extraordinary Fritt.

ALTHO' we may imitate Natural Crystal by help of Art, and make as fine with the Mate∣rials we have shewn how to prepare; yet the way we are going now to describe, of making a Fritt of Natural Crystal, will make one so extraordinary, that it will surpass in beauty all we have yet shewn the Preparations of.

Make Natural Crystal red hot in a Crucible cover∣ed close, then extinguish it in Water, and reiterate the same eight times. Then dry it well, and grind it on a Porphyry Stone to an impalpable Powder. Of∣ten purifie this Powder of Crystal, after the same way we have shewn to purifie Polverine of Rochetta, in Chap. 7, observing all we have said on that Sub∣ject.

Then mix that Crystalline Matter, with about one third part of Salt extracted from Polverine of Rochetta, prepared as in Chap. 7, make a Fritt of it, then put it into a Pot well heated in the Furnace, and when it is in good fusion add to it a proportionable Dose of prepared Manganese of Chap. 17. After that often cast it into the Water to purifie, as we have noted in ordinary Crystal, and purifie it very well at the Fire before you work it, as we have elsewhere hinted. Then you will have a Crystal more beau∣tiful and shining, than you have otherwise ever seen.

CHAP. LXXVII. To make Pearl Colour in Crystal.

TRUE Pearl Colour is so fine and shining, that it might seem difficult to give it to Crystal; yet it is so easie that Tartar alone does it.

Those who have a mind to perform this Process, must calcine their Tartar till it become White, as we have shewn at the end of Chap. 5, then having well purified the Fritt of the Natural Crystal, where∣of we have spoke in the preceding Chapter, and be∣ing in a good fusion in the Furnace, you must cast into it this white Tartar at several times, mixing the whole well each time, which must be continued to be done till the Glass becomes of a Pearl Colour; for there is no other Rule in this Case than Experience to guide your self by.

When the Colour is come to perfection, and the Workman likes it, he must presently work it, be∣cause it will be soon lost, as Experience testifies; and you may make of it Works of an extraordinary Beauty.

CHAP. LXXVIII. The Way to tinge Natural Crystal of a Viper colour.

THE Green Viper Colour is not disagreeable, but it is very dangerous to make, by reason of the Materials whereof it is composed, if you are not very careful in making it. Take two Ounces of Rock Crystal of a good Water, two Ounces of crude Antimony, and as much Orpiment, with one Ounce of Sal-Armoniack; reduce these three last into Pow∣der: Stratifie with these Powders the Pieces of Crystal, in a good Crucible; cover it with another that is bored through the bottom, lute them well to∣gether, and when the Lute is dry, put them in the middle of the Coals in a Furnace, let them be gently lighted that the Crucible may grow hot by degrees. It will smoak very much when it first grows hot, wherefore this Operation must be made in a large Chimney, that the Smoak may fly away, and you must go out of the Laboratory, because it is very dangerous and may prove Mortal. Let the Fire kin∣dle of it self, and the Crucible grow cold; then take out the Pieces of Crystal which lie on the top of the Crucible, which will have the Colour of Rubies, and be marked with fine Spots; and those which are at the bottom will for the most part have the Colour of Vipers. Separate the other pieces from them, which will be of other Colours, and polish the whole at the Wheel like other Stones, then with Foils you may set them in Gold. These Stones will be of a very agreeable colour. You might tinge a great number together, but that would be more charge∣able.

CHAP. LXXIX. To make in Natural Crystal the Colour of Rubies, Topaz, Opal, Gyrasol and others.

IT seems something strange that Crystals mixed with Matters that tinge it, should in the same Vessel receive so many different Colours. But if you consider that the Spirits of these Matters, have Vir∣tues different from those of their Bodies, you will not so much wonder at such Diversities. The Pieces which lie highest, are the most penetrated by these tinging Spirits which always ascend, and so give them more vivacity and colour; and so to the others in proportion to your Orders.

For this Operation, take two Ounces of Orpiment of a yellow Colour approaching Gold or Saffron, and as much White Arsenick; one Ounce of crude An∣timony, and the same weight of Sal-Armoniac; the whole reduced to Powder and mixed together. With this Powder stratifie pieces of Natural Crystal in a great Crucible, putting the least pieces to the bottom, and the greatest at the top which ought to be fine and without Spots. The Crucible being fill'd with the Powder and Crystal, cover it with another bored at the bottom, lute them well and let the lute dry. This last Crucible must (as we have said) be bored at bottom, that the smoak of the Materials as∣cending through the Hole, may better tinge the Crystals in passing, which it would not do so well if it passed out of the sides. When the Lute is dry, put it in the Furnace, and cover it with Coals up to the middle of the Crucible on the top, then put some live Coals to them, that they may kindle ••y themselves

little by little, they ought to be great Coals, and made of Oak. You must take care of the Smoak, it being very dangerous, as we said before; and order it so that they kindle well, that the Business may suc∣ceed, and that the Fire may go out of it self, taking care that no Air can get in at the Mouths of the Cru∣cibles, for that would make the Crystals break, and then they are good for nothing.

The Crucibles being cold unlute them, and take the Crystals out, the greatest parts of which will be tinged with the colours we have mentioned: Polish the best colour'd at the Wheel, which will also brighten their Colours, and make them look like Oriental Stones, and they'll be fair and hard as they are.

All the Success of this Secret consists in the Orpi∣ment, which must be of the colour of Gold; and if you don't succeed the first time, you must try a se∣cond; and observing well what we have said, you may be assured to succeed.

The End of the Third Book.