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 4)

BOOK IV. (Book 4)

CHAP. LXXX. The Way of making Glass of Lead, commonly called Vi∣trum Saturni: To calcine Lead, and extract from it the Colours of Emerald, Topaz, Sea-green or Azure, Granate, Sapphire, Gold, and other Colours.

GLASS of Lead, known to few Artists in this way, because they make no use of it by rea∣son of its brittleness, is beyond doubt, the fairest and noblest Glass of any other. In this Glass you may imitate all the Colours of Oriental precious Stones; and if this Glass were as tough as Crystal, it would far surpass it in beauty. It is true, if you

don't work it with great care, no Pots nor Cruci∣bles will hold it, for it will crack them and run out. I will here give all the Methods of preparing it, and that so distinctly, that the unexperienced may succeed in it. The Business principally consists in knowing well how to calcine the Lead, and re∣calcine it again, which is commonly known, not∣withstanding in the next Chapter we will shew how to do it for the sake of those that do not know it. The better the Lead is calcined, the less apt it is to turn into Lead again, and break the Pots in this Operati∣on. We will also shew, that you must always drop the Glass into Water when it is melted, for the least Lead remaining in it, breaks out the bottoms of the Vessels, and s•• you lose your Matter, which may be avoided by carefully minding what we have said, and which we shall note again in the following Chap∣ters.

It is our Opinion, and that not without reason, that that subtilty whereby the Lead so easily in this case pierces the Pots when it is not wholly calcin'd, comes from a certain unctuous yellow Matter like Oyl, that is seen to swim on the top sometimes in a violent fusion. For we have often observed, That if that unctuous Matter be not taken off as soon as it ap∣pears on the top, it will pierce the Pot, and so all run out among the Coals.

This unctuous Matter has strange and infinite Vir∣tues known to the Adepti, both in curing Diseases, and other Operations. He who knows how to make it Transparent, and give it the Jacynth Colour in E∣zekiel, which is that Electrum spoken of in the first Chapter, may boast he has a Material, from which may be extracted a lac Virginis, in great esteem among the Philosophers. But let this suffice, we are not here to instruct the ignorant in those Arcana, but re∣mit them to the Writings of the Adepti.

Kircher assures us, that if Mercury congealed with the Vapour of Lead, be heated in a Brass-Spoon o∣ver live Coals, it will exhibit a strange variety of Colours, that you cannot imagine the like. And Zibav. speaking of Lead in his seventh Book, C. 20. de Transmut. Metall. That the Melters and Tryers of Metals daily turn Lead into Glass, and that this Glass is Black, Red, Yellow, Green, or otherwise co∣loured, according as the Lead is differently calci∣ned.

CHAP. LXXXI. To Calcine Lead.

LEAD is easie to be calcined, because it is so to melt; for this purpose you may make use of the Furnace described in Chap. 52, or in a Kiln: You must put in a good quantity of Lead at a time; for in two or three Days may be calcined several Hun∣dred Weight. The Fire ought to be hot enough to melt Glass, and not hotter; for if it be hotter it will not calcine the Lead. As soon as the Lead is melted, and it yields on top a yellowish Matter; be∣gin to draw forward the calcined part with an Iron fit for the purpose, always spreading it in the inter∣nal Extremity of the Furnaces or Kilns bottom. This Lead being well calcined for the first time, ought to be put again into the Furnace moderately hot to re∣verberate. You must spread it with the Iron, and stir it continually for several Hours, and at this se∣cond calcination it will become Yellow; then searce it through a fine Sieve, and that which does not go through, must be put with other Lead to calcine a∣fresh; always taking care, that the Furnace have just a moderate heat, and be not too hot.

There are several other ways of calcining Lead which we will not mention here, because this we have shewn is the best and most easie, and will di∣spatch a great quantity in a short time. All the Pot∣ters know how to calcine it, because they make use of it in their Glasing.

CHAP. LXXXII. The Way to make Glass of Lead.

WE have told you the Beauty of this Glass, in Chap. 77, which may be tinged of several Colours, as Black, White, Green, and Red, which are natural to it, the degrees of the Fire only ma∣king it take those different Colours.

This Glass being well made, besides the Beauty it has, which it communicates to Glass, and to Tin∣ctures of precious Stones wherein it is employ'd, it has other great Virtues in Metallick Operations, which are not known to all the World, whereof we could largely treat, if it were not besides our Sub∣ject.

To make Vitrum Saturni: Take fifteen Pound of calcined Lead, as we have shewn in the preceding Chapter, and twelve Pound of Crystal or Rochetta Fritt, according to what colour you would have; mix them well together, and put them in a Pot in the Furnace, where ten Hours after it will be in good fusion; then cast the whole into Water, and take out speedily the remaining Lead at bottom of the Vessel, for fear it should break; then take it out of the Water and dry it, and put it into the same Pot to melt again: Take care not to put in the Grains of Lead (if there by any) which were in the Water, and which will be loosened from the Matter. After

your Matter has been again in fusion six Hours, you may work it.

You may also make a Glass of Lead, by taking three parts of Lead, one of fine Sand, and change them into Glass in the Furnace: As also of three parts of calcined Litharge, and one part of calcin'd Flint, melted and vitrified in the Furnace toge∣ther.

CHAP. LXXXIII. The Way how to Work Glass of Lead.

IT is not enough to shew how to make Glass of Lead, if we don't shew how to work it too. If any one would make Vessels of it for use of any Fi∣gure; he must take a Glass Workman's Iron they use to take the Metal out of the Pots with, and take what quantity of Glass of Lead with it he pleases, when it is in fusion, and let it a little cool, then work it after the manner we have shewn Chap. 3. You must clean well the Marble you make use of, and while the Glass is cooling, you must wet the Marble with cold Water; for otherwise the Glass would scale it, and part of the Marble would stick to it. If the Marble be hard, you have so much the less to fear, for it will not break so easily, nor stick to the Glass.

CHAP. LXXXIV. To make Glass of Lead of a fair Emerald Colour.

THE easiness of tinging Glass of Lead of any colour, is the reason, you may be sure, of gi∣ving it an excellent Emerald-Green, especially be∣cause Green is also Natural to it.

Take twenty Pound of Crystal Fritt powder'd and searced, and sixteen Pound of Galx of Lead also sift∣ed; mix them well together, then put them little by little into a Pot heated in a Furnace, and eight or ten Hours afterwards it will be melted; then cast the melted Matter into Water, and carefully take the re∣maining Lead from it; then put the Matter after it is dried into the same Pot again, and seven or eight Hours after it will be again melted. Reiterate this process of casting the melted Matter into the Water, and separating the Lead that sticks to the Pot, as be∣fore; then this Glass will be cleansed and purified from all the foulness and unctuosity the Calx and Pow∣der would leave in it and be very resplendent. You must put it again in the Pot, where it will melt and purifie in a little time. When it is melted, put to it six Ounces of Scales of Copper thrice calcin'd in Powder, as in Chap. 34, with twenty four Grains of Crocus Martis, made with Vinegar, as in Chap. 25, al∣so in Powder, and mix them together.

This Powder must be cast in at six times, always mixing well the Glass, and taking at each time the interval of saying the Creed: Let it rest one Hour, and then stir it again, and see if the Colour pleases you: If it be as you would have it, let it stand eight Hours, that the whole may well incorporate. Then

stir it well, and let it rest a little, that the Faeces may precipitate to the bottom of the Pot; then it may be wrought, and the colour can scarce be distinguished from true Emerald.

CHAP. LXXXV. Another Way of making Glass of Lead of a fairer Eme∣rald than the former.

FOR this colour, which will be far fairer than the precedent, you must change one Ingredi∣ent of the other Chapter, and instead of Scales of Copper thrice calcined, put the same Dose of Caput Mortuum, of Vitriolum Veneris, prepared as at the end of the seventh Book; then proceed exactly as in the former Chapter, and you'll have a very exquisite Green.

CHAP. LXXXVI. To make a Glass of Lead, of the Colour of Topaz.

TOPAZ is a lighter colour than Emerald, and casts Rays the colour of Gold, wherefore the colour can't be well imitated except this way.

Take fifteen Pound of Crystal Fritt in Powder, and ten Pound of Calx of Lead also in Powder, mix them well, and searce them very fine, then put them in a Pot heated at the Furnace, where leave it eight Hours, that it may be melted. Then cast the Mat∣ter into Water, and take out of the Pot all the Lead (if there be any) that remains. Put the Matter a∣gain into the Pot to be melted, and cast it by inter∣vals

into the Water. Add to that Matter half its weight of Glass tinged of a Golden colour, as in Chap. 62. incorporate and purifie well the whole to∣gether, and you'll have a Glass of the true colour of Oriental Topaz, fit to be wrought.

CHAP. LXXXVII. To make a Sky, or Sea-Green, in Glass of Lead.

WE have shewn several Ways in the first Book to tinge Glass of a Sky-colour, or Sea-Green, which would be needless to repeat here.

That we now shew which is made in Glass of Lead, has no less Beauty. Take sixteen Pound of Crystal Fritt, ten Pound of Calx of Lead, mix them toge∣ther, and put them gently into a Pot heated in the Furnace, where they will be in good fusion in twelve Hours time. Then cast that Matter into Water, as I have shewn before, and take the remaining Lead out of the Pot, and put yout Matter in again to melt. Eight Hours after cast it again into Water, taking the remaining Lead out of the Pot, then it will be well purified. Put it in again to melt in the same Pot, and when it is in good fusion, cast in at four dif∣ferent times, four Ounces of small Copper Leaves, prepared as in Chap. 30, with a quarter of an Ounce of Zaffer, prepared as in Chap. 17. After having mixed these Powders well together, and the Matter at each casting of it in: Two Hours after stir the Matter well in the Pot with an Iron Rod, and make an Essay to see if the Colour be full enough, then let it stand ten Hours to purifie, and to give the Colour time to incorporate with the Glass: Then it may be wrought to the Uses you design it, stirring

it well, and letting it rest a little to settle, before you Work it.

CHAP. LXXXVIII. To make a Granat Colour in Glass of Lead.

THE Vivacity of this Colour appears no less in Glass of Lead than in Crystal, if it be made carefully. To make it, take twenty Pound of Cry∣stal Frit, with sixteen Pound of Calx of Lead; and after having added three Ounces of Manganese of Piedmont to it, and half an Ounce of Zaffer, both prepared as we have shewn; put the whole into a Pot heated in the Furnace: Twelve Hours after, cast that melted Matter into the Water, and take out the Lead that remains behind in the Pot. Then put the Matter again in the same Pot, where it will be purifi∣ed ten Hours after. You must mix it well with the Iron, and let the Faeces precipitate; then see if the Colour pleases you; then work it to what Uses you please, and you'll have a Glass of Lead of a fine Granat-colour.

CHAP. LXXXIX. To make a Sapphire-Colour in Glass of Lead.

THE Beauty of Sapphire is no less imitable in Glass of Lead, than the Colours of other Precious Stones; and its clear Blue Transparent Colour will have as much Splendour. To make it, mix together fifteen Pound of Crystal Frit in Powder, and

twelve Pound of Calx of Lead, then searce it, pounding again what does not pass through the Sieve. Add to that two Ounces of prepared Zaffer, twenty four Grains of Manganese of Piedmont also well prepared, mix the whole well together, put it in a Pot heated in the Furnace, and let it stand to melt during the space of twelve Hours. Then cast the vitrified Matter into Water, and carefully take away the Lead that remains in the Pot; then put the Matter again into the same Pot, and let it stand to be re-purified Twelve Hours. Then see if the Colour pleases you, and you may Work it. You'll have a Colour like the true Ori∣ental Sapphire.

CHAP. XC. The Way to make a Golden-colour in Glass of Lead.

THIS Colour is as fine in Glass of Lead, as in Crystal: It takes that Colour both from the Lead, and the Ingredients mixed with it.

Take sixteen Pound of good Crystal Fritt in Pow∣der, to which add the same weight of Calx of Lead also in Powder, and well searced; then add six Ounces of Copper Scales thrice calcin'd, as in Chap. 34, and forty eight Grains of Crocus Martis, made with Vinegar, as in Chap. 25, the whole mix∣ed well together, put it in a Pot heated in the Furnace: Twelve Hours after cast the Glass in Water, and take the remaining Lead out of the Pot, and then put the Matter again into the same Pot, to be well purified during Twelve other Hours.

After that, stir it well, and see if the Colour pleases you; if it chance to be greenish, add to it some Crocus Martis, and the Greenness will vanish; then you will have a Golden-colour very fine, which may be Wrought.

These are all the Colours we can give to Glass of Lead alone. We shall augment the Number in a Past of Lead, whereof we shall shew the Prepa∣ration in the following Book, because it is useful for imitating Precious Stones, as we shall shew in the same Book; which is the Reason we have not done it in this.

The End of the Fourth BOOK.