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 7)

BOOK VII. Containing the Way to Enamel in all Sorts of Colours on Gold and other Metals: The Order of the Fire and Furnace: The Preparation of Colours for Pourtraying with Enamel, and how to do it. (Book 7)

CHAP. CLXXX.

THO this Undertaking depends not altoge∣ther on our Art of Glass, being no more than an Application of Matters delivered in the Sixth Book; however we resolve to lay down this Manner of Enameling and Pourtraying on Metals, to bring this our Work to an higher perfection.

The Ancient Works of Enamel on Metals, were only of Black and White, with some few Tinges of Carnation, or Flesh-colour, as may be seen in the Limoge Enamel; in Francis the First's Time it became more improv'd, and they made use of Lights and Shadows▪ but the Enamel on Gold was of no better Stuff than that on Copper, and all the Works of it on Gold, Silver, and Copper, were of Transparent Matter; such as wrought it on thick, couched each Colour by it self, as is done now a Days in Enamel∣ing some particular Pieces of Relief, and not other∣wise.

Since then they have found out the way of Ena∣meling with opaque, and thick stuff, and the Art of compounding the Colours, is much more improve∣ing and handsomer than that of the Ancients, as is visible in all our Modern Works; but we must with∣out all Exception, own the fair Works upon Gold, representing Pourtraitures, and entire Histories, so neatly, and to the Life, and coveted as much as Pi∣cture done in Oyl, over which it has the advantage of Natural Lustre and Varnish, which is never tar∣nished, to be the Invention of this latter Age, and the Improvements we owe to the Study of the French therein.

All sorts of Enamel are not to be promiscuously employed on all sorts of Metal; Gold which perfect∣ly bears with as well all the Opaque as Transparent, cannot agree with clear Purple, its Yellow mightily changing the Colour thereof, and produces but a ve∣ry ill Fancy; on the other side, this Purple is very fine on Silver; so the Egmarine, the Azure, and Green all other Colours, as well clear as Opaque, disagreeing therewith, and Copper suits with every thick Enamel, but cannot endure the Limpid, unless prepared for it beforehand, as shall be directed in due place.

Observe that good Enamel must be hard and lasting, such as is soft being full of Lead, and subject to change Colour, easily becoming sullied and foul; of the clear Enamel some is harder, some softer; the hardest is always best, however even of them there is choice; some lose colour in the Fire, some are more or less lively and sparkling, but if you em∣ploy constantly such as we have prescribed in our Sixth Book, you'll never be exposed to those Incon∣veniencies; for the Ingredients being perfectly clean∣sed, will endure all degrees of Fire, any change of Colour or Quality not ensuing.

CHAP. CLXXXI. Of the Furnace for Enameling and Pourtraying.

THE Enameling of Metals, as well as the co∣louring of the Stuff, cannot be effected with∣out Fire, and is wholly different in this point from Painting with the usual Colours in Oyl, which may be dried in the Air only, without other help.

It would be very hard to believe the Fire would not spoil the mixture of the Colours, if our daily ex∣perience which we made, did not vouch the contrary; however care must be taken not to let the Work have too much time, but draw it out as soon as you find it polisht.

The Fire must be Reverberatory, or rather of Suppression, and never to be under the Stuff; 'tis the same as is used for cleansing of Metals, whether in Mints or Goldsmiths Shops, which is very familiar to all the World.

[illustration]

You must have a Furnace round or square, either of Iron or Earth, it's no great matter, how (or whether of these) it is, which must be hollow in the middle, to contain the Work with a good Charcoal∣Fire all about, and over it, to make it melt the bet∣ter; and you must have it so as to be able to take your Stuff out, and put it in again, as occasion requires: You may, for better conveniency, make use of a Goldsmith's Muffle; 'tis a small Arch made of Cru∣cible Earth, in the shape of half a Crucible, cut length-wise, and they place it on the Area or Floor of the Furnace, the Opening of it lying just against the Mouth of the Furnace, to put in and draw out the Work easily; and for more conveniency they place a small Grate over it, which must not touch it, for fear of breaking it; and on this Grate make a good Fire, and so round about the Muffle, to heat the hollow very well, under which they put the Work to be Enamel'd and Painted; and the Essays, or Tri∣als they have a mind to make on a little Iron∣Shovel, to draw the easier out; but for making Es∣says of Ingredients for Enamel, it must be a little Blade of White Enamel, which ought to be provi∣ded purposely for that use.

CHAP. CLXXXII. The Way to Enamel Gold.

WE have already said, that Gold, Silver, and Red Copper may be Enamel'd; now to make true Work, you must use only pure Gold, because Silver makes White Enamel appear Yellow, and Copper rises in Scales, and makes Vapours; for tho all Enamel sticks to it, yet it is but very imperfectly,

and may be easily divided and peeled off again; be∣sides, the Colours are so wretched on it, and lose much of their Charm and Lustre by the Impurity of that Metal.

Therefore, if you would have good Work, let Gold only be your Subject, and of the purest, if you employ clear Enamel, because on impure Gold they grow dull, and become imperfect, that is to say, there appears with this a certain obscure and Cloudy Vapour in the Enamel, which deadens and takes a∣way the Life of its Colour.

The Gold Plate ought to be rising, and when it is forged very even, the Goldsmiths apply white Ena∣mel over and under it, tho it is to be wrought but on one side, but this is necessary for two Reasons: First, Because the Work is neater and fairer for it: And a∣gain, Because if it were only Enamel'd on one side, the Fire would swell it, and so make it rise, and that in Bubbles; because it is always as it were torment∣ed, especially when the Pieces are great, and the Enamel carelesly laid on; this makes it produce Bli∣sterings, which disfigure the Work; the French Chy∣mists call such Vegoter, but their Goldsmiths Petits Ocuillets: This disfiguring of the Work, you may avoid, by laying Enamel on both sides of the Plate of Gold, and thicker over than under, this will keep it equal and even on both sides, the first lay of White Enamel remaining / smooth in this conditi∣on, serves for a Field to place all your other Colours on as we will further discourse of in the Art of Pour∣traying.

Oyl of Spike is used for dissolving thick and opaque Enamel before it can be applied; for the Transpa∣rent you need use nothing but fair Water, as we shall shew in Chap. 185. and then 'tis couched flat and bordered with the Metal, and sometimes we don't border at all, the Field being all Enamel, but this is

troublesome, because the Limpid Enamels as they melt, often mix, and so confound the Colours which constantly happens when the Pieces 〈◊〉〈◊〉 small.

Red Enamels are not so, unless by chance, and come generally Yellowish out of the Fire; assoon as 'tis ap∣plied to the Gold, it alters the Colour; one may soon bring it to a perfect Red Enamel, by turning it at the Mouth of your Furnace, when you are taking it out from the Fire; and then it is that the Work∣men say they make it Red, and give it its compleat Colour.

Gold, as we have already said, admits of all sorts of Enamel, clear or opaque, bright Purple excep∣ted, which is altered by the Yellow-colour of the Gold, and does not take so good effect there, as on Silver, on which it ought still to be used. The Way of working every sort of Enamel, is alike; not to make any useless Repetitions, we will satisfie our selves only to advise you to employ all those Ena∣mels prescribed in the Sixth Book, which have every illustrating and convenient Property to be wished for in this Work.

CHAP. CLXXXIII. To Enamel on Silver.

WE have already taken notice in our former Chapter, that Silver agrees not with all sorts of Enamel, as Gold. We repeat it here again to pre∣vent the use of any but such as serve to produce per∣fect and agreeable Effects.

You are to make least use of White Enamel on Silver, because there it becomes Yellowish, and un∣pleasing,

but nothing can suit better with it, than bright Purple, Green, Blue, and Egmarine, be∣cause the Whiteness of the Silver is then clearly emi∣nent, and gives its just splendour.

The Work and manner of Enameling on Silver, is no way different from that of Gold, in forging the Plates evenly to prepare 'em for the Enamel, you may make use of White on the under side, since the Enamel there serves only to qualifie the Risings and Disturbings of the Metal in the Furnace, which would cause unevenness, or disagreements in the surface, and prevent its becoming just and handsome.

We need not repeat again that way of placing the Enamel on your Plates of Gold or Silver, and so to put them into your little reverberatory Furnace spo∣ken of in Chap. 181. to melt, and as soon as polished to be taken from the Fire.

CHAP. CLXXXIV. To Enamel on Copper.

THO we have before touched upon the way of Enameling on Copper, yet lest the Reader should too slightly apprehend it, as not in order, or a distinct Chapter, therefore we are obliged to enter it here to avoid Imperfection.

The less use is made of this Metal in this Work the better, for the Enamel never sticks to it perfectly, but is easily scaled, divided, and broke off, which ne∣ver happens to Gold; besides, the Copper is so im∣pure, that its Fumes destroy the Beauty of the Ena∣mel so much in the Furnace, that they quite lose their Charm and Splendour by the Malignity of those Va∣pours.

Tho the Copper receives easily all thick or dark Enamels, it can't be brought so well to endure the clear and limpid; now if you would make use of these last, you must first lay a lay of Green, or Black, and thereon a Leaf of Silver to receive the Enamel suitable for that Metal mentioned in the for∣mer Chapter; so that in the main 'tis much better to make use of Silver for the Transparent Enamels, since the Copper is so apt to foul, and the charge in either much the same.

In Enameling on Copper, you must take a Plate of red Copper forged smooth, and even applying your Enamel of what Colour you desire above and under the Plate as before; then put this into the reverbera∣tory Furnace, and when it receives its polishing, draw it out.

CHAP. CLXXXV. To prepare the Enamel for the Metals.

BEFORE you apply your Enamel on the Metal, you must give it this little Preparation, which is the easiest, and best approv'd on by the Goldsmith; we will instance it in White Enamel, because that is more generally made use of than any other.

Take White Enamel of the Sixth Book, Chap. 149. pulverize it very fine, pour on it a little Aqua fortis, and let it afterwards purifie and refine in a small Glass Cucurbit.

Wash it afterwards often in Fair-Water, dry and keep it in a close Vessel for use.

To make use of it, first pound a quantity thereof in a Stone Mortar, wetting it with a little Water, and so spread it on the Plates, and into the Furnace with it as before.

Thus do with all your clear and transparent Ena∣mels, and you'll have all your things in a readiness to go on with your Work as you think convenient.

CHAP. CLXXXVI. To prepare the Colours for Painting on Enamel.

NOTHING can be more splendid than the Paint on Enamel, and for this use must be chosen the liveliest and most Noble Colours, and such as will ea∣sily vitrifie and melt.

All these assigned throughout the Sixth Book, are as equally sufficient for this, as for Enameling; if you grind them first on your Marble with the best Oyl of Spike, or mix'em together with the other Ingredients for that purpose, as we shall give a fuller account in the next Chapter, and of all the Matters to be used with calcined Enamels, which serve to make up the Paint for Enamel mixing them well together as Pain∣ters do on their Pallets: When you want some Co∣lours of Enamel, you may with Blue and Yellow make a good fair Green; a Blue and Red mixt, will produce a fine Violet; a Red and White creates a Rose-colour; a Black and White forms a gallant Gray, and so of others.

Every Workman has his own Secret, and peculiar way of Working, but most of them make use of Rocaille for varnishing their Colours, which has an ill effect, because of too much Lead, which is not per∣fectly purged off; this lessens the Life and Splendour, and it always continues as it were tarnished, cloudy, and dull.

But our Enamel being well refined, will produce Work so fine and agreeable, that 'tis not possible to

find any thing so illustrious and accomplisht; and such as for their one private diversion, would work herein, and have not the conveniency of a Glass-house, may easily be furnished, by proceeding to make one according to the directions already given.

Notwithstanding the sufficiency of our Enamel for affording all sorts of Colours and Tinges in painting on Enamel, we will yet prescribe other means for this, no way inferiour thereto, to answer the Advan∣tage and Curiosity of those who Work at this Excel∣lent Art.

CHAP. CLXXXVII. To make White for Painting on Enamel.

THE best Workmen, for the most part, use the White Enamel ground, which they can ma∣nage with address enough to heighten and illustrate their Lights, which is necessary to be done to all their Colours, as in Miniature: But as it is difficult to pre∣serve the Ground justly for improving those other Colours, and ordering the Compositions (all one as in Carnation) you must take of our Crystal ground prepared with Tin and Lead purged and refined as in Chap. 158. or rather of our Milk-colour Enamel in Chap. 159. which is the fairest can be made; cleanse it with Aqua fortis, wash, dry, and grind it after∣wards with Oyl of Spike.

Or you may prepare another White Ground with∣out Lead, thus: Take very pure Tin calcined, as in the Chapter aforesaid, and let it vitrifie in a Glass-house Pot, with eight times as much Crystal Frit, as we have directed the Preparation in Chap. 6, pulverize

these very fine, and proceed precisely according to Prescription for Purification, &c. in Chap. 158.

CHAP. CLXXXVIII. To make a Black for painting on Enamel.

THO the Black Enamels prescribed in Chap. 156. and those succeeding it may serve to Paint on Enamel with this Colour, without any other Prepa∣ration than grinding it with Oyl of Spike; yet we will add here another Black no less excellent and fine, arising from equal parts of Black-Enamel, and Pere∣grine well calcined, mix and reduce them to an im∣palpable Powder, and then apply Oyl of Spike, and you'll have a Colour which will take with great faci∣lity on the Enamel.

CHAP. CLXXXIX. A Yellow for Paint on Enamel.

WE will only make use of our Enamel, prepa∣red in Chap. 162. mixt and purified with Aqua fortis, and after washed in clean Water, as in Chap. 185. dry and grind this Powder with Oyl of Spike on your Marble, and 'tis fit for use. With this Yellow and a Blue, as we have already hinted, may be made a fair Green; but those Enamels described in Chap. 153. and the succeeding, are so just and fine, that 'tis needless to use any other for that purpose; this Preparation for the Yellow here laid down is suf∣ficient also for it, without any further trouble.

CHAP. CXC. A Blue to paint on Enamel.

THE Enamels of this Colour assigned in Chap. 151. and 152. are the Noblest can be used in this Work, purifie them with Aqua fortis, and grind them with Oyl of Spike, as before directed for the o∣ther Colours.

You may because it is vetrified, make another fine enough Blue thus. Take Painters Enamel prepared, add to this (put into a Glass-Bottle) best rectified Aqua-Vitae, enough to drown the Stuff by four Inches, stop it well, and set it in the Sun-shine for five or six Days, shaking the Bottle well three or four times a Day, that the purer Enamel may dissolve, and the grosser fall to the bottom; take the Enamel out of your Bottle, and steep the Faces, letting them preci∣pitate as useless; then evaporate your Aqua-Vitae, and dry your Azure, which will be a very fine well clean∣sed Matter for all sorts of this Work; grind it after on your Marble. This Enamel so prepared, is most proper for Painting, and far beyond the Vltra Marine, so much made use of.

We shall in the Tenth Book prescribe some other excellent Methods to make Blues very fine, with a Receipt for Vltra Marine, and several other Colours in favour of those who affect that Noble Art of Limn∣ing.

CHAP. CXCI. A Red Paint for Enamel.

THere can nothing exceed the Perfection of our Enamels of this Colour, taught in eight several Chapters of the Sixth Book; the like may be said of our Blood-colour, Rubies, Rose and Carbuncle, which is the most exalted Ingredient for Enameling Metal, or making Paint on Enamel; and those who practise this fine Art, use no other than that of the Glass-house, or such as they make accordingly. Now this Red Enamel is prepared as the other Colours with Aqua∣fortis to purifie it, wash'd, dry'd, and ground with Oyl of Spike for your use.

There is yet another tolerable Red, which they Paint with on Enamel, in which is employed calcined Gold; but this would be much more improved, if instead of their Rocaille they made use of our Matter made of Crystal and Saturnus Glorificatus in Chap. 113. or of our principal prepared Powder prescribed all along the Sixth Book, for these are exceeding well pu∣rified, whereas the Rocaille has too great a Surcharge of Lead, the Impurity whereof always renders the Work defective.

See here their way of calcining Gold, which is not near so fine as that we have given Chap. 115. and as there are an hundred several ways, so every Man makes use of his own as most excellent, and thinks it better than another's.

One takes an Ounce of fine Gold in very thin Plates, these dissolved in eight Ounces of Aqua-fortis, and regulated with Sal-Armoniack, or old strong Salt, in a small Glass Matrass, this is put into a Glass-Cu∣curbit,

wherein was already pour'd eight Paris Pints of Spring-Water, and six Ounces of Mercury, the Cucurbit is placed on a still Fire, and after four and twenty Hours the Gold descends to the bottom in a light Land-red Powder, then the Water is poured off leisurely into an earthen glazed Receiver, or Pan, and the Powder gathered and dryed by a moderate heat, and with a Shamois Skin they separate the Mer∣cury from the Gold, and grind this Powder with twice its weight of Flowers of Sulphur together, and then put all into a Crucible over a small Fire, where the Sulphur will communicate it self with the rest, and then evaporating they find the Powder somewhat ruddy, which ground with Rocaille, is what they make use of on the Enamel.

We own this Calcination to be tolerable as to the Gold, but as for mixing the Calx with the Rocaille, without melting them together to incorporate is dis∣putable: We believe that in grinding them together with Oyl of Spike, they may in some sort incorporate as other Colours, but can never so perfectly unite; besides, the Crystal Matter does not so well receive the Colour of the Gold this way, as if it were done by fusion.

Others make Red inclining to Vermilion, which they use in Painting after this manner. Take Vitriol calcined in two Crucibles well luted together, and set for an Hour over a flow Fire; then purge it with Aqua-fortis, wash it in fair Water, and grind it with Oyl of Spike as before, and so make use of it for Ena∣mel.

All Red Enamel which is good, ought to be hard, and not easily consumed in the Fire; for that which is otherwise, contains much Lead, and soon becomes dull and sullied, and is not of so lasting a substance, which the Workmen ought to be cautious of.

To finish the Preparation of Enamel, and before the manner of painting 'em is prescribed, take no∣tice, that all the Colours before mentioned, which are not pure Enamel, ought to be incorporated with a Crystalline Matter, such as we prescribed in Chap. 148. to the end they may vitrifie the better, which else they'll not easily do, the most Workmen make use of their Rocaille, whether to avoid the trouble of making (or that they are ignorant how to prepare) a better Matter; and this has obliged us to give seve∣ral ways very good and true for their purpose to make fine and perfect Work by.

CHAP. CXCII. The Way to Paint on Enamel.

THIS Art is revered by all Nations, 'tis so fine and so excellent, that the first and Noblest Per∣sons of the World practise in it, as we have said elsewhere: It is certain that the Art of painting on Enamel is modern, but no less estimable for that, since its effects are so wonderfully beautiful, so infi∣nitely lasting, of so Natural a Gloss, and their Splen∣dour never to be defaced.

If it were possible to make large Works of Enamel, as is done in Picture, they would be inestimable be∣cause of their Lustre, and so far surpass what Anti∣quity has had such great respect for, and which these latter Ages still caress with extraordinary esteem.

This way of painting on Enamel, seems much more difficult than Limning; Practice however convinces us, that they are equally easie, and we can with as little trouble represent any History on Enamel, as in Limning; the difference lies only in preparing the

Colours, which is not done the same way; for we dry and varnish our Enamel-paint by Fire, whereas that in Limning is done by the Air.

To paint on Enamel, you must have a Plate of Gold enamel'd with White, on which delineate and pourtray your Design. This done, draw it over a∣gain in dark Red: The Piece being perfectly done off, and the Lines compleat to the Subject, set the Tablet, or Piece in the Muffle, on a reverberatory Fire, to settle as before directed.

Your Tablet being taken out, apply the Colours in a just order as in Limning, with this difference on∣ly, that here you make your White Ground serve for filling, where that Colour is required to set off the heightnings and lustre of the Lights as is done in Miniature; and because it mightily contributes to the heightening thereof in the other Colours as to im∣proving their Lights, we have given a most excellent Receipt in Chap. 187. which very excellently serves upon this occasion.

When the Piece is thus finished, put it again into the Furnace to fix the Colours, and as soon as you perceive it varnish or polish, draw it out least the Colours mix and spoil each other.

You may take out the Work again, and revise it as often as you please, only putting it still into the Furnace until it receives its just Gloss, &c.

This way of renewing and revising the Tables, is done in Limning with Oyl; and the Painters observe that the Pieces must not be handled until they are well dry'd in the Air, so those in Enamel must be let alone until they receive their perfection from the Fire.

This is all to be observed in Painting on Enamel; it remains only for us to shew how to prepare your dark Red for tracing the Design; you may have it thus.

Take the Caput Mortuum which remains in the Re∣tort, after the Aqua-fortis is made of your Vitriol and Nitre, grind it with Oyl of Spike, and so you have the dark Red ready for your use; or you may make it with Crocus Martis, ground with Oyl of Spike.

The End of the Seventh BOOK.