Page:Cyclopaedia, Chambers - Volume 2.djvu/466

 POR

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POR

The Gold is not apply'd till after the baking, and is re- baked in a Furnace for thepurpofe: To apply the Gold, they break and diffolve it in Water at the bottom of a <porcdaifi 7 till a thin gilded Cloud arife on the Surface ; it is ufed with Gum-Water, and to give it a Body, they a dd three parts of Cerufs to thirty of Gold.

There is likewife a kind of marbled Porcelain, which but for Oil to varnifh it withal, ufing that of white Flints, which hatches and cuts the Work with a thoufand humou- rous Strokes, in manner of Mofaic Work. The Colour this Oil gives, is a white, fomewhat amy : The Porcelain is call'd Tfiniki.
 * 5 not made by applying the Marblings with the Pencil ;

There are feveral other kinds of Porcelain $ but they are fuch as are rather for Curiofity than Ufe : The pret- tieft are the Magic 'Porcelains, whofe Colours only appear when fill'd with fome Liquor. Thefe are made double : The outfide is white, and all laid out in Compartiments 3 the infide is a folid Cup, of coloured Porcelain 3 tho* the Cup is fome times of Glafs, which has abetter Effect than Porcelain. The Secret of thefe Magic Porcelains, which the Qoinefe call Kiatfim, is almoft loft 3 yet F. Entrecolles has furnim'd us with the following Account.

The Porcelain to be painted thus, muft be very thin 3 and the Colours, which in other Porcelains are apply'd on the Outfide, are here apply'd on the Infide: When the Colour is dry, they lay over it a light Couch of a Size made of the Porcelain Earth 5 by which means the Colour is inclos'd between two earthen Laming. When the Size is dry, they throw Oil within the Porcelain ; and when it has enough, they return it to the Mould, and the Wheel, to render it as thin and tranfparent as poflible. When dry, 'tis baked in the Common Furnace. The Colours here ufed are always the fineit, and the Figures painted are Fifties $ as the moil fuitable to the Liquor put within them, and in which they feem to fwim.

Thefeveral Kinds of Porcelains above-mention'd, being quite painted, with their feveral Colours, and all the Co- lours dry, are to be polifti'd, to prepare them to receive the Oil or Varnifh 5 which is done with a Pencil of very fine Feathers, moiften'd with Water, and pafs'd lightly o- ver, to take off even the fmallefl Inequalities.

The Oiling or Varnifhing, is the lafl Preparation of the Porcelain, before it be carry'd to the Furnace : This is apply'd more or lefs thick, and feldomer or oftener repeat- ed, according to the Quality of the Work. For thin, fine Porcelains, they give two very thin Couches 3 to others one 3 but that one equivalent to the other two. There is a deal of Art in applying the Varnifli ; both that it be done equally, and not in too great quantity. The Couches on the Infide are given by Afperfion, i. e. by calling in as much Varnifh as is neceffary : Thofe on the Outride, by lmmerfion, or by plunging the Pieces in a Veffel of Oil.

It muft be obferv'd, that the Foot is not yet form'd, but continues in a mere Mafs, till the Work has been var- nim'd ; 'Tis at length finifh'd on the Wheel; and when hollow'd, a little. Circle is painted in it, and fometimes a Chinefe Letter. This Painting being dry, the Foot is var- nifh'd, and the Work now carry'd to the Furnace to be

baked. f. , «.

Our curious Author omits nothing ; not even the Dexterity of the People, who carry the Porcelain to the Bake-houfe : He has been frequently furpriz'd, he tells us, to fee a Man pals thro' feveral Streets full of People, with two very long, narrow Boards, rang'd with Porcelains on his Shoul- ders 3 ftill preferving the Equilibrium fo accurately, as not to do any damage to fo frail a Commodity.

Manner of Baking Porcelain.

There are two Kinds of Ovens ufed in baking of Torcela'm: Large ones, for Works that are only to come to the Fire once, which is the common way 3 and fmall ones, for fuch as require a double baking. The large ones are two Chi- wefe Fathoms deep, and almoft four wide. They are form'dof a Mixture of three Earths 3 one whereof, Yellow and Common, makes the Bafis ; the two others are fcarcer, and dug out of deep Mines, wherein People can only work in Winter. One of them» call'd Laotou, is a very ftrong, itiff Earth 5 the other Teoutou, oily.

The Sides and Roof of the Ovens are fo thick, that one may lay the Hand on them, when the Fire is at its height, without danger of burning. At the Top of the Vault, which is in form of a Tunnel, is a large Aperture to give vent to the Flames and Smoke, which mount up inceffant- ly, as foon as Fire is once fet to the Furnace. Befide the principal Aperrure, there are four or five fmall ones a- round 3 which, by being open'd and fhut, ferve to aug- ment or diminilh the Heat: like the Holes in the Chy- mifts Furnaces, call'd Regi/lers. The Hearth, which takes up the whole Breadth of the Furnace, is placed in Front, precifely againft the opening of the Door, and is two or

three Foot deep, and two broad 3 People paffing over if on a Plank, to go into the Furnace to difpofe the Torcela'm.

As foon as the Fire is lighted, the Door is walPd up ; on- ly leaving an Aperture for the Conveyance of Wood, Laft- ly, the Bottom of the Oven is cover'd with Sand, wherein part of the firft Torcelain Cafes are buried. The Furnace itfelf is ufually placed at the Extremity of a long, narrow Veftible, which ferves in lieu of Bellows; the cold Air and Wind being thus driven directly in the face of each Furnace.

Each Piece of 'Torcelain of any Note, is difpofed, in the Furnace, in its feparate Cafe, or Coffin. Indeed, as to Tea- Difhes, &c. the fame Cafe ferves for feveral. The Cafes are all of the fame Matter with the Furnace : They have no Lids; but ferve each other mutually, the Bottom of a fecond Cafe fitting into the Aperture of the firft ; and thus fucceffively, to the Top of each Column. Each Coffin, which is uiually of a Cylindrical Form, that the Fire may communicate itfelf more equably to the Torcelains in- clofcd, has, ar bottom, a little Lay of very fine Sand, co- ver'd over with Duft of Kaolin, that the Sand may not ftick to the Works and care is taken that the Torcelain may not touch the Sides of the Cafe. In the larger Cafes* which hold the fmall Pieces 3 they leave the Middle va- cant 3 in regard Torcelains placed there would want the ne- ceffary Heat. Each of thefe little Pieces is mounted on a little Maffive of Earth, the thicknefs of two Crowns, co- ver'd with Powder of Kaolin.

F. Entrecolles obferves, that the Torcelains are put in Cafes, to prevent any Diminution of Luftre from the too violent Effect of a naked B'ire 5 adding, that 'tis owing to thefe thick Veils, that the -Beauty, or, as he calls it, the Completion of the Torcelains^ is not tann'd by the Heat of the Fire.

Asfaft as the Cafes are fill'd, a Workman ranges them in the Cavity of the Furnace 3 forming them into Piles or Columns 3 whereof thofe in the middle are at leail feven Foot high : The two Cafes at the bottom of each Column are left empty ; becaufe being partly funk in the Sand, the Fire has thelefs effect on them, and for the fame reafon, the uppermoft one is left empty. In this manner is the whole Cavity of the Furnace fill'd with Columns, except- ing that part precifely under the grand Aperture.

In ranging the Cafes, they obferve always to place the fineft Piles of Torcelain in the Centre 3 the coarfeft at Bot- tom 3 and thofe that are high-colour'd, and confitt of as much Tetunfa as Kaolin^ and wherein the worft Oil is ufed, at the Mouth.

Thefe Piles are all placed very near one another, and are bound together at top, at bottom, and in the middle, by Pieces of Earth ; in fuch manner, as that the Flame may have a free Paffage among them, and infinuate equal- ly on all fides; in which a great part of the Workman's Art lies, and on which the Perfection of the Torcelain much depends. Another thing to bu obferv'd, is, that a Furnace muft never be fet altogether with new Coffins 3 but half one, half t'other : the old ones ar the bottoms and tops of the Pile, and the new ones in the middle, in- deed 'twere better to have them all burnt in a Furnace a-part, e'er they come to be ufed for Torcelain 3 as was antiently done. The Cafes, our Author obierves, are brought ready prepared from a large Village on the Kiver, a League diftant from Kimtetchim. E'er burnt, they are yellow 3 and afterwards of a dark red.

When the Furnace is fill'd, they wall up the Door 3 on- ly leaving a little Aperture for the throwing in of little Pieces of Wood, a Foot long, but very flcnder, to keep up the Fire. 'Tis then heated, by degrees, for the fpace of a Day and Night 5 after which two Men, who relieve one an- other, continue to throw in Wood without any interruption. To know when the Torcelain is baked enough, they open one of theleffer Holes of the Furnace, and with a pair of Tongs take off the Lid of one of the Piles. If the Fire appear very brisk and clear, and the Piles equally inflam'd 5 and efpecially if the Colours of the Torcelains that are uncover'd, dart forth a noble Luftre 3 the CoCtion is futH- cient, they difcontinue the Fire, and wall up what re- main'd of the Door of the Furnace.

If the Furnace be only fill'd with fmall Torcelains, they take them out twelve or fifteen Hours after the Fire is ex- tinct, ; If it be fill'd with larger, they defer opening it for two or three Days. In this the modern Practice differs from the antienr 5 wherein the Door was not open'd till after ten Days for the large Pieces, and five for the fmall ones.

One thing very furprizing, and almoft Inconceivable, F. Entrecolles obferves, is, that there are never found any Afhes on the Hearth of the Furnaces what Quantity of Wood foever is confum'd. He adds another thing, which with him paffes for equally ftrange, that the Workmen em- ploy'd about the Furnaces, flake their Thirft, by conti- nually drinking hot Tea, with Salt diffolv'd in it.

3 5 ' The