Page:Cyclopaedia, Chambers - Volume 2.djvu/465

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Dregs that remain are perfeftly ufelefs, and are emptied out of the Work-houfe when a quantity is got together.

Thefe Work-Houfes are properly vail Yards wall'd round, with Sheds, and other Conveniencies for the Work- men to work under; as well as other Buildings for 'em to live in : Itisalmott inconceivable what number of Per- sons arc employ'd in thefe Works ; there being fcarce a Piece o( 'Porcelain but paffes thro' above twenty hands, e'er it come to the Painter's Work-Houfe ; and above lixty e'er it be brought to Perfection.

To make a juft Mixture of Petunfa and Kaolin, regard mull be had to the Finenefs of the Porcelain to be made : For the finer 'Porcelains, they ufe equal Quantities ; four Farts of Kaolin to fix of Petunfa, for moderate ones ; and never lefs than one of Kaolin to three of Pet unfa, for thecoarfeft.

The hardeft Part of the Work is the Kneading and Tewing the two Earths together ; which is done in a kind of large Bafons, or Pits, well paved and cemented, wherein the Workmen trample continually with their Feet, re- lieving one another, till the Mafs be well mixed, grow hard, and become of the Confidence required to be ufed by the Potter.

The Earth, when taken out of the Bafons, is kneaded a fecond time, but piece-meal, and with the Hands, on large Slates for the purpofe ; and on this Preparation, in effect, it is, that the Perfection of the Work depends ; the leaft heterogeneous Body remaining in the Matter, or the leaft Vacuity that may be found in it, being enough to fpoil the whole. The fmalleft Grain of Sand, nay, fome- timesa fingle Hair, mall make the Porcelain crack, fplin- ter, run, or warp.

The Porcelain is fa/liioii'd or form'd either with the Wheel, like Earthen-Ware; or in Moulds. See Pottery. Smooth Pieces, as Cups, Urns, Difhes, $S?c. are made with the Wheel. The reft, ;'. e. fuch as are in Relievo, as Figures of Men, Animals, £i?c. are form'd in Moulds, but finilh'd with the Chiflel.

The large Pieces are made at twice ; one half of the Piece is raifed on the Wheel by three or four Workmen, who hold it till it have acquired its Figure ; which done, they apply it to the other half, which has been form'd in the fame manner ; uniting the two with Porcelain-Earth, made liquid by adding Water to it, and polifhing the Juncture with a kind of Iron Spatula.

After the fame Manner it is that they join the feveral Pieces of Porcelain formed in Moulds, or by the Hand ; and after the fame Manner they add Handles, ££c. to the Cups and other Worksform'd with the Wheel.

The Moulds are made after the Manner of thofe of our Sculptors, viz. of divers Pieces which feverally give their rcfpecrive Figure to the feveral Parts of the Model to be reprefented ; and which are afterwards united to form a Mould for an entire Figure. The Earth they are made of is yellow and fat, dug out. of its proper Quarries, whereof there are abundance abour Kimtetchim. It is kneaded like glaz'd Earth, and when fufficiently mellow, fine, and mo- derately dry, beating it ffoutly, they form it into Moulds, according to the Works required, either by Hand, or on the Wheel. Thefe Moulds are fold very dear, but laft a long time. See Mould.

All the Works made in Moulds ate finifh'd by the Hand, with feveral Inftruments proper to dig, fmooth, polifh, and to touch up the Strokes that efcape the Mould ; fo that 'tis rather a Work of Sculpture than of Pottery. There are fome Works whereon Relievo's are added, ready made, as Dragons, Flowers, ($c. Others that have Impreflions in Creux ; which laft are engraven with a kind of Puncheons. In the general, all Porcelain Works are to be fhelter'd from the Cold ; their natural Humidity ma- king 'em liable to break when they dry unequally.

To conceive the Number of Hands each Piece of Porce- lain paffes thro' e'er perfect ; we mall clofe this Article with what F. Entrecolles inftances of a common Cup, e'er it be fit for the Painter -. The Cup begins with the Potter, who has the Management of the Wheel, where it acquires its Form, Height, and Diameter. This Operator has not above a Farthing Sterling for a Plate furnifh'd with twenty fix Cups ; accordingly, they go out of his Hands exceedingly imperfect, efpecially towards the Feet, which are only unform'd Lumps of Earth, to be afterwards cut with the Chiflel when the Cup is dry. When it comes from the Wheel, the Cup is received by a fecond Workman, who fits it on its Bafe. A third takes it immediately from him, and applies it on a Mould to bring it to its true Form. This Mould is on a kind of Lathe. A fourth Workman polifhcs the Cup with a Chiflel, efpecially about the Edges ; and brings it to the thinnefs neceffary to make it tranfparent ; in doing which, he moiftens it from time to time, left its drynefs fhould make it break. When of its proper thicknefs, another Workman turns it gently en a Mould, to fmooth its infide; taking a deal of Care it be

done equably, left any Cavity be form'd, or it watp, fvi Workmen add, fome, Ornaments in Relievo ; others I ef preffions in Creux ; others, only Handles, as the quali'ty'of the Cup requires. At laft, they round and hollow ft, Foot on the infide with a Chiflel ; which is the Function f a particular Artift, who does nothing clfe.

This Multiplicity of Workmen, fo far is it from re- tarding the Work, that it is found, by Experience, to „* on the fafter for it ; as well as to be the better done ; e^u Workman, by a continual Attention to the fame thing, De _ coming very dextrous at it : befides faving the time of changing Inftruments, §£?c.

'Painting of Porcelain, and the Colours ufed therein.

The Chinefe Painters, efpecially thofe that meddle with human Figures, our Author obferves, are all forry Work, men : He adds, that the defect is fcarce any where fo fenfible as in the Hoapei, or Porcelain-Painters, among whom, fetting afide Flowers and Landskips, which are fometimes tolerable, the greateft Mafters are not to be compared to ordinary Apprentices among the Europeans for the Beauty and Juftnefs of Defign. But it is otherwife with the Colours thefe Hoapei ufe ; which are fo exceed- ingly lively and brillanr, that there is but little hopes our Workmen fhould ever come tovye with 'em.

The Painting Work is diftributed among a great Num- ber of Workmen, in the fame Laboratory : To one it belongs to form the colour'd Circle about the Edges of the Porcelain ; another traces out Flowers, which another paints: This is for Waters, and Mountains alone; that for Birds, and other Animals ; and a third for human Figures.

There are Porcelains made of all Colours ; both with regard to the Grounds, and to the Reprcfentations thereon. As to the Colours of Landskips, &c. fome are fimple ; fuch are all Blues, which are thofe moil ufually feen in Europe ; others are mixed up of feveral Teints ; and others, again, heighten'd with Gold.

The Slue is made of Lapis Lazuli, prepared by burning it the fpace of twenty four Hours, in a Furnace, where it is buried up in Gravel, to the height of half a foot ; when burnt, they reduce it into an impalpable Powder in Porce- lain Mortars, not.varnifh'd, and with Peftles of the fame Matter.

For the Red, they ufe Copperas, which they call Haofan ; a Pound of this they put in a cover'd Crucible, in the Lid whereof is left a little Aperture, thro' which the Matteron occafion may be feen. The Crucible is heated with a Re- verberatory Fire, till the black Smoke ceafe to afcend, and a fine red one fucceeds it. A Pound of Copperas yields four Ounces of red Liquor, which is found at the bottom of the Crucible, tho' the fineft part is that ufually adhering to the Lid and the Sides of the Crucible.

Befide the natural WhitenefJ of the Porcelain, which is ftill improved by the Oil wherewith they cover it, they have an artificial White, ferving for theGrounds of Porce- lains of feveral Colours ; and made of a tranfparent Flint calcined like the Lapis Lazuli, and mixed with pulverized Cerufs: The Proportion is an Ounce of the latter to half an Ounce of the former.

This Powder of Flint is likewife an Ingredient in moft of the other Colours ; e.gr. fot Green, to three Ounces of" Tbmhoapien, or Scoria of beaten Copper, they ufe half an Ounce of Powder of Flint, and an Ounce of Cerufs. Via. let is made by adding a Dofe of White to the Green al- ready prepared ; the more Green is added, the deeper is the Violet. For Tellow, they ufefeven Drachms of White, and three of the Copperas-Red.

Moft of thefe Colours are mixed up with Gum- Water, for Application ; a little Saltpetre, fometimes Cerufs or Copperas, but more ufually Copperas alone, being firft diflolved in the Water. Indeed for Porcelains that are to be quite red, the Colour is ufually applied with Oil ; i. e. with the common Oil of the Porcelain, or another made of the white Flints.

There is alfo another Red, call'd blown Red, becaufe in reality applied by blowing with a Pipe, one of whofe Orifices is cover'd with a very fine Gauze. The bottom of this Tube is lightly applied to the Colour wherewith the Gauze is fmear'd ; when, blowing againft the Porce' lain, it becomes all fprinkled over with little Points. This Porcelain is very rare, and of great Price.

Slack Porcelain, which they call Oumian, has likewife its beauty : This Colour has a leady Caft, like our Me- tal-burning Mirrors ; and is ufually heighten'd with Gold. It is made of three Ounces of Lapis Lazuli, with feven of the common Oil of Stone ; tho' that Proportion is varied, as the Colour is defigned to be more or lefs deep. The Black is not given the Porcelain till it be dry, n° r muft the Work be put to the Fire till the Colour be

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