PORCELAIN. 



105 



Marbled 

 porcelain 



Porcelain, surface perfectly smooth, gives at the same time a 

 line and a?pect to the figures in proportion to 

 the quantity of it required in filling them up ; so that 

 the whole device is as clearly seen and as exquisitely 

 haded as if the figures had been carefully painted on 

 the outside. This method of stamping porcelain, though 

 simple, has not y*'t been tried in Kuropr ; nor has the 

 following department of this art, though equally sim- 

 ple, been carried on any where but in the east. The 

 kind to which we allude is the marbled porcelain, 

 called by the Chim-si- i \uu-lclii. The vase after being 

 formed, baked, and polished, is covered over, not with 

 the common varnish, but with a sort of coarse agates, 

 calcined to a white powder, and separated from the 

 grosser parts by means of water. The powder, reduced 

 by water to about the consistence of cream, is the var- 

 nish used in this operation. And the great peculiarity 

 of this kind of porcelain is, that this varnish does not 

 spread over the vessel in equal portions, but runs in 

 ridges and veins ; thus forming, though accidentally, 

 the most curious and romantic figures, and often exhi- 

 biting a species of mosaic work of the most exquisite 

 kind ; figures which, instead of seeming the result of 

 accident, appear to have been formed and elaborated 

 by the most correct taste and the highest ingenuity. 

 Our crystal, it has been conjectured, would answer 

 the same purpose as these coarse agates ; and as the 

 preparation is simple, the art could without difficulty 

 be carried into execution in Europe. Of these vessels, 

 the ground is generally white, though sometimes blue ; 

 and the only difference in the preparation is this, that 

 the vessels require two coats instead of one of the agate 

 oil, and that before the second coat is applied, the blue 

 colour must be imparted to them by immersing them 

 in blue varnish. 



In addition to painting, porcelain is frequently orna- 

 mented with gilding ; a process performed in a way 

 similar to painting. The precipitate of gold, from its 

 solution, is ground up with the oil of turpentine and a 

 small quantity of the flux. With this preparation, the 

 parts of the vessel to be gilt are covered ; and are in 

 this state put into the furnace as in painting. The fire 

 causes the oxygen to fly off, the gold being left in its 

 metallic form, firmly adhering to the porcelain. It 

 row requires merely to be varnished ; after which it 

 assumes a rich, glossy, lively appearance. Platina is 

 used in a similar way. 



The only thing now that requires to be done with 

 the porcelain, ere it be carried to the furnace, is oiling 

 or varnishing ; an operation of considerable delicacy, 

 inasmuch as the varnish must be applied equally, and 

 as if it exceed or fall under a certain quantity, the ves- 

 sel is completely spoiled ; and this quantity must be 

 great or small according to circumstances ; that is, ac- 

 cording to the quality of the work, or their colour, or 

 the colour of the figures and devices with which they 

 are adorned. Of the oils of which the Chinese make 

 their vanrnh, we have already spoken. These oils 

 they mix together with great caution and delicacy; and, 

 with an almost endless variety of other slight ingre- 

 dients, form with them varnishes of every hue and 

 every degree of fineness and elegance. The Chinese, 

 though they have not for centuries made any real im- 

 provement in the art of porcelain manufacture, have 

 recently discovered a new varnish of a brown goldish 

 appearance much esteemed, probably on account of 

 its novelty. This varnish is made of a common yellow 

 earth, which they dissolve in water, and of which, al- 

 lowing the coarsest residuum to be thrown out as re- 

 VOL. xvn. PART i. 



Gilding. 



Tarnish- 

 inj. 



fuse, they make use only of the purest and finest parts. I'orcela 

 This, which is first in the form of a oft paste, and """ "V 

 which is afterwards dissolved by a new admixture of 

 water, is mixed, before it can be used, with the com- 

 mon varnish, and other subordinate ingredients, in just 

 proportions. This varnish is applied by immersing 

 the vessels in it ; they are then removed to the oven ; 

 and the baking gives the most beautiful brightness to 

 the colour. 



After the porcelain has received, in the way described Bakinp. 

 above, its proper chape, ornaments, and colour, it re- 

 quires only to be baked to complete the whole opera- 

 tion. The ovens, in which the baking takes place, are 

 formed of three kinds of earth; one yellow and com- 

 mon ; the remaining two scarce, one of them called 

 lautou, a strong stiff earth, the other youtou, oily. 

 These ovens are about two fathoms in height and four 

 in breadth, and their roof and wall are so thick and 

 impervious, that even when the furnace is at the hottest, 

 a person may place his hands on them with impunity. 

 The dome or roof is shaped like a tunnel, with a large 

 aperture at the top, and five smaller ones around, to 

 allow the smoke and flames to escape. In each of the 

 furnaces there is a long vestibule or porch for convey- 

 ing air, which answers instead of bellows. When the 

 fire is lighted, every entrance to the furnace is closed, 

 with the exception of this vestibule, and of a small 

 aperture of a foot in length, but very narrow, for the 

 admission of wood, of which the fire is formed, and 

 which two men, who release each other alternately, 

 continue throwing in without intermission. Every 

 piece of porcelain is inclosed in a separate case, called 

 in Europe saggars, ere it be put into the furnace. The 

 bottom of these cases is covered with a layer of fine 

 sand, which is sprinkled over with the powder of the 

 kaolin, to prevent the sand from adhering to the body 

 of the vessel. These cases are arranged in files, the 

 bottom of the one forming the cover of the other, so 

 that the porcelain may not be subjected to the too di- 

 rect action of the heat. And the difficulty at this step 

 of the progress is, that they be so arranged, and the 

 fire so managed, that the flame may have a free passage, 

 and insinuate itself equally in every quarter of the fur- 

 nace. To know when the porcelain is fully baked, 

 the workmen open a small aperture, and with a pair 

 of tongs take off one of the covers of the cases ; and if 

 the colour of the porcelain exhibit a bright lustre, and 

 if all the piles seem equally inflamed, the coction is re- 

 garded as sufficient ; and the fire being discontinued, 

 the furnace is allowed to cool gradually before it is 

 opened. Some species of porcelain are painted twice, 

 and after having been in the oven just described, they 

 are baked a second time in a smaller oven. Here they 

 require no cases, the oven itself serving that purpose, 

 being about a foot high and half a foot broad ; and the 

 object of this second baking (which takes place chiefly 

 with tea-cups, and other similar elegant vessels) is 

 either to render the lustre of the colours more brilliant, 

 or sometinHs, by covering them with colours, to remove 

 blemishes which have taken place in some former stage 

 of the process. 



On the operation of baking depend the nature and V:trificm- 

 characteristics of the porcelain manufactures. It is lion - 

 not at all difficult to procure earths and other ingre- 

 dients that will exhibit nearly all the appearances of 

 porcelain, ere it be subjected to the fire ; but the great 

 and distinctive property of porcelain is its semi-vitri- 

 fication, to which it owes its lustre and transparency ; 

 a result which has not yet been satisfactorily attained 



