PORCELAIN. 



10-3 



n. In addition to kaolin and petuntse, the Chinese, as 

 -' mentioned above, use also two oils or varnishes in the 

 nianiil'.u-ture of porcelain. Of these oils one is extract- 

 ed from tin- stone of which the petuntses are formed, 

 the kind which is the whitest, and whose spots are the 

 greenest, being chosen for this purpose. To a hundred 

 pounds of this oil they put u mineral stone called 

 >li.-k:iii or kekao, resembling an alum, and which, when 

 reduced to an impalpable powder, serves to give the 

 oil a consistence, though it must always be kept in a 

 liquid state. The other oil is the oil of lime, the pre- 

 paration of which, as stated above, is extremely te- 

 dious. Having dissolved and reduced to powder large 

 pieces of quicklime, they sprinkle water on it. On this 

 powder they lay alternately couches of dry fern and 

 tlaked lime, till they have erected a considerably large 

 pile. They then set fire to it; and, with the ashes 

 that remain, and with dry fern alternately, as before, 

 they repeat the same process five or six times succes- 

 sively ; and the oil, thus prepared, is regarded as an 

 important ingredient (though considerable skill is re- 

 quired to prevent too much of it being used) in the 

 manufacture of porcelain, as imparting to it all its 

 lustre and transparency It may not be improper to 

 mention, that the term oil is used by the Chinese in a 

 very peculiar and vague sense. It seems with them to 

 signify generally any thing in a state of liquidity ; and 

 they call their varnishes oils, though made of the pow- 

 ders of earths and stones, mixed with water. 



There is still another ingredient made use of in the 

 manufacture of porcelain, namely, hoache, a substance 

 of a chalky or siliceous nature. This may be used 

 either instead of kaolin, by undergoing a similar pro- 

 cess of preparation, or as a varnish, the vessel when 

 made being plunged into it, by which means it derives 

 the greatest splendour and whiteness. The porcelain 

 made of hoache is extremely light and brittle, and con- 

 siderably more expensive than that formed of kaolin. 



In preparing the petuntse and kaolin, the first object 

 Tof the is to break and pound them in a mortar-till they are 

 ances. reduced to almost impalpable powder. In this state a 

 quantity of water is applied, and after they have been 

 completely amalgamated, by being stirred with an iron 

 instrument, they skim off from the surface a white 

 substance, of three or four inches in depth, which they 

 put into another vessel of water. This process is re- 

 peated till nothing is left but the coarse residuum of 

 the powder, which is carefully preserved ; and, after 

 being pounded again, is used as a new powder. 



With regard to the second vessel, in which the 

 skimmings of the first were put, the water being soon 

 separated from the ingredients with which it had been 

 blended, is poured out; and the sediment which re- 

 mains at the bottom of the vessel is then put into a 

 mould of a square shape, and after being dried, requires 

 only to be mixed with the proper materials for being 

 fashioned into porcelain. The two substances, petuntse 

 and kaolin, undergo a similar preparation ; though the 

 latter, being naturally soft and more dissoluble, requires 

 not to be broken, but merely to be immersed in water. 



The just admixture of the different ingredients is the 

 next step in the process of the porcelain manufacture, 

 and this must be determined by the quality of the porce- 

 lain to be made. For the finest porcelains they use an 

 equal quantity of petuntse and kaolin ; and the propor- 

 tion of petuntse to increase as six to four, three to one, 

 according to the degree of coarseness which the porcelain 

 is rneattt to assume, the vessel being coarse in proportion 

 as the quantity of petuntse exceeds that of kaolin in the 



manufacture of it. The two ingredients are, when thus Porcelain. 

 combined, put into a large pit, or basin, well paved and ^^^^ 

 cemented, and are trodden by the workmen, and hard- 

 ened, till they obtain a proper degree of consistence. 

 They are then removed from the basin, and rolled and 

 kneaded a second time on a slate : a process which re- 

 quires the greatest care and niceness, aa the smallest 

 vacuum, or the least admixture of any thing extra- 

 neous, even a hair or a grain of sand, would render the 

 operation a complete and total failure, and the mate- 

 rials thus adulterated of no use at any future period. 

 The oils, or varnishes, are next to be applied ; the oil 

 of lime being generally in the ratio of one to ten of 

 the other oil, which, as previously described, is ex- 

 tracted from the stone from which petuntse is obtained. 

 The proportion which these oils must bear to the other 

 ingredients, depends entirely on the quality of the 

 work to which they are applied. The mode of apply- 

 ing these oils will be mentioned in a subsequent part 

 of this article. 



Of the materials amalgamated and prepared in this How the 

 way the porcelain is made. This is done either with porcelain i* 

 the wheel, like our earthen-ware, or in moulds. All o* 

 smooth dishes are made in the former way ; and the 

 largest are finished on the wheel by two operations, 

 one-half being applied at a time. When the two halves 

 have, in this way, been made to acquire the same size 

 and figure, they are united with porcelain earth made 

 liquid by adding water to it ; and the juncture, which 

 is polished by a kind of iron patula, is so perfect that 

 it is not only entirely imperceptible, but is the strong- 

 est part of the vessel. Jt is in this way that handles, 

 spouts, often embossed work, are added. Those ves- 

 sels, on the contrary, that are embellished with figures 

 in relievo, are formed, not on the wheel, but in moulds, 

 and are polished and finished with the chisel. Others 

 that have impressions in creux are engraven with a 

 species of puncheon. Vessels with figures in relievo 

 or in creux, belong, it is evident, in one respect at least, 

 more to the profession of sculpture than to that of por- 

 celain-making. This operation is, of consequence, as- 

 signed to a particular class of workmen ; and as their 

 labour is exclusively confined to this species of em- 

 ployment, it is performed with a degree of delicacy, 

 rapidity, and elegance, which, considering the extreme 

 brittleness of the article, is altogether astonishing. Nor 

 is this the only department assigned to a separate class 

 of workmen. On the contrary, the division of labour 

 is carried to a very great extent in the porcelain manu- 

 factory. Every separate operation, however minute, 

 is done respectively by different persons ; and a single 

 cup runs with expedition from one to another, till, be- 

 fore it is finished, it has passed through the hands of 

 no fewer than seventy individuals. 



The Chinese, for many ages, used only white porce- B )ue pont. 

 lain, which were first superseded by blue, and soon af- UJ D . 

 terwards every variety and shade of colour was intro- 

 duced. The blue, it is supposed, they originally pre- 

 pared from a species of lapis lazuli, which, previous to 

 being used, was calcined, and reduced to a powder of 

 the greatest fineness. But as Britain can supply them , 



with the smalt at a cheaper rate than they can prepare 

 it, they obtain the article from this country. The fine 

 deep blue, by which the most ancient china-ware was 

 characterised, and which is so much valued by the cu- 

 rious, is now no longer to be seen. The art of making 

 it, indeed, seems to be entirely lost ; though it is sup- 

 posed to have been obtained from the oxyd of cobalt, 

 (with other minor preparations ;) a mineral which may 



