614 POTTERY 



the addition of a larger quantity of the wood, till at the end of that period the kiln has 

 a cherry-red colour within. The heat is now greatly increased by the operation termed 

 covering the fire. Instead of throwing billets vertically into the four furnaces, there is 

 placed horizontally on the openings of these furnaces, aspen wood of a sound texture, 

 cleft small, laid in a sloping position. The brisk and long flame which it yields dips 

 into the tunnels, penetrates the kiln, and circulates round the sagger-piles. The heat 

 augments rapidly, and at the end of 13 or 15 hours of this firing the interior of the 

 kiln is so white that the watches can hardly be distinguished. The draught, indeed, 

 is so rapid at this time, that one may place his hand on the slope of the wood without 

 feeling incommoded by the heat. Everything is consumed, no small charcoal remains, 

 smoke is no longer produced, and even the wood-ash is dissipated. It is obvious that 

 the kiln and the saggers must be composed of a very refractory clay, in order to 

 resist such a fire. The heat in the Sevres kilns mounts as high as the 134th degree 

 of Wedgwood. 



At the end of 15 or 20 hours of the great fire, that is, after from 30 to 36 hours' 

 firing, the porcelain is baked ; as is ascertained by taking out and examining the 

 watches. The kiln is suffered to eool during 3 or 4 days, and is then opened and 

 discharged. The sand strewed on the cakes to prevent the adhesion of the articles to 

 them, gets attached to their sole, and is removed by friction with a hard sandstone ; 

 an operation which one woman can perform for a whole kiln in less than 10 days ; 

 and is the last applied to hard porcelain, unless it needs to be returned into the hot 

 kiln to have some defects repaired. 



The materials of fine porcelain are very rare ; and there would be no advantage 

 in making a grey- white porcelain with coarser and somewhat cheaper materials, for 

 the other sources of expense above detailed, and which are of most consequence, 

 would still exist ; while the porcelain, losing much of its brightness, would lose the 

 main part of its value. 



Its pap or dough, which requires tedious grinding and manipulation, is also more 

 difficult to work into shapes, in the ratio of 80 to 1, compared to fine earthenware. 

 Each porcelain plate requires a separate sagger ; so that 12 occupy in the kiln a space 

 sufficient for at least 38 earthenware plates. The temperature of a hard porcelain 

 kiln being very high, involves a proportionate consumption of fuel and waste of 

 saggers. With 40 cubic meters of wood, 12,000 earthenware plates may be completely 

 fired, both in the biscuit- and glaze-kilns ; while the same quantity of wood would bake 

 at most only 1,000 plates of porcelain. 



The process of bisque firing is as follows : the ware being finished from the hands 

 of the potter is brought by him upon boards to the ' green-house,' so called from 

 its being the receptacle for ware in the ' green ' or unfired state. It is here gradually 

 dried for the ovens ; when ready it is carried to the ' sagger-house ' in immediate 

 connection with the oven in which it is to be fired, and here it is placed in the 

 ' saggers :' these are boxes made of a peculiar kind of clay (a native marl) pre- 

 viously fired, and infusible at the heat required for the ware, and of form suited to 

 the articles they are to contain. A little dry, pounded flint is scattered between pieces 

 of china, and sand between earthenware, to prevent adhesion. The purpose of the sagger 

 is to protect the ware from the flames and smoke, and also for its security from 

 breakage, as in the clay state it is exceedingly brittle, and when dry, or what is called 

 ' white,' requires great care in the handling. A plate sagger will hold twenty plates 

 placed one on the other of earthenware, but china plates are fired separately in 

 ' setters ' made of their respective forms. The ' setters ' for china plates and dishes 

 answer the same purpose as the saggers, and are made of the same clay. They take 

 in one dish or plate each, and are ' reared ' in the oven in ' bungs ' one on the 

 other. 



The hovels in which the ovens are built form a very peculiar and striking feature 

 of the pottery towns, and forcibly arrest the attention and excite the surprise of the 

 stranger, resembling as they closely do a succession of gigantic beehives. They are 

 constructed of bricks about 40 feet in diameter, and about 35 feet high, with an 

 aperture at the top for the escape of the smoke. The 'ovens' are of a similar form, 

 about 22 feet diameter, and from 18 to 21 feet high, heated by fireplaces or 

 ' mouths,' about nine in number, built externally around them. Flues in connection 

 with these converge under the bottom of the oven to a central opening, drawing the 

 flames to this point, where they enter the oven ; other flues termed ' bags ' pass up 

 the internal sides to the height of about 4 feet, thus conveying the flames to the 

 upper part. 



When ' setting in ' the oven, the firemen enter by an opening in the side, carrying 

 the saggers with the ware placed as described; these are piled one upon another, 

 from bottom to top of the oven, care being taken to arrange them so that they may 

 receive the heat (which varies in different pnrts) most suited to the articles they 



