250 Porcelain and Earthenware. 
levigated, and to redute the whole to the utmost uniformity and 
smoothness, in which state it is called shp. It is next poured into a 
large vat or cistern, called a slip kiln built with flues under it, con- 
nected with a furnace large enough to produce an ebullition in the 
mixture, which is continued until so much of the water is evaporated 
as will bring the mass to the desired consistence. When the mate- 
rials have thus been consolidated into a paste, it is removed from the 
slip kiln, beaten with mallets and turned over with spades until it is 
as thoroughly tempered as it can be by this mode of operation. It 
should not be forgotten that this prepared clay is a mixture of all the 
ingredients for the body of the ware. After the beating comes the 
process of slapping, which is done by placing a large lump on a 
bench or table; when a workman cuts through its diameter with a 
brass wire, or a twine, and lifting one half with both hands as high 
as his head, brings it down with all his force upon the lump. He 
cross cuts and unites it again and again until all the air bubbles 
of which it was full are driven off. ‘This is an extremely laborious 
operation, but it is essential to expel all the atmospheric air, before 
it is exposed to heat, otherwise when it became expanded in the 
furnace, it would blister and ruin the goods. Mr. Wedgewood and 
others have employed machinery to effect the results produced by 
the severe labor of slapping and blunging, which by some is thought 
equally efficient. 
The prepared paste when brought to this state, it is much improv- 
ed by being kept a long time, the materials thus acquiring a union 
which they do not acquire by mere mechanical force. It is usual in 
China to keep the prepared clay fifteen or twenty years, before it is 
thought fit for use. ‘In some districts it is the custom for the father 
to prepare as much clay as will be sufficient for the son, throughout 
the whole period of his life.”* 
The French manufacturers of porcelain do not observe so much 
mystery about their operations as do those of Dresden, and many other 
European potters. Little is known of the Dresden works, except 
that they employ none but rain water that has been purified and make 
their fires only with white wood that has been seasoned. Such was 
the rivalry between the three royal establishments of Dresden, Ber- 
lin and Sevres, that for a long period each made a profound secret 
of every process and improvement. ‘The same spirit actuates many 
* Parkes’ Essay. 
