Description of the Twenty
Illustrations of the Manufacture of Porcelain

In porcelain-making the first requisite is that of washing and purifying the materials of the paste, so as to make it of fine homogeneous texture. The presence of "stars" or of fragments of stone would cause flaws in the porcelain. Foreign particles or loose paste would lead to cracks.

The method of purifying the paste is to mix the materials with water in large earthenware jars, and to stir the mixture with wooden prongs, so that it remains suspended in the water while the impurities sink to the bottom.

The paste is then passed through a fine horsehair sieve, and next strained through a bag made of a double layer of silk. It is then poured into a series of earthenware jars, from which the water is run off, and the paste is left to become solidified. A wooden box with no bottom having been placed upon a pile composed of several tiers of new bricks, a large cloth of fine cotton is spread inside, and the solidified paste is poured in, wrapped round with the cloth and pressed with more bricks, which absorb all the water.

The prepared paste, freed from the superfluous water, is then thrown on to large stone slabs and worked with iron spades until it has become perfectly compact and ductile, and fit for the manufacture of porcelain.

All the different kinds of paste are prepared in the same way, the various materials having been mixed in definite proportions according to their different properties. The picture contains in detail the various utensils and the different processes of work comprised in this department of preparation of the paste.