THE CERAMIC ART IN CHINA. 435 



The History of the Porcelain manufactories at Chingte-chen, trans- 

 lated by M. Julien, containing as it does a detailed account of the pro- 

 cedure followed there, permits a comparison between the systems em- 

 ployed in China and in Europe. In view of the interest attaching 

 to such a comparison no apology is needed for the following brief notes 

 on that subject, based chiefly upon the preface to M. Julien's work 

 from the pen of M. Salvetat, a member of the directory of the Govern- 

 ment manufactory at Sevres. 



COMPOSITION OF PORCELAIN. 



Porcelain is composed of two parts — the one, infusible, the paste 

 (pate), which is required to supply the body of the vessel, or, as the 

 Chinese term it, to give it "bone;" the other, fusible, the glaze {glag- 

 ure, couverte), which imparts its characteristic transparency to porce- 

 lain and at the same time prevents the vessel retaining its porousness 

 or contracting under the influence of heat. 



The principal ingredients of the paste are clays, which are classed 

 according to their greater or less degree at the same time of plasticity 

 and fusibility. The porcelain day par excellence is kaolin, a white sil- 

 icate of alumina produced by the decomposition of granitic or felds- 

 ])athic rocks, almost infusible, and if not always perfectly white by 

 nature, losing its tint in the kiln. It derives its name originally from 

 that of the hill whence the manufactories at Chingte-chen procured 

 their supply of this clay. The main object of the glaze is, as has been 

 stated, while securing transparency, to prevent the paste remaining 

 porous. Now, the substances unaffected by water but fusible by fire 

 are quartz, silica, certain limestones, pegmatite, feldspar, silex, and the 

 compounds resulting from a superficial fusion of these substances, which 

 are then reduced to a fine powder. The relative proportion of these 

 substances in the composition of the glaze may be raised at will with a 

 corresponding diversity of result — M. Brongniart dividing the com- 

 pound into three classes, each subdivided into three groups. 



In ordinary language porcelain is classified under two grand divisions, 

 hard paste and soft paste — la pate dure and la pate tendre. The latter is 

 characterized by the presence, either naturally or artificially, of limestone 

 products or alkalies, either in the condition of phosphates or in that of 

 marl or chalk, which lower its degree of fusibility, so that it becomes fus- 

 ible or at least soft at a temperature of 800<^ C. The absence of these 

 matters in the hard paste causes it to retain its original consistency in 

 far greater heat, and it can resist a temperature of 1,500° C, or above. 

 Upon these two divisions are grafted several minor ones determined 

 by the kind of glaze, which, according to its composition and mode of 

 application, is termed vernis, emailj or couverte. After unglazed tiles 

 and bricks, the primitive thin glaze, vernis, is found on the pottery of the 

 Etruscans, ancient Arabs, Persians, and the early inhabitants of 

 America; then, on that manufactured in Germany and Italy in tUQ 



