POTTERY 



363 



Fig. 13. 



true soda glass with it, which makes a uniform 

 transparent glazed layer over all the pottery 

 surfaces which it reaches. In this way all glazed 

 sanitary wares and ordinary stoneware jars and 

 bottles are made at one tiring. Common pottery 

 is often figured by printing the design in enamel 

 colours on transfer-paper, 

 and, whilst the printing is 

 still wet, applying it to 

 the biscuit- ware ; the ware 

 absorbs the enamel ink, and 

 the paper is removed by 

 water, leaving the pattern 

 on the ware. It is next 

 fired in seggars, or a muffle, 

 to fix the colour, and is then 

 dipped into composition 

 called glaze, of which three kinds are used in the 

 Staffordshire potteries. The first, for common 

 pipeclay ware, is composed of Cornish granite, 16 

 parts ; flint, 36 parts ; white-lead, 53 parts ; and 

 cullet, or broken flint-gjass, 4 parts. These 

 materials are triturated with water, with the same 

 care and by similar means to those employed in 

 forming paste, and are reduced with water to 

 the same milk-like liquidity. Each workman 

 lias a tub of the glaze before him ; and as 

 the articles of biscuit-ware, either with or without 

 decorations, are brought to him, he dips them 

 in tin- glaze, so as to ensure a uniform coat- 

 ing over them ; and by nice management he pre- 

 vents any large drops or accumulations on one 

 part more than another. The porous biscuit-ware 

 rapidly absorlis the moisture, and dries up the thin 

 film on the surface of the articles, which are again 

 placed in Beggars, and carried to the glaze-kiln, 

 where they undergo another firing, which melts 

 the glaze, and converts it into a transparent glass 

 all over the surface, and renders any pattern previ- 

 ously printed upon it very plain. The temperature 

 in the glaze or enamel kiln is only increased very 

 gradually, and is kept up for about fourteen hours, 

 after which it is allowed to cool slowly, and the 



articles are taken 

 out completed. So 

 far, this descrip- 

 tion has applied to 

 the manufacture of 

 pottery and porce- 

 lain on a large 

 scale, for general 

 purposes; but when 

 it is applied to 

 more costly and 

 artistic works very 

 special arrange- 

 ments are required ; 

 and in the case of 

 remarkably fine 

 pieces, instead of 

 the huge kilns, 

 which hold fre- 

 quently many thou- 

 sand pieces, murlle 

 furnaces (fig. 14) 

 are used for each 

 separate article for 

 the biscuit, the 

 glaze, and the 



Fig. 14. 



coloured and gilded decorations, which, in porcelain, 

 are applied on the glaze, and not on the biscuit. 



In the decoration of painted pottery and porcelain 

 the colours employed are coloured glasses ground 

 to impalpable ]x>wders, and mixed with borax or 

 Minn- other fluxing material. For use they are 

 generally made liquid with oil of spike, and they 

 are hiiil on with hair-pencils, in the same way as 

 oil-ciiluiirs. The whole process is exactly tlie snine 



as in painting or staining glass ; the glaze on the 

 biscuit-porcelain being true glass, and the enamel 

 colours being exactly the same as those used by the 

 glass decorator. The colours may be made by mix- 

 ing the materials of which glass is made with the 

 colouring material and the flux, or simply with the 

 already coloured glass and the flux. When the 

 former plan is employed the principal colouring 

 materials made use of are oxide of chromium for 

 green ; oxide of iron for red, brown, violet, gray, 

 and yellow ; oxide of uranium for orange, yellow, 

 black ; oxide of manganese for violet, brown, black, 

 and purple ; oxide of cobalt for blue, gray, and 

 black ; oxide of antimony for yellow ; oxide of 

 titanium for yellow ; oxide of copper for green ; 

 suboxide of copper for red ; sesquioxide of iridium 

 for fine black ; protochromate of iron for brown ; 

 chromate of lead for yellow ; chromate of barytes 

 for yellow ; chloride of silver for deepening reds and 

 purples ; purple of Cassius for ruby and purple. 

 Several of these colours are much increased in 

 brilliancy by the addition of oxide of zinc, which 

 of itself gives no colour ; and the transparent ones 

 are rendered opaque by the addition of oxide of 

 tin. 



Other fluxes besides borax afe used as sand, 

 felspar, boracic acid, minium or litharge, salt, salt- 

 petre, potash, and soda. For the gilding of pottery 

 gold-leaf is nibbed down with oil of turpentine ; or 

 metallic gold is produced by precipitating the metal 

 from its solution. The finely-divided gold so ob- 

 tained is washed and dried, and then worked up 

 with one-sixteenth of its weight of oxide of bismuth 

 and oil of turpentine, painted on, fired, and after- 

 wards burnished. 



HISTORY. The most ancient pottery of which 

 we have any trace consists of the rude clay 

 urns, vases, and other vessels found in the tombs 

 of the prehistoric races. These remains exhibit 

 the art of the potter in its most elementary con- 

 dition, yet they are not devoid of elegance of 

 form, and the decorative instinct of primitive man 

 found appropriate expression on them in bands of 

 incised lines forming lozenges, zigzags, and other 

 geometrical forms, and in impressed wavy cord 

 marks, &c. See LAKE-DWELLINGS, STONE AGE, 

 TROY. 



Egyptian. If we except the races of the far East, 

 it is to the Egyptians among historical nations to 

 whom precedence must be assigned in the art of 

 the potter. \Ye know that at a very remote period 

 people made bricks of sun-dried clay cemented with 

 straw, which were sufficient for the purposes of 

 construction in a country where there is scarcely 

 any rainfall. Vases of baked earthenware were 

 also in use at the earliest period of Egyptian 

 civilisation, and glazed tiles are preserved which 

 belong to the epoch of Kameses III., not long 

 after the exodus of the Israelites from Egypt. 

 That the Egyptians attained considerable skill as 

 potters is attested by the lustrous red ware they 

 made for holding perfumes, wine, honey, and 

 other delicacies ; but their most remarkable pottery 

 was their so-called porcelain made of a fine sand 

 or frit covered with a thick siliceous glaze, blue, 

 green, white, purple, or yellow in colour. The 

 blue colour which is that principally employed 

 was produced by an oxide of copper which yielded 

 tints of unrivalled beauty and delicacy. This 

 famous porcelain was made as early as the 18th 

 dynasty (alwut 1600 B.C.), and continued to be pro- 

 duced till the period of the Greek and Koman rule. 

 It was fashioned into vases, sepulchral figures of 

 deities, scarabici, beasts, &c. ; and it must have 

 attained a great reputation, for remains of it are 

 found in most of the ancient countries which had 

 commerce with Egypt. The unglazed Egyptian 

 buttle (fig. 15) illustrates the fact, also attested by 



