620 POTTERY 



STONEWARE. 



It is with great difficulty that any satisfactory distinction can be made between the 

 different kinds of ware ; they slide by nice degrees into one another. Stoneware of 

 the ordinary kind, such as we see in jars, drain-pipes, and the variety of chemical 

 utensils which are made in the Lambeth potteries, is constituted of the plastic clay, 

 united in various proportions with some felspathic mineral, sands of different kinds, 

 and in some cases with cement stone or chalk ; these mixtures being subjected to a 

 heat which is sufficient to produce a partial fusion of the mass this condition of 

 semi-fusion being the distinguishing character of stoneware. The finer varieties of 

 stoneware are made from well-selected clays, which, when burnt, will not have much 

 colour. These are united with some fluxing material, by which that condition of 

 semi-fusion is obtained which is necessary to the production of stoneware. The glaze 

 of stoneware was always a salt glaze ; it has, however, recently been the practice to 

 glaze with a mixture of Cornish stone, flint, &c., as for earthenware. 



EABTHENWAHE. 



This ware is exemplified in the Majolica ware, the Fayence of the French, the 

 Dutch or Delft ware, and by the common varieties of pottery which are at present in 

 general use in this country. All the varieties of earthenware and they are many 

 consist of clay bodies, coated with an easily-fusible glaze, containing lead or borax. 

 In Delft and Majolica ware the surface is coated with an opaque white glaze or 

 enamel containing binoxide of tin. 



Poole clay, Devonshire clay, Cornish clay, and many of the clays from the Coal- 

 measures, and other geological formations, enter into the composition of earthenware. 

 These are combined with certain proportions of ground flint. Porous vessels for 

 cooling water and wine, now made extensively in many parts of this country, are 

 similar to the ancient Spanish cooling vessels. 



The Spanish akaraszas, or cooling vessels, are made porous, to favour the exudation 

 of water through them, and maintain a constantly moist evaporating surface. Lasteyrie 

 says, that granular sea salt is an ingredient of the paste of the Spanish alcarazzas ; 

 which being expelled partly by the heat of the baking, and partly by the subsequent 

 watery percolation, leaves the body very open. The biscuit should be charged with 

 a considerable portion of sand, and very moderately fired. 



With what has been already said in reference to the modes of manufacture, added 

 to the remarks on printing, glazing, &c., which are to follow, the general principles 

 which obtain in the manufacture of pottery, will, we think, be sufficiently understood. 



FEINTING, PAINTING, &c. 



There are two distinct methods of printing in use for china and earthenware ; one is 

 transferred on the bisque, and is the method by which the ordinary printed .ware is 

 produced, and the other is transferred on the glaze. The first is called 'press 

 printing,' and the latter 'bat-printing.' The engraving is executed upon copper 

 plates, and for press-printing is cut very deep* to enable it to hold a sufficiency of 

 colour to give a firm and full transfer to the ware. The printer's shop is furnished 

 with a brisk stove, having an iron plate on the top immediately over the fire, for tho 

 convenience of wanning the colour while being worked, also a roller-press and tubs. 

 The printer has two female assistants, called ' transferers,' and also a girl called a 

 ' cutter.' The copper-plate is charged with colour mixed with thick boiled oil by 

 means of a knife and ' dabber,' while held on the hot stove-plate for the purpose of 

 keeping the colour fluid ; and tho engraved portion being filled, the superfluous colour 

 is scraped off the surface of the copper by the knifo, which is further cleaned by being 

 rubbed with a boss made of leather. A thick firm oil is required to keep the different 

 parts of the design from flowing into a mass or becoming confused while under tho 

 pressure of the rubber, in tho process of transferring. A sheet of paper of the neces- 

 sary size and of a peculiarly thin texture, called ' pottery tissue,' after being satu- 

 rated with a thin solution of soap-and-water, is placed upon the copper-plate, and 

 being put under the action of the press, the paper is carefully drawn off again (the 

 engraving being placed on the stove), bringing with it the colour by which die plate 

 was charged, constituting the pattern. This impression is given to the ' cutter," who 

 cuts away the superfluous paper about it ; and if the pattern consists of a border and 

 a centre the border is separated from the centre, as being more convenient to fit to the 

 ware when divided. It is then laid by a transferer upon the ware and rubbed first 

 with a small piece of soaped flannel to fix it, and afterwards with a rubber formed of 

 rolled flannel. This rubber is applied to the impression very forcibly, the friction 



