PJRESS AND BAT FEINTING. 



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

 the superfluous colour is scraped off the surface of the copper with 

 the knife, 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 the pressure of the rubber in the 

 process of transferring. A sheet of paper, of the necessary size and 

 of a peculiarly thin texture, called " pottery tissue," after being 

 saturated 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 colours and design with which the 

 plate was charged. The paper is then laid upon the ware, and 

 rubbed upon it with flannel. During this friction the coloured 

 design upon the paper is partly imbibed by the unglazed surface 

 of the ware, and partly remains upon that surface. The article is 

 then immersed in water, by which the paper being softened, and 

 partially dissolved, it is easily washed off with a sponge, the 

 coloured design alone remaining on the surface of the article. 

 The oil included in the colouring matter is then expelled by 

 exposure to heat in a kiln, called a hardening kiln, after which 

 the design being left in perfectly dry colouring matter, the article 

 is glazed. When covered with the raw glaze, the design is quite 

 invisible, the glaze being opaque in that state ; but when it is 

 vitrified in the oven, it becomes quite transparent, and the design 

 is apparent through it. 



The bat printing is done upon the glaze, and the engravings 

 are for this style exceedingly fine, and no greater depth is required 

 than for ordinary book engravings. The impression is not sub- 

 mitted to the heat necessary for that in the bisque, and the 

 medium of conveying it to the ware is also much purer. Tho 

 copper plate is first charged with linseed oil, and cleaned off by 

 hand, so that the engraved portion alone retains it. A prepara- 

 tion of glue being run upon flat dishes, about a quarter of an inch 

 thick, is cut to the size required for the subject, and then pressed 

 upon it, and being immediately removed, draws on its surface 

 the oil with which the engraving was filled. The glue is then 

 pressed upon the ware, with the oiled part next the glaze ; and 

 being again removed, the design remains, though, being in a 

 pure oil, scarcely perceptible. Colour, finely ground, is then 

 dusted upon it with cotton wool, and a sufficiency adhering to 

 the oil leaves the impression perfect, and ready to be fired in the 

 enamel kilns. 



20. It has been the practice at all the great porcelain manu- 

 factories to stamp upon the bottom, or some other convenient 



173 



