288 CLAYS AND CLAY INDUSTRY. 



very porous, and a series of tests showed an absorption ranging 

 from 15.59 P er cent, to 20.62 per cent. 



Wall tile are molded in dry-press machines and burned first in 

 saggers in a biscuit kiln. They are then glazed and fired in a 

 muffle kiln at a much lower temperature. Many different shapes, 

 colors and styles of decoration are now produced. In some cases 

 the decoration is supplied by a relief design impressed on the 

 surface of the clay during molding, in others different colored 

 glazes are used, or a considerable variation may be obtained in 

 the shades of one color by varying the thickness of the glaze over 

 different parts of the tile. Print work and hand painting are also 

 employed at times to ornament the ware. 



The defects which wall tiles may show are warping, crazing 

 or peeling of the glaze, as well as pin holes, bubbles or spots in 

 latter. Imperfect tile are of course sorted out before shipment. 

 The crazing may, however, sometimes appear after the tile has 

 been in use for some time. 



Glazed wall tiles are much used for interior decoration in hall 

 ways, bathrooms, mantel pieces and other surfaces where clean- 

 liness, brightness and ornament are desired. 



The New Jersey wall tile industry. — Wall tiles are made in 

 New Jersey by six different firms, but the clays used are obtained 

 chiefly from other states. 



The list of producers is as follows : 



Trent Tile Company, Trenton ; 

 Providential Tile Company, Trenton ; 

 Pardee Tile Works, Perth Amboy; 

 Old Bridge Enameled Tile Works, Old Bridge ; 

 Menlo Ceramic Tile Works, Menlo Park; 

 Maywood Art Tile Company, Maywood. 



The value of tile produced in New Jersey in 1902 was $795,i53- 1 

 This included all grades except draintile. 



DRAINTlIvE. 



A plastic clay capable of making a good dense building brick is 

 generally adapted to' the manufacture of draintile, and they are 



1 Mineral Resources, U. S. Geol. Surv., 1902. Loc. cit. 



