774 NEW YORK STATE MUSEUM 



TLOOR TILE 



Tiles made of burned clay are now used to a large extent for 

 flooring as a substitute for marble and slate, for the reason tbat tbey 

 are often more durable, wear more evenly, are harder, and can be 

 made in a greater variety of colors and shapes. 



While floor tiles are made in this state, in the city of Brooklyn,. 

 yet most of the materials used in their manufacture are obtained 

 from other states. 



In floor tile of a solid color, the tint extends through the tile- 

 from the face to the back. In " encaustic tile " the pattern or face 

 color is only about ^^ of an inch thick, while the rest of the tile is 

 made of a different kind of clay. 



Floor tile are made by the dry press process, and, like dry presa 

 brick, are exposed at times to the danger which accompanies this 

 method of molding, viz cracking of the green tile with the ex- 

 pansion of the imprisoned air. When properly pressed, this does 

 not happen. 



It is highly essential that the composition of the body should 

 be such that the ware will both dry and bum without cracking or 

 warping. The temperature attained in the burning of these tile- 

 depends naturally on the nature of the clay, but it often reaches the 

 melting- point of feldspar, as this material is used to a large extent 

 to aid in the vitrification of the body. 



Tiles are open to the same trouble from efflorescence, due to the 

 presence of soluble salts in the clay, as other clay products, and the 

 trouble has to be corrected in the customary'" manner with barium. 



Another method of preventing the formation of these coatings 

 on the surface, is to coat the face of the tile with petroleum or tar 

 so that the evaporation in drying can take place only from the back 

 of the tile. (Langenbeck's Chemistry of pottery, p. 154) In the 

 firing, this coating of oil or other material burns off, without having^ 



