240 GEOLOGY OF OHIO 



keep secret. The main principle of the process is the production of thin 

 flat bars of clay about six by three-eights inches in section, which are 

 then pressed or stamped into the requisite shape. 



The strips may be made by forming a single or multiple bar of clay 

 of this kind, or cutting up a common sized bar into ribbons by wires 

 across the die. 



The manufacture of panel and flooring tiles is a business which calls 

 in play the highest skill of the potters art, coupled with mechanical at- 

 tainments of a superior grade. Panel tiles, which are intended for purely 

 decorative use in fine buildings, are usually made of a white composition, 

 similar to the white body employed by white ware makers. The deco- 

 ration is largely by glazes which are made to produce effects of light and 

 shade by the thickness of the layer which they form in the elevations 

 and depressions of the surface. The use of colored glazes and decora- 

 tion by them becomes a distinct branch of pottery decoration. The de- 

 signs which are produced on the surface are mechanical in the cheap 

 goods, and on the most expensive, artistic skill of high grade is demanded. 



The manufacture of encaustic flooring tile is a matter of far more 

 skill than the production and ornamentation of white ware panel tiles. 

 The process in brief involves the compounding of a separate body-mix- 

 ture for each color which appears in the finished tiles. The body is pro- 

 duced by uniting the clays, flint spar, and metallic oxides, which are to 

 produce the color in a washing plant and the thoroughly mixed ingredi- 

 ents are separated out by the filter press as in common pottery. The 

 cakes from the press are dried in tunnels like brick and are then ground 

 up to a fine powder by high speed disintegrators, and the powder is re- 

 moved by air blast as fast as it is reduced to the proper fineness. This 

 powder is then put away in brick cemented bins, where it retains just 

 the proper dampness for use. Each powder mixture is used in making 

 a tile by just such means as the ground clay is used in making a pressed 

 brick, except that where tile are made showing two or more colors, a 

 separate operation has to be made for each color employed. The presses 

 used are of special construction. The burning of the ware is done in 

 saggers in regular pottery kilns. 



There are three works in Ohio which are engaged in the manufac- 

 ture of artistic panel and encaustic tiles. The American Encaustic Ti- 

 ling Co., of Zanesville is the oldest, largest and best concern of its kind 

 in the United States. It has recently occupied its new factory which has 

 been equipped at a. cost of over a half million of dollars. It has 

 mechanical arrangements for the simultaneous production of eight dif- 

 ferent colors of body mixtures. It uses electricity as a means of trans- 

 mitting power from the engine house to the various parts of its enor- 

 mous plant where power is required. Thirty kilns are in user. 



