NEW JERSEY TERRA-COTTA INDUSTRY. 



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of stone to such a larg'e extent during the last few years. These 

 are i) its durability, which in some cases is equal to, if not 

 greater than stone; 2) the manv shades and colors which can be 

 produced; 3) the almost endless variety of designs; 4) the 

 possibility of producing more delicate outlines than are often 

 obtainable in stone, and 5) the combination of lightness and 

 durability. 



In the manufacture of terra cotta, the clay is usually ground 

 first in a dry pan, having sometimes been previously exposed to 

 the weather, partly for the purpose of disintegrating the clay 

 and thereby increasing its plasticity, and partly for allowing any 

 iron nodules or concretions present to> weather out or rust, so 

 that they can be readily seen and removed. The ground clays 

 are sometimes tempered in a wet pan, and may then be subjected to 

 still further mixing in a pug mill of either vertical or horizontal 

 type. The clay issues from this in a bar about eight inches 

 square, and is cut up into square lumps which are piled away in 

 bins until used. 



Terra-cotta objects are always formed by hand, either in 

 plaster molds or by modeling. The former method is employed for 

 all simple forms, but for intricate undercut designs, it is necessary 

 to model the object free-hand, and every terra-cotta factory, 

 therefore, has its corps of skilled laborers for this purpose. In 

 making a mold, it is first necessary to' make a plaster model 

 around which the mold can be cast. Small simple designs can 

 be molded in one piece, but larger objects or special shapes have 

 to be formed in several pieces which are joined together after 

 burning. 



In filling a plaster mold the tempered clay is pushed into all 

 the corners and crevices and spread over the interior of the moid 

 to a depth of about an inch or an inch and a half. After this 

 the mold is set aside for several hours in order to permit the clay 

 to shrink sufficiently to allow of its being removed from the 

 plaster form. Any rough or uneven edges are then usually 

 trimmed off with a knife. 



Terra cotta is usually dried on steam-heated floors, and this 

 process must be carried on slowly and carefully with large pieces. 



18 civ G 



