CLAYS OF NEW YOKE 791 



POTTEKY 



The term pottery is properly applied to sucli articles for domestic 

 or ornamental nse as can be turned on a potter's wheel. "While this 

 was the original method of forming snch wares, in the progress of 

 the art many other methods have been devised, which, in some 

 cases, have superseded the potter's wheel, though this useful ma- 

 chine is still employed to a large extent. 



Description of different grades 



The more important grades of pottery which are recognized are 

 quite numerous. 



Earthenware, This is the lowest grade of pottery, and is usually 

 made from medium or poorer grades of clay. The body is either 

 red or buff, and more or less porous. Earthenware vessels will not 

 hold liquids unless glazed, owing to their porous nature. The 

 common forms of earthenware are flower pots, crocks and jug^. 



In recent years glazed or slipped earthenware for ornamental 

 application has found an extensive use. 



Stoneware differs from earthenware only in degree, the former 

 being burned to vitrification, with the result that the body is im- 

 pervious to moisture. The color of the body is either red, buff or 

 bluish black, but this is frequently masked by a coating of salt glaze 

 or slip. 



The burning and glazing are done in one operation; and if the 

 ware is coated with slip the latter is applied to the unburned clay. 



The uses of stoneware are chiefly domestic, though much 

 ornamental pottery has a stoneware body; the Flemish ware so ex- 

 tensively imported to this country belongs to this class. 



Stoneware is commonly made from refractory or semi-refractory 

 clays; the best results are often obtained by using a mixture of 

 them. The clays used should have sufficient plasticity to permit 

 their being molded without cracking. The tensile strength should 



