806 NEW YOKE STATE MUSEUM 



water pitcliers and many other articles of a liollow nature are 

 molded in this manner. 



Casting^. Casting consists in ponring a slip of clay into a porous 

 mold, whicli absorbs some of the water, and causes a thin layer of 

 the clay to adhere to the interior surface of the mold. "When this 

 layer is sufficiently thick, the mold is inverted and the remaining 

 slip is poured out. After a few hours the mold can be removed. 

 This method is extensively used in making thin porcelain orna- 

 ments; many white earthenware objects can be formed by the same 

 process. Much of the success of molding depends on the proper 

 consistency and composition of the plaster mold. 



Drying 



The ware after it has been molded is usually set aside on shelves 

 in steam-heated rooms to dry. 



From this point on, the method of manufacture varies somewhat, 

 depending on the kind of ware that is tO' be produced. 



Glazing stoneware 



Stoneware is most commonly glazed either with salt, or by means 

 of slip clays. Slip clays, which are really natural glazes, are very 

 impure, easily fusible clays. The clay is mixed with water to the 

 consistency of cream, and the ware before burning is either dipped 

 into this slip, or the slip is put on the ware by a brush. 



The most desirable thing in a slip clay is that it shall fuse 

 at a low temperature, form a glaze of a uniform color, and this 

 glaze shall not crack or craze. Many fine-grained impure clays 

 fulfil the first requirement but are seldom able tO' comply with the 

 second and the third condition. 



Slip clays have been supplied to a considerable extent by several 

 different states, but the most important and the best thus far used 

 is obtained from the Champlain deposit at Albany, N^. Y. This 

 Albany slip makes a splendid, even colored, natural glaze^ and one 

 which does not crack. It not only works well "l^y itself but gives 



