452 POTTERY AND PORCELAIN. 



marble, and to prevent the tool from heating, which would destroy 

 its temper ; for the free.stone ilust on which tools are edged, is 

 only moistened with water to prevent the iron from heating and 

 taking off the temper of the tool by being rubbed dry ; and the 

 trepans are wetted for the same reason. 



The sculptor uses the bouchard to bore or pierce such parts of 

 his work as the chisel cannot reach without danger of spoiling or 

 breaking them. In using it, he passes it through a piece of lea. 

 ther, which leather covers the hole made by the bouchard, and pre- 

 Yt/nfs the water from spirting up in his face. 



The tools necessary for sculpture on marble or stone, are the 

 roundel, which is a sort of rounded chisel; the houguet, which is 

 a chisel squared and pointed ; and various compasses to take the 

 requisite measures. 



The process of sculpture in stone is the same as in marble, ex. 

 cepting that the material being less hard than marble, the tools 

 used are not so strong, and some of them are of a different form, 

 as the rasp, the hand- saw, the ripe, the straight chisel with three 

 teeth, the roundel, and the grater. 



If the work is executed in free.stone, tools are employed which 

 are made on purpose, as the free-stone is apt to scale, and does not 

 work like hard stone or marble. 



Sculptors in stone have commonly a bowl in which they keep a 

 powder composed of plaister of Paris, mixed with the same stone 

 in which their work is executed. With this composition they fill 

 up the small holes, and repair the defects which they meet with in 

 the stone itself. 



[IValpole. Winckelmann. Du Fresnoy. Pantalog. 



SECTION VIII. 



Pottiry and Porcelain. 



PORCELAIN may be regarded as the finest kind of pottory ; the 

 art of which consists in working and moulding plastic earths, more 

 or less simple into hard brittle vessels of various kinds and forms, 

 an<i designed for various purposes. 



The essential material of pottery is clay, which alone possesses 

 the two requisite qualities of being in its natural state so plastic 

 that with water it becomes a soft uniformly extensible mass, capa. 

 hl of assuming and retaiuingany any form ; and when thoroughly 



