MOULDING AND CASTING. 285 



In order to procure a copy or cast from any 

 figure, bust, medal, &c. it is necessary to obtain a 

 mould by pressing upon the thing to be moulded 

 or copied, some substance which, when soft, is 

 capable of being forced into all the cavities or hol- 

 lows of the sculpture. When this mould is dry and 

 hard, some substance is poured into it, which will 

 fill all the cavities of the mould, and represent the 

 form of the original from which the mould was 

 taken. 



The particular manner of moulding depends 

 upon the form of the subject to be worked upon. 

 When there are no projecting parts but such as 

 form a right or a greater angle with the principal 

 surface of the body, nothing more is required than 

 to cover it over with the substance of which the 

 mould is to be formed, taking care to press it well 

 into all the cavities of the original, and to take it 

 off clean, and without bending. 



The substances used for moulding are various, 

 according to the nature and situation of the sculp- 

 ture. If it may be laid horizontally, and will bear to 

 be oiled without injury, plaster of Paris maybe advan- 

 tageously employed ; which may be poured over it 

 to a convenient thickness, after oiling it, to prevent 

 the plaster from sticking. A composition of bees- 

 wax, resin, and pitch, may also be used; which will 

 be a very desirable mould, if many casts are to be 

 taken from it. But if the situation of the sculpture 

 be perpendicular, so that nothing can be poured 

 upon it, then clay, or some similar substance, must 

 be used. The best kind of clay for this purpose is 

 that used by the sculptors for making their models 

 with ; it must be worked to a due consistence, and 

 having spread it out to a size sufficient to cover all 

 the surface, it must be sprinkled over with whiting, 



