MOULDING AND CASTING. 287 



ject is of a round or spheroidal form, it is best to 

 divide the mould into three parts, which will then 

 easily come off from the model ; and the same will 

 hold good of a cylinder, or any regular curve 

 figure. 



The mould being thus formed and dry, and the 

 parts put together, it must be first oiled, and placed 

 in such a position that the hollow may lie upwards, 

 and then filled with plaster mixed with water; and 

 when the cast is perfectly set and dry, it must be 

 taken out of the mould, and repaired when neces- 

 sary, which finishes the operation. 



In larger masses, where there would otherwise 

 be a great thickness of the plaster, a core may be 

 put within the mould, in order to produce a hollow 

 in the cast, which both saves the expense of the 

 plaster, and renders the cast lighter. 



In the same manner, figures, busts, &c. may 

 be cast of lead, or any other metal in the moulds 

 of plaster or clay ; taking care, however, that the 

 moulds be perfectly dry ; for should there be any 

 moisture, the sudden heat of the metal would 

 convert it into vapour, which would produce an 

 explosion by its expansion, and blow the melted 

 metal about. 



To take a Cast in Metal from any small Animaly 

 Insect, or Vegetable. 



Prepare a box of four boards, sufficiently large 

 to hold the animal, in which it must be suspended 

 by a string ; and the legs, wings, &c. of the animal, 

 or the tendrils, leaves, &c. of the vegetable, must 

 be separated, and adjusted in their right position 

 by a pair of small pincers. A due quantity of 



