PIECE MOULDS IN PLASTER 239 



cast, and also by the original surface being made flat and 

 smooth. When this is not the case, the various tools, Nos. 29 

 to 33, and a long "firmer" chisel may be used to relieve and 

 pare flat the plaster tablet of the model. A fish executed by 

 this process is shown by Fig. 4, Plate XII. 



Piece Moulds in Plaster 



Piece- mould casting is a method by which the artist 

 skilfully builds up a mould, piece by piece, in plaster of Paris 

 in such a manner that although, in casting from an object, he 

 takes in undercuts and under surfaces, each piece, though joining 

 its fellow exactly, " relieves," and when the pieces have been 

 put together and the whole filled with any medium, each piece 

 takes off" easily in a certain sequence, leaving the resultant 

 model complete in itself Such piece moulds of a sepia are 

 shown by Figs, i, 2, 3, and 4, on Plate XVI., and of a gigantic 

 salamander, Cryptobranchus japonicus — in which one half of 

 the tail is made as a " piece " — by Fig. i on Plate XV. This 

 method is explained perhaps sufficiently under the heading 

 of "The Cuttle-Fish" (see p. 284), and from such a mould 

 several models can be made. 



The method by which extremely large fossil reptiles have 

 been modelled and built up is described by Mr. B. Waterhouse 

 Hawkins,^ and although not bearing upon the methods just 

 described, is interesting reading, especially to visitors to the 

 Crystal Palace, where these huge restorations still remain. 



Glue Moulds 



The glue mould is one which, with care, is capable of pro- 

 ducing more than one copy. It will not do very well, if at all, 



' "On Visual Education as applied to Geology, illustrated by Diagrams and 

 Models of the Geological Restorations at the Crystal Palace." Read before the 

 Society of ArtSj 27th May, 1854, and published in the Society's Journal, No. 78. 



