MODELLING-COMPOSITIONS, CEMENTS, ETC. 77 



the whole fitting upon a wooden bottom, around which strips 

 are fixed to keep the framework tight and prevent insects from 

 crawling under it. For strength and convenience of stacking, 

 these frames may have a fixed wooden top. 



DIVISION III 



MODELLING-COMPOSITIONS, CEMENTS, AND VARIOUS 

 GENERAL FORMULA 



The following formulae are accessory to the foregoing, and 

 are chiefly modelling-compositions for introduction under the 

 skin of an animal, together with cements, pastes, and various 

 formula not previously considered, but which are often of 

 great importance, and, indeed, in some cases indispensable. 

 The first is — 



Clay 



Although the artist in plastic materials has usually the 

 advantage of being able to take a cast directly from the 

 specimen itself, yet it sometimes happens that it is desirable 

 to copy certain objects by the eye alone, and for this purpose 

 there are but three materials which are adapted for rapid and 

 satisfactory working : these are clay, wax, and guttapercha, 

 placed in their order of value, and, indeed, of the three, clay 

 is far in advance of the others, whilst guttapercha is of little 

 value for this particular purpose. Plaster of Paris — an indis- 

 pensable accessory to modelling — is fully considered in processes 

 described in these pages. 



Modelling-clay or pipe-clay (for there is no need to use 

 terra-cotta) is to be purchased cheaply from many wholesale 

 merchants who supply sculptors, and also, but at very much 

 higher rates, from artists' colourmen. It should be as white 

 as can be procured, so that light and shade fall pleasantly 



