FIGURES COVERED WITH COPPER. 59 



oiled, a piece of stout paper is pasted upon the bottom of the bust, 

 to prevent the fluid mixture from going inside ; and if it is composed 

 of plaster, sand is put inside to prevent it from swimming. It is 

 next completely drenched in oil, and placed upright in the vessel ; 

 this done, the melted mixture of glue and treacle is poured in till the 

 bust is covered to the depth of an inch. The whole must stand for 

 at least twenty-four hours, till it is perfectly cool throughout ; after 

 which it is taken out by inverting the vessel upon a table, when, of 

 course, the bottom of the bust is presented bare. The mould is now 

 cut, by means of a sharp knife, from the bottom up the back of the 

 bust, to the front of the head. It is next held open by the operator, 

 when an assistant lifts out the bust, and the mould is allowed to re- 

 close ; a piece of brown paper is tied round it to keep it firm. The 

 operator has now a complete mould of the bust in one piece ; but he 

 cannot treat it like wax moulds, as its substance is soluble in water, 

 and would be destroyed if put into the solution. A mixture of wax 

 and rosin, with occasionally a little suet, is melted, and allowed to 

 stand till it is on the point of setting, when it is poured carefully 

 into the mould, and left to cool. The mould is then untied and 

 opened up as before; the wax bust is taken out; and the mould 

 may be tied up for other casts. Besides wax and rosin, there are 

 several other mixtures used deer's fat is preferable to common 

 suet, stearine, &c. The object is to get a mixture that takes a good 

 cast, and becomes solid at a heat less than that which would melt 

 the mould. 



Moulding of Figures. If the model or figure be composed of 

 plaster of Paris, a mould is often taken in copper by deposition : the 

 figure is saturated with wax, as described for a medal, and copper 

 deposited upon it sufficiently thick to bear handling, without damage, 

 when taken from the model. The figure with the copper deposit is 

 carefully sawn in two, and then boiled in water, by which the plaster 

 is softened and easily separated from the copper, which now serves 

 as the mould in which the deposit is to be made. It is prepared in 

 the same way as we have described for depositing in copper moulds. 

 When the deposit is made sufficiently thick, the copper mould is 

 peeled off, and the two halves of the figure soldered together. The 

 copper moulds which are deposited upon the wax models taken in 

 the elastic moulding are often treated in the same manner ; but more 

 generally these moulds are used for depositing silver or gold into 

 them, to obtain fac-similes of the object in these metals, in which case 

 the copper moulds are dissolved off by acids, as will be described in 

 a subsequent section. 



Figures covered with Copper. When plaster busts or figures are 

 wanted in copper, the most usual way is to prepare the figure with 

 wax as described, and to coat it over with a thin deposit of copper, 



