Select an object with few angles and a smooth surface to experiment on; a firm round apple will do. Rub the lard all over the apple until every particle is greased; then lay it in the centre of your board. Take some clay and pack it around it just as high as the middle of the apple, forming a square, as in Fig. 168. Smooth the clay off on the edges and stick pegs in diagonal opposite corners (Fig. 168); then with more clay build a wall close around the apple and its case, making the sides one inch higher than the top of the apple (Fig. 169). Put a cupful of clear water into a pan or dish, and stir in enough plaster of Paris to make it like batter; pour the plaster over the apple, filling the clay box to the top. This makes a half mould of clay and a half mould of plaster.
When the plaster is hard, which will be in a very short time, pull away your clay wall, and take out the apple and half plaster mould together, lifting the apple from its half clay mould.
Remove the clay from your board and set the plaster mould containing the apple in the centre. Rub lard over the apple and upper edge of the mould, build around it the clay wall, as you did the first time; roll a small piece of clay into a slender conical shape and stand it upright on top of the apple, as in Fig. 169. This will make a hole through which to pour the plaster when filling the completed mould, and it must stand high enough to reach above the top of the clay wall.
Pour the plaster over the apple as at first, and let it set or harden. Take away the wall of clay once more, and carefully separate the two parts of the mould with the blade of a table-knife; remove the apple, and all is ready for the final cast which is to produce your plaster fruit (Fig. 170).
Thoroughly grease the inside of your mould, fit the two parts together, and wrap and tie them with string to hold them in place.
Pour in the plaster, through the hole left in one-half of the mould, until it is quite full; then gently shake it to send the plaster into all small crevices.
Let your mould stand without moving again until sufficient time has elapsed for the plaster to harden; then gently separate the two parts and you will find a perfect cast of the apple.
The ridge made by the joining of the mould you must scrape off with a sharp knife, or rub with sand-paper.