CASTING IN PLASTER.
Modelling and taking casts are kindred employments, as by means of the latter process a panel or statuette can be repeated indefinitely with comparatively little expenditure of time or labor. The process is purely mechanical, and can be mastered by any one who is willing to devote the necessary time and patience to it. Casts are made either in plaster of Paris or gelatine. The process is twofold, the first step being to make a mould from which the cast is afterwards taken.
To do this fill a pan or basin half-full of water, and pour gradually into this enough plaster to absorb the water. Then stir with a spoon for a minute or two until you have it about the consistency of thin cream. In this state it is called "slip." This "slip" when poured over a surface to the depth of an inch or two will adapt itself to every inequality of surface while in a liquid state, but will rapidly harden. If, after hardening, it is removed, it will present a reversed copy of the surface over which it has been poured.
Plaster of Paris plaques, for instance, can be readily made by pouring "slip" into a plate or plaque which has been thoroughly oiled. Liquid gum arabic and dissolved alum added to the "slip" will render it extremely hard and durable. A plaque thus made can be painted.
In order to take a cast of a bas-relief in clay build a wall of clay around the object to be cast, making it two
