or three inches high, or, if preferred, a cardboard box exactly fitting it may be used. Oil your model, which must be thoroughly dry, with boiled linseed oil, using a brush to put it on with. Wipe off any superfluous oil, and pour in the "slip" to the required thickness, shaking or gently striking the mould to make sure that the plaster settles into every crevice. In about ten minutes the cast, though still damp, will be firm. Remove the clay wall or the cardboard box, and cut away the edges until you can see the line of separation between the plaster and the clay. Separate them carefully, aiding the process with a dull kitchen knife. It will take about twenty-four hours for the plaster to become thoroughly hard.
The next cast must be taken in the same way, except that the plaster cast just taken is to be used as a mould. The resulting cast, if carefully managed, will be a facsimile of the clay mould. When the "slip" is mixed with gum arabic and alum solution, as directed above, such a cast is durable enough to be used as a panel in a bracket or cabinet.
Fine casts of wood carving or solid leather work can be taken in this way, and if dyed with lamp black, umber, and beer, will be very good imitations of oak.
The slip can be tinted with any desired color by mixing any dissoluble color in the water used for making the slip. In bas-reliefs a fine effect may be obtained by pouring white slip into the sunken portions of the plaster mould, and then filling the mould with slip tinted to a delicate shade of blue. When taken from the mould the design should appear white on a blue ground.
Casts can also be made to imitate ivory by either using milk and water for the slip, or by oiling the completed cast with oil in which a little beeswax has been dissolved. When dry rub with cotton wool, and keep in a smoky room for a while.
