TO MAKE A BLACKBOARD ON COMMON PLASTER.
Stop all cracks and holes with plaster paris mixed in glue size. When dry sandpaper until all is smooth; then paper the wall with white blank wall paper, butt the edges, put on with strong paste, and be careful to rub out all blisters. When dry prime with oil paint, then sandpaper with fine paper, and put on two coats of above slating. This makes an excellent blackboard. Boards which I made in this way twenty years ago are in good shape yet, and will last for years to come with an occasional repainting.