An artist will model a sculpture with many materials ranging from clay and wax to plasticine but all sculptures start from an armature. An armature is a wire framework that supports the molding material, the artist builds up and cuts away at the clay until they are satisfied with the end result of their three dimensional work. Prior to the 1850's, bees wax and clay were the only substances available to sculptors to render their visions into art. Clay was very difficult to work with as the model had to be kept wet constantly, otherwise the clay would dry out, leaving cracks and breaks in the sculpture. Once the clay had accidentally hardened it was almost impossible to continue with the model. The artist was faced with the task of starting over again with another armature. In the winter the damp clay would freeze and crack apart and in the summer the extreme heat required that the model be kept covered with wet towels which could never be allowed to dry. Bees wax, although much more pliable, was also difficult because of changes in temperature and humidity. Many artist returned to their models only to find them as a puddle of melted wax, or worse yet, infested by insects. After 1850 a new modeling substance was invented. It was called plasticine and had all the fine qualities of the best French sculptural clay without all of the problems. It did not need to be kept wet and it did not crack, freeze, or melt. When tooled it rendered extremely fine details. It had only one draw back. It was so expensive that most artists could not afford to use it.