scale-stone

An instrument capable of being easily moved, and which is fitted up with socket-joints and movable arms, is then applied to the scale-stone of the model, and a projecting point or 'needle' is made to touch a particular part of the model itself.

A History of Art for Beginners and Students Painting, Sculpture, Architecture Clara Erskine Clement Waters 1875

This is carefully removed to the scale-stone of the rough block, and the marble is cut away till the 'needle' reaches so far into the block as to correspond with the 'point' taken on the model.

A History of Art for Beginners and Students Painting, Sculpture, Architecture Clara Erskine Clement Waters 1875