ABSTRACT
Structural design by observation of failures prior to the development of the theory of structures was entirely feasible, although by comparison with modern methods it is wasteful in material. However, it depended on a relatively slow change in design principles, and on adherence to certain standard dimensions. The principles of Gothic structure are examined, and the methods by which structural sizes could have been determined are discussed. It would have been necessary to observe failures over a long period of time to arrive at the high span I thickness ratios which were used successfully in some of the cathedrals.
